LXR linux/fs/ext4/xattr

   1/*
   2 * linux/fs/ext4/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/security.h>
  10#include <linux/slab.h>
  11#include "ext4_jbd2.h"
  12#include "ext4.h"
  13#include "xattr.h"
  14
  15static size_t
  16ext4_xattr_security_list(struct dentry *dentry, char *list, size_t list_size,
  17                const char *name, size_t name_len, int type)
  18{
  19        const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
  20        const size_t total_len = prefix_len + name_len + 1;
  21
  22
  23        if (list && total_len <= list_size) {
  24                memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
  25                memcpy(list+prefix_len, name, name_len);
  26                list[prefix_len + name_len] = '\0';
  27        }
  28        return total_len;
  29}
  30
  31static int
  32ext4_xattr_security_get(struct dentry *dentry, const char *name,
  33                       void *buffer, size_t size, int type)
  34{
  35        if (strcmp(name, "") == 0)
  36                return -EINVAL;
  37        return ext4_xattr_get(dentry->d_inode, EXT4_XATTR_INDEX_SECURITY,
  38                              name, buffer, size);
  39}
  40
  41static int
  42ext4_xattr_security_set(struct dentry *dentry, const char *name,
  43                const void *value, size_t size, int flags, int type)
  44{
  45        if (strcmp(name, "") == 0)
  46                return -EINVAL;
  47        return ext4_xattr_set(dentry->d_inode, EXT4_XATTR_INDEX_SECURITY,
  48                              name, value, size, flags);
  49}
  50
  51int
  52ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
  53                   const struct qstr *qstr)
  54{
  55        int err;
  56        size_t len;
  57        void *value;
  58        char *name;
  59
  60        err = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
  61        if (err) {
  62                if (err == -EOPNOTSUPP)
  63                        return 0;
  64                return err;
  65        }
  66        err = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_SECURITY,
  67                                    name, value, len, 0);
  68        kfree(name);
  69        kfree(value);
  70        return err;
  71}
  72
  73const struct xattr_handler ext4_xattr_security_handler = {
  74        .prefix = XATTR_SECURITY_PREFIX,
  75        .list   = ext4_xattr_security_list,
  76        .get    = ext4_xattr_security_get,
  77        .set    = ext4_xattr_security_set,
  78};
  79