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 ext2_initxattrs(struct inode *inode, const struct xattr *xattr_array,
  50                     void *fs_info)
  51 {
  52         const struct xattr *xattr;
  53         int err = 0;
  54
  55         for (xattr = xattr_array; xattr->name != NULL; xattr++) {
  56                 err = ext2_xattr_set(inode, EXT2_XATTR_INDEX_SECURITY,
  57                                      xattr->name, xattr->value,
  58                                      xattr->value_len, 0);
  59                 if (err < 0)
  60                         break;
  61         }
  62         return err;
  63 }
  64
  65 int
  66 ext2_init_security(struct inode *inode, struct inode *dir,
  67                    const struct qstr *qstr)
  68 {
  69         return security_inode_init_security(inode, dir, qstr,
  70                                             &ext2_initxattrs, NULL);
  71 }
  72
  73 const struct xattr_handler ext2_xattr_security_handler = {
  74         .prefix = XATTR_SECURITY_PREFIX,
  75         .list   = ext2_xattr_security_list,
  76         .get    = ext2_xattr_security_get,
  77         .set    = ext2_xattr_security_set,
  78 };