177b14db5SEric W. Biederman /* 277b14db5SEric W. Biederman * /proc/sys support 377b14db5SEric W. Biederman */ 41e0edd3fSAlexey Dobriyan #include <linux/init.h> 577b14db5SEric W. Biederman #include <linux/sysctl.h> 6f1ecf068SLucas De Marchi #include <linux/poll.h> 777b14db5SEric W. Biederman #include <linux/proc_fs.h> 877b14db5SEric W. Biederman #include <linux/security.h> 934286d66SNick Piggin #include <linux/namei.h> 101f87f0b5SEric W. Biederman #include <linux/module.h> 1177b14db5SEric W. Biederman #include "internal.h" 1277b14db5SEric W. Biederman 13d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 1477b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 1503a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 169043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 179043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 1877b14db5SEric W. Biederman 19f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 20f1ecf068SLucas De Marchi { 21f1ecf068SLucas De Marchi if (!poll) 22f1ecf068SLucas De Marchi return; 23f1ecf068SLucas De Marchi 24f1ecf068SLucas De Marchi atomic_inc(&poll->event); 25f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 26f1ecf068SLucas De Marchi } 27f1ecf068SLucas De Marchi 281f87f0b5SEric W. Biederman static struct ctl_table root_table[1]; 291f87f0b5SEric W. Biederman static struct ctl_table_root sysctl_table_root; 301f87f0b5SEric W. Biederman static struct ctl_table_header root_table_header = { 311f87f0b5SEric W. Biederman {{.count = 1, 321f87f0b5SEric W. Biederman .ctl_table = root_table, 331f87f0b5SEric W. Biederman .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}}, 341f87f0b5SEric W. Biederman .root = &sysctl_table_root, 351f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 361f87f0b5SEric W. Biederman }; 371f87f0b5SEric W. Biederman static struct ctl_table_root sysctl_table_root = { 381f87f0b5SEric W. Biederman .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list), 391f87f0b5SEric W. Biederman .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry), 401f87f0b5SEric W. Biederman }; 411f87f0b5SEric W. Biederman 421f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 431f87f0b5SEric W. Biederman 441f87f0b5SEric W. Biederman /* called under sysctl_lock */ 451f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 461f87f0b5SEric W. Biederman { 471f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 481f87f0b5SEric W. Biederman return 0; 491f87f0b5SEric W. Biederman p->used++; 501f87f0b5SEric W. Biederman return 1; 511f87f0b5SEric W. Biederman } 521f87f0b5SEric W. Biederman 531f87f0b5SEric W. Biederman /* called under sysctl_lock */ 541f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 551f87f0b5SEric W. Biederman { 561f87f0b5SEric W. Biederman if (!--p->used) 571f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 581f87f0b5SEric W. Biederman complete(p->unregistering); 591f87f0b5SEric W. Biederman } 601f87f0b5SEric W. Biederman 611f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 621f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 631f87f0b5SEric W. Biederman { 641f87f0b5SEric W. Biederman /* 651f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 661f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 671f87f0b5SEric W. Biederman */ 681f87f0b5SEric W. Biederman if (unlikely(p->used)) { 691f87f0b5SEric W. Biederman struct completion wait; 701f87f0b5SEric W. Biederman init_completion(&wait); 711f87f0b5SEric W. Biederman p->unregistering = &wait; 721f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 731f87f0b5SEric W. Biederman wait_for_completion(&wait); 741f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 751f87f0b5SEric W. Biederman } else { 761f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 771f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 781f87f0b5SEric W. Biederman } 791f87f0b5SEric W. Biederman /* 801f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 811f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 821f87f0b5SEric W. Biederman */ 831f87f0b5SEric W. Biederman list_del_init(&p->ctl_entry); 841f87f0b5SEric W. Biederman } 851f87f0b5SEric W. Biederman 861f87f0b5SEric W. Biederman static void sysctl_head_get(struct ctl_table_header *head) 871f87f0b5SEric W. Biederman { 881f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 891f87f0b5SEric W. Biederman head->count++; 901f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 911f87f0b5SEric W. Biederman } 921f87f0b5SEric W. Biederman 931f87f0b5SEric W. Biederman void sysctl_head_put(struct ctl_table_header *head) 941f87f0b5SEric W. Biederman { 951f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 961f87f0b5SEric W. Biederman if (!--head->count) 971f87f0b5SEric W. Biederman kfree_rcu(head, rcu); 981f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 991f87f0b5SEric W. Biederman } 1001f87f0b5SEric W. Biederman 1011f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 1021f87f0b5SEric W. Biederman { 1031f87f0b5SEric W. Biederman if (!head) 1041f87f0b5SEric W. Biederman BUG(); 1051f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1061f87f0b5SEric W. Biederman if (!use_table(head)) 1071f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 1081f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 1091f87f0b5SEric W. Biederman return head; 1101f87f0b5SEric W. Biederman } 1111f87f0b5SEric W. Biederman 1121f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 1131f87f0b5SEric W. Biederman { 1141f87f0b5SEric W. Biederman if (!head) 1151f87f0b5SEric W. Biederman return; 1161f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1171f87f0b5SEric W. Biederman unuse_table(head); 1181f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 1191f87f0b5SEric W. Biederman } 1201f87f0b5SEric W. Biederman 1211f87f0b5SEric W. Biederman static struct ctl_table_set * 1221f87f0b5SEric W. Biederman lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces) 1231f87f0b5SEric W. Biederman { 1241f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 1251f87f0b5SEric W. Biederman if (root->lookup) 1261f87f0b5SEric W. Biederman set = root->lookup(root, namespaces); 1271f87f0b5SEric W. Biederman return set; 1281f87f0b5SEric W. Biederman } 1291f87f0b5SEric W. Biederman 1301f87f0b5SEric W. Biederman static struct list_head * 1311f87f0b5SEric W. Biederman lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces) 1321f87f0b5SEric W. Biederman { 1331f87f0b5SEric W. Biederman struct ctl_table_set *set = lookup_header_set(root, namespaces); 1341f87f0b5SEric W. Biederman return &set->list; 1351f87f0b5SEric W. Biederman } 1361f87f0b5SEric W. Biederman 1371f87f0b5SEric W. Biederman static struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces, 1381f87f0b5SEric W. Biederman struct ctl_table_header *prev) 1391f87f0b5SEric W. Biederman { 1401f87f0b5SEric W. Biederman struct ctl_table_root *root; 1411f87f0b5SEric W. Biederman struct list_head *header_list; 1421f87f0b5SEric W. Biederman struct ctl_table_header *head; 1431f87f0b5SEric W. Biederman struct list_head *tmp; 1441f87f0b5SEric W. Biederman 1451f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1461f87f0b5SEric W. Biederman if (prev) { 1471f87f0b5SEric W. Biederman head = prev; 1481f87f0b5SEric W. Biederman tmp = &prev->ctl_entry; 1491f87f0b5SEric W. Biederman unuse_table(prev); 1501f87f0b5SEric W. Biederman goto next; 1511f87f0b5SEric W. Biederman } 1521f87f0b5SEric W. Biederman tmp = &root_table_header.ctl_entry; 1531f87f0b5SEric W. Biederman for (;;) { 1541f87f0b5SEric W. Biederman head = list_entry(tmp, struct ctl_table_header, ctl_entry); 1551f87f0b5SEric W. Biederman 1561f87f0b5SEric W. Biederman if (!use_table(head)) 1571f87f0b5SEric W. Biederman goto next; 1581f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 1591f87f0b5SEric W. Biederman return head; 1601f87f0b5SEric W. Biederman next: 1611f87f0b5SEric W. Biederman root = head->root; 1621f87f0b5SEric W. Biederman tmp = tmp->next; 1631f87f0b5SEric W. Biederman header_list = lookup_header_list(root, namespaces); 1641f87f0b5SEric W. Biederman if (tmp != header_list) 1651f87f0b5SEric W. Biederman continue; 1661f87f0b5SEric W. Biederman 1671f87f0b5SEric W. Biederman do { 1681f87f0b5SEric W. Biederman root = list_entry(root->root_list.next, 1691f87f0b5SEric W. Biederman struct ctl_table_root, root_list); 1701f87f0b5SEric W. Biederman if (root == &sysctl_table_root) 1711f87f0b5SEric W. Biederman goto out; 1721f87f0b5SEric W. Biederman header_list = lookup_header_list(root, namespaces); 1731f87f0b5SEric W. Biederman } while (list_empty(header_list)); 1741f87f0b5SEric W. Biederman tmp = header_list->next; 1751f87f0b5SEric W. Biederman } 1761f87f0b5SEric W. Biederman out: 1771f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 1781f87f0b5SEric W. Biederman return NULL; 1791f87f0b5SEric W. Biederman } 1801f87f0b5SEric W. Biederman 1811f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev) 1821f87f0b5SEric W. Biederman { 1831f87f0b5SEric W. Biederman return __sysctl_head_next(current->nsproxy, prev); 1841f87f0b5SEric W. Biederman } 1851f87f0b5SEric W. Biederman 1861f87f0b5SEric W. Biederman void register_sysctl_root(struct ctl_table_root *root) 1871f87f0b5SEric W. Biederman { 1881f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1891f87f0b5SEric W. Biederman list_add_tail(&root->root_list, &sysctl_table_root.root_list); 1901f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 1911f87f0b5SEric W. Biederman } 1921f87f0b5SEric W. Biederman 1931f87f0b5SEric W. Biederman /* 1941f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 1951f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 1961f87f0b5SEric W. Biederman */ 1971f87f0b5SEric W. Biederman 1981f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 1991f87f0b5SEric W. Biederman { 2001f87f0b5SEric W. Biederman if (!current_euid()) 2011f87f0b5SEric W. Biederman mode >>= 6; 2021f87f0b5SEric W. Biederman else if (in_egroup_p(0)) 2031f87f0b5SEric W. Biederman mode >>= 3; 2041f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 2051f87f0b5SEric W. Biederman return 0; 2061f87f0b5SEric W. Biederman return -EACCES; 2071f87f0b5SEric W. Biederman } 2081f87f0b5SEric W. Biederman 2091f87f0b5SEric W. Biederman static int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op) 2101f87f0b5SEric W. Biederman { 2111f87f0b5SEric W. Biederman int mode; 2121f87f0b5SEric W. Biederman 2131f87f0b5SEric W. Biederman if (root->permissions) 2141f87f0b5SEric W. Biederman mode = root->permissions(root, current->nsproxy, table); 2151f87f0b5SEric W. Biederman else 2161f87f0b5SEric W. Biederman mode = table->mode; 2171f87f0b5SEric W. Biederman 2181f87f0b5SEric W. Biederman return test_perm(mode, op); 2191f87f0b5SEric W. Biederman } 2201f87f0b5SEric W. Biederman 2211f87f0b5SEric W. Biederman static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table) 2221f87f0b5SEric W. Biederman { 2231f87f0b5SEric W. Biederman for (; table->procname; table++) { 2241f87f0b5SEric W. Biederman table->parent = parent; 2251f87f0b5SEric W. Biederman if (table->child) 2261f87f0b5SEric W. Biederman sysctl_set_parent(table, table->child); 2271f87f0b5SEric W. Biederman } 2281f87f0b5SEric W. Biederman } 2291f87f0b5SEric W. Biederman 2301f87f0b5SEric W. Biederman 2319043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 2329043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 23377b14db5SEric W. Biederman { 23477b14db5SEric W. Biederman struct inode *inode; 2359043476fSAl Viro struct proc_inode *ei; 23677b14db5SEric W. Biederman 2379043476fSAl Viro inode = new_inode(sb); 23877b14db5SEric W. Biederman if (!inode) 23977b14db5SEric W. Biederman goto out; 24077b14db5SEric W. Biederman 24185fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 24285fe4025SChristoph Hellwig 2439043476fSAl Viro sysctl_head_get(head); 24477b14db5SEric W. Biederman ei = PROC_I(inode); 2459043476fSAl Viro ei->sysctl = head; 2469043476fSAl Viro ei->sysctl_entry = table; 2479043476fSAl Viro 24877b14db5SEric W. Biederman inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 2499043476fSAl Viro inode->i_mode = table->mode; 2509043476fSAl Viro if (!table->child) { 2519043476fSAl Viro inode->i_mode |= S_IFREG; 25277b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 25377b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 2549043476fSAl Viro } else { 2559043476fSAl Viro inode->i_mode |= S_IFDIR; 2569043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 2579043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 2589043476fSAl Viro } 25977b14db5SEric W. Biederman out: 26077b14db5SEric W. Biederman return inode; 26177b14db5SEric W. Biederman } 26277b14db5SEric W. Biederman 2639043476fSAl Viro static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name) 26477b14db5SEric W. Biederman { 2652315ffa0SEric W. Biederman for ( ; p->procname; p++) { 26636885d7bSLucas De Marchi if (strlen(p->procname) != name->len) 26777b14db5SEric W. Biederman continue; 26877b14db5SEric W. Biederman 26936885d7bSLucas De Marchi if (memcmp(p->procname, name->name, name->len) != 0) 27077b14db5SEric W. Biederman continue; 27177b14db5SEric W. Biederman 27277b14db5SEric W. Biederman /* I have a match */ 2739043476fSAl Viro return p; 27477b14db5SEric W. Biederman } 27577b14db5SEric W. Biederman return NULL; 27677b14db5SEric W. Biederman } 27777b14db5SEric