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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mscode_parser.c (2775B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/* Parse a Microsoft Individual Code Signing blob
      3 *
      4 * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
      5 * Written by David Howells (dhowells@redhat.com)
      6 */
      7
      8#define pr_fmt(fmt) "MSCODE: "fmt
      9#include <linux/kernel.h>
     10#include <linux/slab.h>
     11#include <linux/err.h>
     12#include <linux/oid_registry.h>
     13#include <crypto/pkcs7.h>
     14#include "verify_pefile.h"
     15#include "mscode.asn1.h"
     16
     17/*
     18 * Parse a Microsoft Individual Code Signing blob
     19 */
     20int mscode_parse(void *_ctx, const void *content_data, size_t data_len,
     21		 size_t asn1hdrlen)
     22{
     23	struct pefile_context *ctx = _ctx;
     24
     25	content_data -= asn1hdrlen;
     26	data_len += asn1hdrlen;
     27	pr_devel("Data: %zu [%*ph]\n", data_len, (unsigned)(data_len),
     28		 content_data);
     29
     30	return asn1_ber_decoder(&mscode_decoder, ctx, content_data, data_len);
     31}
     32
     33/*
     34 * Check the content type OID
     35 */
     36int mscode_note_content_type(void *context, size_t hdrlen,
     37			     unsigned char tag,
     38			     const void *value, size_t vlen)
     39{
     40	enum OID oid;
     41
     42	oid = look_up_OID(value, vlen);
     43	if (oid == OID__NR) {
     44		char buffer[50];
     45
     46		sprint_oid(value, vlen, buffer, sizeof(buffer));
     47		pr_err("Unknown OID: %s\n", buffer);
     48		return -EBADMSG;
     49	}
     50
     51	/*
     52	 * pesign utility had a bug where it was putting
     53	 * OID_msIndividualSPKeyPurpose instead of OID_msPeImageDataObjId
     54	 * So allow both OIDs.
     55	 */
     56	if (oid != OID_msPeImageDataObjId &&
     57	    oid != OID_msIndividualSPKeyPurpose) {
     58		pr_err("Unexpected content type OID %u\n", oid);
     59		return -EBADMSG;
     60	}
     61
     62	return 0;
     63}
     64
     65/*
     66 * Note the digest algorithm OID
     67 */
     68int mscode_note_digest_algo(void *context, size_t hdrlen,
     69			    unsigned char tag,
     70			    const void *value, size_t vlen)
     71{
     72	struct pefile_context *ctx = context;
     73	char buffer[50];
     74	enum OID oid;
     75
     76	oid = look_up_OID(value, vlen);
     77	switch (oid) {
     78	case OID_md4:
     79		ctx->digest_algo = "md4";
     80		break;
     81	case OID_md5:
     82		ctx->digest_algo = "md5";
     83		break;
     84	case OID_sha1:
     85		ctx->digest_algo = "sha1";
     86		break;
     87	case OID_sha256:
     88		ctx->digest_algo = "sha256";
     89		break;
     90	case OID_sha384:
     91		ctx->digest_algo = "sha384";
     92		break;
     93	case OID_sha512:
     94		ctx->digest_algo = "sha512";
     95		break;
     96	case OID_sha224:
     97		ctx->digest_algo = "sha224";
     98		break;
     99
    100	case OID__NR:
    101		sprint_oid(value, vlen, buffer, sizeof(buffer));
    102		pr_err("Unknown OID: %s\n", buffer);
    103		return -EBADMSG;
    104
    105	default:
    106		pr_err("Unsupported content type: %u\n", oid);
    107		return -ENOPKG;
    108	}
    109
    110	return 0;
    111}
    112
    113/*
    114 * Note the digest we're guaranteeing with this certificate
    115 */
    116int mscode_note_digest(void *context, size_t hdrlen,
    117		       unsigned char tag,
    118		       const void *value, size_t vlen)
    119{
    120	struct pefile_context *ctx = context;
    121
    122	ctx->digest = kmemdup(value, vlen, GFP_KERNEL);
    123	if (!ctx->digest)
    124		return -ENOMEM;
    125
    126	ctx->digest_len = vlen;
    127
    128	return 0;
    129}