// SPDX-License-Identifier: GPL-2.0-or-later
/* PKCS#7 parser
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#define pr_fmt(fmt) "PKCS7: "fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/oid_registry.h>
#include <crypto/public_key.h>
#include "pkcs7_parser.h"
#include "pkcs7.asn1.h"
MODULE_DESCRIPTION("PKCS#7 parser");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
struct pkcs7_parse_context {
struct pkcs7_message *msg; /* Message being constructed */
struct pkcs7_signed_info *sinfo; /* SignedInfo being constructed */
struct pkcs7_signed_info **ppsinfo;
struct x509_certificate *certs; /* Certificate cache */
struct x509_certificate **ppcerts;
unsigned long data; /* Start of data */
enum OID last_oid; /* Last OID encountered */
unsigned x509_index;
unsigned sinfo_index;
const void *raw_serial;
unsigned raw_serial_size;
unsigned raw_issuer_size;
const void *raw_issuer;
const void *raw_skid;
unsigned raw_skid_size;
bool expect_skid;
};
/*
* Free a signed information block.
*/
static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo)
{
if (sinfo) {
public_key_signature_free(sinfo->sig);
kfree(sinfo);
}
}
/**
* pkcs7_free_message - Free a PKCS#7 message
* @pkcs7: The PKCS#7 message to free
*/
void pkcs7_free_message(struct pkcs7_message *pkcs7)
{
struct x509_certificate *cert;
struct pkcs7_signed_info *sinfo;
if (pkcs7) {
while (pkcs7->certs) {
cert = pkcs7->certs;
pkcs7->certs = cert->next;
x509_free_certificate(cert);
}
while (pkcs7->crl) {
cert = pkcs7->crl;
pkcs7->crl = cert->next;
x509_free_certificate(cert);
}
while (pkcs7->signed_infos) {
sinfo = pkcs7->signed_infos;
pkcs7->signed_infos = sinfo->next;
pkcs7_free_signed_info(sinfo);
}
kfree(pkcs7);
}
}
EXPORT_SYMBOL_GPL(pkcs7_free_message);
/*
* Check authenticatedAttributes are provided or not provided consistently.
*/
static int pkcs7_check_authattrs(struct pkcs7_message *msg)
{
struct pkcs7_signed_info *sinfo;
bool want = false;
sinfo = msg->signed_infos;
if (!sinfo)
goto inconsistent;
if (sinfo->authattrs) {
want = true;
msg->have_authattrs = true;
}
for (sinfo = sinfo->next; sinfo; sinfo = sinfo->next)
if (!!sinfo->authattrs != want)
goto inconsistent;
return 0;
inconsistent:
pr_warn("Inconsistently supplied authAttrs\n");
return -EINVAL;
}
/**
* pkcs7_parse_message - Parse a PKCS#7 message
* @data: The raw binary ASN.1 encoded message to be parsed
* @datalen: The size of the encoded message
*/
struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen)
{
struct pkcs7_parse_context *ctx;
struct pkcs7_message *msg = ERR_PTR(-ENOMEM);
int ret;
ctx = kzalloc(sizeof(struct pkcs7_parse_context), GFP_KERNEL);
if (!ctx)
goto out_no_ctx;
ctx->msg = kzalloc(sizeof(struct pkcs7_message), GFP_KERNEL);
if (!ctx->msg)
goto out_no_msg;
ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
if (!ctx->sinfo)
goto out_no_sinfo;
ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature),
GFP_KERNEL);
if (!ctx->sinfo->sig)
goto out_no_sig;
ctx->data = (unsigned long)data;
ctx->ppcerts = &ctx->certs;
ctx->ppsinfo = &ctx->msg->signed_infos;
/* Attempt to decode the signature */
ret = asn1_ber_decoder(&pkcs7_decoder, ctx, data, datalen);
if (ret < 0) {
msg = ERR_PTR(ret);
goto out;
}
ret = pkcs7_check_authattrs(ctx->msg);
if (ret < 0) {
msg = ERR_PTR(ret);
goto out;
}
msg = ctx->msg;
ctx->msg = NULL;
out:
while (ctx->certs) {
struct x509_certificate *cert = ctx->certs;
ctx->certs = cert->next;
x509_free_certificate(cert);
}
out_no_sig:
pkcs7_free_signed_info(ctx->sinfo);
out_no_sinfo:
pkcs7_free_message(ctx->msg);
out_no_msg:
kfree(ctx);
out_no_ctx:
return msg;
}
EXPORT_SYMBOL_GPL(pkcs7_parse_message);
/**
* pkcs7_get_content_data - Get access to the PKCS#7 content
* @pkcs7: The preparsed PKCS#7 message to access
* @_data: Place to return a pointer to the data
* @_data_len: Place to return the data length
* @_headerlen: Size of ASN.1 header not included in _data
*
* Get access to the data content of the PKCS#7 message. The size of the
* header of the ASN.1 object that contains it is also provided and can be used
* to adjust *_data and *_data_len to get the entire object.