W. Biederman 27881324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 27977b14db5SEric W. Biederman { 2809043476fSAl Viro if (PROC_I(inode)->sysctl) 2819043476fSAl Viro return sysctl_head_grab(PROC_I(inode)->sysctl); 2829043476fSAl Viro else 2839043476fSAl Viro return sysctl_head_next(NULL); 28477b14db5SEric W. Biederman } 28577b14db5SEric W. Biederman 28677b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 28777b14db5SEric W. Biederman struct nameidata *nd) 28877b14db5SEric W. Biederman { 2899043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 2909043476fSAl Viro struct ctl_table *table = PROC_I(dir)->sysctl_entry; 2919043476fSAl Viro struct ctl_table_header *h = NULL; 2929043476fSAl Viro struct qstr *name = &dentry->d_name; 2939043476fSAl Viro struct ctl_table *p; 29477b14db5SEric W. Biederman struct inode *inode; 2959043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 29677b14db5SEric W. Biederman 2979043476fSAl Viro if (IS_ERR(head)) 2989043476fSAl Viro return ERR_CAST(head); 2999043476fSAl Viro 3009043476fSAl Viro if (table && !table->child) { 3019043476fSAl Viro WARN_ON(1); 3029043476fSAl Viro goto out; 3039043476fSAl Viro } 3049043476fSAl Viro 3059043476fSAl Viro table = table ? table->child : head->ctl_table; 3069043476fSAl Viro 3079043476fSAl Viro p = find_in_table(table, name); 3089043476fSAl Viro if (!p) { 3099043476fSAl Viro for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { 3109043476fSAl Viro if (h->attached_to != table) 3119043476fSAl Viro continue; 3129043476fSAl Viro p = find_in_table(h->attached_by, name); 3139043476fSAl Viro if (p) 3149043476fSAl Viro break; 3159043476fSAl Viro } 3169043476fSAl Viro } 3179043476fSAl Viro 3189043476fSAl Viro if (!p) 31977b14db5SEric W. Biederman goto out; 32077b14db5SEric W. Biederman 32177b14db5SEric W. Biederman err = ERR_PTR(-ENOMEM); 3229043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 3239043476fSAl Viro if (h) 3249043476fSAl Viro sysctl_head_finish(h); 3259043476fSAl Viro 32677b14db5SEric W. Biederman if (!inode) 32777b14db5SEric W. Biederman goto out; 32877b14db5SEric W. Biederman 32977b14db5SEric W. Biederman err = NULL; 330fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 33177b14db5SEric W. Biederman d_add(dentry, inode); 33277b14db5SEric W. Biederman 33377b14db5SEric W. Biederman out: 33477b14db5SEric W. Biederman sysctl_head_finish(head); 33577b14db5SEric W. Biederman return err; 33677b14db5SEric W. Biederman } 33777b14db5SEric W. Biederman 3387708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 3397708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 34077b14db5SEric W. Biederman { 3419043476fSAl Viro struct inode *inode = filp->f_path.dentry->d_inode; 3429043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 3439043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 3442a2da53bSDavid Howells ssize_t error; 3452a2da53bSDavid Howells size_t res; 34677b14db5SEric W. Biederman 3479043476fSAl Viro if (IS_ERR(head)) 3489043476fSAl Viro return PTR_ERR(head); 34977b14db5SEric W. Biederman 35077b14db5SEric W. Biederman /* 35177b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 35277b14db5SEric W. Biederman * and won't be until we finish. 35377b14db5SEric W. Biederman */ 35477b14db5SEric W. Biederman error = -EPERM; 355d7321cd6SPavel Emelyanov if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ)) 35677b14db5SEric W. Biederman goto out; 35777b14db5SEric W. Biederman 3589043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 3599043476fSAl Viro error = -EINVAL; 3609043476fSAl Viro if (!table->proc_handler) 3619043476fSAl Viro goto out; 3629043476fSAl Viro 36377b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 36477b14db5SEric W. Biederman res = count; 3658d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 36677b14db5SEric W. Biederman if (!error) 36777b14db5SEric W. Biederman error = res; 36877b14db5SEric W. Biederman out: 36977b14db5SEric W. Biederman sysctl_head_finish(head); 37077b14db5SEric W. Biederman 37177b14db5SEric W. Biederman return error; 37277b14db5SEric W. Biederman } 37377b14db5SEric W. Biederman 3747708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 3757708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 3767708bfb1SPavel Emelyanov { 3777708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 3787708bfb1SPavel Emelyanov } 3797708bfb1SPavel Emelyanov 38077b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 38177b14db5SEric W. Biederman size_t count, loff_t *ppos) 38277b14db5SEric W. Biederman { 3837708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 38477b14db5SEric W. Biederman } 38577b14db5SEric W. Biederman 386f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 387f1ecf068SLucas De Marchi { 388f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 389f1ecf068SLucas De Marchi 390f1ecf068SLucas De Marchi if (table->poll) 391f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 392f1ecf068SLucas De Marchi 393f1ecf068SLucas De Marchi return 0; 394f1ecf068SLucas De Marchi } 395f1ecf068SLucas De Marchi 396f1ecf068SLucas De Marchi static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) 397f1ecf068SLucas De Marchi { 398f1ecf068SLucas De Marchi struct inode *inode = filp->f_path.dentry->d_inode; 399f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 400f1ecf068SLucas De Marchi unsigned long event = (unsigned long)filp->private_data; 401f1ecf068SLucas De Marchi unsigned int ret = DEFAULT_POLLMASK; 402f1ecf068SLucas De Marchi 403f1ecf068SLucas De Marchi if (!table->proc_handler) 404f1ecf068SLucas De Marchi goto out; 405f1ecf068SLucas De Marchi 406f1ecf068SLucas De Marchi if (!table->poll) 407f1ecf068SLucas De Marchi goto out; 408f1ecf068SLucas De Marchi 409f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 410f1ecf068SLucas De Marchi 411f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 412f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 413f1ecf068SLucas De Marchi ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; 414f1ecf068SLucas De Marchi } 415f1ecf068SLucas De Marchi 416f1ecf068SLucas De Marchi out: 417f1ecf068SLucas De Marchi return ret; 418f1ecf068SLucas De Marchi } 41977b14db5SEric W. Biederman 42077b14db5SEric W. Biederman static int proc_sys_fill_cache(struct file *filp, void *dirent, 4219043476fSAl Viro filldir_t filldir, 4229043476fSAl Viro struct ctl_table_header *head, 4239043476fSAl Viro struct ctl_table *table) 42477b14db5SEric W. Biederman { 42577b14db5SEric W. Biederman struct dentry *child, *dir = filp->f_path.dentry; 42677b14db5SEric W. Biederman struct inode *inode; 42777b14db5SEric W. Biederman struct qstr qname; 42877b14db5SEric W. Biederman ino_t