linux/crypto/asymmetric_keys/pkcs7_parser.c
David Howells e68503bd68 KEYS: Generalise system_verify_data() to provide access to internal content
Generalise system_verify_data() to provide access to internal content
through a callback.  This allows all the PKCS#7 stuff to be hidden inside
this function and removed from the PE file parser and the PKCS#7 test key.

If external content is not required, NULL should be passed as data to the
function.  If the callback is not required, that can be set to NULL.

The function is now called verify_pkcs7_signature() to contrast with
verify_pefile_signature() and the definitions of both have been moved into
linux/verification.h along with the key_being_used_for enum.

Signed-off-by: David Howells <dhowells@redhat.com>
2016-04-06 16:14:24 +01:00

676 lines
16 KiB
C

/* PKCS#7 parser
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#define pr_fmt(fmt) "PKCS7: "fmt
#include <linux/kernel.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"
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->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)
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_md4:
ctx->sinfo->sig->hash_algo = "md4";
break;
case OID_md5:
ctx->sinfo->sig->hash_algo = "md5";
break;
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;
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";
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;
}