*
* Returns -ENODATA if the data object was missing from the message.
*/
int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
const void **_data, size_t *_data_len,
size_t *_headerlen)
{
if (!pkcs7->data)
return -ENODATA;
*_data = pkcs7->data;
*_data_len = pkcs7->data_len;
if (_headerlen)
*_headerlen = pkcs7->data_hdrlen;
return 0;
}
EXPORT_SYMBOL_GPL(pkcs7_get_content_data);
/*
* Note an OID when we find one for later processing when we know how
* to interpret it.
*/
int pkcs7_note_OID(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
ctx->last_oid = look_up_OID(value, vlen);
if (ctx->last_oid == OID__NR) {
char buffer[50];
sprint_oid(value, vlen, buffer, sizeof(buffer));
printk("PKCS7: Unknown OID: [%lu] %s\n",
(unsigned long)value - ctx->data, buffer);
}
return 0;
}
/*
* Note the digest algorithm for the signature.
*/
int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
switch (ctx->last_oid) {
case OID_sha1:
ctx->sinfo->sig->hash_algo = "sha1";
break;
case OID_sha256:
ctx->sinfo->sig->hash_algo = "sha256";
break;
case OID_sha384:
ctx->sinfo->sig->hash_algo = "sha384";
break;
case OID_sha512:
ctx->sinfo->sig->hash_algo = "sha512";
break;
case OID_sha224:
ctx->sinfo->sig->hash_algo = "sha224";
break;
case OID_sm3:
ctx->sinfo->sig->hash_algo = "sm3";
break;
case OID_gost2012Digest256:
ctx->sinfo->sig->hash_algo = "streebog256";
break;
case OID_gost2012Digest512:
ctx->sinfo->sig->hash_algo = "streebog512";
break;
case OID_sha3_256:
ctx->sinfo->sig->hash_algo = "sha3-256";
break;
case OID_sha3_384:
ctx->sinfo->sig->hash_algo = "sha3-384";
break;
case OID_sha3_512:
ctx->sinfo->sig->hash_algo = "sha3-512";
break;
default:
printk("Unsupported digest algo: %u\n", ctx->last_oid);
return -ENOPKG;
}
return 0;
}
/*
* Note the public key algorithm for the signature.
*/
int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
switch (ctx->last_oid) {
case OID_rsaEncryption:
ctx->sinfo->sig->pkey_algo = "rsa";
ctx->sinfo->sig->encoding = "pkcs1";
break;
case OID_id_ecdsa_with_sha1:
case OID_id_ecdsa_with_sha224:
case OID_id_ecdsa_with_sha256:
case OID_id_ecdsa_with_sha384:
case OID_id_ecdsa_with_sha512:
case OID_id_ecdsa_with_sha3_256:
case OID_id_ecdsa_with_sha3_384:
case OID_id_ecdsa_with_sha3_512:
ctx->sinfo->sig->pkey_algo = "ecdsa";
ctx->sinfo->sig->encoding = "x962";
break;
case OID_gost2012PKey256:
case OID_gost2012PKey512:
ctx->sinfo->sig->pkey_algo = "ecrdsa";
ctx->sinfo->sig->encoding = "raw";
break;
default:
printk("Unsupported pkey algo: %u\n", ctx->last_oid);
return -ENOPKG;
}
return 0;
}
/*
* We only support signed data [RFC2315 sec 9].