ino = 0; 42977b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 43077b14db5SEric W. Biederman 43177b14db5SEric W. Biederman qname.name = table->procname; 43277b14db5SEric W. Biederman qname.len = strlen(table->procname); 43377b14db5SEric W. Biederman qname.hash = full_name_hash(qname.name, qname.len); 43477b14db5SEric W. Biederman 43577b14db5SEric W. Biederman child = d_lookup(dir, &qname); 43677b14db5SEric W. Biederman if (!child) { 4379043476fSAl Viro child = d_alloc(dir, &qname); 4389043476fSAl Viro if (child) { 4399043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 4409043476fSAl Viro if (!inode) { 4419043476fSAl Viro dput(child); 4429043476fSAl Viro return -ENOMEM; 4439043476fSAl Viro } else { 444fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 4459043476fSAl Viro d_add(child, inode); 44677b14db5SEric W. Biederman } 4479043476fSAl Viro } else { 4489043476fSAl Viro return -ENOMEM; 44977b14db5SEric W. Biederman } 45077b14db5SEric W. Biederman } 45177b14db5SEric W. Biederman inode = child->d_inode; 45277b14db5SEric W. Biederman ino = inode->i_ino; 45377b14db5SEric W. Biederman type = inode->i_mode >> 12; 45477b14db5SEric W. Biederman dput(child); 4559043476fSAl Viro return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type); 4569043476fSAl Viro } 4579043476fSAl Viro 4589043476fSAl Viro static int scan(struct ctl_table_header *head, ctl_table *table, 4599043476fSAl Viro unsigned long *pos, struct file *file, 4609043476fSAl Viro void *dirent, filldir_t filldir) 4619043476fSAl Viro { 4629043476fSAl Viro 4632315ffa0SEric W. Biederman for (; table->procname; table++, (*pos)++) { 4649043476fSAl Viro int res; 4659043476fSAl Viro 4669043476fSAl Viro if (*pos < file->f_pos) 4679043476fSAl Viro continue; 4689043476fSAl Viro 4699043476fSAl Viro res = proc_sys_fill_cache(file, dirent, filldir, head, table); 4709043476fSAl Viro if (res) 4719043476fSAl Viro return res; 4729043476fSAl Viro 4739043476fSAl Viro file->f_pos = *pos + 1; 4749043476fSAl Viro } 4759043476fSAl Viro return 0; 47677b14db5SEric W. Biederman } 47777b14db5SEric W. Biederman 47877b14db5SEric W. Biederman static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir) 47977b14db5SEric W. Biederman { 4809043476fSAl Viro struct dentry *dentry = filp->f_path.dentry; 48177b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 4829043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 4839043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 4849043476fSAl Viro struct ctl_table_header *h = NULL; 48577b14db5SEric W. Biederman unsigned long pos; 4869043476fSAl Viro int ret = -EINVAL; 48777b14db5SEric W. Biederman 4889043476fSAl Viro if (IS_ERR(head)) 4899043476fSAl Viro return PTR_ERR(head); 4909043476fSAl Viro 4919043476fSAl Viro if (table && !table->child) { 4929043476fSAl Viro WARN_ON(1); 49377b14db5SEric W. Biederman goto out; 4949043476fSAl Viro } 4959043476fSAl Viro 4969043476fSAl Viro table = table ? table->child : head->ctl_table; 49777b14db5SEric W. Biederman 49877b14db5SEric W. Biederman ret = 0; 49977b14db5SEric W. Biederman /* Avoid a switch here: arm builds fail with missing __cmpdi2 */ 50077b14db5SEric W. Biederman if (filp->f_pos == 0) { 50177b14db5SEric W. Biederman if (filldir(dirent, ".", 1, filp->f_pos, 50277b14db5SEric W. Biederman inode->i_ino, DT_DIR) < 0) 50377b14db5SEric W. Biederman goto out; 50477b14db5SEric W. Biederman filp->f_pos++; 50577b14db5SEric W. Biederman } 50677b14db5SEric W. Biederman if (filp->f_pos == 1) { 50777b14db5SEric W. Biederman if (filldir(dirent, "..", 2, filp->f_pos, 50877b14db5SEric W. Biederman parent_ino(dentry), DT_DIR) < 0) 50977b14db5SEric W. Biederman goto out; 51077b14db5SEric W. Biederman filp->f_pos++; 51177b14db5SEric W. Biederman } 51277b14db5SEric W. Biederman pos = 2; 51377b14db5SEric W. Biederman 5149043476fSAl Viro ret = scan(head, table, &pos, filp, dirent, filldir); 5159043476fSAl Viro if (ret) 51677b14db5SEric W. Biederman goto out; 5179043476fSAl Viro 5189043476fSAl Viro for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { 5199043476fSAl Viro if (h->attached_to != table) 5209043476fSAl Viro continue; 5219043476fSAl Viro ret = scan(h, h->attached_by, &pos, filp, dirent, filldir); 5229043476fSAl Viro if (ret) { 5239043476fSAl Viro sysctl_head_finish(h); 5249043476fSAl Viro break; 52577b14db5SEric W. Biederman } 52677b14db5SEric W. Biederman } 52777b14db5SEric W. Biederman ret = 1; 52877b14db5SEric W. Biederman out: 52977b14db5SEric W. Biederman sysctl_head_finish(head); 53077b14db5SEric W. Biederman return ret; 53177b14db5SEric W. Biederman } 53277b14db5SEric W. Biederman 53310556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 53477b14db5SEric W. Biederman { 53577b14db5SEric W. Biederman /* 53677b14db5SEric W. Biederman * sysctl entries that are not writeable, 53777b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 53877b14db5SEric W. Biederman */ 539f696a365SMiklos Szeredi struct ctl_table_header *head; 540f696a365SMiklos Szeredi struct ctl_table *table; 54177b14db5SEric W. Biederman int error; 54277b14db5SEric W. Biederman 543f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 544f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 545f696a365SMiklos Szeredi return -EACCES; 546f696a365SMiklos Szeredi 547f696a365SMiklos Szeredi head = grab_header(inode); 5489043476fSAl Viro if (IS_ERR(head)) 5499043476fSAl Viro return PTR_ERR(head); 55077b14db5SEric W. Biederman 551f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 5529043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 5539043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 5549043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 5551fc0f78cSAl Viro error = sysctl_perm(head->root, table, mask & ~MAY_NOT_BLOCK); 5569043476fSAl Viro 55777b14db5SEric W. Biederman sysctl_head_finish(head); 55877b14db5SEric W. Biederman return error; 55977b14db5SEric W. Biederman } 56077b14db5SEric W. Biederman 56177b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 56277b14db5SEric W. Biederman { 56377b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 56477b14db5SEric W. Biederman int error; 56577b14db5SEric W. Biederman 56677b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 56777b14db5SEric W. Biederman return -EPERM; 56877b14db5SEric W. Biederman 56977b14db5SEric W. Biederman error = inode_change_ok(inode, attr); 5701025774cSChristoph Hellwig if (error) 57177b14db5SEric W. Biederman return error; 5721025774cSChristoph Hellwig 5731025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 5741025774cSChristoph Hellwig attr->ia_size != i_size_read(inode)) { 5751025774cSChristoph Hellwig error = vmtruncate(inode, attr->ia_size); 