11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/fs/namei.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 1991, 1992 Linus Torvalds 51da177e4SLinus Torvalds */ 61da177e4SLinus Torvalds 71da177e4SLinus Torvalds /* 81da177e4SLinus Torvalds * Some corrections by tytso. 91da177e4SLinus Torvalds */ 101da177e4SLinus Torvalds 111da177e4SLinus Torvalds /* [Feb 1997 T. Schoebel-Theuer] Complete rewrite of the pathname 121da177e4SLinus Torvalds * lookup logic. 131da177e4SLinus Torvalds */ 141da177e4SLinus Torvalds /* [Feb-Apr 2000, AV] Rewrite to the new namespace architecture. 151da177e4SLinus Torvalds */ 161da177e4SLinus Torvalds 171da177e4SLinus Torvalds #include <linux/init.h> 181da177e4SLinus Torvalds #include <linux/module.h> 191da177e4SLinus Torvalds #include <linux/slab.h> 201da177e4SLinus Torvalds #include <linux/fs.h> 211da177e4SLinus Torvalds #include <linux/namei.h> 221da177e4SLinus Torvalds #include <linux/quotaops.h> 231da177e4SLinus Torvalds #include <linux/pagemap.h> 240eeca283SRobert Love #include <linux/fsnotify.h> 251da177e4SLinus Torvalds #include <linux/personality.h> 261da177e4SLinus Torvalds #include <linux/security.h> 276146f0d5SMimi Zohar #include <linux/ima.h> 281da177e4SLinus Torvalds #include <linux/syscalls.h> 291da177e4SLinus Torvalds #include <linux/mount.h> 301da177e4SLinus Torvalds #include <linux/audit.h> 3116f7e0feSRandy Dunlap #include <linux/capability.h> 32834f2a4aSTrond Myklebust #include <linux/file.h> 335590ff0dSUlrich Drepper #include <linux/fcntl.h> 3408ce5f16SSerge E. Hallyn #include <linux/device_cgroup.h> 355ad4e53bSAl Viro #include <linux/fs_struct.h> 361da177e4SLinus Torvalds #include <asm/uaccess.h> 371da177e4SLinus Torvalds 381da177e4SLinus Torvalds #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE]) 391da177e4SLinus Torvalds 401da177e4SLinus Torvalds /* [Feb-1997 T. Schoebel-Theuer] 411da177e4SLinus Torvalds * Fundamental changes in the pathname lookup mechanisms (namei) 421da177e4SLinus Torvalds * were necessary because of omirr. The reason is that omirr needs 431da177e4SLinus Torvalds * to know the _real_ pathname, not the user-supplied one, in case 441da177e4SLinus Torvalds * of symlinks (and also when transname replacements occur). 451da177e4SLinus Torvalds * 461da177e4SLinus Torvalds * The new code replaces the old recursive symlink resolution with 471da177e4SLinus Torvalds * an iterative one (in case of non-nested symlink chains). It does 481da177e4SLinus Torvalds * this with calls to <fs>_follow_link(). 491da177e4SLinus Torvalds * As a side effect, dir_namei(), _namei() and follow_link() are now 501da177e4SLinus Torvalds * replaced with a single function lookup_dentry() that can handle all 511da177e4SLinus Torvalds * the special cases of the former code. 521da177e4SLinus Torvalds * 531da177e4SLinus Torvalds * With the new dcache, the pathname is stored at each inode, at least as 541da177e4SLinus Torvalds * long as the refcount of the inode is positive. As a side effect, the 551da177e4SLinus Torvalds * size of the dcache depends on the inode cache and thus is dynamic. 561da177e4SLinus Torvalds * 571da177e4SLinus Torvalds * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink 581da177e4SLinus Torvalds * resolution to correspond with current state of the code. 591da177e4SLinus Torvalds * 601da177e4SLinus Torvalds * Note that the symlink resolution is not *completely* iterative. 611da177e4SLinus Torvalds * There is still a significant amount of tail- and mid- recursion in 621da177e4SLinus Torvalds * the algorithm. Also, note that <fs>_readlink() is not used in 631da177e4SLinus Torvalds * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink() 641da177e4SLinus Torvalds * may return different results than <fs>_follow_link(). Many virtual 651da177e4SLinus Torvalds * filesystems (including /proc) exhibit this behavior. 661da177e4SLinus Torvalds */ 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation: 691da177e4SLinus Torvalds * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL 701da177e4SLinus Torvalds * and the name already exists in form of a symlink, try to create the new 711da177e4SLinus Torvalds * name indicated by the symlink. The old code always complained that the 721da177e4SLinus Torvalds * name already exists, due to not following the symlink even if its target 731da177e4SLinus Torvalds * is nonexistent. The new semantics affects also mknod() and link() when 741da177e4SLinus Torvalds * the name is a symlink pointing to a non-existant name. 751da177e4SLinus Torvalds * 761da177e4SLinus Torvalds * I don't know which semantics is the right one, since I have no access 771da177e4SLinus Torvalds * to standards. But I found by trial that HP-UX 9.0 has the full "new" 781da177e4SLinus Torvalds * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the 791da177e4SLinus Torvalds * "old" one. Personally, I think the new semantics is much more logical. 801da177e4SLinus Torvalds * Note that "ln old new" where "new" is a symlink pointing to a non-existing 811da177e4SLinus Torvalds * file does succeed in both HP-UX and SunOs, but not in Solaris 821da177e4SLinus Torvalds * and in the old Linux semantics. 831da177e4SLinus Torvalds */ 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink 861da177e4SLinus Torvalds * semantics. See the comments in "open_namei" and "do_link" below. 871da177e4SLinus Torvalds * 881da177e4SLinus Torvalds * [10-Sep-98 Alan Modra] Another symlink change. 891da177e4SLinus Torvalds */ 901da177e4SLinus Torvalds 911da177e4SLinus Torvalds /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks: 921da177e4SLinus Torvalds * inside the path - always follow. 931da177e4SLinus Torvalds * in the last component in creation/removal/renaming - never follow. 941da177e4SLinus Torvalds * if LOOKUP_FOLLOW passed - follow. 951da177e4SLinus Torvalds * if the pathname has trailing slashes - follow. 961da177e4SLinus Torvalds * otherwise - don't follow. 971da177e4SLinus Torvalds * (applied in that order). 981da177e4SLinus Torvalds * 991da177e4SLinus Torvalds * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT 1001da177e4SLinus Torvalds * restored for 2.4. This is the last surviving part of old 4.2BSD bug. 1011da177e4SLinus Torvalds * During the 2.4 we need to fix the userland stuff depending on it - 1021da177e4SLinus Torvalds * hopefully we will be able to get rid of that wart in 2.5. So far only 1031da177e4SLinus Torvalds * XEmacs seems to be relying on it... 1041da177e4SLinus Torvalds */ 1051da177e4SLinus Torvalds /* 1061da177e4SLinus Torvalds * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland) 107a11f3a05SArjan van de Ven * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives 1081da177e4SLinus Torvalds * any extra contention... 1091da177e4SLinus Torvalds */ 1101da177e4SLinus Torvalds 111a02f76c3SAl Viro static int __link_path_walk(const char *name, struct nameidata *nd); 112c4a7808fSJosef 'Jeff' Sipek 1131da177e4SLinus Torvalds /* In order to reduce some races, while at the same time doing additional 1141da177e4SLinus Torvalds * checking and hopefully speeding things up, we copy filenames to the 1151da177e4SLinus Torvalds * kernel data space before using them.. 1161da177e4SLinus Torvalds * 1171da177e4SLinus Torvalds * POSIX.1 2.4: an empty pathname is invalid (ENOENT). 1181da177e4SLinus Torvalds * PATH_MAX includes the nul terminator --RR. 1191da177e4SLinus Torvalds */ 120858119e1SArjan van de Ven static int do_getname(const char __user *filename, char *page) 1211da177e4SLinus Torvalds { 1221da177e4SLinus Torvalds int retval; 1231da177e4SLinus Torvalds unsigned long len = PATH_MAX; 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds if (!segment_eq(get_fs(), KERNEL_DS)) { 1261da177e4SLinus Torvalds if ((unsigned long) filename >= TASK_SIZE) 1271da177e4SLinus Torvalds return -EFAULT; 1281da177e4SLinus Torvalds if (TASK_SIZE - (unsigned long) filename < PATH_MAX) 1291da177e4SLinus Torvalds len = TASK_SIZE - (unsigned long) filename; 1301da177e4SLinus Torvalds } 1311da177e4SLinus Torvalds 1321da177e4SLinus Torvalds retval = strncpy_from_user(page, filename, len); 1331da177e4SLinus Torvalds if (retval > 0) { 1341da177e4SLinus Torvalds if (retval < len) 1351da177e4SLinus Torvalds return 0; 1361da177e4SLinus Torvalds return -ENAMETOOLONG; 1371da177e4SLinus Torvalds } else if (!retval) 1381da177e4SLinus Torvalds retval = -ENOENT; 1391da177e4SLinus Torvalds return retval; 1401da177e4SLinus Torvalds } 1411da177e4SLinus Torvalds 1421da177e4SLinus Torvalds char * getname(const char __user * filename) 1431da177e4SLinus Torvalds { 1441da177e4SLinus Torvalds char *tmp, *result; 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds result = ERR_PTR(-ENOMEM); 1471da177e4SLinus Torvalds tmp = __getname(); 1481da177e4SLinus Torvalds if (tmp) { 1491da177e4SLinus Torvalds int retval = do_getname(filename, tmp); 1501da177e4SLinus Torvalds 1511da177e4SLinus Torvalds result = tmp; 1521da177e4SLinus Torvalds if (retval < 0) { 1531da177e4SLinus Torvalds __putname(tmp); 1541da177e4SLinus Torvalds result = ERR_PTR(retval); 1551da177e4SLinus Torvalds } 1561da177e4SLinus Torvalds } 1571da177e4SLinus Torvalds audit_getname(result); 1581da177e4SLinus Torvalds return result; 1591da177e4SLinus Torvalds } 1601da177e4SLinus Torvalds 1611da177e4SLinus Torvalds #ifdef CONFIG_AUDITSYSCALL 1621da177e4SLinus Torvalds void putname(const char *name) 1631da177e4SLinus Torvalds { 1645ac3a9c2SAl Viro if (unlikely(!audit_dummy_context())) 1651da177e4SLinus Torvalds audit_putname(name); 1661da177e4SLinus Torvalds else 1671da177e4SLinus Torvalds __putname(name); 1681da177e4SLinus Torvalds } 1691da177e4SLinus Torvalds EXPORT_SYMBOL(putname); 1701da177e4SLinus Torvalds #endif 1711da177e4SLinus Torvalds 1721da177e4SLinus Torvalds 1731da177e4SLinus Torvalds /** 1741da177e4SLinus Torvalds * generic_permission - check for access rights on a Posix-like filesystem 1751da177e4SLinus Torvalds * @inode: inode to check access rights for 1761da177e4SLinus Torvalds * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 1771da177e4SLinus Torvalds * @check_acl: optional callback to check for Posix ACLs 1781da177e4SLinus Torvalds * 1791da177e4SLinus Torvalds * Used to check for read/write/execute permissions on a file. 1801da177e4SLinus Torvalds * We use "fsuid" for this, letting us set arbitrary permissions 1811da177e4SLinus Torvalds * for filesystem access without changing the "normal" uids which 1821da177e4SLinus Torvalds * are used for other things.. 1831da177e4SLinus Torvalds */ 1841da177e4SLinus Torvalds int generic_permission(struct inode *inode, int mask, 1851da177e4SLinus Torvalds int (*check_acl)(struct inode *inode, int mask)) 1861da177e4SLinus Torvalds { 1871da177e4SLinus Torvalds umode_t mode = inode->i_mode; 1881da177e4SLinus Torvalds 189e6305c43SAl Viro mask &= MAY_READ | MAY_WRITE | MAY_EXEC; 190e6305c43SAl Viro 191da9592edSDavid Howells if (current_fsuid() == inode->i_uid) 1921da177e4SLinus Torvalds mode >>= 6; 1931da177e4SLinus Torvalds else { 1941da177e4SLinus Torvalds if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) { 1951da177e4SLinus Torvalds int error = check_acl(inode, mask); 1961da177e4SLinus Torvalds if (error == -EACCES) 1971da177e4SLinus Torvalds goto check_capabilities; 1981da177e4SLinus Torvalds else if (error != -EAGAIN) 1991da177e4SLinus Torvalds return error; 2001da177e4SLinus Torvalds } 2011da177e4SLinus Torvalds 2021da177e4SLinus Torvalds if (in_group_p(inode->i_gid)) 2031da177e4SLinus Torvalds mode >>= 3; 2041da177e4SLinus Torvalds } 2051da177e4SLinus Torvalds 2061da177e4SLinus Torvalds /* 2071da177e4SLinus Torvalds * If the DACs are ok we don't need any capability check. 2081da177e4SLinus Torvalds */ 209e6305c43SAl Viro if ((mask & ~mode) == 0) 2101da177e4SLinus Torvalds return 0; 2111da177e4SLinus Torvalds 2121da177e4SLinus Torvalds check_capabilities: 2131da177e4SLinus Torvalds /* 2141da177e4SLinus Torvalds * Read/write DACs are always overridable. 2151da177e4SLinus Torvalds * Executable DACs are overridable if at least one exec bit is set. 2161da177e4SLinus Torvalds */ 217f696a365SMiklos Szeredi if (!(mask & MAY_EXEC) || execute_ok(inode)) 2181da177e4SLinus Torvalds if (capable(CAP_DAC_OVERRIDE)) 2191da177e4SLinus Torvalds return 0; 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvalds /* 2221da177e4SLinus Torvalds * Searching includes executable on directories, else just read. 2231da177e4SLinus Torvalds */ 2241da177e4SLinus Torvalds if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) 2251da177e4SLinus Torvalds if (capable(CAP_DAC_READ_SEARCH)) 2261da177e4SLinus Torvalds return 0; 2271da177e4SLinus Torvalds 2281da177e4SLinus Torvalds return -EACCES; 2291da177e4SLinus Torvalds } 2301da177e4SLinus Torvalds 231cb23beb5SChristoph Hellwig /** 232cb23beb5SChristoph Hellwig * inode_permission - check for access rights to a given inode 233cb23beb5SChristoph Hellwig * @inode: inode to check permission on 234cb23beb5SChristoph Hellwig * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 235cb23beb5SChristoph Hellwig * 236cb23beb5SChristoph Hellwig * Used to check for read/write/execute permissions on an inode. 237cb23beb5SChristoph Hellwig * We use "fsuid" for this, letting us set arbitrary permissions 238cb23beb5SChristoph Hellwig * for filesystem access without changing the "normal" uids which 239cb23beb5SChristoph Hellwig * are used for other things. 240cb23beb5SChristoph Hellwig */ 241f419a2e3SAl Viro int inode_permission(struct inode *inode, int mask) 2421da177e4SLinus Torvalds { 243e6305c43SAl Viro int retval; 2441da177e4SLinus Torvalds 2451da177e4SLinus Torvalds if (mask & MAY_WRITE) { 24622590e41SMiklos Szeredi umode_t mode = inode->i_mode; 2471da177e4SLinus Torvalds 2481da177e4SLinus Torvalds /* 2491da177e4SLinus Torvalds * Nobody gets write access to a read-only fs. 2501da177e4SLinus Torvalds */ 2511da177e4SLinus Torvalds if (IS_RDONLY(inode) && 2521da177e4SLinus Torvalds (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) 2531da177e4SLinus Torvalds return -EROFS; 2541da177e4SLinus Torvalds 2551da177e4SLinus Torvalds /* 2561da177e4SLinus Torvalds * Nobody gets write access to an immutable file. 2571da177e4SLinus Torvalds */ 2581da177e4SLinus Torvalds if (IS_IMMUTABLE(inode)) 2591da177e4SLinus Torvalds return -EACCES; 2601da177e4SLinus Torvalds } 2611da177e4SLinus Torvalds 262acfa4380SAl Viro if (inode->i_op->permission) 263b77b0646SAl Viro retval = inode->i_op->permission(inode, mask); 264f696a365SMiklos Szeredi else 265e6305c43SAl Viro retval = generic_permission(inode, mask, NULL); 266f696a365SMiklos Szeredi 2671da177e4SLinus Torvalds if (retval) 2681da177e4SLinus Torvalds return retval; 2691da177e4SLinus Torvalds 27008ce5f16SSerge E. Hallyn retval = devcgroup_inode_permission(inode, mask); 27108ce5f16SSerge E. Hallyn if (retval) 27208ce5f16SSerge E. Hallyn return retval; 27308ce5f16SSerge E. Hallyn 274e6305c43SAl Viro return security_inode_permission(inode, 275f418b006SStephen Smalley mask & (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND)); 2761da177e4SLinus Torvalds } 2771da177e4SLinus Torvalds 278e4543eddSChristoph Hellwig /** 2798c744fb8SChristoph Hellwig * file_permission - check for additional access rights to a given file 2808c744fb8SChristoph Hellwig * @file: file to check access rights for 2818c744fb8SChristoph Hellwig * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 2828c744fb8SChristoph Hellwig * 2838c744fb8SChristoph Hellwig * Used to check for read/write/execute permissions on an already opened 2848c744fb8SChristoph Hellwig * file. 2858c744fb8SChristoph Hellwig * 2868c744fb8SChristoph Hellwig * Note: 2878c744fb8SChristoph Hellwig * Do not use this function in new code. All access checks should 288cb23beb5SChristoph Hellwig * be done using inode_permission(). 2898c744fb8SChristoph Hellwig */ 2908c744fb8SChristoph Hellwig int file_permission(struct file *file, int mask) 2918c744fb8SChristoph Hellwig { 292f419a2e3SAl Viro return inode_permission(file->f_path.dentry->d_inode, mask); 2938c744fb8SChristoph Hellwig } 2948c744fb8SChristoph Hellwig 2951da177e4SLinus Torvalds /* 2961da177e4SLinus Torvalds * get_write_access() gets write permission for a file. 2971da177e4SLinus Torvalds * put_write_access() releases this write permission. 2981da177e4SLinus Torvalds * This is used for regular files. 2991da177e4SLinus Torvalds * We cannot support write (and maybe mmap read-write shared) accesses and 3001da177e4SLinus Torvalds * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode 3011da177e4SLinus Torvalds * can have the following values: 3021da177e4SLinus Torvalds * 0: no writers, no VM_DENYWRITE mappings 3031da177e4SLinus Torvalds * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist 3041da177e4SLinus Torvalds * > 0: (i_writecount) users are writing to the file. 3051da177e4SLinus Torvalds * 3061da177e4SLinus Torvalds * Normally we operate on that counter with atomic_{inc,dec} and it's safe 3071da177e4SLinus Torvalds * except for the cases where we don't hold i_writecount yet. Then we need to 3081da177e4SLinus Torvalds * use {get,deny}_write_access() - these functions check the sign and refuse 3091da177e4SLinus Torvalds * to do the change if sign is wrong. Exclusion between them is provided by 3101da177e4SLinus Torvalds * the inode->i_lock spinlock. 