fs/reiserfs/xattr_security.c

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