5761025774cSChristoph Hellwig if (error) 5771025774cSChristoph Hellwig return error; 5781025774cSChristoph Hellwig } 5791025774cSChristoph Hellwig 5801025774cSChristoph Hellwig setattr_copy(inode, attr); 5811025774cSChristoph Hellwig mark_inode_dirty(inode); 5821025774cSChristoph Hellwig return 0; 58377b14db5SEric W. Biederman } 58477b14db5SEric W. Biederman 5859043476fSAl Viro static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 5869043476fSAl Viro { 5879043476fSAl Viro struct inode *inode = dentry->d_inode; 5889043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5899043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5909043476fSAl Viro 5919043476fSAl Viro if (IS_ERR(head)) 5929043476fSAl Viro return PTR_ERR(head); 5939043476fSAl Viro 5949043476fSAl Viro generic_fillattr(inode, stat); 5959043476fSAl Viro if (table) 5969043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 5979043476fSAl Viro 5989043476fSAl Viro sysctl_head_finish(head); 5999043476fSAl Viro return 0; 6009043476fSAl Viro } 6019043476fSAl Viro 60277b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 603f1ecf068SLucas De Marchi .open = proc_sys_open, 604f1ecf068SLucas De Marchi .poll = proc_sys_poll, 60577b14db5SEric W. Biederman .read = proc_sys_read, 60677b14db5SEric W. Biederman .write = proc_sys_write, 6076038f373SArnd Bergmann .llseek = default_llseek, 6089043476fSAl Viro }; 6099043476fSAl Viro 6109043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 611887df078SPavel Emelyanov .read = generic_read_dir, 61277b14db5SEric W. Biederman .readdir = proc_sys_readdir, 6133222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 61477b14db5SEric W. Biederman }; 61577b14db5SEric W. Biederman 61603a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 6179043476fSAl Viro .permission = proc_sys_permission, 6189043476fSAl Viro .setattr = proc_sys_setattr, 6199043476fSAl Viro .getattr = proc_sys_getattr, 6209043476fSAl Viro }; 6219043476fSAl Viro 6229043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 62377b14db5SEric W. Biederman .lookup = proc_sys_lookup, 62477b14db5SEric W. Biederman .permission = proc_sys_permission, 62577b14db5SEric W. Biederman .setattr = proc_sys_setattr, 6269043476fSAl Viro .getattr = proc_sys_getattr, 62777b14db5SEric W. Biederman }; 62877b14db5SEric W. Biederman 62977b14db5SEric W. Biederman static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd) 63077b14db5SEric W. Biederman { 63134286d66SNick Piggin if (nd->flags & LOOKUP_RCU) 63234286d66SNick Piggin return -ECHILD; 6339043476fSAl Viro return !PROC_I(dentry->d_inode)->sysctl->unregistering; 6349043476fSAl Viro } 6359043476fSAl Viro 636fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 6379043476fSAl Viro { 6389043476fSAl Viro return !!PROC_I(dentry->d_inode)->sysctl->unregistering; 6399043476fSAl Viro } 6409043476fSAl Viro 6411f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 6421f87f0b5SEric W. Biederman { 6431f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 6441f87f0b5SEric W. Biederman int res; 6451f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 6461f87f0b5SEric W. Biederman if (p->unregistering) 6471f87f0b5SEric W. Biederman res = 0; 6481f87f0b5SEric W. Biederman else if (!set->is_seen) 6491f87f0b5SEric W. Biederman res = 1; 6501f87f0b5SEric W. Biederman else 6511f87f0b5SEric W. Biederman res = set->is_seen(set); 6521f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 6531f87f0b5SEric W. Biederman return res; 6541f87f0b5SEric W. Biederman } 6551f87f0b5SEric W. Biederman 656621e155aSNick Piggin static int proc_sys_compare(const struct dentry *parent, 657621e155aSNick Piggin const struct inode *pinode, 658621e155aSNick Piggin const struct dentry *dentry, const struct inode *inode, 659621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 6609043476fSAl Viro { 661dfef6dcdSAl Viro struct ctl_table_header *head; 66231e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 66331e6b01fSNick Piggin * that inode here can be NULL */ 664dfef6dcdSAl Viro /* AV: can it, indeed? */ 66531e6b01fSNick Piggin if (!inode) 666dfef6dcdSAl Viro return 1; 667621e155aSNick Piggin if (name->len != len) 6689043476fSAl Viro return 1; 669621e155aSNick Piggin if (memcmp(name->name, str, len)) 6709043476fSAl Viro return 1; 671dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 672dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 67377b14db5SEric W. Biederman } 67477b14db5SEric W. Biederman 675d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 67677b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 6779043476fSAl Viro .d_delete = proc_sys_delete, 6789043476fSAl Viro .d_compare = proc_sys_compare, 67977b14db5SEric W. Biederman }; 68077b14db5SEric W. Biederman 6811f87f0b5SEric W. Biederman static struct ctl_table *is_branch_in(struct ctl_table *branch, 6821f87f0b5SEric W. Biederman struct ctl_table *table) 6831f87f0b5SEric W. Biederman { 6841f87f0b5SEric W. Biederman struct ctl_table *p; 6851f87f0b5SEric W. Biederman const char *s = branch->procname; 6861f87f0b5SEric W. Biederman 6871f87f0b5SEric W. Biederman /* branch should have named subdirectory as its first element */ 6881f87f0b5SEric W. Biederman if (!s || !branch->child) 6891f87f0b5SEric W. Biederman return NULL; 6901f87f0b5SEric W. Biederman 6911f87f0b5SEric W. Biederman /* ... and nothing else */ 6921f87f0b5SEric W. Biederman if (branch[1].procname) 6931f87f0b5SEric W. Biederman return NULL; 6941f87f0b5SEric W. Biederman 6951f87f0b5SEric W. Biederman /* table should contain subdirectory with the same name */ 6961f87f0b5SEric W. Biederman for (p = table; p->procname; p++) { 6971f87f0b5SEric W. Biederman if (!p->child) 6981f87f0b5SEric W. Biederman continue; 6991f87f0b5SEric W. Biederman if (p->procname && strcmp(p->procname, s) == 0) 7001f87f0b5SEric W. Biederman return p; 7011f87f0b5SEric W. Biederman } 7021f87f0b5SEric W. Biederman return NULL; 7031f87f0b5SEric W. Biederman } 7041f87f0b5SEric W. Biederman 7051f87f0b5SEric W. Biederman /* see if attaching q to p would be an improvement */ 7061f87f0b5SEric W. Biederman static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q) 7071f87f0b5SEric W. Biederman { 7081f87f0b5SEric W. Biederman struct ctl_table *to = p->ctl_table, *by = q->ctl_table; 7091f87f0b5SEric W. Biederman struct ctl_table *next; 7101f87f0b5SEric W. Biederman int is_better = 0; 7111f87f0b5SEric W. Biederman int not_in_parent = !p->attached_by; 7121f87f0b5SEric W. Biederman 7131f87f0b5SEric W. Biederman while ((next = is_branch_in(by, to)) != NULL) { 7141f87f0b5SEric W. Biederman if (by == q->attached_by) 7151f87f0b5SEric W. Biederman is_better = 1; 7161f87f0b5SEric W. Biederman if (to == p->attached_by) 7171f87f0b5SEric W. Biederman not_in_parent = 1; 7181f87f0b5SEric W. Biederman by = by->child; 7191f87f0b5SEric W. Biederman to = next->child; 7201f87f0b5SEric W. Biederman } 7211f87f0b5SEric W. Biederman 7221f87f0b5SEric W. Biederman if (is_better && not_in_parent) { 7231f87f0b5SEric W. Biederman q->attached_by = by; 7241f87f0b5SEric W. Biederman q->attached_to = to; 7251f87f0b5SEric W. Biederman q->parent = p; 7261f87f0b5SEric W. Biederman } 7271f87f0b5SEric W. Biederman } 7281f87f0b5SEric W. Biederman 7291f87f0b5SEric W. Biederman #ifdef CONFIG_SYSCTL_SYSCALL_CHECK 7301f87f0b5SEric W. Biederman static int sysctl_depth(struct ctl_table *table) 7311f87f0b5SEric W. Biederman { 7321f87f0b5SEric W. Biederman struct ctl_table *tmp; 7331f87f0b5SEric W. Biederman int depth; 7341f87f0b5SEric W. Biederman 7351f87f0b5SEric W. Biederman depth = 0; 7361f87f0b5SEric W. Biederman for (tmp = table; tmp->parent; tmp = tmp->parent) 7371f87f0b5SEric W. Biederman depth++; 7381f87f0b5SEric W. Biederman 7391f87f0b5SEric W. Biederman return depth; 7401f87f0b5SEric W. Biederman } 7411f87f0b5SEric W. Biederman 7421f87f0b5SEric W. Biederman static struct ctl_table *sysctl_parent(struct ctl_table *table, int n) 7431f87f0b5SEric W. Biederman { 7441f87f0b5SEric W. Biederman int i; 7451f87f0b5SEric W. Biederman 7461f87f0b5SEric W. Biederman for (i = 0; table && i < n; i++) 7471f87f0b5SEric W. Biederman table = table->parent; 7481f87f0b5SEric W. Biederman 7491f87f0b5SEric W. Biederman return table; 7501f87f0b5SEric W. Biederman } 7511f87f0b5SEric W. Biederman 7521f87f0b5SEric W. Biederman 7531f87f0b5SEric W. Biederman static void sysctl_print_path(struct ctl_table *table) 7541f87f0b5SEric W. Biederman { 7551f87f0b5SEric W. Biederman struct ctl_table *tmp; 7561f87f0b5SEric W. Biederman int depth, i; 7571f87f0b5SEric W. Biederman depth = sysctl_depth(table); 7581f87f0b5SEric W. Biederman if (table->procname) { 7591f87f0b5SEric W. Biederman for (i = depth; i >= 0; i--) { 7601f87f0b5SEric W. Biederman tmp = sysctl_parent(table, i); 7611f87f0b5SEric W. Biederman printk("/%s", tmp->procname?tmp->procname:""); 7621f87f0b5SEric W. Biederman } 7631f87f0b5SEric W. Biederman } 7641f87f0b5SEric W. Biederman printk(" "); 7651f87f0b5SEric W. Biederman } 7661f87f0b5SEric W. Biederman 7671f87f0b5SEric W. Biederman static struct ctl_table *sysctl_check_lookup(struct nsproxy *namespaces, 7681f87f0b5SEric W. Biederman struct ctl_table *table) 7691f87f0b5SEric W. Biederman { 7701f87f0b5SEric W. Biederman struct ctl_table_header *head; 7711f87f0b5SEric W. Biederman struct ctl_table *ref, *test; 7721f87f0b5SEric W. Biederman int depth, cur_depth; 7731f87f0b5SEric W. Biederman 7741f87f0b5SEric W. Biederman depth = sysctl_depth(table); 7751f87f0b5SEric W. Biederman 7761f87f0b5SEric W. Biederman for (head = __sysctl_head_next(namespaces, NULL); head; 7771f87f0b5SEric W. Biederman head = __sysctl_head_next(namespaces, head)) { 7781f87f0b5SEric W. Biederman cur_depth = depth; 7791f87f0b5SEric W. Biederman ref = head->ctl_table; 7801f87f0b5SEric W. Biederman repeat: 7811f87f0b5SEric W. Biederman test = sysctl_parent(table, cur_depth); 7821f87f0b5SEric W. Biederman for (; ref->procname; ref++) { 7831f87f0b5SEric W. Biederman int match = 0; 7841f87f0b5SEric W. Biederman if (cur_depth && !ref->child) 7851f87f0b5SEric W. Biederman continue; 7861f87f0b5SEric W. Biederman 7871f87f0b5SEric W. Biederman if (test->procname && ref->procname && 7881f87f0b5SEric W. Biederman (strcmp(test->procname, ref->procname) == 0)) 7891f87f0b5SEric W. Biederman match++; 7901f87f0b5SEric W. Biederman 7911f87f0b5SEric W. Biederman if (match) { 7921f87f0b5SEric W. Biederman if (cur_depth != 0) { 7931f87f0b5SEric W. Biederman cur_depth--; 7941f87f0b5SEric W. Biederman ref = ref->child; 7951f87f0b5SEric W. Biederman goto repeat; 7961f87f0b5SEric W. Biederman } 7971f87f0b5SEric W. Biederman goto out; 7981f87f0b5SEric W. Biederman } 7991f87f0b5SEric W. Biederman } 8001f87f0b5SEric W. Biederman } 8011f87f0b5SEric W. Biederman ref = NULL; 8021f87f0b5SEric W. Biederman out: 8031f87f0b5SEric W. Biederman sysctl_head_finish(head); 8041f87f0b5SEric W. Biederman return ref; 8051f87f0b5SEric W. Biederman } 8061f87f0b5SEric W. Biederman 8071f87f0b5SEric W. Biederman static void set_fail(const char **fail, struct ctl_table *table, const char *str) 8081f87f0b5SEric W. Biederman { 8091f87f0b5SEric W. Biederman if (*fail) { 8101f87f0b5SEric W. Biederman printk(KERN_ERR "sysctl table check failed: "); 8111f87f0b5SEric W. Biederman sysctl_print_path(table); 8121f87f0b5SEric W. Biederman printk(" %s\n", *fail); 8131f87f0b5SEric W. Biederman dump_stack(); 8141f87f0b5SEric W. Biederman } 8151f87f0b5SEric W. Biederman *fail = str; 8161f87f0b5SEric W. Biederman } 8171f87f0b5SEric W. Biederman 8181f87f0b5SEric W. Biederman static void sysctl_check_leaf(struct nsproxy *namespaces, 8191f87f0b5SEric W. Biederman struct ctl_table *table, const char **fail) 8201f87f0b5SEric W. Biederman { 8211f87f0b5SEric W. Biederman struct ctl_table *ref; 8221f87f0b5SEric W. Biederman 8231f87f0b5SEric W. Biederman ref = sysctl_check_lookup(namespaces, table); 8241f87f0b5SEric W. Biederman if (ref && (ref != table)) 8251f87f0b5SEric W. Biederman set_fail(fail, table, "Sysctl already exists"); 8261f87f0b5SEric W. Biederman } 8271f87f0b5SEric W. Biederman 8281f87f0b5SEric W. Biederman static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table) 8291f87f0b5SEric W. Biederman { 8301f87f0b5SEric W. Biederman int error = 0; 8311f87f0b5SEric W. Biederman for (; table->procname; table++) { 8321f87f0b5SEric W. Biederman const char *fail = NULL; 8331f87f0b5SEric W. Biederman 8341f87f0b5SEric W. Biederman if (table->parent) { 8351f87f0b5SEric W. Biederman if (!table->parent->procname) 8361f87f0b5SEric W. Biederman set_fail(&fail, table, "Parent without procname"); 8371f87f0b5SEric W. Biederman } 8381f87f0b5SEric W. Biederman if (table->child) { 8391f87f0b5SEric W. Biederman if (table->data) 8401f87f0b5SEric W. Biederman set_fail(&fail, table, "Directory with data?"); 8411f87f0b5SEric W. Biederman if (table->maxlen) 8421f87f0b5SEric W. Biederman set_fail(&fail, table, "Directory with maxlen?"); 8431f87f0b5SEric W. Biederman if ((table->mode & (S_IRUGO|S_IXUGO)) != table->mode) 8441f87f0b5SEric W. Biederman set_fail(&fail, table, "Writable sysctl directory"); 8451f87f0b5SEric W. Biederman if (table->proc_handler) 8461f87f0b5SEric W. Biederman set_fail(&fail, table, "Directory with proc_handler"); 8471f87f0b5SEric W. Biederman if (table->extra1) 8481f87f0b5SEric W. Biederman set_fail(&fail, table, "Directory with extra1"); 8491f87f0b5SEric W. Biederman if (table->extra2) 8501f87f0b5SEric W. Biederman set_fail(&fail, table, "Directory with extra2"); 8511f87f0b5SEric W. Biederman } else { 8521f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 8531f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 8541f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 8551f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 8561f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 8571f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 8581f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 8591f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 8601f87f0b5SEric W. Biederman if (!table->data) 8611f87f0b5SEric W. Biederman set_fail(&fail, table, "No data"); 8621f87f0b5SEric W. Biederman if (!table->maxlen) 8631f87f0b5SEric W. Biederman set_fail(&fail, table, "No maxlen"); 8641f87f0b5SEric W. Biederman } 8651f87f0b5SEric W. Biederman #ifdef CONFIG_PROC_SYSCTL 8661f87f0b5SEric W. Biederman if (!table->proc_handler) 8671f87f0b5SEric W. Biederman set_fail(&fail, table, "No proc_handler"); 8681f87f0b5SEric W. Biederman #endif 8691f87f0b5SEric W. Biederman sysctl_check_leaf(namespaces, table, &fail); 8701f87f0b5SEric W. Biederman } 8711f87f0b5SEric W. Biederman if (table->mode > 0777) 8721f87f0b5SEric W. Biederman set_fail(&fail, table, "bogus .mode"); 8731f87f0b5SEric W. Biederman if (fail) { 8741f87f0b5SEric W. Biederman set_fail(&fail, table, NULL); 8751f87f0b5SEric W. Biederman error = -EINVAL; 8761f87f0b5SEric W. Biederman } 8771f87f0b5SEric W. Biederman if (table->child) 8781f87f0b5SEric W. Biederman error |= sysctl_check_table(namespaces, table->child); 8791f87f0b5SEric W. Biederman } 8801f87f0b5SEric W. Biederman return error; 8811f87f0b5SEric W. Biederman } 8821f87f0b5SEric W. Biederman #endif /* CONFIG_SYSCTL_SYSCALL_CHECK */ 8831f87f0b5SEric W. Biederman 8841f87f0b5SEric W. Biederman /** 8851f87f0b5SEric W. Biederman * __register_sysctl_paths - register a sysctl hierarchy 8861f87f0b5SEric W. Biederman * @root: List of sysctl headers to register on 8871f87f0b5SEric W. Biederman * @namespaces: Data to compute which lists of sysctl entries are visible 8881f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 8891f87f0b5SEric W. Biederman * @table: the top-level table structure 8901f87f0b5SEric W. Biederman * 8911f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 8921f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 8931f87f0b5SEric W. Biederman * 8941f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 8951f87f0b5SEric W. Biederman * 8961f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 8971f87f0b5SEric W. Biederman * enter a sysctl file 8981f87f0b5SEric W. Biederman * 8991f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 9001f87f0b5SEric W. Biederman * 9011f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 9021f87f0b5SEric W. Biederman * 9031f87f0b5SEric W. Biederman * mode - the file permissions for the /proc/sys file, and for sysctl(2) 9041f87f0b5SEric W. Biederman * 9051f87f0b5SEric W. Biederman * child - a pointer to the child sysctl table if this entry is a directory, or 9061f87f0b5SEric W. Biederman * %NULL. 9071f87f0b5SEric W. Biederman * 9081f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 9091f87f0b5SEric W. Biederman * 9101f87f0b5SEric W. Biederman * de - for internal use by the sysctl routines 9111f87f0b5SEric W. Biederman * 9121f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 9131f87f0b5SEric W. Biederman * 9141f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 9151f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 9161f87f0b5SEric W. Biederman * 9171f87f0b5SEric W. Biederman * sysctl(2) can automatically manage read and write requests through 9181f87f0b5SEric W. Biederman * the sysctl table. The data and maxlen fields of the ctl_table 9191f87f0b5SEric W. Biederman * struct enable minimal validation of the values being written to be 9201f87f0b5SEric W. Biederman * performed, and the mode field allows minimal authentication. 9211f87f0b5SEric W. Biederman * 9221f87f0b5SEric W. Biederman * There must be a proc_handler routine for any terminal nodes 9231f87f0b5SEric W. Biederman * mirrored under /proc/sys (non-terminals are handled by a built-in 9241f87f0b5SEric W. Biederman * directory handler). Several default handlers are available to 9251f87f0b5SEric W. Biederman * cover common cases - 9261f87f0b5SEric W. Biederman * 9271f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 9281f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 9291f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 9301f87f0b5SEric W. Biederman * 9311f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 9321f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 9331f87f0b5SEric W. Biederman * 9341f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 9351f87f0b5SEric W. Biederman * to the table header on success. 9361f87f0b5SEric W. Biederman */ 9371f87f0b5SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 9381f87f0b5SEric W. Biederman struct ctl_table_root *root, 9391f87f0b5SEric W. Biederman struct nsproxy *namespaces, 9401f87f0b5SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 9411f87f0b5SEric W. Biederman { 9421f87f0b5SEric W. Biederman struct ctl_table_header *header; 9431f87f0b5SEric W. Biederman struct ctl_table *new, **prevp; 9441f87f0b5SEric W. Biederman unsigned int n, npath; 9451f87f0b5SEric W. Biederman struct ctl_table_set *set; 9461f87f0b5SEric W. Biederman 9471f87f0b5SEric W. Biederman /* Count the path components */ 9481f87f0b5SEric W. Biederman for (npath = 0; path[npath].procname; ++npath) 9491f87f0b5SEric W. Biederman ; 9501f87f0b5SEric W. Biederman 9511f87f0b5SEric W. Biederman /* 9521f87f0b5SEric W. Biederman * For each path component, allocate a 2-element ctl_table array. 9531f87f0b5SEric W. Biederman * The first array element will be filled with the sysctl entry 9541f87f0b5SEric W. Biederman * for this, the second will be the sentinel (procname == 0). 9551f87f0b5SEric W. Biederman * 9561f87f0b5SEric W. Biederman * We allocate everything in one go so that we don't have to 9571f87f0b5SEric W. Biederman * worry about freeing additional memory in unregister_sysctl_table. 