3111da177e4SLinus Torvalds */ 3121da177e4SLinus Torvalds 3131da177e4SLinus Torvalds int get_write_access(struct inode * inode) 3141da177e4SLinus Torvalds { 3151da177e4SLinus Torvalds spin_lock(&inode->i_lock); 3161da177e4SLinus Torvalds if (atomic_read(&inode->i_writecount) < 0) { 3171da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3181da177e4SLinus Torvalds return -ETXTBSY; 3191da177e4SLinus Torvalds } 3201da177e4SLinus Torvalds atomic_inc(&inode->i_writecount); 3211da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3221da177e4SLinus Torvalds 3231da177e4SLinus Torvalds return 0; 3241da177e4SLinus Torvalds } 3251da177e4SLinus Torvalds 3261da177e4SLinus Torvalds int deny_write_access(struct file * file) 3271da177e4SLinus Torvalds { 3280f7fc9e4SJosef "Jeff" Sipek struct inode *inode = file->f_path.dentry->d_inode; 3291da177e4SLinus Torvalds 3301da177e4SLinus Torvalds spin_lock(&inode->i_lock); 3311da177e4SLinus Torvalds if (atomic_read(&inode->i_writecount) > 0) { 3321da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3331da177e4SLinus Torvalds return -ETXTBSY; 3341da177e4SLinus Torvalds } 3351da177e4SLinus Torvalds atomic_dec(&inode->i_writecount); 3361da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3371da177e4SLinus Torvalds 3381da177e4SLinus Torvalds return 0; 3391da177e4SLinus Torvalds } 3401da177e4SLinus Torvalds 3411d957f9bSJan Blunck /** 3425dd784d0SJan Blunck * path_get - get a reference to a path 3435dd784d0SJan Blunck * @path: path to get the reference to 3445dd784d0SJan Blunck * 3455dd784d0SJan Blunck * Given a path increment the reference count to the dentry and the vfsmount. 3465dd784d0SJan Blunck */ 3475dd784d0SJan Blunck void path_get(struct path *path) 3485dd784d0SJan Blunck { 3495dd784d0SJan Blunck mntget(path->mnt); 3505dd784d0SJan Blunck dget(path->dentry); 3515dd784d0SJan Blunck } 3525dd784d0SJan Blunck EXPORT_SYMBOL(path_get); 3535dd784d0SJan Blunck 3545dd784d0SJan Blunck /** 3551d957f9bSJan Blunck * path_put - put a reference to a path 3561d957f9bSJan Blunck * @path: path to put the reference to 3571d957f9bSJan Blunck * 3581d957f9bSJan Blunck * Given a path decrement the reference count to the dentry and the vfsmount. 3591d957f9bSJan Blunck */ 3601d957f9bSJan Blunck void path_put(struct path *path) 3611da177e4SLinus Torvalds { 3621d957f9bSJan Blunck dput(path->dentry); 3631d957f9bSJan Blunck mntput(path->mnt); 3641da177e4SLinus Torvalds } 3651d957f9bSJan Blunck EXPORT_SYMBOL(path_put); 3661da177e4SLinus Torvalds 367834f2a4aSTrond Myklebust /** 368834f2a4aSTrond Myklebust * release_open_intent - free up open intent resources 369834f2a4aSTrond Myklebust * @nd: pointer to nameidata 370834f2a4aSTrond Myklebust */ 371834f2a4aSTrond Myklebust void release_open_intent(struct nameidata *nd) 372834f2a4aSTrond Myklebust { 3730f7fc9e4SJosef "Jeff" Sipek if (nd->intent.open.file->f_path.dentry == NULL) 374834f2a4aSTrond Myklebust put_filp(nd->intent.open.file); 375834f2a4aSTrond Myklebust else 376834f2a4aSTrond Myklebust fput(nd->intent.open.file); 377834f2a4aSTrond Myklebust } 378834f2a4aSTrond Myklebust 379bcdc5e01SIan Kent static inline struct dentry * 380bcdc5e01SIan Kent do_revalidate(struct dentry *dentry, struct nameidata *nd) 381bcdc5e01SIan Kent { 382bcdc5e01SIan Kent int status = dentry->d_op->d_revalidate(dentry, nd); 383bcdc5e01SIan Kent if (unlikely(status <= 0)) { 384bcdc5e01SIan Kent /* 385bcdc5e01SIan Kent * The dentry failed validation. 386bcdc5e01SIan Kent * If d_revalidate returned 0 attempt to invalidate 387bcdc5e01SIan Kent * the dentry otherwise d_revalidate is asking us 388bcdc5e01SIan Kent * to return a fail status. 389bcdc5e01SIan Kent */ 390bcdc5e01SIan Kent if (!status) { 391bcdc5e01SIan Kent if (!d_invalidate(dentry)) { 392bcdc5e01SIan Kent dput(dentry); 393bcdc5e01SIan Kent dentry = NULL; 394bcdc5e01SIan Kent } 395bcdc5e01SIan Kent } else { 396bcdc5e01SIan Kent dput(dentry); 397bcdc5e01SIan Kent dentry = ERR_PTR(status); 398bcdc5e01SIan Kent } 399bcdc5e01SIan Kent } 400bcdc5e01SIan Kent return dentry; 401bcdc5e01SIan Kent } 402bcdc5e01SIan Kent 4031da177e4SLinus Torvalds /* 4041da177e4SLinus Torvalds * Internal lookup() using the new generic dcache. 4051da177e4SLinus Torvalds * SMP-safe 4061da177e4SLinus Torvalds */ 4071da177e4SLinus Torvalds static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) 4081da177e4SLinus Torvalds { 4091da177e4SLinus Torvalds struct dentry * dentry = __d_lookup(parent, name); 4101da177e4SLinus Torvalds 4111da177e4SLinus Torvalds /* lockess __d_lookup may fail due to concurrent d_move() 4121da177e4SLinus Torvalds * in some unrelated directory, so try with d_lookup 4131da177e4SLinus Torvalds */ 4141da177e4SLinus Torvalds if (!dentry) 4151da177e4SLinus Torvalds dentry = d_lookup(parent, name); 4161da177e4SLinus Torvalds 417bcdc5e01SIan Kent if (dentry && dentry->d_op && dentry->d_op->d_revalidate) 418bcdc5e01SIan Kent dentry = do_revalidate(dentry, nd); 419bcdc5e01SIan Kent 4201da177e4SLinus Torvalds return dentry; 4211da177e4SLinus Torvalds } 4221da177e4SLinus Torvalds 4231da177e4SLinus Torvalds /* 4241da177e4SLinus Torvalds * Short-cut version of permission(), for calling by 4251da177e4SLinus Torvalds * path_walk(), when dcache lock is held. Combines parts 4261da177e4SLinus Torvalds * of permission() and generic_permission(), and tests ONLY for 4271da177e4SLinus Torvalds * MAY_EXEC permission. 4281da177e4SLinus Torvalds * 4291da177e4SLinus Torvalds * If appropriate, check DAC only. If not appropriate, or 4301da177e4SLinus Torvalds * short-cut DAC fails, then call permission() to do more 4311da177e4SLinus Torvalds * complete permission check. 4321da177e4SLinus Torvalds */ 433672b16b2SAl Viro static int exec_permission_lite(struct inode *inode) 4341da177e4SLinus Torvalds { 4351da177e4SLinus Torvalds umode_t mode = inode->i_mode; 4361da177e4SLinus Torvalds 437acfa4380SAl Viro if (inode->i_op->permission) 4381da177e4SLinus Torvalds return -EAGAIN; 4391da177e4SLinus Torvalds 440da9592edSDavid Howells if (current_fsuid() == inode->i_uid) 4411da177e4SLinus Torvalds mode >>= 6; 4421da177e4SLinus Torvalds else if (in_group_p(inode->i_gid)) 4431da177e4SLinus Torvalds mode >>= 3; 4441da177e4SLinus Torvalds 4451da177e4SLinus Torvalds if (mode & MAY_EXEC) 4461da177e4SLinus Torvalds goto ok; 4471da177e4SLinus Torvalds 4481da177e4SLinus Torvalds if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE)) 4491da177e4SLinus Torvalds goto ok; 4501da177e4SLinus Torvalds 4511da177e4SLinus Torvalds if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE)) 4521da177e4SLinus Torvalds goto ok; 4531da177e4SLinus Torvalds 4541da177e4SLinus Torvalds if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH)) 4551da177e4SLinus Torvalds goto ok; 4561da177e4SLinus Torvalds 4571da177e4SLinus Torvalds return -EACCES; 4581da177e4SLinus Torvalds ok: 459b77b0646SAl Viro return security_inode_permission(inode, MAY_EXEC); 4601da177e4SLinus Torvalds } 4611da177e4SLinus Torvalds 4621da177e4SLinus Torvalds /* 4631da177e4SLinus Torvalds * This is called when everything else fails, and we actually have 4641da177e4SLinus Torvalds * to go to the low-level filesystem to find out what we should do.. 4651da177e4SLinus Torvalds * 4661da177e4SLinus Torvalds * We get the directory semaphore, and after getting that we also 4671da177e4SLinus Torvalds * make sure that nobody added the entry to the dcache in the meantime.. 4681da177e4SLinus Torvalds * SMP-safe 4691da177e4SLinus Torvalds */ 4701da177e4SLinus Torvalds static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) 4711da177e4SLinus Torvalds { 4721da177e4SLinus Torvalds struct dentry * result; 4731da177e4SLinus Torvalds struct inode *dir = parent->d_inode; 4741da177e4SLinus Torvalds 4751b1dcc1bSJes Sorensen mutex_lock(&dir->i_mutex); 4761da177e4SLinus Torvalds /* 4771da177e4SLinus Torvalds * First re-do the cached lookup just in case it was created 4781da177e4SLinus Torvalds * while we waited for the directory semaphore.. 4791da177e4SLinus Torvalds * 4801da177e4SLinus Torvalds * FIXME! This could use version numbering or similar to 4811da177e4SLinus Torvalds * avoid unnecessary cache lookups. 4821da177e4SLinus Torvalds * 4831da177e4SLinus Torvalds * The "dcache_lock" is purely to protect the RCU list walker 4841da177e4SLinus Torvalds * from concurrent renames at this point (we mustn't get false 4851da177e4SLinus Torvalds * negatives from the RCU list walk here, unlike the optimistic 4861da177e4SLinus Torvalds * fast walk). 4871da177e4SLinus Torvalds * 4881da177e4SLinus Torvalds * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup 4891da177e4SLinus Torvalds */ 4901da177e4SLinus Torvalds result = d_lookup(parent, name); 4911da177e4SLinus Torvalds if (!result) { 492d70b67c8SMiklos Szeredi struct dentry *dentry; 493d70b67c8SMiklos Szeredi 494d70b67c8SMiklos Szeredi /* Don't create child dentry for a dead directory. */ 495d70b67c8SMiklos Szeredi result = ERR_PTR(-ENOENT); 496d70b67c8SMiklos Szeredi if (IS_DEADDIR(dir)) 497d70b67c8SMiklos Szeredi goto out_unlock; 498d70b67c8SMiklos Szeredi 499d70b67c8SMiklos Szeredi dentry = d_alloc(parent, name); 5001da177e4SLinus Torvalds result = ERR_PTR(-ENOMEM); 5011da177e4SLinus Torvalds if (dentry) { 5021da177e4SLinus Torvalds result = dir->i_op->lookup(dir, dentry, nd); 5031da177e4SLinus Torvalds if (result) 5041da177e4SLinus Torvalds dput(dentry); 5051da177e4SLinus Torvalds else 5061da177e4SLinus Torvalds result = dentry; 5071da177e4SLinus Torvalds } 508d70b67c8SMiklos Szeredi out_unlock: 5091b1dcc1bSJes Sorensen mutex_unlock(&dir->i_mutex); 5101da177e4SLinus Torvalds return result; 5111da177e4SLinus Torvalds } 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds /* 5141da177e4SLinus Torvalds * Uhhuh! Nasty case: the cache was re-populated while 5151da177e4SLinus Torvalds * we waited on the semaphore. Need to revalidate. 5161da177e4SLinus Torvalds */ 5171b1dcc1bSJes Sorensen mutex_unlock(&dir->i_mutex); 5181da177e4SLinus Torvalds if (result->d_op && result->d_op->d_revalidate) { 519bcdc5e01SIan Kent result = do_revalidate(result, nd); 520bcdc5e01SIan Kent if (!result) 5211da177e4SLinus Torvalds result = ERR_PTR(-ENOENT); 5221da177e4SLinus Torvalds } 5231da177e4SLinus Torvalds return result; 5241da177e4SLinus Torvalds } 5251da177e4SLinus Torvalds 526a02f76c3SAl Viro /* 527a02f76c3SAl Viro * Wrapper to retry pathname resolution whenever the underlying 528a02f76c3SAl Viro * file system returns an ESTALE. 529a02f76c3SAl Viro * 530a02f76c3SAl Viro * Retry the whole path once, forcing real lookup requests 531a02f76c3SAl Viro * instead of relying on the dcache. 532a02f76c3SAl Viro */ 533a02f76c3SAl Viro static __always_inline int link_path_walk(const char *name, struct nameidata *nd) 534a02f76c3SAl Viro { 535a02f76c3SAl Viro struct path save = nd->path; 536a02f76c3SAl Viro int result; 537a02f76c3SAl Viro 538a02f76c3SAl Viro /* make sure the stuff we saved doesn't go away */ 539c8e7f449SJan Blunck path_get(&save); 540a02f76c3SAl Viro 541a02f76c3SAl Viro result = __link_path_walk(name, nd); 542a02f76c3SAl Viro if (result == -ESTALE) { 543a02f76c3SAl Viro /* nd->path had been dropped */ 544a02f76c3SAl Viro nd->path = save; 545c8e7f449SJan Blunck path_get(&nd->path); 546a02f76c3SAl Viro nd->flags |= LOOKUP_REVAL; 547a02f76c3SAl Viro result = __link_path_walk(name, nd); 548a02f76c3SAl Viro } 549a02f76c3SAl Viro 550a02f76c3SAl Viro path_put(&save); 551a02f76c3SAl Viro 552a02f76c3SAl Viro return result; 553a02f76c3SAl Viro } 554a02f76c3SAl Viro 555f1662356SArjan van de Ven static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) 5561da177e4SLinus Torvalds { 5571da177e4SLinus Torvalds int res = 0; 5581da177e4SLinus Torvalds char *name; 5591da177e4SLinus Torvalds if (IS_ERR(link)) 5601da177e4SLinus Torvalds goto fail; 5611da177e4SLinus Torvalds 5621da177e4SLinus Torvalds if (*link == '/') { 563b4091d5fSChristoph Hellwig struct fs_struct *fs = current->fs; 564b4091d5fSChristoph Hellwig 5651d957f9bSJan Blunck path_put(&nd->path); 566b4091d5fSChristoph Hellwig 567b4091d5fSChristoph Hellwig read_lock(&fs->lock); 568b4091d5fSChristoph Hellwig nd->path = fs->root; 569b4091d5fSChristoph Hellwig path_get(&fs->root); 570b4091d5fSChristoph Hellwig read_unlock(&fs->lock); 5711da177e4SLinus Torvalds } 572b4091d5fSChristoph Hellwig 5731da177e4SLinus Torvalds res = link_path_walk(link, nd); 5741da177e4SLinus Torvalds if (nd->depth || res || nd->last_type!=LAST_NORM) 5751da177e4SLinus Torvalds return res; 5761da177e4SLinus Torvalds /* 5771da177e4SLinus Torvalds * If it is an iterative symlinks resolution in open_namei() we 5781da177e4SLinus Torvalds * have to copy the last component. And all that crap because of 5791da177e4SLinus Torvalds * bloody create() on broken symlinks. Furrfu... 5801da177e4SLinus Torvalds */ 5811da177e4SLinus Torvalds name = __getname(); 5821da177e4SLinus Torvalds if (unlikely(!name)) { 5831d957f9bSJan Blunck path_put(&nd->path); 5841da177e4SLinus Torvalds return -ENOMEM; 5851da177e4SLinus Torvalds } 5861da177e4SLinus Torvalds strcpy(name, nd->last.name); 5871da177e4SLinus Torvalds nd->last.name = name; 5881da177e4SLinus Torvalds return 0; 5891da177e4SLinus Torvalds fail: 5901d957f9bSJan Blunck path_put(&nd->path); 5911da177e4SLinus Torvalds return PTR_ERR(link); 5921da177e4SLinus Torvalds } 5931da177e4SLinus Torvalds 5941d957f9bSJan Blunck static void path_put_conditional(struct path *path, struct nameidata *nd) 595051d3812SIan Kent { 596051d3812SIan Kent dput(path->dentry); 5974ac91378SJan Blunck if (path->mnt != nd->path.mnt) 598051d3812SIan Kent mntput(path->mnt); 599051d3812SIan Kent } 600051d3812SIan Kent 601051d3812SIan Kent static inline void path_to_nameidata(struct path *path, struct nameidata *nd) 602051d3812SIan Kent { 6034ac91378SJan Blunck dput(nd->path.dentry); 6044ac91378SJan Blunck if (nd->path.mnt != path->mnt) 6054ac91378SJan Blunck mntput(nd->path.mnt); 6064ac91378SJan Blunck nd->path.mnt = path->mnt; 6074ac91378SJan Blunck nd->path.dentry = path->dentry; 608051d3812SIan Kent } 609051d3812SIan Kent 610f1662356SArjan van de Ven static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd) 6111da177e4SLinus Torvalds { 6121da177e4SLinus Torvalds int error; 613cc314eefSLinus Torvalds void *cookie; 614cd4e91d3SAl Viro struct dentry *dentry = path->dentry; 6151da177e4SLinus Torvalds 616d671a1cbSAl Viro touch_atime(path->mnt, dentry); 6171da177e4SLinus Torvalds nd_set_link(nd, NULL); 618cd4e91d3SAl Viro 6194ac91378SJan Blunck if (path->mnt != nd->path.mnt) { 620051d3812SIan Kent path_to_nameidata(path, nd); 621051d3812SIan Kent dget(dentry); 622051d3812SIan Kent } 623cd4e91d3SAl Viro mntget(path->mnt); 624cc314eefSLinus Torvalds cookie = dentry->d_inode->i_op->follow_link(dentry, nd); 625cc314eefSLinus Torvalds error = PTR_ERR(cookie); 626cc314eefSLinus Torvalds if (!IS_ERR(cookie)) { 6271da177e4SLinus Torvalds char *s = nd_get_link(nd); 628cc314eefSLinus Torvalds error = 0; 6291da177e4SLinus Torvalds if (s) 6301da177e4SLinus Torvalds error = __vfs_follow_link(nd, s); 6311da177e4SLinus Torvalds if (dentry->d_inode->i_op->put_link) 632cc314eefSLinus Torvalds dentry->d_inode->i_op->put_link(dentry, nd, cookie); 6331da177e4SLinus Torvalds } 63409da5916SJan Blunck path_put(path); 6351da177e4SLinus Torvalds 6361da177e4SLinus Torvalds return error; 6371da177e4SLinus Torvalds } 6381da177e4SLinus Torvalds 6391da177e4SLinus Torvalds /* 6401da177e4SLinus Torvalds * This limits recursive symlink follows to 8, while 6411da177e4SLinus Torvalds * limiting consecutive symlinks to 40. 6421da177e4SLinus Torvalds * 6431da177e4SLinus Torvalds * Without that kind of total limit, nasty chains of consecutive 6441da177e4SLinus Torvalds * symlinks can cause almost arbitrarily long lookups. 6451da177e4SLinus Torvalds */ 64690ebe565SAl Viro static inline int do_follow_link(struct path *path, struct nameidata *nd) 6471da177e4SLinus Torvalds { 6481da177e4SLinus Torvalds int err = -ELOOP; 6491da177e4SLinus Torvalds if (current->link_count >= MAX_NESTED_LINKS) 6501da177e4SLinus Torvalds goto loop; 6511da177e4SLinus Torvalds if (current->total_link_count >= 40) 6521da177e4SLinus Torvalds goto loop; 6531da177e4SLinus Torvalds BUG_ON(nd->depth >= MAX_NESTED_LINKS); 6541da177e4SLinus Torvalds cond_resched(); 65590ebe565SAl Viro err = security_inode_follow_link(path->dentry, nd); 6561da177e4SLinus Torvalds if (err) 6571da177e4SLinus Torvalds goto loop; 6581da177e4SLinus Torvalds current->link_count++; 6591da177e4SLinus Torvalds current->total_link_count++; 6601da177e4SLinus Torvalds nd->depth++; 661cd4e91d3SAl Viro err = __do_follow_link(path, nd); 6621da177e4SLinus Torvalds current->link_count--; 6631da177e4SLinus Torvalds nd->depth--; 6641da177e4SLinus Torvalds return err; 6651da177e4SLinus Torvalds loop: 6661d957f9bSJan Blunck path_put_conditional(path, nd); 6671d957f9bSJan Blunck path_put(&nd->path); 6681da177e4SLinus Torvalds return err; 6691da177e4SLinus Torvalds } 6701da177e4SLinus Torvalds 6711da177e4SLinus Torvalds int follow_up(struct vfsmount **mnt, struct dentry **dentry) 6721da177e4SLinus Torvalds { 6731da177e4SLinus Torvalds struct vfsmount *parent; 6741da177e4SLinus Torvalds struct dentry *mountpoint; 6751da177e4SLinus Torvalds spin_lock(&vfsmount_lock); 6761da177e4SLinus Torvalds parent=(*mnt)->mnt_parent; 6771da177e4SLinus Torvalds if (parent == *mnt) { 6781da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 6791da177e4SLinus Torvalds return 0; 6801da177e4SLinus Torvalds } 6811da177e4SLinus Torvalds mntget(parent); 6821da177e4SLinus Torvalds mountpoint=dget((*mnt)->mnt_mountpoint); 6831da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 6841da177e4SLinus Torvalds dput(*dentry); 6851da177e4SLinus Torvalds *dentry = mountpoint; 6861da177e4SLinus Torvalds mntput(*mnt); 6871da177e4SLinus Torvalds *mnt = parent; 6881da177e4SLinus Torvalds return 1; 6891da177e4SLinus Torvalds } 6901da177e4SLinus Torvalds 6911da177e4SLinus Torvalds /* no need for dcache_lock, as serialization is taken care in 6921da177e4SLinus Torvalds * namespace.c 6931da177e4SLinus Torvalds */ 694463ffb2eSAl Viro static int __follow_mount(struct path *path) 695463ffb2eSAl Viro { 696463ffb2eSAl Viro int res = 0; 697463ffb2eSAl Viro while (d_mountpoint(path->dentry)) { 698463ffb2eSAl Viro struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry); 699463ffb2eSAl Viro if (!mounted) 700463ffb2eSAl Viro break; 701463ffb2eSAl Viro dput(path->dentry); 702463ffb2eSAl Viro if (res) 703463ffb2eSAl Viro mntput(path->mnt); 704463ffb2eSAl Viro path->mnt = mounted; 705463ffb2eSAl Viro path->dentry = dget(mounted->mnt_root); 706463ffb2eSAl Viro res = 1; 707463ffb2eSAl Viro } 708463ffb2eSAl Viro return res; 709463ffb2eSAl Viro } 710463ffb2eSAl Viro 71158c465ebSAl Viro static void follow_mount(struct vfsmount **mnt, struct dentry **dentry) 7121da177e4SLinus Torvalds { 7131da177e4SLinus Torvalds while (d_mountpoint(*dentry)) { 