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/slab.h>
   8 #include <linux/string.h>
   9 #include <linux/fs.h>
  10 #include <linux/ext2_fs.h>
  11 #include <linux/security.h>
  12 #include "xattr.h"
  13
  14 static size_t
  15 ext2_xattr_security_list(struct dentry *dentry, char *list, size_t list_size,
  16                          const char *name, size_t name_len, int type)
  17 {
  18         const int prefix_len = XATTR_SECURITY_PREFIX_LEN;
  19         const size_t total_len = prefix_len + name_len + 1;
  20
  21         if (list && total_len <= list_size) {
  22                 memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
  23                 memcpy(list+prefix_len, name, name_len);
  24                 list[prefix_len + name_len] = '\0';
  25         }
  26         return total_len;
  27 }
  28
  29 static int
  30 ext2_xattr_security_get(struct dentry *dentry, const char *name,
  31                        void *buffer, size_t size, int type)
  32 {
  33         if (strcmp(name, "") == 0)
  34                 return -EINVAL;
  35         return ext2_xattr_get(dentry->d_inode, EXT2_XATTR_INDEX_SECURITY, name,
  36                               buffer, size);
  37 }
  38
  39 static int
  40 ext2_xattr_security_set(struct dentry *dentry, const char *name,
  41                 const void *value, size_t size, int flags, int type)
  42 {
  43         if (strcmp(name, "") == 0)
  44                 return -EINVAL;
  45         return ext2_xattr_set(dentry->d_inode, EXT2_XATTR_INDEX_SECURITY, name,
  46                               value, size, flags);
  47 }
  48
  49 int
  50 ext2_init_security(struct inode *inode, struct inode *dir,
  51                    const struct qstr *qstr)
  52 {
  53         int err;
  54         size_t len;
  55         void *value;
  56         char *name;
  57
  58         err = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
  59         if (err) {
  60                 if (err == -EOPNOTSUPP)
  61                         return 0;
  62                 return err;
  63         }
  64         err = ext2_xattr_set(inode, EXT2_XATTR_INDEX_SECURITY,
  65                              name, value, len, 0);
  66         kfree(name);
  67         kfree(value);
  68         return err;
  69 }
  70
  71 const struct xattr_handler ext2_xattr_security_handler = {
  72         .prefix = XATTR_SECURITY_PREFIX,
  73         .list   = ext2_xattr_security_list,
  74         .get    = ext2_xattr_security_get,
  75         .set    = ext2_xattr_security_set,
  76 };