9581f87f0b5SEric W. Biederman */ 9591f87f0b5SEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 9601f87f0b5SEric W. Biederman (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL); 9611f87f0b5SEric W. Biederman if (!header) 9621f87f0b5SEric W. Biederman return NULL; 9631f87f0b5SEric W. Biederman 9641f87f0b5SEric W. Biederman new = (struct ctl_table *) (header + 1); 9651f87f0b5SEric W. Biederman 9661f87f0b5SEric W. Biederman /* Now connect the dots */ 9671f87f0b5SEric W. Biederman prevp = &header->ctl_table; 9681f87f0b5SEric W. Biederman for (n = 0; n < npath; ++n, ++path) { 9691f87f0b5SEric W. Biederman /* Copy the procname */ 9701f87f0b5SEric W. Biederman new->procname = path->procname; 9711f87f0b5SEric W. Biederman new->mode = 0555; 9721f87f0b5SEric W. Biederman 9731f87f0b5SEric W. Biederman *prevp = new; 9741f87f0b5SEric W. Biederman prevp = &new->child; 9751f87f0b5SEric W. Biederman 9761f87f0b5SEric W. Biederman new += 2; 9771f87f0b5SEric W. Biederman } 9781f87f0b5SEric W. Biederman *prevp = table; 9791f87f0b5SEric W. Biederman header->ctl_table_arg = table; 9801f87f0b5SEric W. Biederman 9811f87f0b5SEric W. Biederman INIT_LIST_HEAD(&header->ctl_entry); 9821f87f0b5SEric W. Biederman header->used = 0; 9831f87f0b5SEric W. Biederman header->unregistering = NULL; 9841f87f0b5SEric W. Biederman header->root = root; 9851f87f0b5SEric W. Biederman sysctl_set_parent(NULL, header->ctl_table); 9861f87f0b5SEric W. Biederman header->count = 1; 9871f87f0b5SEric W. Biederman #ifdef CONFIG_SYSCTL_SYSCALL_CHECK 9881f87f0b5SEric W. Biederman if (sysctl_check_table(namespaces, header->ctl_table)) { 9891f87f0b5SEric W. Biederman kfree(header); 9901f87f0b5SEric W. Biederman return NULL; 9911f87f0b5SEric W. Biederman } 9921f87f0b5SEric W. Biederman #endif 9931f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 9941f87f0b5SEric W. Biederman header->set = lookup_header_set(root, namespaces); 9951f87f0b5SEric W. Biederman header->attached_by = header->ctl_table; 9961f87f0b5SEric W. Biederman header->attached_to = root_table; 9971f87f0b5SEric W. Biederman header->parent = &root_table_header; 9981f87f0b5SEric W. Biederman for (set = header->set; set; set = set->parent) { 9991f87f0b5SEric W. Biederman struct ctl_table_header *p; 10001f87f0b5SEric W. Biederman list_for_each_entry(p, &set->list, ctl_entry) { 10011f87f0b5SEric W. Biederman if (p->unregistering) 10021f87f0b5SEric W. Biederman continue; 10031f87f0b5SEric W. Biederman try_attach(p, header); 10041f87f0b5SEric W. Biederman } 10051f87f0b5SEric W. Biederman } 10061f87f0b5SEric W. Biederman header->parent->count++; 10071f87f0b5SEric W. Biederman list_add_tail(&header->ctl_entry, &header->set->list); 10081f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 10091f87f0b5SEric W. Biederman 10101f87f0b5SEric W. Biederman return header; 10111f87f0b5SEric W. Biederman } 10121f87f0b5SEric W. Biederman 10131f87f0b5SEric W. Biederman /** 10141f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 10151f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 10161f87f0b5SEric W. Biederman * @table: the top-level table structure 10171f87f0b5SEric W. Biederman * 10181f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 10191f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 10201f87f0b5SEric W. Biederman * 10211f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 10221f87f0b5SEric W. Biederman */ 10231f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 10241f87f0b5SEric W. Biederman struct ctl_table *table) 10251f87f0b5SEric W. Biederman { 10261f87f0b5SEric W. Biederman return __register_sysctl_paths(&sysctl_table_root, current->nsproxy, 10271f87f0b5SEric W. Biederman path, table); 10281f87f0b5SEric W. Biederman } 10291f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 10301f87f0b5SEric W. Biederman 10311f87f0b5SEric W. Biederman /** 10321f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 10331f87f0b5SEric W. Biederman * @table: the top-level table structure 10341f87f0b5SEric W. Biederman * 10351f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 10361f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 10371f87f0b5SEric W. Biederman * 10381f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 10391f87f0b5SEric W. Biederman */ 10401f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 10411f87f0b5SEric W. Biederman { 10421f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 10431f87f0b5SEric W. Biederman 10441f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 10451f87f0b5SEric W. Biederman } 10461f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 10471f87f0b5SEric W. Biederman 10481f87f0b5SEric W. Biederman /** 10491f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 10501f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 10511f87f0b5SEric W. Biederman * 10521f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 10531f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 10541f87f0b5SEric W. Biederman */ 10551f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 10561f87f0b5SEric W. Biederman { 10571f87f0b5SEric W. Biederman might_sleep(); 10581f87f0b5SEric W. Biederman 10591f87f0b5SEric W. Biederman if (header == NULL) 10601f87f0b5SEric W. Biederman return; 10611f87f0b5SEric W. Biederman 10621f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 10631f87f0b5SEric W. Biederman start_unregistering(header); 10641f87f0b5SEric W. Biederman if (!--header->parent->count) { 10651f87f0b5SEric W. Biederman WARN_ON(1); 10661f87f0b5SEric W. Biederman kfree_rcu(header->parent, rcu); 10671f87f0b5SEric W. Biederman } 10681f87f0b5SEric W. Biederman if (!--header->count) 10691f87f0b5SEric W. Biederman kfree_rcu(header, rcu); 10701f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 10711f87f0b5SEric W. Biederman } 10721f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 10731f87f0b5SEric W. Biederman 10741f87f0b5SEric W. Biederman void setup_sysctl_set(struct ctl_table_set *p, 10751f87f0b5SEric W. Biederman struct ctl_table_set *parent, 10761f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 10771f87f0b5SEric W. Biederman { 10781f87f0b5SEric W. Biederman INIT_LIST_HEAD(&p->list); 10791f87f0b5SEric W. Biederman p->parent = parent ? parent : &sysctl_table_root.default_set; 10801f87f0b5SEric W. Biederman p->is_seen = is_seen; 10811f87f0b5SEric W. Biederman } 10821f87f0b5SEric W. Biederman 108397324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 108497324cd8SEric W. Biederman { 108597324cd8SEric W. Biederman WARN_ON(!list_empty(&set->list)); 108697324cd8SEric W. Biederman } 10871f87f0b5SEric W. Biederman 10881e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 108977b14db5SEric W. Biederman { 1090e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1091e1675231SAlexey Dobriyan 109277b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 10939043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 10949043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 109577b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1096de4e83bdSEric W. Biederman 1097de4e83bdSEric W. Biederman return sysctl_init(); 109877b14db5SEric W. Biederman } 1099