7141da177e4SLinus Torvalds struct vfsmount *mounted = lookup_mnt(*mnt, *dentry); 7151da177e4SLinus Torvalds if (!mounted) 7161da177e4SLinus Torvalds break; 71758c465ebSAl Viro dput(*dentry); 7181da177e4SLinus Torvalds mntput(*mnt); 7191da177e4SLinus Torvalds *mnt = mounted; 7201da177e4SLinus Torvalds *dentry = dget(mounted->mnt_root); 7211da177e4SLinus Torvalds } 7221da177e4SLinus Torvalds } 7231da177e4SLinus Torvalds 7241da177e4SLinus Torvalds /* no need for dcache_lock, as serialization is taken care in 7251da177e4SLinus Torvalds * namespace.c 7261da177e4SLinus Torvalds */ 727e13b210fSAl Viro int follow_down(struct vfsmount **mnt, struct dentry **dentry) 7281da177e4SLinus Torvalds { 7291da177e4SLinus Torvalds struct vfsmount *mounted; 7301da177e4SLinus Torvalds 7311da177e4SLinus Torvalds mounted = lookup_mnt(*mnt, *dentry); 7321da177e4SLinus Torvalds if (mounted) { 733e13b210fSAl Viro dput(*dentry); 7341da177e4SLinus Torvalds mntput(*mnt); 7351da177e4SLinus Torvalds *mnt = mounted; 7361da177e4SLinus Torvalds *dentry = dget(mounted->mnt_root); 7371da177e4SLinus Torvalds return 1; 7381da177e4SLinus Torvalds } 7391da177e4SLinus Torvalds return 0; 7401da177e4SLinus Torvalds } 7411da177e4SLinus Torvalds 742f1662356SArjan van de Ven static __always_inline void follow_dotdot(struct nameidata *nd) 7431da177e4SLinus Torvalds { 744e518ddb7SAndreas Mohr struct fs_struct *fs = current->fs; 745e518ddb7SAndreas Mohr 7461da177e4SLinus Torvalds while(1) { 7471da177e4SLinus Torvalds struct vfsmount *parent; 7484ac91378SJan Blunck struct dentry *old = nd->path.dentry; 7491da177e4SLinus Torvalds 750e518ddb7SAndreas Mohr read_lock(&fs->lock); 7516ac08c39SJan Blunck if (nd->path.dentry == fs->root.dentry && 7526ac08c39SJan Blunck nd->path.mnt == fs->root.mnt) { 753e518ddb7SAndreas Mohr read_unlock(&fs->lock); 7541da177e4SLinus Torvalds break; 7551da177e4SLinus Torvalds } 756e518ddb7SAndreas Mohr read_unlock(&fs->lock); 7571da177e4SLinus Torvalds spin_lock(&dcache_lock); 7584ac91378SJan Blunck if (nd->path.dentry != nd->path.mnt->mnt_root) { 7594ac91378SJan Blunck nd->path.dentry = dget(nd->path.dentry->d_parent); 7601da177e4SLinus Torvalds spin_unlock(&dcache_lock); 7611da177e4SLinus Torvalds dput(old); 7621da177e4SLinus Torvalds break; 7631da177e4SLinus Torvalds } 7641da177e4SLinus Torvalds spin_unlock(&dcache_lock); 7651da177e4SLinus Torvalds spin_lock(&vfsmount_lock); 7664ac91378SJan Blunck parent = nd->path.mnt->mnt_parent; 7674ac91378SJan Blunck if (parent == nd->path.mnt) { 7681da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 7691da177e4SLinus Torvalds break; 7701da177e4SLinus Torvalds } 7711da177e4SLinus Torvalds mntget(parent); 7724ac91378SJan Blunck nd->path.dentry = dget(nd->path.mnt->mnt_mountpoint); 7731da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 7741da177e4SLinus Torvalds dput(old); 7754ac91378SJan Blunck mntput(nd->path.mnt); 7764ac91378SJan Blunck nd->path.mnt = parent; 7771da177e4SLinus Torvalds } 7784ac91378SJan Blunck follow_mount(&nd->path.mnt, &nd->path.dentry); 7791da177e4SLinus Torvalds } 7801da177e4SLinus Torvalds 7811da177e4SLinus Torvalds /* 7821da177e4SLinus Torvalds * It's more convoluted than I'd like it to be, but... it's still fairly 7831da177e4SLinus Torvalds * small and for now I'd prefer to have fast path as straight as possible. 7841da177e4SLinus Torvalds * It _is_ time-critical. 7851da177e4SLinus Torvalds */ 7861da177e4SLinus Torvalds static int do_lookup(struct nameidata *nd, struct qstr *name, 7871da177e4SLinus Torvalds struct path *path) 7881da177e4SLinus Torvalds { 7894ac91378SJan Blunck struct vfsmount *mnt = nd->path.mnt; 7904ac91378SJan Blunck struct dentry *dentry = __d_lookup(nd->path.dentry, name); 7911da177e4SLinus Torvalds 7921da177e4SLinus Torvalds if (!dentry) 7931da177e4SLinus Torvalds goto need_lookup; 7941da177e4SLinus Torvalds if (dentry->d_op && dentry->d_op->d_revalidate) 7951da177e4SLinus Torvalds goto need_revalidate; 7961da177e4SLinus Torvalds done: 7971da177e4SLinus Torvalds path->mnt = mnt; 7981da177e4SLinus Torvalds path->dentry = dentry; 799634ee701SAl Viro __follow_mount(path); 8001da177e4SLinus Torvalds return 0; 8011da177e4SLinus Torvalds 8021da177e4SLinus Torvalds need_lookup: 8034ac91378SJan Blunck dentry = real_lookup(nd->path.dentry, name, nd); 8041da177e4SLinus Torvalds if (IS_ERR(dentry)) 8051da177e4SLinus Torvalds goto fail; 8061da177e4SLinus Torvalds goto done; 8071da177e4SLinus Torvalds 8081da177e4SLinus Torvalds need_revalidate: 809bcdc5e01SIan Kent dentry = do_revalidate(dentry, nd); 810bcdc5e01SIan Kent if (!dentry) 8111da177e4SLinus Torvalds goto need_lookup; 812bcdc5e01SIan Kent if (IS_ERR(dentry)) 813bcdc5e01SIan Kent goto fail; 814bcdc5e01SIan Kent goto done; 8151da177e4SLinus Torvalds 8161da177e4SLinus Torvalds fail: 8171da177e4SLinus Torvalds return PTR_ERR(dentry); 8181da177e4SLinus Torvalds } 8191da177e4SLinus Torvalds 8201da177e4SLinus Torvalds /* 8211da177e4SLinus Torvalds * Name resolution. 822ea3834d9SPrasanna Meda * This is the basic name resolution function, turning a pathname into 823ea3834d9SPrasanna Meda * the final dentry. We expect 'base' to be positive and a directory. 8241da177e4SLinus Torvalds * 825ea3834d9SPrasanna Meda * Returns 0 and nd will have valid dentry and mnt on success. 826ea3834d9SPrasanna Meda * Returns error and drops reference to input namei data on failure. 8271da177e4SLinus Torvalds */ 828fc9b52cdSHarvey Harrison static int __link_path_walk(const char *name, struct nameidata *nd) 8291da177e4SLinus Torvalds { 8301da177e4SLinus Torvalds struct path next; 8311da177e4SLinus Torvalds struct inode *inode; 8321da177e4SLinus Torvalds int err; 8331da177e4SLinus Torvalds unsigned int lookup_flags = nd->flags; 8341da177e4SLinus Torvalds 8351da177e4SLinus Torvalds while (*name=='/') 8361da177e4SLinus Torvalds name++; 8371da177e4SLinus Torvalds if (!*name) 8381da177e4SLinus Torvalds goto return_reval; 8391da177e4SLinus Torvalds 8404ac91378SJan Blunck inode = nd->path.dentry->d_inode; 8411da177e4SLinus Torvalds if (nd->depth) 842f55eab82STrond Myklebust lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE); 8431da177e4SLinus Torvalds 8441da177e4SLinus Torvalds /* At this point we know we have a real path component. */ 8451da177e4SLinus Torvalds for(;;) { 8461da177e4SLinus Torvalds unsigned long hash; 8471da177e4SLinus Torvalds struct qstr this; 8481da177e4SLinus Torvalds unsigned int c; 8491da177e4SLinus Torvalds 850cdce5d6bSTrond Myklebust nd->flags |= LOOKUP_CONTINUE; 851672b16b2SAl Viro err = exec_permission_lite(inode); 852e4543eddSChristoph Hellwig if (err == -EAGAIN) 853cb23beb5SChristoph Hellwig err = inode_permission(nd->path.dentry->d_inode, 854cb23beb5SChristoph Hellwig MAY_EXEC); 8556146f0d5SMimi Zohar if (!err) 856b9fc745dSMimi Zohar err = ima_path_check(&nd->path, MAY_EXEC, 857b9fc745dSMimi Zohar IMA_COUNT_UPDATE); 8581da177e4SLinus Torvalds if (err) 8591da177e4SLinus Torvalds break; 8601da177e4SLinus Torvalds 8611da177e4SLinus Torvalds this.name = name; 8621da177e4SLinus Torvalds c = *(const unsigned char *)name; 8631da177e4SLinus Torvalds 8641da177e4SLinus Torvalds hash = init_name_hash(); 8651da177e4SLinus Torvalds do { 8661da177e4SLinus Torvalds name++; 8671da177e4SLinus Torvalds hash = partial_name_hash(c, hash); 8681da177e4SLinus Torvalds c = *(const unsigned char *)name; 8691da177e4SLinus Torvalds } while (c && (c != '/')); 8701da177e4SLinus Torvalds this.len = name - (const char *) this.name; 8711da177e4SLinus Torvalds this.hash = end_name_hash(hash); 8721da177e4SLinus Torvalds 8731da177e4SLinus Torvalds /* remove trailing slashes? */ 8741da177e4SLinus Torvalds if (!c) 8751da177e4SLinus Torvalds goto last_component; 8761da177e4SLinus Torvalds while (*++name == '/'); 8771da177e4SLinus Torvalds if (!*name) 8781da177e4SLinus Torvalds goto last_with_slashes; 8791da177e4SLinus Torvalds 8801da177e4SLinus Torvalds /* 8811da177e4SLinus Torvalds * "." and ".." are special - ".." especially so because it has 8821da177e4SLinus Torvalds * to be able to know about the current root directory and 8831da177e4SLinus Torvalds * parent relationships. 8841da177e4SLinus Torvalds */ 8851da177e4SLinus Torvalds if (this.name[0] == '.') switch (this.len) { 8861da177e4SLinus Torvalds default: 8871da177e4SLinus Torvalds break; 8881da177e4SLinus Torvalds case 2: 8891da177e4SLinus Torvalds if (this.name[1] != '.') 8901da177e4SLinus Torvalds break; 89158c465ebSAl Viro follow_dotdot(nd); 8924ac91378SJan Blunck inode = nd->path.dentry->d_inode; 8931da177e4SLinus Torvalds /* fallthrough */ 8941da177e4SLinus Torvalds case 1: 8951da177e4SLinus Torvalds continue; 8961da177e4SLinus Torvalds } 8971da177e4SLinus Torvalds /* 8981da177e4SLinus Torvalds * See if the low-level filesystem might want 8991da177e4SLinus Torvalds * to use its own hash.. 9001da177e4SLinus Torvalds */ 9014ac91378SJan Blunck if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { 9024ac91378SJan Blunck err = nd->path.dentry->d_op->d_hash(nd->path.dentry, 9034ac91378SJan Blunck &this); 9041da177e4SLinus Torvalds if (err < 0) 9051da177e4SLinus Torvalds break; 9061da177e4SLinus Torvalds } 9071da177e4SLinus Torvalds /* This does the actual lookups.. */ 9081da177e4SLinus Torvalds err = do_lookup(nd, &this, &next); 9091da177e4SLinus Torvalds if (err) 9101da177e4SLinus Torvalds break; 9111da177e4SLinus Torvalds 9121da177e4SLinus Torvalds err = -ENOENT; 9131da177e4SLinus Torvalds inode = next.dentry->d_inode; 9141da177e4SLinus Torvalds if (!inode) 9151da177e4SLinus Torvalds goto out_dput; 9161da177e4SLinus Torvalds 9171da177e4SLinus Torvalds if (inode->i_op->follow_link) { 91890ebe565SAl Viro err = do_follow_link(&next, nd); 9191da177e4SLinus Torvalds if (err) 9201da177e4SLinus Torvalds goto return_err; 9211da177e4SLinus Torvalds err = -ENOENT; 9224ac91378SJan Blunck inode = nd->path.dentry->d_inode; 9231da177e4SLinus Torvalds if (!inode) 9241da177e4SLinus Torvalds break; 92509dd17d3SMiklos Szeredi } else 92609dd17d3SMiklos Szeredi path_to_nameidata(&next, nd); 9271da177e4SLinus Torvalds err = -ENOTDIR; 9281da177e4SLinus Torvalds if (!inode->i_op->lookup) 9291da177e4SLinus Torvalds break; 9301da177e4SLinus Torvalds continue; 9311da177e4SLinus Torvalds /* here ends the main loop */ 9321da177e4SLinus Torvalds 9331da177e4SLinus Torvalds last_with_slashes: 9341da177e4SLinus Torvalds lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; 9351da177e4SLinus Torvalds last_component: 936f55eab82STrond Myklebust /* Clear LOOKUP_CONTINUE iff it was previously unset */ 937f55eab82STrond Myklebust nd->flags &= lookup_flags | ~LOOKUP_CONTINUE; 9381da177e4SLinus Torvalds if (lookup_flags & LOOKUP_PARENT) 9391da177e4SLinus Torvalds goto lookup_parent; 9401da177e4SLinus Torvalds if (this.name[0] == '.') switch (this.len) { 9411da177e4SLinus Torvalds default: 9421da177e4SLinus Torvalds break; 9431da177e4SLinus Torvalds case 2: 9441da177e4SLinus Torvalds if (this.name[1] != '.') 9451da177e4SLinus Torvalds break; 94658c465ebSAl Viro follow_dotdot(nd); 9474ac91378SJan Blunck inode = nd->path.dentry->d_inode; 9481da177e4SLinus Torvalds /* fallthrough */ 9491da177e4SLinus Torvalds case 1: 9501da177e4SLinus Torvalds goto return_reval; 9511da177e4SLinus Torvalds } 9524ac91378SJan Blunck if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { 9534ac91378SJan Blunck err = nd->path.dentry->d_op->d_hash(nd->path.dentry, 9544ac91378SJan Blunck &this); 9551da177e4SLinus Torvalds if (err < 0) 9561da177e4SLinus Torvalds break; 9571da177e4SLinus Torvalds } 9581da177e4SLinus Torvalds err = do_lookup(nd, &this, &next); 9591da177e4SLinus Torvalds if (err) 9601da177e4SLinus Torvalds break; 9611da177e4SLinus Torvalds inode = next.dentry->d_inode; 9621da177e4SLinus Torvalds if ((lookup_flags & LOOKUP_FOLLOW) 963acfa4380SAl Viro && inode && inode->i_op->follow_link) { 96490ebe565SAl Viro err = do_follow_link(&next, nd); 9651da177e4SLinus Torvalds if (err) 9661da177e4SLinus Torvalds goto return_err; 9674ac91378SJan Blunck inode = nd->path.dentry->d_inode; 96809dd17d3SMiklos Szeredi } else 96909dd17d3SMiklos Szeredi path_to_nameidata(&next, nd); 9701da177e4SLinus Torvalds err = -ENOENT; 9711da177e4SLinus Torvalds if (!inode) 9721da177e4SLinus Torvalds break; 9731da177e4SLinus Torvalds if (lookup_flags & LOOKUP_DIRECTORY) { 9741da177e4SLinus Torvalds err = -ENOTDIR; 975acfa4380SAl Viro if (!inode->i_op->lookup) 9761da177e4SLinus Torvalds break; 9771da177e4SLinus Torvalds } 9781da177e4SLinus Torvalds goto return_base; 9791da177e4SLinus Torvalds lookup_parent: 9801da177e4SLinus Torvalds nd->last = this; 9811da177e4SLinus Torvalds nd->last_type = LAST_NORM; 9821da177e4SLinus Torvalds if (this.name[0] != '.') 9831da177e4SLinus Torvalds goto return_base; 9841da177e4SLinus Torvalds if (this.len == 1) 9851da177e4SLinus Torvalds nd->last_type = LAST_DOT; 9861da177e4SLinus Torvalds else if (this.len == 2 && this.name[1] == '.') 9871da177e4SLinus Torvalds nd->last_type = LAST_DOTDOT; 9881da177e4SLinus Torvalds else 9891da177e4SLinus Torvalds goto return_base; 9901da177e4SLinus Torvalds return_reval: 9911da177e4SLinus Torvalds /* 9921da177e4SLinus Torvalds * We bypassed the ordinary revalidation routines. 9931da177e4SLinus Torvalds * We may need to check the cached dentry for staleness. 9941da177e4SLinus Torvalds */ 9954ac91378SJan Blunck if (nd->path.dentry && nd->path.dentry->d_sb && 9964ac91378SJan Blunck (nd->path.dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) { 9971da177e4SLinus Torvalds err = -ESTALE; 9981da177e4SLinus Torvalds /* Note: we do not d_invalidate() */ 9994ac91378SJan Blunck if (!nd->path.dentry->d_op->d_revalidate( 10004ac91378SJan Blunck nd->path.dentry, nd)) 10011da177e4SLinus Torvalds break; 10021da177e4SLinus Torvalds } 10031da177e4SLinus Torvalds return_base: 10041da177e4SLinus Torvalds return 0; 10051da177e4SLinus Torvalds out_dput: 10061d957f9bSJan Blunck path_put_conditional(&next, nd); 10071da177e4SLinus Torvalds break; 10081da177e4SLinus Torvalds } 10091d957f9bSJan Blunck path_put(&nd->path); 10101da177e4SLinus Torvalds return_err: 10111da177e4SLinus Torvalds return err; 10121da177e4SLinus Torvalds } 10131da177e4SLinus Torvalds 1014fc9b52cdSHarvey Harrison static int path_walk(const char *name, struct nameidata *nd) 10151da177e4SLinus Torvalds { 10161da177e4SLinus Torvalds current->total_link_count = 0; 10171da177e4SLinus Torvalds return link_path_walk(name, nd); 10181da177e4SLinus Torvalds } 10191da177e4SLinus Torvalds 10209b4a9b14SAl Viro static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd) 10211da177e4SLinus Torvalds { 1022ea3834d9SPrasanna Meda int retval = 0; 1023170aa3d0SUlrich Drepper int fput_needed; 1024170aa3d0SUlrich Drepper struct file *file; 1025e518ddb7SAndreas Mohr struct fs_struct *fs = current->fs; 10261da177e4SLinus Torvalds 10271da177e4SLinus Torvalds nd->last_type = LAST_ROOT; /* if there are only slashes... */ 10281da177e4SLinus Torvalds nd->flags = flags; 10291da177e4SLinus Torvalds nd->depth = 0; 10301da177e4SLinus Torvalds 10311da177e4SLinus Torvalds if (*name=='/') { 1032e518ddb7SAndreas Mohr read_lock(&fs->lock); 10336ac08c39SJan Blunck nd->path = fs->root; 10346ac08c39SJan Blunck path_get(&fs->root); 1035e518ddb7SAndreas Mohr read_unlock(&fs->lock); 10365590ff0dSUlrich Drepper } else if (dfd == AT_FDCWD) { 1037e518ddb7SAndreas Mohr read_lock(&fs->lock); 10386ac08c39SJan Blunck nd->path = fs->pwd; 10396ac08c39SJan Blunck path_get(&fs->pwd); 1040e518ddb7SAndreas Mohr read_unlock(&fs->lock); 10415590ff0dSUlrich Drepper } else { 10425590ff0dSUlrich Drepper struct dentry *dentry; 10435590ff0dSUlrich Drepper 10445590ff0dSUlrich Drepper file = fget_light(dfd, &fput_needed); 10455590ff0dSUlrich Drepper retval = -EBADF; 1046170aa3d0SUlrich Drepper if (!file) 10476d09bb62STrond Myklebust goto out_fail; 10485590ff0dSUlrich Drepper 10490f7fc9e4SJosef "Jeff" Sipek dentry = file->f_path.dentry; 10505590ff0dSUlrich Drepper 10515590ff0dSUlrich Drepper retval = -ENOTDIR; 1052170aa3d0SUlrich Drepper if (!S_ISDIR(dentry->d_inode->i_mode)) 10536d09bb62STrond Myklebust goto fput_fail; 10545590ff0dSUlrich Drepper 10555590ff0dSUlrich Drepper retval = file_permission(file, MAY_EXEC); 1056170aa3d0SUlrich Drepper if (retval) 10576d09bb62STrond Myklebust goto fput_fail; 10585590ff0dSUlrich Drepper 10595dd784d0SJan Blunck nd->path = file->f_path; 10605dd784d0SJan Blunck path_get(&file->f_path); 10615590ff0dSUlrich Drepper 10625590ff0dSUlrich Drepper fput_light(file, fput_needed); 10631da177e4SLinus Torvalds } 10649b4a9b14SAl Viro return 0; 10652dfdd266SJosef 'Jeff' Sipek 10669b4a9b14SAl Viro fput_fail: 10679b4a9b14SAl Viro fput_light(file, fput_needed); 10689b4a9b14SAl Viro out_fail: 10699b4a9b14SAl Viro return retval; 10709b4a9b14SAl Viro } 10719b4a9b14SAl Viro 10729b4a9b14SAl Viro /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ 10739b4a9b14SAl Viro static int do_path_lookup(int dfd, const char *name, 10749b4a9b14SAl Viro unsigned int flags, struct nameidata *nd) 10759b4a9b14SAl Viro { 10769b4a9b14SAl Viro int retval = path_init(dfd, name, flags, nd); 10779b4a9b14SAl Viro if (!retval) 10782dfdd266SJosef 'Jeff' Sipek retval = path_walk(name, nd); 10794ac91378SJan Blunck if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && 10804ac91378SJan Blunck nd->path.dentry->d_inode)) 10814ac91378SJan Blunck audit_inode(name, nd->path.dentry); 1082170aa3d0SUlrich Drepper return retval; 10831da177e4SLinus Torvalds } 10841da177e4SLinus Torvalds 1085fc9b52cdSHarvey Harrison int path_lookup(const char *name, unsigned int flags, 10865590ff0dSUlrich Drepper struct nameidata *nd) 10875590ff0dSUlrich Drepper { 10885590ff0dSUlrich Drepper return do_path_lookup(AT_FDCWD, name, flags, nd); 10895590ff0dSUlrich Drepper } 10905590ff0dSUlrich Drepper 1091d1811465SAl Viro int kern_path(const char *name, unsigned int flags, struct path *path) 1092d1811465SAl Viro { 1093d1811465SAl Viro struct nameidata nd; 1094d1811465SAl Viro int res = do_path_lookup(AT_FDCWD, name, flags, &nd); 1095d1811465SAl Viro if (!res) 1096d1811465SAl Viro *path = nd.path; 1097d1811465SAl Viro return res; 1098d1811465SAl Viro } 