*/
int pkcs7_check_content_type(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
if (ctx->last_oid != OID_signed_data) {
pr_warn("Only support pkcs7_signedData type\n");
return -EINVAL;
}
return 0;
}
/*
* Note the SignedData version
*/
int pkcs7_note_signeddata_version(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
unsigned version;
if (vlen != 1)
goto unsupported;
ctx->msg->version = version = *(const u8 *)value;
switch (version) {
case 1:
/* PKCS#7 SignedData [RFC2315 sec 9.1]
* CMS ver 1 SignedData [RFC5652 sec 5.1]
*/
break;
case 3:
/* CMS ver 3 SignedData [RFC2315 sec 5.1] */
break;
default:
goto unsupported;
}
return 0;
unsupported:
pr_warn("Unsupported SignedData version\n");
return -EINVAL;
}
/*
* Note the SignerInfo version
*/
int pkcs7_note_signerinfo_version(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
unsigned version;
if (vlen != 1)
goto unsupported;
version = *(const u8 *)value;
switch (version) {
case 1:
/* PKCS#7 SignerInfo [RFC2315 sec 9.2]
* CMS ver 1 SignerInfo [RFC5652 sec 5.3]
*/
if (ctx->msg->version != 1)
goto version_mismatch;
ctx->expect_skid = false;
break;
case 3:
/* CMS ver 3 SignerInfo [RFC2315 sec 5.3] */
if (ctx->msg->version == 1)
goto version_mismatch;
ctx->expect_skid = true;
break;
default:
goto unsupported;
}
return 0;
unsupported:
pr_warn("Unsupported SignerInfo version\n");
return -EINVAL;
version_mismatch:
pr_warn("SignedData-SignerInfo version mismatch\n");
return -EBADMSG;
}
/*
* Extract a certificate and store it in the context.
*/
int pkcs7_extract_cert(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
struct x509_certificate *x509;
if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) {
pr_debug("Cert began with tag %02x at %lu\n",
tag, (unsigned long)ctx - ctx->data);
return -EBADMSG;
}
/* We have to correct for the header so that the X.509 parser can start
* from the beginning. Note that since X.509 stipulates DER, there
* probably shouldn't be an EOC trailer - but it is in PKCS#7 (which
* stipulates BER).
*/
value -= hdrlen;
vlen += hdrlen;
if (((u8*)value)[1] == 0x80)
vlen += 2; /* Indefinite length - there should be an EOC */
x509 = x509_cert_parse(value, vlen);
if (IS_ERR(x509))
return PTR_ERR(x509);
x509->index = ++ctx->x509_index;
pr_debug("Got cert %u for %s\n", x509->index, x509->subject);
pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data);
*ctx->ppcerts = x509;
ctx->ppcerts = &x509->next;
return 0;
}
/*
* Save the certificate list
*/
int pkcs7_note_certificate_list(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
pr_devel("Got cert list (%02x)\n", tag);
*ctx->ppcerts = ctx->msg->certs;
ctx->msg->certs = ctx->certs;
ctx->certs = NULL;
ctx->ppcerts = &ctx->certs;
return 0;
}
/*
* Note the content type.
*/
int pkcs7_note_content(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
if (ctx->last_oid != OID_data &&
ctx->last_oid != OID_msIndirectData) {
pr_warn("Unsupported data type %d\n", ctx->last_oid);
return -EINVAL;
}
ctx->msg->data_type = ctx->last_oid;
return 0;
}
/*
* Extract the data from the message and store that and its content type OID in
* the context.
*/
int pkcs7_note_data(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
pr_debug("Got data\n");
ctx->msg->data = value;
ctx->msg->data_len = vlen;
ctx->msg->data_hdrlen = hdrlen;
return 0;
}
/*
* Parse authenticated attributes.
*/
int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
struct pkcs7_signed_info *sinfo = ctx->sinfo;
enum OID content_type;
pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
switch (ctx->last_oid) {
case OID_contentType:
if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set))
goto repeated;
content_type = look_up_OID(value, vlen);
if (content_type != ctx->msg->data_type) {
pr_warn("Mismatch between global data type (%d) and sinfo %u (%d)\n",
ctx->msg->data_type, sinfo->index,
content_type);
return -EBADMSG;
}
return 0;
case OID_signingTime:
if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set))
goto repeated;
/* Should we check that the signing time is consistent
* with the signer's X.509 cert?
