1 // SPDX-License-Identifier: GPL-2.0 2 #include "reiserfs.h" 3 #include <linux/errno.h> 4 #include <linux/fs.h> 5 #include <linux/pagemap.h> 6 #include <linux/xattr.h> 7 #include <linux/slab.h> 8 #include "xattr.h" 9 #include <linux/security.h> 10 #include <linux/uaccess.h> 11 12 static int 13 security_get(const struct xattr_handler *handler, struct dentry *unused, 14 struct inode *inode, const char *name, void *buffer, size_t size) 15 { 16 if (IS_PRIVATE(inode)) 17 return -EPERM; 18 19 return reiserfs_xattr_get(inode, xattr_full_name(handler, name), 20 buffer, size); 21 } 22 23 static int 24 security_set(const struct xattr_handler *handler, 25 struct mnt_idmap *idmap, struct dentry *unused, 26 struct inode *inode, const char *name, const void *buffer, 27 size_t size, int flags) 28 { 29 if (IS_PRIVATE(inode)) 30 return -EPERM; 31 32 return reiserfs_xattr_set(inode, 33 xattr_full_name(handler, name), 34 buffer, size, flags); 35 } 36 37 static bool security_list(struct dentry *dentry) 38 { 39 return !IS_PRIVATE(d_inode(dentry)); 40 } 41 42 static int 43 reiserfs_initxattrs(struct inode *inode, const struct xattr *xattr_array, 44 void *fs_info) 45 { 46 struct reiserfs_security_handle *sec = fs_info; 47 48 sec->value = kmemdup(xattr_array->value, xattr_array->value_len, 49 GFP_KERNEL); 50 if (!sec->value) 51 return -ENOMEM; 52 53 sec->name = xattr_array->name; 54 sec->length = xattr_array->value_len; 55 return 0; 56 } 57 58 /* Initializes the security context for a new inode and returns the number 59 * of blocks needed for the transaction. If successful, reiserfs_security 60 * must be released using reiserfs_security_free when the caller is done. */ 61 int reiserfs_security_init(struct inode *dir, struct inode *inode, 62 const struct qstr *qstr, 63 struct reiserfs_security_handle *sec) 64 { 65 int blocks = 0; 66 int error; 67 68 sec->name = NULL; 69 sec->value = NULL; 70 sec->length = 0; 71 72 /* Don't add selinux attributes on xattrs - they'll never get used */ 73 if (IS_PRIVATE(dir)) 74 return 0; 75 76 error = security_inode_init_security(inode, dir, qstr, 77 &reiserfs_initxattrs, sec); 78 if (error) { 79 sec->name = NULL; 80 sec->value = NULL; 81 sec->length = 0; 82 return error; 83 } 84 85 if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) { 86 blocks = reiserfs_xattr_jcreate_nblocks(inode) + 87 reiserfs_xattr_nblocks(inode, sec->length); 88 /* We don't want to count the directories twice if we have 89 * a default ACL. */ 90 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 91 } 92 return blocks; 93 } 94 95 int reiserfs_security_write(struct reiserfs_transaction_handle *th, 96 struct inode *inode, 97 struct reiserfs_security_handle *sec) 98 { 99 char xattr_name[XATTR_NAME_MAX + 1] = XATTR_SECURITY_PREFIX; 100 int error; 101 102 if (XATTR_SECURITY_PREFIX_LEN + strlen(sec->name) > XATTR_NAME_MAX) 103 return -EINVAL; 104 105 strlcat(xattr_name, sec->name, sizeof(xattr_name)); 106 107 error = reiserfs_xattr_set_handle(th, inode, xattr_name, sec->value, 108 sec->length, XATTR_CREATE); 109 if (error == -ENODATA || error == -EOPNOTSUPP) 110 error = 0; 111 112 return error; 113 } 114 115 void reiserfs_security_free(struct reiserfs_security_handle *sec) 116 { 117 kfree(sec->value); 118 sec->name = NULL; 119 sec->value = NULL; 120 } 121 122 const struct xattr_handler reiserfs_xattr_security_handler = { 123 .prefix = XATTR_SECURITY_PREFIX, 124 .get = security_get, 125 .set = security_set, 126 .list = security_list, 127 }; 128