1099d1811465SAl Viro 110016f18200SJosef 'Jeff' Sipek /** 110116f18200SJosef 'Jeff' Sipek * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair 110216f18200SJosef 'Jeff' Sipek * @dentry: pointer to dentry of the base directory 110316f18200SJosef 'Jeff' Sipek * @mnt: pointer to vfs mount of the base directory 110416f18200SJosef 'Jeff' Sipek * @name: pointer to file name 110516f18200SJosef 'Jeff' Sipek * @flags: lookup flags 110616f18200SJosef 'Jeff' Sipek * @nd: pointer to nameidata 110716f18200SJosef 'Jeff' Sipek */ 110816f18200SJosef 'Jeff' Sipek int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, 110916f18200SJosef 'Jeff' Sipek const char *name, unsigned int flags, 111016f18200SJosef 'Jeff' Sipek struct nameidata *nd) 111116f18200SJosef 'Jeff' Sipek { 111216f18200SJosef 'Jeff' Sipek int retval; 111316f18200SJosef 'Jeff' Sipek 111416f18200SJosef 'Jeff' Sipek /* same as do_path_lookup */ 111516f18200SJosef 'Jeff' Sipek nd->last_type = LAST_ROOT; 111616f18200SJosef 'Jeff' Sipek nd->flags = flags; 111716f18200SJosef 'Jeff' Sipek nd->depth = 0; 111816f18200SJosef 'Jeff' Sipek 1119c8e7f449SJan Blunck nd->path.dentry = dentry; 1120c8e7f449SJan Blunck nd->path.mnt = mnt; 1121c8e7f449SJan Blunck path_get(&nd->path); 112216f18200SJosef 'Jeff' Sipek 112316f18200SJosef 'Jeff' Sipek retval = path_walk(name, nd); 11244ac91378SJan Blunck if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && 11254ac91378SJan Blunck nd->path.dentry->d_inode)) 11264ac91378SJan Blunck audit_inode(name, nd->path.dentry); 112716f18200SJosef 'Jeff' Sipek 112816f18200SJosef 'Jeff' Sipek return retval; 112916f18200SJosef 'Jeff' Sipek 113016f18200SJosef 'Jeff' Sipek } 113116f18200SJosef 'Jeff' Sipek 1132834f2a4aSTrond Myklebust /** 1133834f2a4aSTrond Myklebust * path_lookup_open - lookup a file path with open intent 11347045f37bSMartin Waitz * @dfd: the directory to use as base, or AT_FDCWD 1135834f2a4aSTrond Myklebust * @name: pointer to file name 1136834f2a4aSTrond Myklebust * @lookup_flags: lookup intent flags 1137834f2a4aSTrond Myklebust * @nd: pointer to nameidata 1138834f2a4aSTrond Myklebust * @open_flags: open intent flags 1139834f2a4aSTrond Myklebust */ 11406e8341a1SAl Viro static int path_lookup_open(int dfd, const char *name, 11416e8341a1SAl Viro unsigned int lookup_flags, struct nameidata *nd, int open_flags) 1142834f2a4aSTrond Myklebust { 11438737f3a1SAl Viro struct file *filp = get_empty_filp(); 11448737f3a1SAl Viro int err; 1145834f2a4aSTrond Myklebust 11468737f3a1SAl Viro if (filp == NULL) 11478737f3a1SAl Viro return -ENFILE; 11488737f3a1SAl Viro nd->intent.open.file = filp; 11498737f3a1SAl Viro nd->intent.open.flags = open_flags; 11508737f3a1SAl Viro nd->intent.open.create_mode = 0; 11518737f3a1SAl Viro err = do_path_lookup(dfd, name, lookup_flags|LOOKUP_OPEN, nd); 11528737f3a1SAl Viro if (IS_ERR(nd->intent.open.file)) { 11538737f3a1SAl Viro if (err == 0) { 11548737f3a1SAl Viro err = PTR_ERR(nd->intent.open.file); 11558737f3a1SAl Viro path_put(&nd->path); 11568737f3a1SAl Viro } 11578737f3a1SAl Viro } else if (err != 0) 11588737f3a1SAl Viro release_open_intent(nd); 11598737f3a1SAl Viro return err; 1160834f2a4aSTrond Myklebust } 1161834f2a4aSTrond Myklebust 1162eead1911SChristoph Hellwig static struct dentry *__lookup_hash(struct qstr *name, 1163eead1911SChristoph Hellwig struct dentry *base, struct nameidata *nd) 11641da177e4SLinus Torvalds { 11651da177e4SLinus Torvalds struct dentry *dentry; 11661da177e4SLinus Torvalds struct inode *inode; 11671da177e4SLinus Torvalds int err; 11681da177e4SLinus Torvalds 11691da177e4SLinus Torvalds inode = base->d_inode; 11701da177e4SLinus Torvalds 11711da177e4SLinus Torvalds /* 11721da177e4SLinus Torvalds * See if the low-level filesystem might want 11731da177e4SLinus Torvalds * to use its own hash.. 11741da177e4SLinus Torvalds */ 11751da177e4SLinus Torvalds if (base->d_op && base->d_op->d_hash) { 11761da177e4SLinus Torvalds err = base->d_op->d_hash(base, name); 11771da177e4SLinus Torvalds dentry = ERR_PTR(err); 11781da177e4SLinus Torvalds if (err < 0) 11791da177e4SLinus Torvalds goto out; 11801da177e4SLinus Torvalds } 11811da177e4SLinus Torvalds 11821da177e4SLinus Torvalds dentry = cached_lookup(base, name, nd); 11831da177e4SLinus Torvalds if (!dentry) { 1184d70b67c8SMiklos Szeredi struct dentry *new; 1185d70b67c8SMiklos Szeredi 1186d70b67c8SMiklos Szeredi /* Don't create child dentry for a dead directory. */ 1187d70b67c8SMiklos Szeredi dentry = ERR_PTR(-ENOENT); 1188d70b67c8SMiklos Szeredi if (IS_DEADDIR(inode)) 1189d70b67c8SMiklos Szeredi goto out; 1190d70b67c8SMiklos Szeredi 1191d70b67c8SMiklos Szeredi new = d_alloc(base, name); 11921da177e4SLinus Torvalds dentry = ERR_PTR(-ENOMEM); 11931da177e4SLinus Torvalds if (!new) 11941da177e4SLinus Torvalds goto out; 11951da177e4SLinus Torvalds dentry = inode->i_op->lookup(inode, new, nd); 11961da177e4SLinus Torvalds if (!dentry) 11971da177e4SLinus Torvalds dentry = new; 11981da177e4SLinus Torvalds else 11991da177e4SLinus Torvalds dput(new); 12001da177e4SLinus Torvalds } 12011da177e4SLinus Torvalds out: 12021da177e4SLinus Torvalds return dentry; 12031da177e4SLinus Torvalds } 12041da177e4SLinus Torvalds 1205057f6c01SJames Morris /* 1206057f6c01SJames Morris * Restricted form of lookup. Doesn't follow links, single-component only, 1207057f6c01SJames Morris * needs parent already locked. Doesn't follow mounts. 1208057f6c01SJames Morris * SMP-safe. 1209057f6c01SJames Morris */ 1210a244e169SAdrian Bunk static struct dentry *lookup_hash(struct nameidata *nd) 12111da177e4SLinus Torvalds { 1212eead1911SChristoph Hellwig int err; 1213eead1911SChristoph Hellwig 1214f419a2e3SAl Viro err = inode_permission(nd->path.dentry->d_inode, MAY_EXEC); 1215eead1911SChristoph Hellwig if (err) 1216eead1911SChristoph Hellwig return ERR_PTR(err); 12174ac91378SJan Blunck return __lookup_hash(&nd->last, nd->path.dentry, nd); 12181da177e4SLinus Torvalds } 12191da177e4SLinus Torvalds 1220eead1911SChristoph Hellwig static int __lookup_one_len(const char *name, struct qstr *this, 1221eead1911SChristoph Hellwig struct dentry *base, int len) 12221da177e4SLinus Torvalds { 12231da177e4SLinus Torvalds unsigned long hash; 12241da177e4SLinus Torvalds unsigned int c; 12251da177e4SLinus Torvalds 1226057f6c01SJames Morris this->name = name; 1227057f6c01SJames Morris this->len = len; 12281da177e4SLinus Torvalds if (!len) 1229057f6c01SJames Morris return -EACCES; 12301da177e4SLinus Torvalds 12311da177e4SLinus Torvalds hash = init_name_hash(); 12321da177e4SLinus Torvalds while (len--) { 12331da177e4SLinus Torvalds c = *(const unsigned char *)name++; 12341da177e4SLinus Torvalds if (c == '/' || c == '\0') 1235057f6c01SJames Morris return -EACCES; 12361da177e4SLinus Torvalds hash = partial_name_hash(c, hash); 12371da177e4SLinus Torvalds } 1238057f6c01SJames Morris this->hash = end_name_hash(hash); 1239057f6c01SJames Morris return 0; 1240057f6c01SJames Morris } 12411da177e4SLinus Torvalds 1242eead1911SChristoph Hellwig /** 1243a6b91919SRandy Dunlap * lookup_one_len - filesystem helper to lookup single pathname component 1244eead1911SChristoph Hellwig * @name: pathname component to lookup 1245eead1911SChristoph Hellwig * @base: base directory to lookup from 1246eead1911SChristoph Hellwig * @len: maximum length @len should be interpreted to 1247eead1911SChristoph Hellwig * 1248a6b91919SRandy Dunlap * Note that this routine is purely a helper for filesystem usage and should 1249a6b91919SRandy Dunlap * not be called by generic code. Also note that by using this function the 1250eead1911SChristoph Hellwig * nameidata argument is passed to the filesystem methods and a filesystem 1251eead1911SChristoph Hellwig * using this helper needs to be prepared for that. 1252eead1911SChristoph Hellwig */ 1253057f6c01SJames Morris struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) 1254057f6c01SJames Morris { 1255057f6c01SJames Morris int err; 1256057f6c01SJames Morris struct qstr this; 1257057f6c01SJames Morris 12582f9092e1SDavid Woodhouse WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); 12592f9092e1SDavid Woodhouse 1260057f6c01SJames Morris err = __lookup_one_len(name, &this, base, len); 1261057f6c01SJames Morris if (err) 1262057f6c01SJames Morris return ERR_PTR(err); 1263eead1911SChristoph Hellwig 1264f419a2e3SAl Viro err = inode_permission(base->d_inode, MAY_EXEC); 1265eead1911SChristoph Hellwig if (err) 1266eead1911SChristoph Hellwig return ERR_PTR(err); 126749705b77SChristoph Hellwig return __lookup_hash(&this, base, NULL); 1268057f6c01SJames Morris } 1269057f6c01SJames Morris 1270eead1911SChristoph Hellwig /** 1271eead1911SChristoph Hellwig * lookup_one_noperm - bad hack for sysfs 1272eead1911SChristoph Hellwig * @name: pathname component to lookup 1273eead1911SChristoph Hellwig * @base: base directory to lookup from 1274eead1911SChristoph Hellwig * 1275eead1911SChristoph Hellwig * This is a variant of lookup_one_len that doesn't perform any permission 1276eead1911SChristoph Hellwig * checks. It's a horrible hack to work around the braindead sysfs 1277eead1911SChristoph Hellwig * architecture and should not be used anywhere else. 1278eead1911SChristoph Hellwig * 1279eead1911SChristoph Hellwig * DON'T USE THIS FUNCTION EVER, thanks. 1280eead1911SChristoph Hellwig */ 1281eead1911SChristoph Hellwig struct dentry *lookup_one_noperm(const char *name, struct dentry *base) 1282057f6c01SJames Morris { 1283057f6c01SJames Morris int err; 1284057f6c01SJames Morris struct qstr this; 1285057f6c01SJames Morris 1286eead1911SChristoph Hellwig err = __lookup_one_len(name, &this, base, strlen(name)); 1287057f6c01SJames Morris if (err) 1288057f6c01SJames Morris return ERR_PTR(err); 1289eead1911SChristoph Hellwig return __lookup_hash(&this, base, NULL); 12901da177e4SLinus Torvalds } 12911da177e4SLinus Torvalds 12922d8f3038SAl Viro int user_path_at(int dfd, const char __user *name, unsigned flags, 12932d8f3038SAl Viro struct path *path) 12941da177e4SLinus Torvalds { 12952d8f3038SAl Viro struct nameidata nd; 12961da177e4SLinus Torvalds char *tmp = getname(name); 12971da177e4SLinus Torvalds int err = PTR_ERR(tmp); 12981da177e4SLinus Torvalds if (!IS_ERR(tmp)) { 12992d8f3038SAl Viro 13002d8f3038SAl Viro BUG_ON(flags & LOOKUP_PARENT); 13012d8f3038SAl Viro 13022d8f3038SAl Viro err = do_path_lookup(dfd, tmp, flags, &nd); 13031da177e4SLinus Torvalds putname(tmp); 13042d8f3038SAl Viro if (!err) 13052d8f3038SAl Viro *path = nd.path; 13061da177e4SLinus Torvalds } 13071da177e4SLinus Torvalds return err; 13081da177e4SLinus Torvalds } 13091da177e4SLinus Torvalds 13102ad94ae6SAl Viro static int user_path_parent(int dfd, const char __user *path, 13112ad94ae6SAl Viro struct nameidata *nd, char **name) 13122ad94ae6SAl Viro { 13132ad94ae6SAl Viro char *s = getname(path); 13142ad94ae6SAl Viro int error; 13152ad94ae6SAl Viro 13162ad94ae6SAl Viro if (IS_ERR(s)) 13172ad94ae6SAl Viro return PTR_ERR(s); 13182ad94ae6SAl Viro 13192ad94ae6SAl Viro error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd); 13202ad94ae6SAl Viro if (error) 13212ad94ae6SAl Viro putname(s); 13222ad94ae6SAl Viro else 13232ad94ae6SAl Viro *name = s; 13242ad94ae6SAl Viro 13252ad94ae6SAl Viro return error; 13262ad94ae6SAl Viro } 13272ad94ae6SAl Viro 13281da177e4SLinus Torvalds /* 13291da177e4SLinus Torvalds * It's inline, so penalty for filesystems that don't use sticky bit is 13301da177e4SLinus Torvalds * minimal. 13311da177e4SLinus Torvalds */ 13321da177e4SLinus Torvalds static inline int check_sticky(struct inode *dir, struct inode *inode) 13331da177e4SLinus Torvalds { 1334da9592edSDavid Howells uid_t fsuid = current_fsuid(); 1335da9592edSDavid Howells 13361da177e4SLinus Torvalds if (!(dir->i_mode & S_ISVTX)) 13371da177e4SLinus Torvalds return 0; 1338da9592edSDavid Howells if (inode->i_uid == fsuid) 13391da177e4SLinus Torvalds return 0; 1340da9592edSDavid Howells if (dir->i_uid == fsuid) 13411da177e4SLinus Torvalds return 0; 13421da177e4SLinus Torvalds return !capable(CAP_FOWNER); 13431da177e4SLinus Torvalds } 13441da177e4SLinus Torvalds 13451da177e4SLinus Torvalds /* 13461da177e4SLinus Torvalds * Check whether we can remove a link victim from directory dir, check 13471da177e4SLinus Torvalds * whether the type of victim is right. 13481da177e4SLinus Torvalds * 1. We can't do it if dir is read-only (done in permission()) 13491da177e4SLinus Torvalds * 2. We should have write and exec permissions on dir 13501da177e4SLinus Torvalds * 3. We can't remove anything from append-only dir 13511da177e4SLinus Torvalds * 4. We can't do anything with immutable dir (done in permission()) 13521da177e4SLinus Torvalds * 5. If the sticky bit on dir is set we should either 13531da177e4SLinus Torvalds * a. be owner of dir, or 13541da177e4SLinus Torvalds * b. be owner of victim, or 13551da177e4SLinus Torvalds * c. have CAP_FOWNER capability 13561da177e4SLinus Torvalds * 6. If the victim is append-only or immutable we can't do antyhing with 13571da177e4SLinus Torvalds * links pointing to it. 13581da177e4SLinus Torvalds * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. 13591da177e4SLinus Torvalds * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. 13601da177e4SLinus Torvalds * 9. We can't remove a root or mountpoint. 13611da177e4SLinus Torvalds * 10. We don't allow removal of NFS sillyrenamed files; it's handled by 13621da177e4SLinus Torvalds * nfs_async_unlink(). 13631da177e4SLinus Torvalds */ 1364858119e1SArjan van de Ven static int may_delete(struct inode *dir,struct dentry *victim,int isdir) 13651da177e4SLinus Torvalds { 13661da177e4SLinus Torvalds int error; 13671da177e4SLinus Torvalds 13681da177e4SLinus Torvalds if (!victim->d_inode) 13691da177e4SLinus Torvalds return -ENOENT; 13701da177e4SLinus Torvalds 13711da177e4SLinus Torvalds BUG_ON(victim->d_parent->d_inode != dir); 13725a190ae6SAl Viro audit_inode_child(victim->d_name.name, victim, dir); 13731da177e4SLinus Torvalds 1374f419a2e3SAl Viro error = inode_permission(dir, MAY_WRITE | MAY_EXEC); 13751da177e4SLinus Torvalds if (error) 13761da177e4SLinus Torvalds return error; 13771da177e4SLinus Torvalds if (IS_APPEND(dir)) 13781da177e4SLinus Torvalds return -EPERM; 13791da177e4SLinus Torvalds if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| 1380f9454548SHugh Dickins IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) 13811da177e4SLinus Torvalds return -EPERM; 13821da177e4SLinus Torvalds if (isdir) { 13831da177e4SLinus Torvalds if (!S_ISDIR(victim->d_inode->i_mode)) 13841da177e4SLinus Torvalds return -ENOTDIR; 13851da177e4SLinus Torvalds if (IS_ROOT(victim)) 13861da177e4SLinus Torvalds return -EBUSY; 13871da177e4SLinus Torvalds } else if (S_ISDIR(victim->d_inode->i_mode)) 13881da177e4SLinus Torvalds return -EISDIR; 13891da177e4SLinus Torvalds if (IS_DEADDIR(dir)) 13901da177e4SLinus Torvalds return -ENOENT; 13911da177e4SLinus Torvalds if (victim->d_flags & DCACHE_NFSFS_RENAMED) 13921da177e4SLinus Torvalds return -EBUSY; 13931da177e4SLinus Torvalds return 0; 13941da177e4SLinus Torvalds } 13951da177e4SLinus Torvalds 13961da177e4SLinus Torvalds /* Check whether we can create an object with dentry child in directory 13971da177e4SLinus Torvalds * dir. 13981da177e4SLinus Torvalds * 1. We can't do it if child already exists (open has special treatment for 13991da177e4SLinus Torvalds * this case, but since we are inlined it's OK) 14001da177e4SLinus Torvalds * 2. We can't do it if dir is read-only (done in permission()) 14011da177e4SLinus Torvalds * 3. We should have write and exec permissions on dir 14021da177e4SLinus Torvalds * 4. We can't do it if dir is immutable (done in permission()) 14031da177e4SLinus Torvalds */ 1404a95164d9SMiklos Szeredi static inline int may_create(struct inode *dir, struct dentry *child) 14051da177e4SLinus Torvalds { 14061da177e4SLinus Torvalds if (child->d_inode) 14071da177e4SLinus Torvalds return -EEXIST; 14081da177e4SLinus Torvalds if (IS_DEADDIR(dir)) 14091da177e4SLinus Torvalds return -ENOENT; 1410f419a2e3SAl Viro return inode_permission(dir, MAY_WRITE | MAY_EXEC); 14111da177e4SLinus Torvalds } 14121da177e4SLinus Torvalds 14131da177e4SLinus Torvalds /* 14141da177e4SLinus Torvalds * O_DIRECTORY translates into forcing a directory lookup. 