mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-22 00:40:03 +00:00
![Sowmini Varadhan](/assets/img/avatar_default.png)
On sparc, we see unaligned access messages on each modprobe[-r]: Kernel unaligned access at TPC[6ad9b4] pkcs7_verify [..] Kernel unaligned access at TPC[6a5484] crypto_shash_finup [..] Kernel unaligned access at TPC[6a5390] crypto_shash_update [..] Kernel unaligned access at TPC[10150308] sha1_sparc64_update [..] Kernel unaligned access at TPC[101501ac] __sha1_sparc64_update [..] These ware triggered by mod_verify_sig() invocations of pkcs_verify(), and are are being caused by an unaligned desc at (sha1, digest_size is 0x14) desc = digest + digest_size; To fix this, pkcs7_verify needs to make sure that desc is pointing at an aligned value past the digest_size, and kzalloc appropriately, taking alignment values into consideration. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
471 lines
13 KiB
C
471 lines
13 KiB
C
/* Verify the signature on a PKCS#7 message.
|
|
*
|
|
* 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/asn1.h>
|
|
#include <crypto/hash.h>
|
|
#include "public_key.h"
|
|
#include "pkcs7_parser.h"
|
|
|
|
/*
|
|
* Digest the relevant parts of the PKCS#7 data
|
|
*/
|
|
static int pkcs7_digest(struct pkcs7_message *pkcs7,
|
|
struct pkcs7_signed_info *sinfo)
|
|
{
|
|
struct crypto_shash *tfm;
|
|
struct shash_desc *desc;
|
|
size_t digest_size, desc_size;
|
|
void *digest;
|
|
int ret;
|
|
|
|
kenter(",%u,%u", sinfo->index, sinfo->sig.pkey_hash_algo);
|
|
|
|
if (sinfo->sig.pkey_hash_algo >= PKEY_HASH__LAST ||
|
|
!hash_algo_name[sinfo->sig.pkey_hash_algo])
|
|
return -ENOPKG;
|
|
|
|
/* Allocate the hashing algorithm we're going to need and find out how
|
|
* big the hash operational data will be.
|
|
*/
|
|
tfm = crypto_alloc_shash(hash_algo_name[sinfo->sig.pkey_hash_algo],
|
|
0, 0);
|
|
if (IS_ERR(tfm))
|
|
return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm);
|
|
|
|
desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
|
|
sinfo->sig.digest_size = digest_size = crypto_shash_digestsize(tfm);
|
|
|
|
ret = -ENOMEM;
|
|
digest = kzalloc(ALIGN(digest_size, __alignof__(*desc)) + desc_size,
|
|
GFP_KERNEL);
|
|
if (!digest)
|
|
goto error_no_desc;
|
|
|
|
desc = PTR_ALIGN(digest + digest_size, __alignof__(*desc));
|
|
desc->tfm = tfm;
|
|
desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
|
|
|
|
/* Digest the message [RFC2315 9.3] */
|
|
ret = crypto_shash_init(desc);
|
|
if (ret < 0)
|
|
goto error;
|
|
ret = crypto_shash_finup(desc, pkcs7->data, pkcs7->data_len, digest);
|
|
if (ret < 0)
|
|
goto error;
|
|
pr_devel("MsgDigest = [%*ph]\n", 8, digest);
|
|
|
|
/* However, if there are authenticated attributes, there must be a
|
|
* message digest attribute amongst them which corresponds to the
|
|
* digest we just calculated.
|
|
*/
|
|
if (sinfo->authattrs) {
|
|
u8 tag;
|
|
|
|
if (!sinfo->msgdigest) {
|
|
pr_warn("Sig %u: No messageDigest\n", sinfo->index);
|
|
ret = -EKEYREJECTED;
|
|
goto error;
|
|
}
|
|
|
|
if (sinfo->msgdigest_len != sinfo->sig.digest_size) {
|
|
pr_debug("Sig %u: Invalid digest size (%u)\n",
|
|
sinfo->index, sinfo->msgdigest_len);
|
|
ret = -EBADMSG;
|
|
goto error;
|
|
}
|
|
|
|
if (memcmp(digest, sinfo->msgdigest, sinfo->msgdigest_len) != 0) {
|
|
pr_debug("Sig %u: Message digest doesn't match\n",
|
|
sinfo->index);
|
|
ret = -EKEYREJECTED;
|
|
goto error;
|
|
}
|
|
|
|
/* We then calculate anew, using the authenticated attributes
|
|
* as the contents of the digest instead. Note that we need to
|
|
* convert the attributes from a CONT.0 into a SET before we
|
|
* hash it.
