cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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module_signature.c (1116B)

      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * Module signature checker
      4 *
      5 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
      6 * Written by David Howells (dhowells@redhat.com)
      7 */
      8
      9#include <linux/errno.h>
     10#include <linux/printk.h>
     11#include <linux/module_signature.h>
     12#include <asm/byteorder.h>
     13
     14/**
     15 * mod_check_sig - check that the given signature is sane
     16 *
     17 * @ms:		Signature to check.
     18 * @file_len:	Size of the file to which @ms is appended.
     19 * @name:	What is being checked. Used for error messages.
     20 */
     21int mod_check_sig(const struct module_signature *ms, size_t file_len,
     22		  const char *name)
     23{
     24	if (be32_to_cpu(ms->sig_len) >= file_len - sizeof(*ms))
     25		return -EBADMSG;
     26
     27	if (ms->id_type != PKEY_ID_PKCS7) {
     28		pr_err("%s: not signed with expected PKCS#7 message\n",
     29		       name);
     30		return -ENOPKG;
     31	}
     32
     33	if (ms->algo != 0 ||
     34	    ms->hash != 0 ||
     35	    ms->signer_len != 0 ||
     36	    ms->key_id_len != 0 ||
     37	    ms->__pad[0] != 0 ||
     38	    ms->__pad[1] != 0 ||
     39	    ms->__pad[2] != 0) {
     40		pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n",
     41		       name);
     42		return -EBADMSG;
     43	}
     44
     45	return 0;
     46}