14151da177e4SLinus Torvalds */ 14161da177e4SLinus Torvalds static inline int lookup_flags(unsigned int f) 14171da177e4SLinus Torvalds { 14181da177e4SLinus Torvalds unsigned long retval = LOOKUP_FOLLOW; 14191da177e4SLinus Torvalds 14201da177e4SLinus Torvalds if (f & O_NOFOLLOW) 14211da177e4SLinus Torvalds retval &= ~LOOKUP_FOLLOW; 14221da177e4SLinus Torvalds 14231da177e4SLinus Torvalds if (f & O_DIRECTORY) 14241da177e4SLinus Torvalds retval |= LOOKUP_DIRECTORY; 14251da177e4SLinus Torvalds 14261da177e4SLinus Torvalds return retval; 14271da177e4SLinus Torvalds } 14281da177e4SLinus Torvalds 14291da177e4SLinus Torvalds /* 14301da177e4SLinus Torvalds * p1 and p2 should be directories on the same fs. 14311da177e4SLinus Torvalds */ 14321da177e4SLinus Torvalds struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) 14331da177e4SLinus Torvalds { 14341da177e4SLinus Torvalds struct dentry *p; 14351da177e4SLinus Torvalds 14361da177e4SLinus Torvalds if (p1 == p2) { 1437f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 14381da177e4SLinus Torvalds return NULL; 14391da177e4SLinus Torvalds } 14401da177e4SLinus Torvalds 1441a11f3a05SArjan van de Ven mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); 14421da177e4SLinus Torvalds 1443e2761a11SOGAWA Hirofumi p = d_ancestor(p2, p1); 1444e2761a11SOGAWA Hirofumi if (p) { 1445f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); 1446f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); 14471da177e4SLinus Torvalds return p; 14481da177e4SLinus Torvalds } 14491da177e4SLinus Torvalds 1450e2761a11SOGAWA Hirofumi p = d_ancestor(p1, p2); 1451e2761a11SOGAWA Hirofumi if (p) { 1452f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 1453f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); 14541da177e4SLinus Torvalds return p; 14551da177e4SLinus Torvalds } 14561da177e4SLinus Torvalds 1457f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 1458f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); 14591da177e4SLinus Torvalds return NULL; 14601da177e4SLinus Torvalds } 14611da177e4SLinus Torvalds 14621da177e4SLinus Torvalds void unlock_rename(struct dentry *p1, struct dentry *p2) 14631da177e4SLinus Torvalds { 14641b1dcc1bSJes Sorensen mutex_unlock(&p1->d_inode->i_mutex); 14651da177e4SLinus Torvalds if (p1 != p2) { 14661b1dcc1bSJes Sorensen mutex_unlock(&p2->d_inode->i_mutex); 1467a11f3a05SArjan van de Ven mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); 14681da177e4SLinus Torvalds } 14691da177e4SLinus Torvalds } 14701da177e4SLinus Torvalds 14711da177e4SLinus Torvalds int vfs_create(struct inode *dir, struct dentry *dentry, int mode, 14721da177e4SLinus Torvalds struct nameidata *nd) 14731da177e4SLinus Torvalds { 1474a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 14751da177e4SLinus Torvalds 14761da177e4SLinus Torvalds if (error) 14771da177e4SLinus Torvalds return error; 14781da177e4SLinus Torvalds 1479acfa4380SAl Viro if (!dir->i_op->create) 14801da177e4SLinus Torvalds return -EACCES; /* shouldn't it be ENOSYS? */ 14811da177e4SLinus Torvalds mode &= S_IALLUGO; 14821da177e4SLinus Torvalds mode |= S_IFREG; 14831da177e4SLinus Torvalds error = security_inode_create(dir, dentry, mode); 14841da177e4SLinus Torvalds if (error) 14851da177e4SLinus Torvalds return error; 14869e3509e2SJan Kara vfs_dq_init(dir); 14871da177e4SLinus Torvalds error = dir->i_op->create(dir, dentry, mode, nd); 1488a74574aaSStephen Smalley if (!error) 1489f38aa942SAmy Griffis fsnotify_create(dir, dentry); 14901da177e4SLinus Torvalds return error; 14911da177e4SLinus Torvalds } 14921da177e4SLinus Torvalds 14933fb64190SChristoph Hellwig int may_open(struct path *path, int acc_mode, int flag) 14941da177e4SLinus Torvalds { 14953fb64190SChristoph Hellwig struct dentry *dentry = path->dentry; 14961da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 14971da177e4SLinus Torvalds int error; 14981da177e4SLinus Torvalds 14991da177e4SLinus Torvalds if (!inode) 15001da177e4SLinus Torvalds return -ENOENT; 15011da177e4SLinus Torvalds 1502c8fe8f30SChristoph Hellwig switch (inode->i_mode & S_IFMT) { 1503c8fe8f30SChristoph Hellwig case S_IFLNK: 15041da177e4SLinus Torvalds return -ELOOP; 1505c8fe8f30SChristoph Hellwig case S_IFDIR: 1506c8fe8f30SChristoph Hellwig if (acc_mode & MAY_WRITE) 15071da177e4SLinus Torvalds return -EISDIR; 1508c8fe8f30SChristoph Hellwig break; 1509c8fe8f30SChristoph Hellwig case S_IFBLK: 1510c8fe8f30SChristoph Hellwig case S_IFCHR: 15113fb64190SChristoph Hellwig if (path->mnt->mnt_flags & MNT_NODEV) 15121da177e4SLinus Torvalds return -EACCES; 1513c8fe8f30SChristoph Hellwig /*FALLTHRU*/ 1514c8fe8f30SChristoph Hellwig case S_IFIFO: 1515c8fe8f30SChristoph Hellwig case S_IFSOCK: 15161da177e4SLinus Torvalds flag &= ~O_TRUNC; 1517c8fe8f30SChristoph Hellwig break; 15184a3fd211SDave Hansen } 1519b41572e9SDave Hansen 15203fb64190SChristoph Hellwig error = inode_permission(inode, acc_mode); 1521b41572e9SDave Hansen if (error) 1522b41572e9SDave Hansen return error; 15236146f0d5SMimi Zohar 1524cb5629b1SJames Morris error = ima_path_check(path, 1525b9fc745dSMimi Zohar acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC), 1526b9fc745dSMimi Zohar IMA_COUNT_UPDATE); 15276146f0d5SMimi Zohar if (error) 15286146f0d5SMimi Zohar return error; 15291da177e4SLinus Torvalds /* 15301da177e4SLinus Torvalds * An append-only file must be opened in append mode for writing. 15311da177e4SLinus Torvalds */ 15321da177e4SLinus Torvalds if (IS_APPEND(inode)) { 15331da177e4SLinus Torvalds if ((flag & FMODE_WRITE) && !(flag & O_APPEND)) 15341da177e4SLinus Torvalds return -EPERM; 15351da177e4SLinus Torvalds if (flag & O_TRUNC) 15361da177e4SLinus Torvalds return -EPERM; 15371da177e4SLinus Torvalds } 15381da177e4SLinus Torvalds 15391da177e4SLinus Torvalds /* O_NOATIME can only be set by the owner or superuser */ 15401da177e4SLinus Torvalds if (flag & O_NOATIME) 15413bd858abSSatyam Sharma if (!is_owner_or_cap(inode)) 15421da177e4SLinus Torvalds return -EPERM; 15431da177e4SLinus Torvalds 15441da177e4SLinus Torvalds /* 15451da177e4SLinus Torvalds * Ensure there are no outstanding leases on the file. 15461da177e4SLinus Torvalds */ 15471da177e4SLinus Torvalds error = break_lease(inode, flag); 15481da177e4SLinus Torvalds if (error) 15491da177e4SLinus Torvalds return error; 15501da177e4SLinus Torvalds 15511da177e4SLinus Torvalds if (flag & O_TRUNC) { 15521da177e4SLinus Torvalds error = get_write_access(inode); 15531da177e4SLinus Torvalds if (error) 15541da177e4SLinus Torvalds return error; 15551da177e4SLinus Torvalds 15561da177e4SLinus Torvalds /* 15571da177e4SLinus Torvalds * Refuse to truncate files with mandatory locks held on them. 15581da177e4SLinus Torvalds */ 15591da177e4SLinus Torvalds error = locks_verify_locked(inode); 1560be6d3e56SKentaro Takeda if (!error) 15613fb64190SChristoph Hellwig error = security_path_truncate(path, 0, 1562be6d3e56SKentaro Takeda ATTR_MTIME|ATTR_CTIME|ATTR_OPEN); 15631da177e4SLinus Torvalds if (!error) { 15649e3509e2SJan Kara vfs_dq_init(inode); 15651da177e4SLinus Torvalds 1566d139d7ffSMiklos Szeredi error = do_truncate(dentry, 0, 1567d139d7ffSMiklos Szeredi ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, 1568d139d7ffSMiklos Szeredi NULL); 15691da177e4SLinus Torvalds } 15701da177e4SLinus Torvalds put_write_access(inode); 15711da177e4SLinus Torvalds if (error) 15721da177e4SLinus Torvalds return error; 15731da177e4SLinus Torvalds } else 15741da177e4SLinus Torvalds if (flag & FMODE_WRITE) 15759e3509e2SJan Kara vfs_dq_init(inode); 15761da177e4SLinus Torvalds 15771da177e4SLinus Torvalds return 0; 15781da177e4SLinus Torvalds } 15791da177e4SLinus Torvalds 1580d57999e1SDave Hansen /* 1581d57999e1SDave Hansen * Be careful about ever adding any more callers of this 1582d57999e1SDave Hansen * function. Its flags must be in the namei format, not 1583d57999e1SDave Hansen * what get passed to sys_open(). 1584d57999e1SDave Hansen */ 1585d57999e1SDave Hansen static int __open_namei_create(struct nameidata *nd, struct path *path, 1586aab520e2SDave Hansen int flag, int mode) 1587aab520e2SDave Hansen { 1588aab520e2SDave Hansen int error; 15894ac91378SJan Blunck struct dentry *dir = nd->path.dentry; 1590aab520e2SDave Hansen 1591aab520e2SDave Hansen if (!IS_POSIXACL(dir->d_inode)) 1592ce3b0f8dSAl Viro mode &= ~current_umask(); 1593be6d3e56SKentaro Takeda error = security_path_mknod(&nd->path, path->dentry, mode, 0); 1594be6d3e56SKentaro Takeda if (error) 1595be6d3e56SKentaro Takeda goto out_unlock; 1596aab520e2SDave Hansen error = vfs_create(dir->d_inode, path->dentry, mode, nd); 1597be6d3e56SKentaro Takeda out_unlock: 1598aab520e2SDave Hansen mutex_unlock(&dir->d_inode->i_mutex); 15994ac91378SJan Blunck dput(nd->path.dentry); 16004ac91378SJan Blunck nd->path.dentry = path->dentry; 1601aab520e2SDave Hansen if (error) 1602aab520e2SDave Hansen return error; 1603aab520e2SDave Hansen /* Don't check for write permission, don't truncate */ 16043fb64190SChristoph Hellwig return may_open(&nd->path, 0, flag & ~O_TRUNC); 1605aab520e2SDave Hansen } 1606aab520e2SDave Hansen 16071da177e4SLinus Torvalds /* 1608d57999e1SDave Hansen * Note that while the flag value (low two bits) for sys_open means: 1609d57999e1SDave Hansen * 00 - read-only 1610d57999e1SDave Hansen * 01 - write-only 1611d57999e1SDave Hansen * 10 - read-write 1612d57999e1SDave Hansen * 11 - special 1613d57999e1SDave Hansen * it is changed into 1614d57999e1SDave Hansen * 00 - no permissions needed 1615d57999e1SDave Hansen * 01 - read-permission 1616d57999e1SDave Hansen * 10 - write-permission 1617d57999e1SDave Hansen * 11 - read-write 1618d57999e1SDave Hansen * for the internal routines (ie open_namei()/follow_link() etc) 1619d57999e1SDave Hansen * This is more logical, and also allows the 00 "no perm needed" 1620d57999e1SDave Hansen * to be used for symlinks (where the permissions are checked 1621d57999e1SDave Hansen * later). 1622d57999e1SDave Hansen * 1623d57999e1SDave Hansen */ 1624d57999e1SDave Hansen static inline int open_to_namei_flags(int flag) 1625d57999e1SDave Hansen { 1626d57999e1SDave Hansen if ((flag+1) & O_ACCMODE) 1627d57999e1SDave Hansen flag++; 1628d57999e1SDave Hansen return flag; 1629d57999e1SDave Hansen } 1630d57999e1SDave Hansen 16314a3fd211SDave Hansen static int open_will_write_to_fs(int flag, struct inode *inode) 16324a3fd211SDave Hansen { 1633d57999e1SDave Hansen /* 16344a3fd211SDave Hansen * We'll never write to the fs underlying 16354a3fd211SDave Hansen * a device file. 16364a3fd211SDave Hansen */ 16374a3fd211SDave Hansen if (special_file(inode->i_mode)) 16384a3fd211SDave Hansen return 0; 16394a3fd211SDave Hansen return (flag & O_TRUNC); 16404a3fd211SDave Hansen } 16414a3fd211SDave Hansen 16424a3fd211SDave Hansen /* 16434a3fd211SDave Hansen * Note that the low bits of the passed in "open_flag" 16444a3fd211SDave Hansen * are not the same as in the local variable "flag". See 16454a3fd211SDave Hansen * open_to_namei_flags() for more details. 16461da177e4SLinus Torvalds */ 1647a70e65dfSChristoph Hellwig struct file *do_filp_open(int dfd, const char *pathname, 16486e8341a1SAl Viro int open_flag, int mode, int acc_mode) 16491da177e4SLinus Torvalds { 16504a3fd211SDave Hansen struct file *filp; 1651a70e65dfSChristoph Hellwig struct nameidata nd; 16526e8341a1SAl Viro int error; 16534e7506e4SAl Viro struct path path; 16541da177e4SLinus Torvalds struct dentry *dir; 16551da177e4SLinus Torvalds int count = 0; 16564a3fd211SDave Hansen int will_write; 1657d57999e1SDave Hansen int flag = open_to_namei_flags(open_flag); 16581da177e4SLinus Torvalds 16596e8341a1SAl Viro if (!acc_mode) 1660b77b0646SAl Viro acc_mode = MAY_OPEN | ACC_MODE(flag); 16611da177e4SLinus Torvalds 1662834f2a4aSTrond Myklebust /* O_TRUNC implies we need access checks for write permissions */ 1663834f2a4aSTrond Myklebust if (flag & O_TRUNC) 1664834f2a4aSTrond Myklebust acc_mode |= MAY_WRITE; 1665834f2a4aSTrond Myklebust 16661da177e4SLinus Torvalds /* Allow the LSM permission hook to distinguish append 16671da177e4SLinus Torvalds access from general write access. */ 16681da177e4SLinus Torvalds if (flag & O_APPEND) 16691da177e4SLinus Torvalds acc_mode |= MAY_APPEND; 16701da177e4SLinus Torvalds 16711da177e4SLinus Torvalds /* 16721da177e4SLinus Torvalds * The simplest case - just a plain lookup. 16731da177e4SLinus Torvalds */ 16741da177e4SLinus Torvalds if (!(flag & O_CREAT)) { 16755590ff0dSUlrich Drepper error = path_lookup_open(dfd, pathname, lookup_flags(flag), 1676a70e65dfSChristoph Hellwig &nd, flag); 16771da177e4SLinus Torvalds if (error) 1678a70e65dfSChristoph Hellwig return ERR_PTR(error); 16791da177e4SLinus Torvalds goto ok; 16801da177e4SLinus Torvalds } 16811da177e4SLinus Torvalds 16821da177e4SLinus Torvalds /* 16831da177e4SLinus Torvalds * Create - we need to know the parent. 16841da177e4SLinus Torvalds */ 16859b4a9b14SAl Viro error = path_init(dfd, pathname, LOOKUP_PARENT, &nd); 16861da177e4SLinus Torvalds if (error) 1687a70e65dfSChristoph Hellwig return ERR_PTR(error); 16889b4a9b14SAl Viro error = path_walk(pathname, &nd); 16899b4a9b14SAl Viro if (error) 16909b4a9b14SAl Viro return ERR_PTR(error); 16919b4a9b14SAl Viro if (unlikely(!audit_dummy_context())) 16929b4a9b14SAl Viro audit_inode(pathname, nd.path.dentry); 16931da177e4SLinus Torvalds 16941da177e4SLinus Torvalds /* 16951da177e4SLinus Torvalds * We have the parent and last component. First of all, check 16961da177e4SLinus Torvalds * that we are not asked to creat(2) an obvious directory - that 16971da177e4SLinus Torvalds * will not do. 16981da177e4SLinus Torvalds */ 16991da177e4SLinus Torvalds error = -EISDIR; 1700a70e65dfSChristoph Hellwig if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len]) 17018737f3a1SAl Viro goto exit_parent; 17021da177e4SLinus Torvalds 17038737f3a1SAl Viro error = -ENFILE; 17048737f3a1SAl Viro filp = get_empty_filp(); 17058737f3a1SAl Viro if (filp == NULL) 17068737f3a1SAl Viro goto exit_parent; 17078737f3a1SAl Viro nd.intent.open.file = filp; 17088737f3a1SAl Viro nd.intent.open.flags = flag; 17098737f3a1SAl Viro nd.intent.open.create_mode = mode; 1710a70e65dfSChristoph Hellwig dir = nd.path.dentry; 1711a70e65dfSChristoph Hellwig nd.flags &= ~LOOKUP_PARENT; 17128737f3a1SAl Viro nd.flags |= LOOKUP_CREATE | LOOKUP_OPEN; 17133516586aSAl Viro if (flag & O_EXCL) 17143516586aSAl Viro nd.flags |= LOOKUP_EXCL; 17151b1dcc1bSJes Sorensen mutex_lock(&dir->d_inode->i_mutex); 1716a70e65dfSChristoph Hellwig path.dentry = lookup_hash(&nd); 1717a70e65dfSChristoph Hellwig path.mnt = nd.path.mnt; 17181da177e4SLinus Torvalds 17191da177e4SLinus Torvalds do_last: 17204e7506e4SAl Viro error = PTR_ERR(path.dentry); 17214e7506e4SAl Viro if (IS_ERR(path.dentry)) { 17221b1dcc1bSJes Sorensen mutex_unlock(&dir->d_inode->i_mutex); 17231da177e4SLinus Torvalds goto exit; 17241da177e4SLinus Torvalds } 17251da177e4SLinus Torvalds 1726a70e65dfSChristoph Hellwig if (IS_ERR(nd.intent.open.file)) { 1727a70e65dfSChristoph Hellwig error = PTR_ERR(nd.intent.open.file); 17284a3fd211SDave Hansen goto exit_mutex_unlock; 17294af4c52fSOleg Drokin } 17304af4c52fSOleg Drokin 17311da177e4SLinus Torvalds /* Negative dentry, just create the file */ 17324e7506e4SAl Viro if (!path.dentry->d_inode) { 17334a3fd211SDave Hansen /* 17344a3fd211SDave Hansen * This write is needed to ensure that a 17354a3fd211SDave Hansen * ro->rw transition does not occur between 17364a3fd211SDave Hansen * the time when the file is created and when 17374a3fd211SDave Hansen * a permanent write count is taken through 17384a3fd211SDave Hansen * the 'struct file' in nameidata_to_filp(). 17394a3fd211SDave Hansen */ 17404a3fd211SDave Hansen error = mnt_want_write(nd.path.mnt); 17411da177e4SLinus Torvalds if (error) 17424a3fd211SDave Hansen goto exit_mutex_unlock; 17434a3fd211SDave Hansen error = __open_namei_create(&nd, &path, flag, mode); 17444a3fd211SDave Hansen if (error) { 17454a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17461da177e4SLinus Torvalds goto exit; 17474a3fd211SDave Hansen } 17484a3fd211SDave Hansen filp = nameidata_to_filp(&nd, open_flag); 17494a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17504a3fd211SDave Hansen return filp; 17511da177e4SLinus Torvalds } 17521da177e4SLinus Torvalds 17531da177e4SLinus Torvalds /* 17541da177e4SLinus Torvalds * It already exists. 17551da177e4SLinus Torvalds */ 17561b1dcc1bSJes Sorensen mutex_unlock(&dir->d_inode->i_mutex); 17575a190ae6SAl Viro audit_inode(pathname, path.dentry); 17581da177e4SLinus Torvalds 17591da177e4SLinus Torvalds error = -EEXIST; 17601da177e4SLinus Torvalds if (flag & O_EXCL) 17611da177e4SLinus Torvalds goto exit_dput; 17621da177e4SLinus Torvalds 1763e13b210fSAl Viro if (__follow_mount(&path)) { 17641da177e4SLinus Torvalds error = -ELOOP; 1765ba7a4c1aSAl Viro if (flag & O_NOFOLLOW) 1766ba7a4c1aSAl Viro goto exit_dput; 17671da177e4SLinus Torvalds } 17683e2efce0SAmy Griffis 17691da177e4SLinus Torvalds error = -ENOENT; 17704e7506e4SAl Viro if (!path.dentry->d_inode) 17711da177e4SLinus Torvalds goto exit_dput; 1772acfa4380SAl Viro if (path.dentry->d_inode->i_op->follow_link) 17731da177e4SLinus Torvalds goto do_link; 17741da177e4SLinus Torvalds 1775a70e65dfSChristoph Hellwig path_to_nameidata(&path, &nd); 17761da177e4SLinus Torvalds error = -EISDIR; 17774e7506e4SAl Viro if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode)) 17781da177e4SLinus Torvalds goto exit; 17791da177e4SLinus Torvalds ok: 17804a3fd211SDave Hansen /* 17814a3fd211SDave Hansen * Consider: 17824a3fd211SDave Hansen * 1. may_open() truncates a file 17834a3fd211SDave Hansen * 2. a rw->ro mount transition occurs 17844a3fd211SDave Hansen * 3. nameidata_to_filp() fails due to 17854a3fd211SDave Hansen * the ro mount. 17864a3fd211SDave Hansen * That would be inconsistent, and should 17874a3fd211SDave Hansen * be avoided. Taking this mnt write here 17884a3fd211SDave Hansen * ensures that (2) can not occur. 17894a3fd211SDave Hansen */ 17904a3fd211SDave Hansen will_write = open_will_write_to_fs(flag, nd.path.dentry->d_inode); 17914a3fd211SDave Hansen if (will_write) { 17924a3fd211SDave Hansen error = mnt_want_write(nd.path.mnt); 17931da177e4SLinus Torvalds if (error) 17941da177e4SLinus Torvalds goto exit; 17954a3fd211SDave Hansen } 17963fb64190SChristoph Hellwig error = may_open(&nd.path, acc_mode, flag); 17974a3fd211SDave Hansen if (error) { 17984a3fd211SDave Hansen if (will_write) 17994a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 18004a3fd211SDave Hansen goto exit; 18014a3fd211SDave Hansen } 18024a3fd211SDave Hansen filp = nameidata_to_filp(&nd, open_flag); 18034a3fd211SDave Hansen /* 18044a3fd211SDave Hansen * It is now safe to drop the mnt write 18054a3fd211SDave Hansen * because the filp has had a write taken 18064a3fd211SDave Hansen * on its behalf. 18074a3fd211SDave Hansen */ 18084a3fd211SDave Hansen if (will_write) 18094a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 18104a3fd211SDave Hansen return filp; 18111da177e4SLinus Torvalds 18124a3fd211SDave Hansen exit_mutex_unlock: 18134a3fd211SDave Hansen mutex_unlock(&dir->d_inode->i_mutex); 18141da177e4SLinus Torvalds exit_dput: 1815a70e65dfSChristoph Hellwig path_put_conditional(&path, &nd); 18161da177e4SLinus Torvalds exit: 1817a70e65dfSChristoph Hellwig if (!IS_ERR(nd.intent.open.file)) 1818a70e65dfSChristoph Hellwig release_open_intent(&nd); 18198737f3a1SAl Viro exit_parent: 1820a70e65dfSChristoph Hellwig path_put(&nd.path); 1821a70e65dfSChristoph Hellwig return ERR_PTR(error); 18221da177e4SLinus Torvalds 18231da177e4SLinus Torvalds do_link: 18241da177e4SLinus Torvalds error = -ELOOP; 18251da177e4SLinus Torvalds if (flag & O_NOFOLLOW) 18261da177e4SLinus Torvalds goto exit_dput; 18271da177e4SLinus Torvalds /* 18281da177e4SLinus Torvalds * This is subtle. Instead of calling do_follow_link() we do the 18291da177e4SLinus Torvalds * thing by hands. The reason is that this way we have zero link_count 18301da177e4SLinus Torvalds * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT. 18311da177e4SLinus Torvalds * After that we have the parent and last component, i.e. 18321da177e4SLinus Torvalds * we are in the same situation as after the first path_walk(). 