LXR linux/kernel/module

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* Module signature checker
   3 *
   4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
   6 */
   7
   8#include <linux/kernel.h>
   9#include <linux/errno.h>
  10#include <linux/module.h>
  11#include <linux/module_signature.h>
  12#include <linux/string.h>
  13#include <linux/verification.h>
  14#include <crypto/public_key.h>
  15#include "module-internal.h"
  16
  17/*
  18 * Verify the signature on a module.
  19 */
  20int mod_verify_sig(const void *mod, struct load_info *info)
  21{
  22        struct module_signature ms;
  23        size_t sig_len, modlen = info->len;
  24        int ret;
  25
  26        pr_devel("==>%s(,%zu)\n", __func__, modlen);
  27
  28        if (modlen <= sizeof(ms))
  29                return -EBADMSG;
  30
  31        memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
  32
  33        ret = mod_check_sig(&ms, modlen, "module");
  34        if (ret)
  35                return ret;
  36
  37        sig_len = be32_to_cpu(ms.sig_len);
  38        modlen -= sig_len + sizeof(ms);
  39        info->len = modlen;
  40
  41        return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
  42                                      VERIFY_USE_SECONDARY_KEYRING,
  43                                      VERIFYING_MODULE_SIGNATURE,
  44                                      NULL, NULL);
  45}
  46