release/src-rt-6.x.4708/linux/linux-2.6.36/fs/reiserfs/xattr_security.c

   1 #include <linux/reiserfs_fs.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 <linux/reiserfs_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                            struct reiserfs_security_handle *sec)
  58 {
  59         int blocks = 0;
  60         int error;
  61
  62         sec->name = NULL;
  63
  64         /* Don't add selinux attributes on xattrs - they'll never get used */
  65         if (IS_PRIVATE(dir))
  66                 return 0;
  67
  68         error = security_inode_init_security(inode, dir, &sec->name,
  69                                              &sec->value, &sec->length);
  70         if (error) {
  71                 if (error == -EOPNOTSUPP)
  72                         error = 0;
  73
  74                 sec->name = NULL;
  75                 sec->value = NULL;
  76                 sec->length = 0;
  77                 return error;
  78         }
  79
  80         if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
  81                 blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  82                          reiserfs_xattr_nblocks(inode, sec->length);
  83                 /* We don't want to count the directories twice if we have
  84                  * a default ACL. */
  85                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
  86         }
  87         return blocks;
  88 }
  89
  90 int reiserfs_security_write(struct reiserfs_transaction_handle *th,
  91                             struct inode *inode,
  92                             struct reiserfs_security_handle *sec)
  93 {
  94         int error;
  95         if (strlen(sec->name) < sizeof(XATTR_SECURITY_PREFIX))
  96                 return -EINVAL;
  97
  98         error = reiserfs_xattr_set_handle(th, inode, sec->name, sec->value,
  99                                           sec->length, XATTR_CREATE);
 100         if (error == -ENODATA || error == -EOPNOTSUPP)
 101                 error = 0;
 102
 103         return error;
 104 }
 105
 106 void reiserfs_security_free(struct reiserfs_security_handle *sec)
 107 {
 108         kfree(sec->name);
 109         kfree(sec->value);
 110         sec->name = NULL;
 111         sec->value = NULL;
 112 }
 113
 114 const struct xattr_handler reiserfs_xattr_security_handler = {
 115         .prefix = XATTR_SECURITY_PREFIX,
 116         .get = security_get,
 117         .set = security_set,
 118         .list = security_list,
 119 };