18331da177e4SLinus Torvalds * Well, almost - if the last component is normal we get its copy 18341da177e4SLinus Torvalds * stored in nd->last.name and we will have to putname() it when we 18351da177e4SLinus Torvalds * are done. Procfs-like symlinks just set LAST_BIND. 18361da177e4SLinus Torvalds */ 1837a70e65dfSChristoph Hellwig nd.flags |= LOOKUP_PARENT; 1838a70e65dfSChristoph Hellwig error = security_inode_follow_link(path.dentry, &nd); 18391da177e4SLinus Torvalds if (error) 18401da177e4SLinus Torvalds goto exit_dput; 1841a70e65dfSChristoph Hellwig error = __do_follow_link(&path, &nd); 1842de459215SKirill Korotaev if (error) { 1843de459215SKirill Korotaev /* Does someone understand code flow here? Or it is only 1844de459215SKirill Korotaev * me so stupid? Anathema to whoever designed this non-sense 1845de459215SKirill Korotaev * with "intent.open". 1846de459215SKirill Korotaev */ 1847a70e65dfSChristoph Hellwig release_open_intent(&nd); 1848a70e65dfSChristoph Hellwig return ERR_PTR(error); 1849de459215SKirill Korotaev } 1850a70e65dfSChristoph Hellwig nd.flags &= ~LOOKUP_PARENT; 1851a70e65dfSChristoph Hellwig if (nd.last_type == LAST_BIND) 18521da177e4SLinus Torvalds goto ok; 18531da177e4SLinus Torvalds error = -EISDIR; 1854a70e65dfSChristoph Hellwig if (nd.last_type != LAST_NORM) 18551da177e4SLinus Torvalds goto exit; 1856a70e65dfSChristoph Hellwig if (nd.last.name[nd.last.len]) { 1857a70e65dfSChristoph Hellwig __putname(nd.last.name); 18581da177e4SLinus Torvalds goto exit; 18591da177e4SLinus Torvalds } 18601da177e4SLinus Torvalds error = -ELOOP; 18611da177e4SLinus Torvalds if (count++==32) { 1862a70e65dfSChristoph Hellwig __putname(nd.last.name); 18631da177e4SLinus Torvalds goto exit; 18641da177e4SLinus Torvalds } 1865a70e65dfSChristoph Hellwig dir = nd.path.dentry; 18661b1dcc1bSJes Sorensen mutex_lock(&dir->d_inode->i_mutex); 1867a70e65dfSChristoph Hellwig path.dentry = lookup_hash(&nd); 1868a70e65dfSChristoph Hellwig path.mnt = nd.path.mnt; 1869a70e65dfSChristoph Hellwig __putname(nd.last.name); 18701da177e4SLinus Torvalds goto do_last; 18711da177e4SLinus Torvalds } 18721da177e4SLinus Torvalds 18731da177e4SLinus Torvalds /** 1874a70e65dfSChristoph Hellwig * filp_open - open file and return file pointer 1875a70e65dfSChristoph Hellwig * 1876a70e65dfSChristoph Hellwig * @filename: path to open 1877a70e65dfSChristoph Hellwig * @flags: open flags as per the open(2) second argument 1878a70e65dfSChristoph Hellwig * @mode: mode for the new file if O_CREAT is set, else ignored 1879a70e65dfSChristoph Hellwig * 1880a70e65dfSChristoph Hellwig * This is the helper to open a file from kernelspace if you really 1881a70e65dfSChristoph Hellwig * have to. But in generally you should not do this, so please move 1882a70e65dfSChristoph Hellwig * along, nothing to see here.. 1883a70e65dfSChristoph Hellwig */ 1884a70e65dfSChristoph Hellwig struct file *filp_open(const char *filename, int flags, int mode) 1885a70e65dfSChristoph Hellwig { 18866e8341a1SAl Viro return do_filp_open(AT_FDCWD, filename, flags, mode, 0); 1887a70e65dfSChristoph Hellwig } 1888a70e65dfSChristoph Hellwig EXPORT_SYMBOL(filp_open); 1889a70e65dfSChristoph Hellwig 1890a70e65dfSChristoph Hellwig /** 18911da177e4SLinus Torvalds * lookup_create - lookup a dentry, creating it if it doesn't exist 18921da177e4SLinus Torvalds * @nd: nameidata info 18931da177e4SLinus Torvalds * @is_dir: directory flag 18941da177e4SLinus Torvalds * 18951da177e4SLinus Torvalds * Simple function to lookup and return a dentry and create it 18961da177e4SLinus Torvalds * if it doesn't exist. Is SMP-safe. 1897c663e5d8SChristoph Hellwig * 18984ac91378SJan Blunck * Returns with nd->path.dentry->d_inode->i_mutex locked. 18991da177e4SLinus Torvalds */ 19001da177e4SLinus Torvalds struct dentry *lookup_create(struct nameidata *nd, int is_dir) 19011da177e4SLinus Torvalds { 1902c663e5d8SChristoph Hellwig struct dentry *dentry = ERR_PTR(-EEXIST); 19031da177e4SLinus Torvalds 19044ac91378SJan Blunck mutex_lock_nested(&nd->path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 1905c663e5d8SChristoph Hellwig /* 1906c663e5d8SChristoph Hellwig * Yucky last component or no last component at all? 1907c663e5d8SChristoph Hellwig * (foo/., foo/.., /////) 1908c663e5d8SChristoph Hellwig */ 19091da177e4SLinus Torvalds if (nd->last_type != LAST_NORM) 19101da177e4SLinus Torvalds goto fail; 19111da177e4SLinus Torvalds nd->flags &= ~LOOKUP_PARENT; 19123516586aSAl Viro nd->flags |= LOOKUP_CREATE | LOOKUP_EXCL; 1913a634904aSASANO Masahiro nd->intent.open.flags = O_EXCL; 1914c663e5d8SChristoph Hellwig 1915c663e5d8SChristoph Hellwig /* 1916c663e5d8SChristoph Hellwig * Do the final lookup. 1917c663e5d8SChristoph Hellwig */ 191849705b77SChristoph Hellwig dentry = lookup_hash(nd); 19191da177e4SLinus Torvalds if (IS_ERR(dentry)) 19201da177e4SLinus Torvalds goto fail; 1921c663e5d8SChristoph Hellwig 1922e9baf6e5SAl Viro if (dentry->d_inode) 1923e9baf6e5SAl Viro goto eexist; 1924c663e5d8SChristoph Hellwig /* 1925c663e5d8SChristoph Hellwig * Special case - lookup gave negative, but... we had foo/bar/ 1926c663e5d8SChristoph Hellwig * From the vfs_mknod() POV we just have a negative dentry - 1927c663e5d8SChristoph Hellwig * all is fine. Let's be bastards - you had / on the end, you've 1928c663e5d8SChristoph Hellwig * been asking for (non-existent) directory. -ENOENT for you. 1929c663e5d8SChristoph Hellwig */ 1930e9baf6e5SAl Viro if (unlikely(!is_dir && nd->last.name[nd->last.len])) { 19311da177e4SLinus Torvalds dput(dentry); 19321da177e4SLinus Torvalds dentry = ERR_PTR(-ENOENT); 1933e9baf6e5SAl Viro } 1934e9baf6e5SAl Viro return dentry; 1935e9baf6e5SAl Viro eexist: 1936e9baf6e5SAl Viro dput(dentry); 1937e9baf6e5SAl Viro dentry = ERR_PTR(-EEXIST); 19381da177e4SLinus Torvalds fail: 19391da177e4SLinus Torvalds return dentry; 19401da177e4SLinus Torvalds } 1941f81a0bffSChristoph Hellwig EXPORT_SYMBOL_GPL(lookup_create); 19421da177e4SLinus Torvalds 19431da177e4SLinus Torvalds int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 19441da177e4SLinus Torvalds { 1945a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 19461da177e4SLinus Torvalds 19471da177e4SLinus Torvalds if (error) 19481da177e4SLinus Torvalds return error; 19491da177e4SLinus Torvalds 19501da177e4SLinus Torvalds if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) 19511da177e4SLinus Torvalds return -EPERM; 19521da177e4SLinus Torvalds 1953acfa4380SAl Viro if (!dir->i_op->mknod) 19541da177e4SLinus Torvalds return -EPERM; 19551da177e4SLinus Torvalds 195608ce5f16SSerge E. Hallyn error = devcgroup_inode_mknod(mode, dev); 195708ce5f16SSerge E. Hallyn if (error) 195808ce5f16SSerge E. Hallyn return error; 195908ce5f16SSerge E. Hallyn 19601da177e4SLinus Torvalds error = security_inode_mknod(dir, dentry, mode, dev); 19611da177e4SLinus Torvalds if (error) 19621da177e4SLinus Torvalds return error; 19631da177e4SLinus Torvalds 19649e3509e2SJan Kara vfs_dq_init(dir); 19651da177e4SLinus Torvalds error = dir->i_op->mknod(dir, dentry, mode, dev); 1966a74574aaSStephen Smalley if (!error) 1967f38aa942SAmy Griffis fsnotify_create(dir, dentry); 19681da177e4SLinus Torvalds return error; 19691da177e4SLinus Torvalds } 19701da177e4SLinus Torvalds 1971463c3197SDave Hansen static int may_mknod(mode_t mode) 1972463c3197SDave Hansen { 1973463c3197SDave Hansen switch (mode & S_IFMT) { 1974463c3197SDave Hansen case S_IFREG: 1975463c3197SDave Hansen case S_IFCHR: 1976463c3197SDave Hansen case S_IFBLK: 1977463c3197SDave Hansen case S_IFIFO: 1978463c3197SDave Hansen case S_IFSOCK: 1979463c3197SDave Hansen case 0: /* zero mode translates to S_IFREG */ 1980463c3197SDave Hansen return 0; 1981463c3197SDave Hansen case S_IFDIR: 1982463c3197SDave Hansen return -EPERM; 1983463c3197SDave Hansen default: 1984463c3197SDave Hansen return -EINVAL; 1985463c3197SDave Hansen } 1986463c3197SDave Hansen } 1987463c3197SDave Hansen 19882e4d0924SHeiko Carstens SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, int, mode, 19892e4d0924SHeiko Carstens unsigned, dev) 19901da177e4SLinus Torvalds { 19912ad94ae6SAl Viro int error; 19921da177e4SLinus Torvalds char *tmp; 19931da177e4SLinus Torvalds struct dentry *dentry; 19941da177e4SLinus Torvalds struct nameidata nd; 19951da177e4SLinus Torvalds 19961da177e4SLinus Torvalds if (S_ISDIR(mode)) 19971da177e4SLinus Torvalds return -EPERM; 19981da177e4SLinus Torvalds 19992ad94ae6SAl Viro error = user_path_parent(dfd, filename, &nd, &tmp); 20001da177e4SLinus Torvalds if (error) 20012ad94ae6SAl Viro return error; 20022ad94ae6SAl Viro 20031da177e4SLinus Torvalds dentry = lookup_create(&nd, 0); 2004463c3197SDave Hansen if (IS_ERR(dentry)) { 20051da177e4SLinus Torvalds error = PTR_ERR(dentry); 2006463c3197SDave Hansen goto out_unlock; 2007463c3197SDave Hansen } 20084ac91378SJan Blunck if (!IS_POSIXACL(nd.path.dentry->d_inode)) 2009ce3b0f8dSAl Viro mode &= ~current_umask(); 2010463c3197SDave Hansen error = may_mknod(mode); 2011463c3197SDave Hansen if (error) 2012463c3197SDave Hansen goto out_dput; 2013463c3197SDave Hansen error = mnt_want_write(nd.path.mnt); 2014463c3197SDave Hansen if (error) 2015463c3197SDave Hansen goto out_dput; 2016be6d3e56SKentaro Takeda error = security_path_mknod(&nd.path, dentry, mode, dev); 2017be6d3e56SKentaro Takeda if (error) 2018be6d3e56SKentaro Takeda goto out_drop_write; 20191da177e4SLinus Torvalds switch (mode & S_IFMT) { 20201da177e4SLinus Torvalds case 0: case S_IFREG: 20214ac91378SJan Blunck error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd); 20221da177e4SLinus Torvalds break; 20231da177e4SLinus Torvalds case S_IFCHR: case S_IFBLK: 20244ac91378SJan Blunck error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode, 20251da177e4SLinus Torvalds new_decode_dev(dev)); 20261da177e4SLinus Torvalds break; 20271da177e4SLinus Torvalds case S_IFIFO: case S_IFSOCK: 20284ac91378SJan Blunck error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0); 20291da177e4SLinus Torvalds break; 20301da177e4SLinus Torvalds } 2031be6d3e56SKentaro Takeda out_drop_write: 2032463c3197SDave Hansen mnt_drop_write(nd.path.mnt); 2033463c3197SDave Hansen out_dput: 20341da177e4SLinus Torvalds dput(dentry); 2035463c3197SDave Hansen out_unlock: 20364ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 20371d957f9bSJan Blunck path_put(&nd.path); 20381da177e4SLinus Torvalds putname(tmp); 20391da177e4SLinus Torvalds 20401da177e4SLinus Torvalds return error; 20411da177e4SLinus Torvalds } 20421da177e4SLinus Torvalds 20433480b257SHeiko Carstens SYSCALL_DEFINE3(mknod, const char __user *, filename, int, mode, unsigned, dev) 20445590ff0dSUlrich Drepper { 20455590ff0dSUlrich Drepper return sys_mknodat(AT_FDCWD, filename, mode, dev); 20465590ff0dSUlrich Drepper } 20475590ff0dSUlrich Drepper 20481da177e4SLinus Torvalds int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 20491da177e4SLinus Torvalds { 2050a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 20511da177e4SLinus Torvalds 20521da177e4SLinus Torvalds if (error) 20531da177e4SLinus Torvalds return error; 20541da177e4SLinus Torvalds 2055acfa4380SAl Viro if (!dir->i_op->mkdir) 20561da177e4SLinus Torvalds return -EPERM; 20571da177e4SLinus Torvalds 20581da177e4SLinus Torvalds mode &= (S_IRWXUGO|S_ISVTX); 20591da177e4SLinus Torvalds error = security_inode_mkdir(dir, dentry, mode); 20601da177e4SLinus Torvalds if (error) 20611da177e4SLinus Torvalds return error; 20621da177e4SLinus Torvalds 20639e3509e2SJan Kara vfs_dq_init(dir); 20641da177e4SLinus Torvalds error = dir->i_op->mkdir(dir, dentry, mode); 2065a74574aaSStephen Smalley if (!error) 2066f38aa942SAmy Griffis fsnotify_mkdir(dir, dentry); 20671da177e4SLinus Torvalds return error; 20681da177e4SLinus Torvalds } 20691da177e4SLinus Torvalds 20702e4d0924SHeiko Carstens SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, int, mode) 20711da177e4SLinus Torvalds { 20721da177e4SLinus Torvalds int error = 0; 20731da177e4SLinus Torvalds char * tmp; 20746902d925SDave Hansen struct dentry *dentry; 20756902d925SDave Hansen struct nameidata nd; 20761da177e4SLinus Torvalds 20772ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &tmp); 20782ad94ae6SAl Viro if (error) 20796902d925SDave Hansen goto out_err; 20801da177e4SLinus Torvalds 20811da177e4SLinus Torvalds dentry = lookup_create(&nd, 1); 20821da177e4SLinus Torvalds error = PTR_ERR(dentry); 20836902d925SDave Hansen if (IS_ERR(dentry)) 20846902d925SDave Hansen goto out_unlock; 20856902d925SDave Hansen 20864ac91378SJan Blunck if (!IS_POSIXACL(nd.path.dentry->d_inode)) 2087ce3b0f8dSAl Viro mode &= ~current_umask(); 2088463c3197SDave Hansen error = mnt_want_write(nd.path.mnt); 2089463c3197SDave Hansen if (error) 2090463c3197SDave Hansen goto out_dput; 2091be6d3e56SKentaro Takeda error = security_path_mkdir(&nd.path, dentry, mode); 2092be6d3e56SKentaro Takeda if (error) 2093be6d3e56SKentaro Takeda goto out_drop_write; 20944ac91378SJan Blunck error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode); 2095be6d3e56SKentaro Takeda out_drop_write: 2096463c3197SDave Hansen mnt_drop_write(nd.path.mnt); 2097463c3197SDave Hansen out_dput: 20981da177e4SLinus Torvalds dput(dentry); 20996902d925SDave Hansen out_unlock: 21004ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 21011d957f9bSJan Blunck path_put(&nd.path); 21021da177e4SLinus Torvalds putname(tmp); 21036902d925SDave Hansen out_err: 21041da177e4SLinus Torvalds return error; 21051da177e4SLinus Torvalds } 21061da177e4SLinus Torvalds 21073cdad428SHeiko Carstens SYSCALL_DEFINE2(mkdir, const char __user *, pathname, int, mode) 21085590ff0dSUlrich Drepper { 21095590ff0dSUlrich Drepper return sys_mkdirat(AT_FDCWD, pathname, mode); 21105590ff0dSUlrich Drepper } 21115590ff0dSUlrich Drepper 21121da177e4SLinus Torvalds /* 21131da177e4SLinus Torvalds * We try to drop the dentry early: we should have 21141da177e4SLinus Torvalds * a usage count of 2 if we're the only user of this 21151da177e4SLinus Torvalds * dentry, and if that is true (possibly after pruning 21161da177e4SLinus Torvalds * the dcache), then we drop the dentry now. 21171da177e4SLinus Torvalds * 21181da177e4SLinus Torvalds * A low-level filesystem can, if it choses, legally 21191da177e4SLinus Torvalds * do a 21201da177e4SLinus Torvalds * 21211da177e4SLinus Torvalds * if (!d_unhashed(dentry)) 21221da177e4SLinus Torvalds * return -EBUSY; 21231da177e4SLinus Torvalds * 21241da177e4SLinus Torvalds * if it cannot handle the case of removing a directory 21251da177e4SLinus Torvalds * that is still in use by something else.. 21261da177e4SLinus Torvalds */ 21271da177e4SLinus Torvalds void dentry_unhash(struct dentry *dentry) 21281da177e4SLinus Torvalds { 21291da177e4SLinus Torvalds dget(dentry); 21301da177e4SLinus Torvalds shrink_dcache_parent(dentry); 21311da177e4SLinus Torvalds spin_lock(&dcache_lock); 21321da177e4SLinus Torvalds spin_lock(&dentry->d_lock); 21331da177e4SLinus Torvalds if (atomic_read(&dentry->d_count) == 2) 21341da177e4SLinus Torvalds __d_drop(dentry); 21351da177e4SLinus Torvalds spin_unlock(&dentry->d_lock); 21361da177e4SLinus Torvalds spin_unlock(&dcache_lock); 21371da177e4SLinus Torvalds } 21381da177e4SLinus Torvalds 21391da177e4SLinus Torvalds int vfs_rmdir(struct inode *dir, struct dentry *dentry) 21401da177e4SLinus Torvalds { 21411da177e4SLinus Torvalds int error = may_delete(dir, dentry, 1); 21421da177e4SLinus Torvalds 21431da177e4SLinus Torvalds if (error) 21441da177e4SLinus Torvalds return error; 21451da177e4SLinus Torvalds 2146acfa4380SAl Viro if (!dir->i_op->rmdir) 21471da177e4SLinus Torvalds return -EPERM; 21481da177e4SLinus Torvalds 21499e3509e2SJan Kara vfs_dq_init(dir); 21501da177e4SLinus Torvalds 21511b1dcc1bSJes Sorensen mutex_lock(&dentry->d_inode->i_mutex); 21521da177e4SLinus Torvalds dentry_unhash(dentry); 21531da177e4SLinus Torvalds if (d_mountpoint(dentry)) 21541da177e4SLinus Torvalds error = -EBUSY; 21551da177e4SLinus Torvalds else { 21561da177e4SLinus Torvalds error = security_inode_rmdir(dir, dentry); 21571da177e4SLinus Torvalds if (!error) { 21581da177e4SLinus Torvalds error = dir->i_op->rmdir(dir, dentry); 21591da177e4SLinus Torvalds if (!error) 21601da177e4SLinus Torvalds dentry->d_inode->i_flags |= S_DEAD; 21611da177e4SLinus Torvalds } 21621da177e4SLinus Torvalds } 21631b1dcc1bSJes Sorensen mutex_unlock(&dentry->d_inode->i_mutex); 21641da177e4SLinus Torvalds if (!error) { 21651da177e4SLinus Torvalds d_delete(dentry); 21661da177e4SLinus Torvalds } 21671da177e4SLinus Torvalds dput(dentry); 21681da177e4SLinus Torvalds 21691da177e4SLinus Torvalds return error; 21701da177e4SLinus Torvalds } 21711da177e4SLinus Torvalds 21725590ff0dSUlrich Drepper static long do_rmdir(int dfd, const char __user *pathname) 21731da177e4SLinus Torvalds { 21741da177e4SLinus Torvalds int error = 0; 21751da177e4SLinus Torvalds char * name; 21761da177e4SLinus Torvalds struct dentry *dentry; 21771da177e4SLinus Torvalds struct nameidata nd; 21781da177e4SLinus Torvalds 21792ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &name); 21801da177e4SLinus Torvalds if (error) 21812ad94ae6SAl Viro return error; 21821da177e4SLinus Torvalds 21831da177e4SLinus Torvalds switch(nd.last_type) { 21841da177e4SLinus Torvalds case LAST_DOTDOT: 21851da177e4SLinus Torvalds error = -ENOTEMPTY; 21861da177e4SLinus Torvalds goto exit1; 21871da177e4SLinus Torvalds case LAST_DOT: 21881da177e4SLinus Torvalds error = -EINVAL; 21891da177e4SLinus Torvalds goto exit1; 21901da177e4SLinus Torvalds case LAST_ROOT: 21911da177e4SLinus Torvalds error = -EBUSY; 21921da177e4SLinus Torvalds goto exit1; 21931da177e4SLinus Torvalds } 21940612d9fbSOGAWA Hirofumi 21950612d9fbSOGAWA Hirofumi nd.flags &= ~LOOKUP_PARENT; 21960612d9fbSOGAWA Hirofumi 21974ac91378SJan Blunck mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 219849705b77SChristoph Hellwig dentry = lookup_hash(&nd); 21991da177e4SLinus Torvalds error = PTR_ERR(dentry); 22006902d925SDave Hansen if (IS_ERR(dentry)) 22016902d925SDave Hansen goto exit2; 22020622753bSDave Hansen error = mnt_want_write(nd.path.mnt); 