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/string.h>
   7#include <linux/fs.h>
   8#include <linux/security.h>
   9#include <linux/slab.h>
  10#include "ext4_jbd2.h"
  11#include "ext4.h"
  12#include "xattr.h"
  13
  14static size_t
  15ext4_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 size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
  19        const size_t total_len = prefix_len + name_len + 1;
  20
  21
  22        if (list && total_len <= list_size) {
  23                memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
  24                memcpy(list+prefix_len, name, name_len);
  25                list[prefix_len + name_len] = '\0';
  26        }
  27        return total_len;
  28}
  29
  30static int
  31ext4_xattr_security_get(struct dentry *dentry, const char *name,
  32                       void *buffer, size_t size, int type)
  33{
  34        if (strcmp(name, "") == 0)
  35                return -EINVAL;
  36        return ext4_xattr_get(dentry->d_inode, EXT4_XATTR_INDEX_SECURITY,
  37                              name, buffer, size);
  38}
  39
  40static int
  41ext4_xattr_security_set(struct dentry *dentry, const char *name,
  42                const void *value, size_t size, int flags, int type)
  43{
  44        if (strcmp(name, "") == 0)
  45                return -EINVAL;
  46        return ext4_xattr_set(dentry->d_inode, EXT4_XATTR_INDEX_SECURITY,
  47                              name, value, size, flags);
  48}
  49
  50static int
  51ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
  52                void *fs_info)
  53{
  54        const struct xattr *xattr;
  55        handle_t *handle = fs_info;
  56        int err = 0;
  57
  58        for (xattr = xattr_array; xattr->name != NULL; xattr++) {
  59                err = ext4_xattr_set_handle(handle, inode,
  60                                            EXT4_XATTR_INDEX_SECURITY,
  61                                            xattr->name, xattr->value,
  62                                            xattr->value_len, 0);
  63                if (err < 0)
  64                        break;
  65        }
  66        return err;
  67}
  68
  69int
  70ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
  71                   const struct qstr *qstr)
  72{
  73        return security_inode_init_security(inode, dir, qstr,
  74                                            &ext4_initxattrs, handle);
  75}
  76
  77const struct xattr_handler ext4_xattr_security_handler = {
  78        .prefix = XATTR_SECURITY_PREFIX,
  79        .list   = ext4_xattr_security_list,
  80        .get    = ext4_xattr_security_get,
  81        .set    = ext4_xattr_security_set,
  82};
  83