fs/ext2/xattr_security.c

   1 /*
   2  * linux/fs/ext2/xattr_security.c
   3  * Handler for storing security labels as extended attributes.
   4  */
   5
   6 #include <linux/module.h>
   7 #include <linux/string.h>
   8 #include <linux/fs.h>
   9 #include <linux/ext2_fs.h>
  10 #include <linux/security.h>
  11 #include "xattr.h"
  12
  13 static size_t
  14 ext2_xattr_security_list(struct inode *inode, char *list, size_t list_size,
  15                          const char *name, size_t name_len)
  16 {
  17         const int prefix_len = XATTR_SECURITY_PREFIX_LEN;
  18         const size_t total_len = prefix_len + name_len + 1;
  19
  20         if (list && total_len <= list_size) {
  21                 memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
  22                 memcpy(list+prefix_len, name, name_len);
  23                 list[prefix_len + name_len] = '\0';
  24         }
  25         return total_len;
  26 }
  27
  28 static int
  29 ext2_xattr_security_get(struct inode *inode, const char *name,
  30                        void *buffer, size_t size)
  31 {
  32         if (strcmp(name, "") == 0)
  33                 return -EINVAL;
  34         return ext2_xattr_get(inode, EXT2_XATTR_INDEX_SECURITY, name,
  35                               buffer, size);
  36 }
  37
  38 static int
  39 ext2_xattr_security_set(struct inode *inode, const char *name,
  40                        const void *value, size_t size, int flags)
  41 {
  42         if (strcmp(name, "") == 0)
  43                 return -EINVAL;
  44         return ext2_xattr_set(inode, EXT2_XATTR_INDEX_SECURITY, name,
  45                               value, size, flags);
  46 }
  47
  48 int
  49 ext2_init_security(struct inode *inode, struct inode *dir)
  50 {
  51         int err;
  52         size_t len;
  53         void *value;
  54         char *name;
  55
  56         err = security_inode_init_security(inode, dir, &name, &value, &len);
  57         if (err) {
  58                 if (err == -EOPNOTSUPP)
  59                         return 0;
  60                 return err;
  61         }
  62         err = ext2_xattr_set(inode, EXT2_XATTR_INDEX_SECURITY,
  63                              name, value, len, 0);
  64         kfree(name);
  65         kfree(value);
  66         return err;
  67 }
  68
  69 struct xattr_handler ext2_xattr_security_handler = {
  70         .prefix = XATTR_SECURITY_PREFIX,
  71         .list   = ext2_xattr_security_list,
  72         .get    = ext2_xattr_security_get,
  73         .set    = ext2_xattr_security_set,
  74 };