22030622753bSDave Hansen if (error) 22040622753bSDave Hansen goto exit3; 2205be6d3e56SKentaro Takeda error = security_path_rmdir(&nd.path, dentry); 2206be6d3e56SKentaro Takeda if (error) 2207be6d3e56SKentaro Takeda goto exit4; 22084ac91378SJan Blunck error = vfs_rmdir(nd.path.dentry->d_inode, dentry); 2209be6d3e56SKentaro Takeda exit4: 22100622753bSDave Hansen mnt_drop_write(nd.path.mnt); 22110622753bSDave Hansen exit3: 22121da177e4SLinus Torvalds dput(dentry); 22136902d925SDave Hansen exit2: 22144ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 22151da177e4SLinus Torvalds exit1: 22161d957f9bSJan Blunck path_put(&nd.path); 22171da177e4SLinus Torvalds putname(name); 22181da177e4SLinus Torvalds return error; 22191da177e4SLinus Torvalds } 22201da177e4SLinus Torvalds 22213cdad428SHeiko Carstens SYSCALL_DEFINE1(rmdir, const char __user *, pathname) 22225590ff0dSUlrich Drepper { 22235590ff0dSUlrich Drepper return do_rmdir(AT_FDCWD, pathname); 22245590ff0dSUlrich Drepper } 22255590ff0dSUlrich Drepper 22261da177e4SLinus Torvalds int vfs_unlink(struct inode *dir, struct dentry *dentry) 22271da177e4SLinus Torvalds { 22281da177e4SLinus Torvalds int error = may_delete(dir, dentry, 0); 22291da177e4SLinus Torvalds 22301da177e4SLinus Torvalds if (error) 22311da177e4SLinus Torvalds return error; 22321da177e4SLinus Torvalds 2233acfa4380SAl Viro if (!dir->i_op->unlink) 22341da177e4SLinus Torvalds return -EPERM; 22351da177e4SLinus Torvalds 22369e3509e2SJan Kara vfs_dq_init(dir); 22371da177e4SLinus Torvalds 22381b1dcc1bSJes Sorensen mutex_lock(&dentry->d_inode->i_mutex); 22391da177e4SLinus Torvalds if (d_mountpoint(dentry)) 22401da177e4SLinus Torvalds error = -EBUSY; 22411da177e4SLinus Torvalds else { 22421da177e4SLinus Torvalds error = security_inode_unlink(dir, dentry); 22431da177e4SLinus Torvalds if (!error) 22441da177e4SLinus Torvalds error = dir->i_op->unlink(dir, dentry); 22451da177e4SLinus Torvalds } 22461b1dcc1bSJes Sorensen mutex_unlock(&dentry->d_inode->i_mutex); 22471da177e4SLinus Torvalds 22481da177e4SLinus Torvalds /* We don't d_delete() NFS sillyrenamed files--they still exist. */ 22491da177e4SLinus Torvalds if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { 2250ece95912SJan Kara fsnotify_link_count(dentry->d_inode); 22511da177e4SLinus Torvalds d_delete(dentry); 22521da177e4SLinus Torvalds } 22530eeca283SRobert Love 22541da177e4SLinus Torvalds return error; 22551da177e4SLinus Torvalds } 22561da177e4SLinus Torvalds 22571da177e4SLinus Torvalds /* 22581da177e4SLinus Torvalds * Make sure that the actual truncation of the file will occur outside its 22591b1dcc1bSJes Sorensen * directory's i_mutex. Truncate can take a long time if there is a lot of 22601da177e4SLinus Torvalds * writeout happening, and we don't want to prevent access to the directory 22611da177e4SLinus Torvalds * while waiting on the I/O. 22621da177e4SLinus Torvalds */ 22635590ff0dSUlrich Drepper static long do_unlinkat(int dfd, const char __user *pathname) 22641da177e4SLinus Torvalds { 22652ad94ae6SAl Viro int error; 22661da177e4SLinus Torvalds char *name; 22671da177e4SLinus Torvalds struct dentry *dentry; 22681da177e4SLinus Torvalds struct nameidata nd; 22691da177e4SLinus Torvalds struct inode *inode = NULL; 22701da177e4SLinus Torvalds 22712ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &name); 22721da177e4SLinus Torvalds if (error) 22732ad94ae6SAl Viro return error; 22742ad94ae6SAl Viro 22751da177e4SLinus Torvalds error = -EISDIR; 22761da177e4SLinus Torvalds if (nd.last_type != LAST_NORM) 22771da177e4SLinus Torvalds goto exit1; 22780612d9fbSOGAWA Hirofumi 22790612d9fbSOGAWA Hirofumi nd.flags &= ~LOOKUP_PARENT; 22800612d9fbSOGAWA Hirofumi 22814ac91378SJan Blunck mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 228249705b77SChristoph Hellwig dentry = lookup_hash(&nd); 22831da177e4SLinus Torvalds error = PTR_ERR(dentry); 22841da177e4SLinus Torvalds if (!IS_ERR(dentry)) { 22851da177e4SLinus Torvalds /* Why not before? Because we want correct error value */ 22861da177e4SLinus Torvalds if (nd.last.name[nd.last.len]) 22871da177e4SLinus Torvalds goto slashes; 22881da177e4SLinus Torvalds inode = dentry->d_inode; 22891da177e4SLinus Torvalds if (inode) 22901da177e4SLinus Torvalds atomic_inc(&inode->i_count); 22910622753bSDave Hansen error = mnt_want_write(nd.path.mnt); 22920622753bSDave Hansen if (error) 22930622753bSDave Hansen goto exit2; 2294be6d3e56SKentaro Takeda error = security_path_unlink(&nd.path, dentry); 2295be6d3e56SKentaro Takeda if (error) 2296be6d3e56SKentaro Takeda goto exit3; 22974ac91378SJan Blunck error = vfs_unlink(nd.path.dentry->d_inode, dentry); 2298be6d3e56SKentaro Takeda exit3: 22990622753bSDave Hansen mnt_drop_write(nd.path.mnt); 23001da177e4SLinus Torvalds exit2: 23011da177e4SLinus Torvalds dput(dentry); 23021da177e4SLinus Torvalds } 23034ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 23041da177e4SLinus Torvalds if (inode) 23051da177e4SLinus Torvalds iput(inode); /* truncate the inode here */ 23061da177e4SLinus Torvalds exit1: 23071d957f9bSJan Blunck path_put(&nd.path); 23081da177e4SLinus Torvalds putname(name); 23091da177e4SLinus Torvalds return error; 23101da177e4SLinus Torvalds 23111da177e4SLinus Torvalds slashes: 23121da177e4SLinus Torvalds error = !dentry->d_inode ? -ENOENT : 23131da177e4SLinus Torvalds S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; 23141da177e4SLinus Torvalds goto exit2; 23151da177e4SLinus Torvalds } 23161da177e4SLinus Torvalds 23172e4d0924SHeiko Carstens SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag) 23185590ff0dSUlrich Drepper { 23195590ff0dSUlrich Drepper if ((flag & ~AT_REMOVEDIR) != 0) 23205590ff0dSUlrich Drepper return -EINVAL; 23215590ff0dSUlrich Drepper 23225590ff0dSUlrich Drepper if (flag & AT_REMOVEDIR) 23235590ff0dSUlrich Drepper return do_rmdir(dfd, pathname); 23245590ff0dSUlrich Drepper 23255590ff0dSUlrich Drepper return do_unlinkat(dfd, pathname); 23265590ff0dSUlrich Drepper } 23275590ff0dSUlrich Drepper 23283480b257SHeiko Carstens SYSCALL_DEFINE1(unlink, const char __user *, pathname) 23295590ff0dSUlrich Drepper { 23305590ff0dSUlrich Drepper return do_unlinkat(AT_FDCWD, pathname); 23315590ff0dSUlrich Drepper } 23325590ff0dSUlrich Drepper 2333db2e747bSMiklos Szeredi int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) 23341da177e4SLinus Torvalds { 2335a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 23361da177e4SLinus Torvalds 23371da177e4SLinus Torvalds if (error) 23381da177e4SLinus Torvalds return error; 23391da177e4SLinus Torvalds 2340acfa4380SAl Viro if (!dir->i_op->symlink) 23411da177e4SLinus Torvalds return -EPERM; 23421da177e4SLinus Torvalds 23431da177e4SLinus Torvalds error = security_inode_symlink(dir, dentry, oldname); 23441da177e4SLinus Torvalds if (error) 23451da177e4SLinus Torvalds return error; 23461da177e4SLinus Torvalds 23479e3509e2SJan Kara vfs_dq_init(dir); 23481da177e4SLinus Torvalds error = dir->i_op->symlink(dir, dentry, oldname); 2349a74574aaSStephen Smalley if (!error) 2350f38aa942SAmy Griffis fsnotify_create(dir, dentry); 23511da177e4SLinus Torvalds return error; 23521da177e4SLinus Torvalds } 23531da177e4SLinus Torvalds 23542e4d0924SHeiko Carstens SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, 23552e4d0924SHeiko Carstens int, newdfd, const char __user *, newname) 23561da177e4SLinus Torvalds { 23572ad94ae6SAl Viro int error; 23581da177e4SLinus Torvalds char *from; 23591da177e4SLinus Torvalds char *to; 23606902d925SDave Hansen struct dentry *dentry; 23616902d925SDave Hansen struct nameidata nd; 23621da177e4SLinus Torvalds 23631da177e4SLinus Torvalds from = getname(oldname); 23641da177e4SLinus Torvalds if (IS_ERR(from)) 23651da177e4SLinus Torvalds return PTR_ERR(from); 23662ad94ae6SAl Viro 23672ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &nd, &to); 23682ad94ae6SAl Viro if (error) 23696902d925SDave Hansen goto out_putname; 23701da177e4SLinus Torvalds 23711da177e4SLinus Torvalds dentry = lookup_create(&nd, 0); 23721da177e4SLinus Torvalds error = PTR_ERR(dentry); 23736902d925SDave Hansen if (IS_ERR(dentry)) 23746902d925SDave Hansen goto out_unlock; 23756902d925SDave Hansen 237675c3f29dSDave Hansen error = mnt_want_write(nd.path.mnt); 237775c3f29dSDave Hansen if (error) 237875c3f29dSDave Hansen goto out_dput; 2379be6d3e56SKentaro Takeda error = security_path_symlink(&nd.path, dentry, from); 2380be6d3e56SKentaro Takeda if (error) 2381be6d3e56SKentaro Takeda goto out_drop_write; 2382db2e747bSMiklos Szeredi error = vfs_symlink(nd.path.dentry->d_inode, dentry, from); 2383be6d3e56SKentaro Takeda out_drop_write: 238475c3f29dSDave Hansen mnt_drop_write(nd.path.mnt); 238575c3f29dSDave Hansen out_dput: 23861da177e4SLinus Torvalds dput(dentry); 23876902d925SDave Hansen out_unlock: 23884ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 23891d957f9bSJan Blunck path_put(&nd.path); 23901da177e4SLinus Torvalds putname(to); 23916902d925SDave Hansen out_putname: 23921da177e4SLinus Torvalds putname(from); 23931da177e4SLinus Torvalds return error; 23941da177e4SLinus Torvalds } 23951da177e4SLinus Torvalds 23963480b257SHeiko Carstens SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) 23975590ff0dSUlrich Drepper { 23985590ff0dSUlrich Drepper return sys_symlinkat(oldname, AT_FDCWD, newname); 23995590ff0dSUlrich Drepper } 24005590ff0dSUlrich Drepper 24011da177e4SLinus Torvalds int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) 24021da177e4SLinus Torvalds { 24031da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 24041da177e4SLinus Torvalds int error; 24051da177e4SLinus Torvalds 24061da177e4SLinus Torvalds if (!inode) 24071da177e4SLinus Torvalds return -ENOENT; 24081da177e4SLinus Torvalds 2409a95164d9SMiklos Szeredi error = may_create(dir, new_dentry); 24101da177e4SLinus Torvalds if (error) 24111da177e4SLinus Torvalds return error; 24121da177e4SLinus Torvalds 24131da177e4SLinus Torvalds if (dir->i_sb != inode->i_sb) 24141da177e4SLinus Torvalds return -EXDEV; 24151da177e4SLinus Torvalds 24161da177e4SLinus Torvalds /* 24171da177e4SLinus Torvalds * A link to an append-only or immutable file cannot be created. 24181da177e4SLinus Torvalds */ 24191da177e4SLinus Torvalds if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) 24201da177e4SLinus Torvalds return -EPERM; 2421acfa4380SAl Viro if (!dir->i_op->link) 24221da177e4SLinus Torvalds return -EPERM; 24237e79eedbSTetsuo Handa if (S_ISDIR(inode->i_mode)) 24241da177e4SLinus Torvalds return -EPERM; 24251da177e4SLinus Torvalds 24261da177e4SLinus Torvalds error = security_inode_link(old_dentry, dir, new_dentry); 24271da177e4SLinus Torvalds if (error) 24281da177e4SLinus Torvalds return error; 24291da177e4SLinus Torvalds 24307e79eedbSTetsuo Handa mutex_lock(&inode->i_mutex); 24319e3509e2SJan Kara vfs_dq_init(dir); 24321da177e4SLinus Torvalds error = dir->i_op->link(old_dentry, dir, new_dentry); 24337e79eedbSTetsuo Handa mutex_unlock(&inode->i_mutex); 2434e31e14ecSStephen Smalley if (!error) 24357e79eedbSTetsuo Handa fsnotify_link(dir, inode, new_dentry); 24361da177e4SLinus Torvalds return error; 24371da177e4SLinus Torvalds } 24381da177e4SLinus Torvalds 24391da177e4SLinus Torvalds /* 24401da177e4SLinus Torvalds * Hardlinks are often used in delicate situations. We avoid 24411da177e4SLinus Torvalds * security-related surprises by not following symlinks on the 24421da177e4SLinus Torvalds * newname. --KAB 24431da177e4SLinus Torvalds * 24441da177e4SLinus Torvalds * We don't follow them on the oldname either to be compatible 24451da177e4SLinus Torvalds * with linux 2.0, and to avoid hard-linking to directories 24461da177e4SLinus Torvalds * and other special files. --ADM 24471da177e4SLinus Torvalds */ 24482e4d0924SHeiko Carstens SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, 24492e4d0924SHeiko Carstens int, newdfd, const char __user *, newname, int, flags) 24501da177e4SLinus Torvalds { 24511da177e4SLinus Torvalds struct dentry *new_dentry; 24522d8f3038SAl Viro struct nameidata nd; 24532d8f3038SAl Viro struct path old_path; 24541da177e4SLinus Torvalds int error; 24551da177e4SLinus Torvalds char *to; 24561da177e4SLinus Torvalds 245745c9b11aSUlrich Drepper if ((flags & ~AT_SYMLINK_FOLLOW) != 0) 2458c04030e1SUlrich Drepper return -EINVAL; 2459c04030e1SUlrich Drepper 24602d8f3038SAl Viro error = user_path_at(olddfd, oldname, 246145c9b11aSUlrich Drepper flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0, 24622d8f3038SAl Viro &old_path); 24631da177e4SLinus Torvalds if (error) 24642ad94ae6SAl Viro return error; 24652ad94ae6SAl Viro 24662ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &nd, &to); 24671da177e4SLinus Torvalds if (error) 24681da177e4SLinus Torvalds goto out; 24691da177e4SLinus Torvalds error = -EXDEV; 24702d8f3038SAl Viro if (old_path.mnt != nd.path.mnt) 24711da177e4SLinus Torvalds goto out_release; 24721da177e4SLinus Torvalds new_dentry = lookup_create(&nd, 0); 24731da177e4SLinus Torvalds error = PTR_ERR(new_dentry); 24746902d925SDave Hansen if (IS_ERR(new_dentry)) 24756902d925SDave Hansen goto out_unlock; 247675c3f29dSDave Hansen error = mnt_want_write(nd.path.mnt); 247775c3f29dSDave Hansen if (error) 247875c3f29dSDave Hansen goto out_dput; 2479be6d3e56SKentaro Takeda error = security_path_link(old_path.dentry, &nd.path, new_dentry); 2480be6d3e56SKentaro Takeda if (error) 2481be6d3e56SKentaro Takeda goto out_drop_write; 24822d8f3038SAl Viro error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); 2483be6d3e56SKentaro Takeda out_drop_write: 248475c3f29dSDave Hansen mnt_drop_write(nd.path.mnt); 248575c3f29dSDave Hansen out_dput: 24861da177e4SLinus Torvalds dput(new_dentry); 24876902d925SDave Hansen out_unlock: 24884ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 24891da177e4SLinus Torvalds out_release: 24901d957f9bSJan Blunck path_put(&nd.path); 24912ad94ae6SAl Viro putname(to); 24921da177e4SLinus Torvalds out: 24932d8f3038SAl Viro path_put(&old_path); 24941da177e4SLinus Torvalds 24951da177e4SLinus Torvalds return error; 24961da177e4SLinus Torvalds } 24971da177e4SLinus Torvalds 24983480b257SHeiko Carstens SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) 24995590ff0dSUlrich Drepper { 2500c04030e1SUlrich Drepper return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); 25015590ff0dSUlrich Drepper } 25025590ff0dSUlrich Drepper 25031da177e4SLinus Torvalds /* 25041da177e4SLinus Torvalds * The worst of all namespace operations - renaming directory. "Perverted" 25051da177e4SLinus Torvalds * doesn't even start to describe it. Somebody in UCB had a heck of a trip... 25061da177e4SLinus Torvalds * Problems: 25071da177e4SLinus Torvalds * a) we can get into loop creation. Check is done in is_subdir(). 25081da177e4SLinus Torvalds * b) race potential - two innocent renames can create a loop together. 25091da177e4SLinus Torvalds * That's where 4.4 screws up. Current fix: serialization on 2510a11f3a05SArjan van de Ven * sb->s_vfs_rename_mutex. We might be more accurate, but that's another 25111da177e4SLinus Torvalds * story. 25121da177e4SLinus Torvalds * c) we have to lock _three_ objects - parents and victim (if it exists). 25131b1dcc1bSJes Sorensen * And that - after we got ->i_mutex on parents (until then we don't know 25141da177e4SLinus Torvalds * whether the target exists). Solution: try to be smart with locking 25151da177e4SLinus Torvalds * order for inodes. We rely on the fact that tree topology may change 2516a11f3a05SArjan van de Ven * only under ->s_vfs_rename_mutex _and_ that parent of the object we 25171da177e4SLinus Torvalds * move will be locked. Thus we can rank directories by the tree 25181da177e4SLinus Torvalds * (ancestors first) and rank all non-directories after them. 25191da177e4SLinus Torvalds * That works since everybody except rename does "lock parent, lookup, 2520a11f3a05SArjan van de Ven * lock child" and rename is under ->s_vfs_rename_mutex. 25211da177e4SLinus Torvalds * HOWEVER, it relies on the assumption that any object with ->lookup() 25221da177e4SLinus Torvalds * has no more than 1 dentry. If "hybrid" objects will ever appear, 25231da177e4SLinus Torvalds * we'd better make sure that there's no link(2) for them. 25241da177e4SLinus Torvalds * d) some filesystems don't support opened-but-unlinked directories, 25251da177e4SLinus Torvalds * either because of layout or because they are not ready to deal with 25261da177e4SLinus Torvalds * all cases correctly. The latter will be fixed (taking this sort of 25271da177e4SLinus Torvalds * stuff into VFS), but the former is not going away. Solution: the same 25281da177e4SLinus Torvalds * trick as in rmdir(). 25291da177e4SLinus Torvalds * e) conversion from fhandle to dentry may come in the wrong moment - when 25301b1dcc1bSJes Sorensen * we are removing the target. Solution: we will have to grab ->i_mutex 25311da177e4SLinus Torvalds * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on 25321b1dcc1bSJes Sorensen * ->i_mutex on parents, which works but leads to some truely excessive 25331da177e4SLinus Torvalds * locking]. 25341da177e4SLinus Torvalds */ 253575c96f85SAdrian Bunk static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, 25361da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 25371da177e4SLinus Torvalds { 25381da177e4SLinus Torvalds int error = 0; 25391da177e4SLinus Torvalds struct inode *target; 25401da177e4SLinus Torvalds 25411da177e4SLinus Torvalds /* 25421da177e4SLinus Torvalds * If we are going to change the parent - check write permissions, 25431da177e4SLinus Torvalds * we'll need to flip '..'. 