*/
return x509_decode_time(&sinfo->signing_time,
hdrlen, tag, value, vlen);
case OID_messageDigest:
if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set))
goto repeated;
if (tag != ASN1_OTS)
return -EBADMSG;
sinfo->msgdigest = value;
sinfo->msgdigest_len = vlen;
return 0;
case OID_smimeCapabilites:
if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set))
goto repeated;
if (ctx->msg->data_type != OID_msIndirectData) {
pr_warn("S/MIME Caps only allowed with Authenticode\n");
return -EKEYREJECTED;
}
return 0;
/* Microsoft SpOpusInfo seems to be contain cont[0] 16-bit BE
* char URLs and cont[1] 8-bit char URLs.
*
* Microsoft StatementType seems to contain a list of OIDs that
* are also used as extendedKeyUsage types in X.509 certs.
*/
case OID_msSpOpusInfo:
if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set))
goto repeated;
goto authenticode_check;
case OID_msStatementType:
if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set))
goto repeated;
authenticode_check:
if (ctx->msg->data_type != OID_msIndirectData) {
pr_warn("Authenticode AuthAttrs only allowed with Authenticode\n");
return -EKEYREJECTED;
}
/* I'm not sure how to validate these */
return 0;
default:
return 0;
}
repeated:
/* We permit max one item per AuthenticatedAttribute and no repeats */
pr_warn("Repeated/multivalue AuthAttrs not permitted\n");
return -EKEYREJECTED;
}
/*
* Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3]
*/
int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
struct pkcs7_signed_info *sinfo = ctx->sinfo;
if (!test_bit(sinfo_has_content_type, &sinfo->aa_set) ||
!test_bit(sinfo_has_message_digest, &sinfo->aa_set)) {
pr_warn("Missing required AuthAttr\n");
return -EBADMSG;
}
if (ctx->msg->data_type != OID_msIndirectData &&
test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) {
pr_warn("Unexpected Authenticode AuthAttr\n");
return -EBADMSG;
}
/* We need to switch the 'CONT 0' to a 'SET OF' when we digest */
sinfo->authattrs = value - (hdrlen - 1);
sinfo->authattrs_len = vlen + (hdrlen - 1);
return 0;
}
/*
* Note the issuing certificate serial number
*/
int pkcs7_sig_note_serial(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
ctx->raw_serial = value;
ctx->raw_serial_size = vlen;
return 0;
}
/*
* Note the issuer's name
*/
int pkcs7_sig_note_issuer(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
ctx->raw_issuer = value;
ctx->raw_issuer_size = vlen;
return 0;
}
/*
* Note the issuing cert's subjectKeyIdentifier
*/
int pkcs7_sig_note_skid(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
pr_devel("SKID: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
ctx->raw_skid = value;
ctx->raw_skid_size = vlen;
return 0;
}
/*
* Note the signature data
*/
int pkcs7_sig_note_signature(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
ctx->sinfo->sig->s = kmemdup(value, vlen, GFP_KERNEL);
if (!ctx->sinfo->sig->s)
return -ENOMEM;
ctx->sinfo->sig->s_size = vlen;
return 0;
}
/*
* Note a signature information block
*/
int pkcs7_note_signed_info(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
struct pkcs7_signed_info *sinfo = ctx->sinfo;
struct asymmetric_key_id *kid;
if (ctx->msg->data_type == OID_msIndirectData && !sinfo->authattrs) {
pr_warn("Authenticode requires AuthAttrs\n");
return -EBADMSG;
}
/* Generate cert issuer + serial number key ID */
if (!ctx->expect_skid) {
kid = asymmetric_key_generate_id(ctx->raw_serial,
ctx->raw_serial_size,
ctx->raw_issuer,
ctx->raw_issuer_size);
} else {
kid = asymmetric_key_generate_id(ctx->raw_skid,
ctx->raw_skid_size,
"", 0);
}
if (IS_ERR(kid))
return PTR_ERR(kid);
pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data);
sinfo->sig->auth_ids[0] = kid;
sinfo->index = ++ctx->sinfo_index;
*ctx->ppsinfo = sinfo;
ctx->ppsinfo = &sinfo->next;
ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
if (!ctx->sinfo)
return -ENOMEM;
ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature),
GFP_KERNEL);
if (!ctx->sinfo->sig)
return -ENOMEM;
return 0;
}
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