|
|
*/
|
|
memset(digest, 0, sinfo->sig.digest_size);
|
|
|
|
ret = crypto_shash_init(desc);
|
|
if (ret < 0)
|
|
goto error;
|
|
tag = ASN1_CONS_BIT | ASN1_SET;
|
|
ret = crypto_shash_update(desc, &tag, 1);
|
|
if (ret < 0)
|
|
goto error;
|
|
ret = crypto_shash_finup(desc, sinfo->authattrs,
|
|
sinfo->authattrs_len, digest);
|
|
if (ret < 0)
|
|
goto error;
|
|
pr_devel("AADigest = [%*ph]\n", 8, digest);
|
|
}
|
|
|
|
sinfo->sig.digest = digest;
|
|
digest = NULL;
|
|
|
|
error:
|
|
kfree(digest);
|
|
error_no_desc:
|
|
crypto_free_shash(tfm);
|
|
kleave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Find the key (X.509 certificate) to use to verify a PKCS#7 message. PKCS#7
|
|
* uses the issuer's name and the issuing certificate serial number for
|
|
* matching purposes. These must match the certificate issuer's name (not
|
|
* subject's name) and the certificate serial number [RFC 2315 6.7].
|
|
*/
|
|
static int pkcs7_find_key(struct pkcs7_message *pkcs7,
|
|
struct pkcs7_signed_info *sinfo)
|
|
{
|
|
struct x509_certificate *x509;
|
|
unsigned certix = 1;
|
|
|
|
kenter("%u", sinfo->index);
|
|
|
|
for (x509 = pkcs7->certs; x509; x509 = x509->next, certix++) {
|
|
/* I'm _assuming_ that the generator of the PKCS#7 message will
|
|
* encode the fields from the X.509 cert in the same way in the
|
|
* PKCS#7 message - but I can't be 100% sure of that. It's
|
|
* possible this will need element-by-element comparison.
|
|
*/
|
|
if (!asymmetric_key_id_same(x509->id, sinfo->signing_cert_id))
|
|
continue;
|
|
pr_devel("Sig %u: Found cert serial match X.509[%u]\n",
|
|
sinfo->index, certix);
|
|
|
|
if (x509->pub->pkey_algo != sinfo->sig.pkey_algo) {
|
|
pr_warn("Sig %u: X.509 algo and PKCS#7 sig algo don't match\n",
|
|
sinfo->index);
|
|
continue;
|
|
}
|
|
|
|
sinfo->signer = x509;
|
|
return 0;
|
|
}
|
|
|
|
/* The relevant X.509 cert isn't found here, but it might be found in
|
|
* the trust keyring.
|
|
*/
|
|
pr_debug("Sig %u: Issuing X.509 cert not found (#%*phN)\n",
|
|
sinfo->index,
|
|
sinfo->signing_cert_id->len, sinfo->signing_cert_id->data);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Verify the internal certificate chain as best we can.
|
|
*/
|
|
static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
|
|
struct pkcs7_signed_info *sinfo)
|
|
{
|
|
struct x509_certificate *x509 = sinfo->signer, *p;
|
|
struct asymmetric_key_id *auth;
|
|
int ret;
|
|
|
|
kenter("");
|
|
|
|
for (p = pkcs7->certs; p; p = p->next)
|
|
p->seen = false;
|
|
|
|
for (;;) {
|
|
pr_debug("verify %s: %*phN\n",
|
|
x509->subject,
|
|
x509->raw_serial_size, x509->raw_serial);
|
|
x509->seen = true;
|
|
ret = x509_get_sig_params(x509);
|
|
if (ret < 0)
|
|
goto maybe_missing_crypto_in_x509;
|
|
|
|
pr_debug("- issuer %s\n", x509->issuer);
|
|
if (x509->akid_id)
|
|
pr_debug("- authkeyid.id %*phN\n",
|
|
x509->akid_id->len, x509->akid_id->data);
|
|
if (x509->akid_skid)
|
|
pr_debug("- authkeyid.skid %*phN\n",
|
|
x509->akid_skid->len, x509->akid_skid->data);
|
|
|
|
if ((!x509->akid_id && !x509->akid_skid) ||
|
|
strcmp(x509->subject, x509->issuer) == 0) {
|
|
/* If there's no authority certificate specified, then
|
|
* the certificate must be self-signed and is the root
|
|
* of the chain. Likewise if the cert is its own
|
|
* authority.