25441da177e4SLinus Torvalds */ 25451da177e4SLinus Torvalds if (new_dir != old_dir) { 2546f419a2e3SAl Viro error = inode_permission(old_dentry->d_inode, MAY_WRITE); 25471da177e4SLinus Torvalds if (error) 25481da177e4SLinus Torvalds return error; 25491da177e4SLinus Torvalds } 25501da177e4SLinus Torvalds 25511da177e4SLinus Torvalds error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); 25521da177e4SLinus Torvalds if (error) 25531da177e4SLinus Torvalds return error; 25541da177e4SLinus Torvalds 25551da177e4SLinus Torvalds target = new_dentry->d_inode; 25561da177e4SLinus Torvalds if (target) { 25571b1dcc1bSJes Sorensen mutex_lock(&target->i_mutex); 25581da177e4SLinus Torvalds dentry_unhash(new_dentry); 25591da177e4SLinus Torvalds } 25601da177e4SLinus Torvalds if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) 25611da177e4SLinus Torvalds error = -EBUSY; 25621da177e4SLinus Torvalds else 25631da177e4SLinus Torvalds error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); 25641da177e4SLinus Torvalds if (target) { 25651da177e4SLinus Torvalds if (!error) 25661da177e4SLinus Torvalds target->i_flags |= S_DEAD; 25671b1dcc1bSJes Sorensen mutex_unlock(&target->i_mutex); 25681da177e4SLinus Torvalds if (d_unhashed(new_dentry)) 25691da177e4SLinus Torvalds d_rehash(new_dentry); 25701da177e4SLinus Torvalds dput(new_dentry); 25711da177e4SLinus Torvalds } 2572e31e14ecSStephen Smalley if (!error) 2573349457ccSMark Fasheh if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) 25741da177e4SLinus Torvalds d_move(old_dentry,new_dentry); 25751da177e4SLinus Torvalds return error; 25761da177e4SLinus Torvalds } 25771da177e4SLinus Torvalds 257875c96f85SAdrian Bunk static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, 25791da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 25801da177e4SLinus Torvalds { 25811da177e4SLinus Torvalds struct inode *target; 25821da177e4SLinus Torvalds int error; 25831da177e4SLinus Torvalds 25841da177e4SLinus Torvalds error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); 25851da177e4SLinus Torvalds if (error) 25861da177e4SLinus Torvalds return error; 25871da177e4SLinus Torvalds 25881da177e4SLinus Torvalds dget(new_dentry); 25891da177e4SLinus Torvalds target = new_dentry->d_inode; 25901da177e4SLinus Torvalds if (target) 25911b1dcc1bSJes Sorensen mutex_lock(&target->i_mutex); 25921da177e4SLinus Torvalds if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) 25931da177e4SLinus Torvalds error = -EBUSY; 25941da177e4SLinus Torvalds else 25951da177e4SLinus Torvalds error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); 25961da177e4SLinus Torvalds if (!error) { 2597349457ccSMark Fasheh if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) 25981da177e4SLinus Torvalds d_move(old_dentry, new_dentry); 25991da177e4SLinus Torvalds } 26001da177e4SLinus Torvalds if (target) 26011b1dcc1bSJes Sorensen mutex_unlock(&target->i_mutex); 26021da177e4SLinus Torvalds dput(new_dentry); 26031da177e4SLinus Torvalds return error; 26041da177e4SLinus Torvalds } 26051da177e4SLinus Torvalds 26061da177e4SLinus Torvalds int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, 26071da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 26081da177e4SLinus Torvalds { 26091da177e4SLinus Torvalds int error; 26101da177e4SLinus Torvalds int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); 26110eeca283SRobert Love const char *old_name; 26121da177e4SLinus Torvalds 26131da177e4SLinus Torvalds if (old_dentry->d_inode == new_dentry->d_inode) 26141da177e4SLinus Torvalds return 0; 26151da177e4SLinus Torvalds 26161da177e4SLinus Torvalds error = may_delete(old_dir, old_dentry, is_dir); 26171da177e4SLinus Torvalds if (error) 26181da177e4SLinus Torvalds return error; 26191da177e4SLinus Torvalds 26201da177e4SLinus Torvalds if (!new_dentry->d_inode) 2621a95164d9SMiklos Szeredi error = may_create(new_dir, new_dentry); 26221da177e4SLinus Torvalds else 26231da177e4SLinus Torvalds error = may_delete(new_dir, new_dentry, is_dir); 26241da177e4SLinus Torvalds if (error) 26251da177e4SLinus Torvalds return error; 26261da177e4SLinus Torvalds 2627acfa4380SAl Viro if (!old_dir->i_op->rename) 26281da177e4SLinus Torvalds return -EPERM; 26291da177e4SLinus Torvalds 26309e3509e2SJan Kara vfs_dq_init(old_dir); 26319e3509e2SJan Kara vfs_dq_init(new_dir); 26321da177e4SLinus Torvalds 26330eeca283SRobert Love old_name = fsnotify_oldname_init(old_dentry->d_name.name); 26340eeca283SRobert Love 26351da177e4SLinus Torvalds if (is_dir) 26361da177e4SLinus Torvalds error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); 26371da177e4SLinus Torvalds else 26381da177e4SLinus Torvalds error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); 26391da177e4SLinus Torvalds if (!error) { 26400eeca283SRobert Love const char *new_name = old_dentry->d_name.name; 264189204c40SJohn McCutchan fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir, 26425a190ae6SAl Viro new_dentry->d_inode, old_dentry); 26431da177e4SLinus Torvalds } 26440eeca283SRobert Love fsnotify_oldname_free(old_name); 26450eeca283SRobert Love 26461da177e4SLinus Torvalds return error; 26471da177e4SLinus Torvalds } 26481da177e4SLinus Torvalds 26492e4d0924SHeiko Carstens SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, 26502e4d0924SHeiko Carstens int, newdfd, const char __user *, newname) 26511da177e4SLinus Torvalds { 26521da177e4SLinus Torvalds struct dentry *old_dir, *new_dir; 26531da177e4SLinus Torvalds struct dentry *old_dentry, *new_dentry; 26541da177e4SLinus Torvalds struct dentry *trap; 26551da177e4SLinus Torvalds struct nameidata oldnd, newnd; 26562ad94ae6SAl Viro char *from; 26572ad94ae6SAl Viro char *to; 26582ad94ae6SAl Viro int error; 26591da177e4SLinus Torvalds 26602ad94ae6SAl Viro error = user_path_parent(olddfd, oldname, &oldnd, &from); 26611da177e4SLinus Torvalds if (error) 26621da177e4SLinus Torvalds goto exit; 26631da177e4SLinus Torvalds 26642ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &newnd, &to); 26651da177e4SLinus Torvalds if (error) 26661da177e4SLinus Torvalds goto exit1; 26671da177e4SLinus Torvalds 26681da177e4SLinus Torvalds error = -EXDEV; 26694ac91378SJan Blunck if (oldnd.path.mnt != newnd.path.mnt) 26701da177e4SLinus Torvalds goto exit2; 26711da177e4SLinus Torvalds 26724ac91378SJan Blunck old_dir = oldnd.path.dentry; 26731da177e4SLinus Torvalds error = -EBUSY; 26741da177e4SLinus Torvalds if (oldnd.last_type != LAST_NORM) 26751da177e4SLinus Torvalds goto exit2; 26761da177e4SLinus Torvalds 26774ac91378SJan Blunck new_dir = newnd.path.dentry; 26781da177e4SLinus Torvalds if (newnd.last_type != LAST_NORM) 26791da177e4SLinus Torvalds goto exit2; 26801da177e4SLinus Torvalds 26810612d9fbSOGAWA Hirofumi oldnd.flags &= ~LOOKUP_PARENT; 26820612d9fbSOGAWA Hirofumi newnd.flags &= ~LOOKUP_PARENT; 26834e9ed2f8SOGAWA Hirofumi newnd.flags |= LOOKUP_RENAME_TARGET; 26840612d9fbSOGAWA Hirofumi 26851da177e4SLinus Torvalds trap = lock_rename(new_dir, old_dir); 26861da177e4SLinus Torvalds 268749705b77SChristoph Hellwig old_dentry = lookup_hash(&oldnd); 26881da177e4SLinus Torvalds error = PTR_ERR(old_dentry); 26891da177e4SLinus Torvalds if (IS_ERR(old_dentry)) 26901da177e4SLinus Torvalds goto exit3; 26911da177e4SLinus Torvalds /* source must exist */ 26921da177e4SLinus Torvalds error = -ENOENT; 26931da177e4SLinus Torvalds if (!old_dentry->d_inode) 26941da177e4SLinus Torvalds goto exit4; 26951da177e4SLinus Torvalds /* unless the source is a directory trailing slashes give -ENOTDIR */ 26961da177e4SLinus Torvalds if (!S_ISDIR(old_dentry->d_inode->i_mode)) { 26971da177e4SLinus Torvalds error = -ENOTDIR; 26981da177e4SLinus Torvalds if (oldnd.last.name[oldnd.last.len]) 26991da177e4SLinus Torvalds goto exit4; 27001da177e4SLinus Torvalds if (newnd.last.name[newnd.last.len]) 27011da177e4SLinus Torvalds goto exit4; 27021da177e4SLinus Torvalds } 27031da177e4SLinus Torvalds /* source should not be ancestor of target */ 27041da177e4SLinus Torvalds error = -EINVAL; 27051da177e4SLinus Torvalds if (old_dentry == trap) 27061da177e4SLinus Torvalds goto exit4; 270749705b77SChristoph Hellwig new_dentry = lookup_hash(&newnd); 27081da177e4SLinus Torvalds error = PTR_ERR(new_dentry); 27091da177e4SLinus Torvalds if (IS_ERR(new_dentry)) 27101da177e4SLinus Torvalds goto exit4; 27111da177e4SLinus Torvalds /* target should not be an ancestor of source */ 27121da177e4SLinus Torvalds error = -ENOTEMPTY; 27131da177e4SLinus Torvalds if (new_dentry == trap) 27141da177e4SLinus Torvalds goto exit5; 27151da177e4SLinus Torvalds 27169079b1ebSDave Hansen error = mnt_want_write(oldnd.path.mnt); 27179079b1ebSDave Hansen if (error) 27189079b1ebSDave Hansen goto exit5; 2719be6d3e56SKentaro Takeda error = security_path_rename(&oldnd.path, old_dentry, 2720be6d3e56SKentaro Takeda &newnd.path, new_dentry); 2721be6d3e56SKentaro Takeda if (error) 2722be6d3e56SKentaro Takeda goto exit6; 27231da177e4SLinus Torvalds error = vfs_rename(old_dir->d_inode, old_dentry, 27241da177e4SLinus Torvalds new_dir->d_inode, new_dentry); 2725be6d3e56SKentaro Takeda exit6: 27269079b1ebSDave Hansen mnt_drop_write(oldnd.path.mnt); 27271da177e4SLinus Torvalds exit5: 27281da177e4SLinus Torvalds dput(new_dentry); 27291da177e4SLinus Torvalds exit4: 27301da177e4SLinus Torvalds dput(old_dentry); 27311da177e4SLinus Torvalds exit3: 27321da177e4SLinus Torvalds unlock_rename(new_dir, old_dir); 27331da177e4SLinus Torvalds exit2: 27341d957f9bSJan Blunck path_put(&newnd.path); 27352ad94ae6SAl Viro putname(to); 27361da177e4SLinus Torvalds exit1: 27371d957f9bSJan Blunck path_put(&oldnd.path); 27381da177e4SLinus Torvalds putname(from); 27392ad94ae6SAl Viro exit: 27401da177e4SLinus Torvalds return error; 27411da177e4SLinus Torvalds } 27421da177e4SLinus Torvalds 2743a26eab24SHeiko Carstens SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) 27445590ff0dSUlrich Drepper { 27455590ff0dSUlrich Drepper return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); 27465590ff0dSUlrich Drepper } 27475590ff0dSUlrich Drepper 27481da177e4SLinus Torvalds int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) 27491da177e4SLinus Torvalds { 27501da177e4SLinus Torvalds int len; 27511da177e4SLinus Torvalds 27521da177e4SLinus Torvalds len = PTR_ERR(link); 27531da177e4SLinus Torvalds if (IS_ERR(link)) 27541da177e4SLinus Torvalds goto out; 27551da177e4SLinus Torvalds 27561da177e4SLinus Torvalds len = strlen(link); 27571da177e4SLinus Torvalds if (len > (unsigned) buflen) 27581da177e4SLinus Torvalds len = buflen; 27591da177e4SLinus Torvalds if (copy_to_user(buffer, link, len)) 27601da177e4SLinus Torvalds len = -EFAULT; 27611da177e4SLinus Torvalds out: 27621da177e4SLinus Torvalds return len; 27631da177e4SLinus Torvalds } 27641da177e4SLinus Torvalds 27651da177e4SLinus Torvalds /* 27661da177e4SLinus Torvalds * A helper for ->readlink(). This should be used *ONLY* for symlinks that 27671da177e4SLinus Torvalds * have ->follow_link() touching nd only in nd_set_link(). Using (or not 27681da177e4SLinus Torvalds * using) it for any given inode is up to filesystem. 27691da177e4SLinus Torvalds */ 27701da177e4SLinus Torvalds int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) 27711da177e4SLinus Torvalds { 27721da177e4SLinus Torvalds struct nameidata nd; 2773cc314eefSLinus Torvalds void *cookie; 2774694a1764SMarcin Slusarz int res; 2775cc314eefSLinus Torvalds 27761da177e4SLinus Torvalds nd.depth = 0; 2777cc314eefSLinus Torvalds cookie = dentry->d_inode->i_op->follow_link(dentry, &nd); 2778694a1764SMarcin Slusarz if (IS_ERR(cookie)) 2779694a1764SMarcin Slusarz return PTR_ERR(cookie); 2780694a1764SMarcin Slusarz 2781694a1764SMarcin Slusarz res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd)); 27821da177e4SLinus Torvalds if (dentry->d_inode->i_op->put_link) 2783cc314eefSLinus Torvalds dentry->d_inode->i_op->put_link(dentry, &nd, cookie); 2784694a1764SMarcin Slusarz return res; 27851da177e4SLinus Torvalds } 27861da177e4SLinus Torvalds 27871da177e4SLinus Torvalds int vfs_follow_link(struct nameidata *nd, const char *link) 27881da177e4SLinus Torvalds { 27891da177e4SLinus Torvalds return __vfs_follow_link(nd, link); 27901da177e4SLinus Torvalds } 27911da177e4SLinus Torvalds 27921da177e4SLinus Torvalds /* get the link contents into pagecache */ 27931da177e4SLinus Torvalds static char *page_getlink(struct dentry * dentry, struct page **ppage) 27941da177e4SLinus Torvalds { 2795ebd09abbSDuane Griffin char *kaddr; 27961da177e4SLinus Torvalds struct page *page; 27971da177e4SLinus Torvalds struct address_space *mapping = dentry->d_inode->i_mapping; 2798090d2b18SPekka Enberg page = read_mapping_page(mapping, 0, NULL); 27991da177e4SLinus Torvalds if (IS_ERR(page)) 28006fe6900eSNick Piggin return (char*)page; 28011da177e4SLinus Torvalds *ppage = page; 2802ebd09abbSDuane Griffin kaddr = kmap(page); 2803ebd09abbSDuane Griffin nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); 2804ebd09abbSDuane Griffin return kaddr; 28051da177e4SLinus Torvalds } 28061da177e4SLinus Torvalds 28071da177e4SLinus Torvalds int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) 28081da177e4SLinus Torvalds { 28091da177e4SLinus Torvalds struct page *page = NULL; 28101da177e4SLinus Torvalds char *s = page_getlink(dentry, &page); 28111da177e4SLinus Torvalds int res = vfs_readlink(dentry,buffer,buflen,s); 28121da177e4SLinus Torvalds if (page) { 28131da177e4SLinus Torvalds kunmap(page); 28141da177e4SLinus Torvalds page_cache_release(page); 28151da177e4SLinus Torvalds } 28161da177e4SLinus Torvalds return res; 28171da177e4SLinus Torvalds } 28181da177e4SLinus Torvalds 2819cc314eefSLinus Torvalds void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd) 28201da177e4SLinus Torvalds { 2821cc314eefSLinus Torvalds struct page *page = NULL; 28221da177e4SLinus Torvalds nd_set_link(nd, page_getlink(dentry, &page)); 2823cc314eefSLinus Torvalds return page; 28241da177e4SLinus Torvalds } 28251da177e4SLinus Torvalds 2826cc314eefSLinus Torvalds void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 28271da177e4SLinus Torvalds { 2828cc314eefSLinus Torvalds struct page *page = cookie; 2829cc314eefSLinus Torvalds 2830cc314eefSLinus Torvalds if (page) { 28311da177e4SLinus Torvalds kunmap(page); 28321da177e4SLinus Torvalds page_cache_release(page); 28331da177e4SLinus Torvalds } 28341da177e4SLinus Torvalds } 28351da177e4SLinus Torvalds 283654566b2cSNick Piggin /* 283754566b2cSNick Piggin * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS 283854566b2cSNick Piggin */ 283954566b2cSNick Piggin int __page_symlink(struct inode *inode, const char *symname, int len, int nofs) 28401da177e4SLinus Torvalds { 28411da177e4SLinus Torvalds struct address_space *mapping = inode->i_mapping; 28420adb25d2SKirill Korotaev struct page *page; 2843afddba49SNick Piggin void *fsdata; 2844beb497abSDmitriy Monakhov int err; 28451da177e4SLinus Torvalds char *kaddr; 284654566b2cSNick Piggin unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE; 284754566b2cSNick Piggin if (nofs) 284854566b2cSNick Piggin flags |= AOP_FLAG_NOFS; 28491da177e4SLinus Torvalds 28507e53cac4SNeilBrown retry: 2851afddba49SNick Piggin err = pagecache_write_begin(NULL, mapping, 0, len-1, 285254566b2cSNick Piggin flags, &page, &fsdata); 28531da177e4SLinus Torvalds if (err) 2854afddba49SNick Piggin goto fail; 2855afddba49SNick Piggin 28561da177e4SLinus Torvalds kaddr = kmap_atomic(page, KM_USER0); 28571da177e4SLinus Torvalds memcpy(kaddr, symname, len-1); 28581da177e4SLinus Torvalds kunmap_atomic(kaddr, KM_USER0); 2859afddba49SNick Piggin 2860afddba49SNick Piggin err = pagecache_write_end(NULL, mapping, 0, len-1, len-1, 2861afddba49SNick Piggin page, fsdata); 28621da177e4SLinus Torvalds if (err < 0) 28631da177e4SLinus Torvalds goto fail; 2864afddba49SNick Piggin if (err < len-1) 2865afddba49SNick Piggin goto retry; 2866afddba49SNick Piggin 28671da177e4SLinus Torvalds mark_inode_dirty(inode); 28681da177e4SLinus Torvalds return 0; 28691da177e4SLinus Torvalds fail: 28701da177e4SLinus Torvalds return err; 28711da177e4SLinus Torvalds } 28721da177e4SLinus Torvalds 28730adb25d2SKirill Korotaev int page_symlink(struct inode *inode, const char *symname, int len) 28740adb25d2SKirill Korotaev { 28750adb25d2SKirill Korotaev return __page_symlink(inode, symname, len, 287654566b2cSNick Piggin !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS)); 28770adb25d2SKirill Korotaev } 28780adb25d2SKirill Korotaev 287992e1d5beSArjan van de Ven const struct inode_operations page_symlink_inode_operations = { 28801da177e4SLinus Torvalds .readlink = generic_readlink, 28811da177e4SLinus Torvalds .follow_link = page_follow_link_light, 28821da177e4SLinus Torvalds .put_link = page_put_link, 28831da177e4SLinus Torvalds }; 28841da177e4SLinus Torvalds 28852d8f3038SAl Viro EXPORT_SYMBOL(user_path_at); 28861da177e4SLinus Torvalds EXPORT_SYMBOL(follow_down); 28871da177e4SLinus Torvalds EXPORT_SYMBOL(follow_up); 28881da177e4SLinus Torvalds EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ 28891da177e4SLinus Torvalds EXPORT_SYMBOL(getname); 28901da177e4SLinus Torvalds EXPORT_SYMBOL(lock_rename); 28911da177e4SLinus Torvalds EXPORT_SYMBOL(lookup_one_len); 28921da177e4SLinus Torvalds EXPORT_SYMBOL(page_follow_link_light); 28931da177e4SLinus Torvalds EXPORT_SYMBOL(page_put_link); 28941da177e4SLinus Torvalds EXPORT_SYMBOL(page_readlink); 28950adb25d2SKirill Korotaev EXPORT_SYMBOL(__page_symlink); 28961da177e4SLinus Torvalds EXPORT_SYMBOL(page_symlink); 28971da177e4SLinus Torvalds EXPORT_SYMBOL(page_symlink_inode_operations); 28981da177e4SLinus Torvalds EXPORT_SYMBOL(path_lookup); 2899d1811465SAl Viro EXPORT_SYMBOL(kern_path); 290016f18200SJosef 'Jeff' Sipek EXPORT_SYMBOL(vfs_path_lookup); 2901f419a2e3SAl Viro EXPORT_SYMBOL(inode_permission); 29028c744fb8SChristoph Hellwig EXPORT_SYMBOL(file_permission); 29031da177e4SLinus Torvalds EXPORT_SYMBOL(unlock_rename); 29041da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_create); 29051da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_follow_link); 29061da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_link); 29071da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_mkdir); 29081da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_mknod); 29091da177e4SLinus Torvalds EXPORT_SYMBOL(generic_permission); 29101da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_readlink); 29111da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_rename); 29121da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_rmdir); 29131da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_symlink); 29141da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_unlink); 29151da177e4SLinus Torvalds EXPORT_SYMBOL(dentry_unhash); 29161da177e4SLinus Torvalds EXPORT_SYMBOL(generic_readlink); 2917