|
|
*/
|
|
pr_debug("- no auth?\n");
|
|
if (x509->raw_subject_size != x509->raw_issuer_size ||
|
|
memcmp(x509->raw_subject, x509->raw_issuer,
|
|
x509->raw_issuer_size) != 0)
|
|
return 0;
|
|
|
|
ret = x509_check_signature(x509->pub, x509);
|
|
if (ret < 0)
|
|
goto maybe_missing_crypto_in_x509;
|
|
x509->signer = x509;
|
|
pr_debug("- self-signed\n");
|
|
return 0;
|
|
}
|
|
|
|
/* Look through the X.509 certificates in the PKCS#7 message's
|
|
* list to see if the next one is there.
|
|
*/
|
|
auth = x509->akid_id;
|
|
if (auth) {
|
|
pr_debug("- want %*phN\n", auth->len, auth->data);
|
|
for (p = pkcs7->certs; p; p = p->next) {
|
|
pr_debug("- cmp [%u] %*phN\n",
|
|
p->index, p->id->len, p->id->data);
|
|
if (asymmetric_key_id_same(p->id, auth))
|
|
goto found_issuer_check_skid;
|
|
}
|
|
} else {
|
|
auth = x509->akid_skid;
|
|
pr_debug("- want %*phN\n", auth->len, auth->data);
|
|
for (p = pkcs7->certs; p; p = p->next) {
|
|
if (!p->skid)
|
|
continue;
|
|
pr_debug("- cmp [%u] %*phN\n",
|
|
p->index, p->skid->len, p->skid->data);
|
|
if (asymmetric_key_id_same(p->skid, auth))
|
|
goto found_issuer;
|
|
}
|
|
}
|
|
|
|
/* We didn't find the root of this chain */
|
|
pr_debug("- top\n");
|
|
return 0;
|
|
|
|
found_issuer_check_skid:
|
|
/* We matched issuer + serialNumber, but if there's an
|
|
* authKeyId.keyId, that must match the CA subjKeyId also.
|
|
*/
|
|
if (x509->akid_skid &&
|
|
!asymmetric_key_id_same(p->skid, x509->akid_skid)) {
|
|
pr_warn("Sig %u: X.509 chain contains auth-skid nonmatch (%u->%u)\n",
|
|
sinfo->index, x509->index, p->index);
|
|
return -EKEYREJECTED;
|
|
}
|
|
found_issuer:
|
|
pr_debug("- subject %s\n", p->subject);
|
|
if (p->seen) {
|
|
pr_warn("Sig %u: X.509 chain contains loop\n",
|
|
sinfo->index);
|
|
return 0;
|
|
}
|
|
ret = x509_check_signature(p->pub, x509);
|
|
if (ret < 0)
|
|
return ret;
|
|
x509->signer = p;
|
|
if (x509 == p) {
|
|
pr_debug("- self-signed\n");
|
|
return 0;
|
|
}
|
|
x509 = p;
|
|
might_sleep();
|
|
}
|
|
|
|
maybe_missing_crypto_in_x509:
|
|
/* Just prune the certificate chain at this point if we lack some
|
|
* crypto module to go further. Note, however, we don't want to set
|
|
* sinfo->missing_crypto as the signed info block may still be
|
|
* validatable against an X.509 cert lower in the chain that we have a
|
|
* trusted copy of.
|
|
*/
|
|
if (ret == -ENOPKG)
|
|
return 0;
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Verify one signed information block from a PKCS#7 message.
|
|
*/
|
|
static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
|
|
struct pkcs7_signed_info *sinfo)
|
|
{
|
|
int ret;
|
|
|
|
kenter(",%u", sinfo->index);
|
|
|
|
/* First of all, digest the data in the PKCS#7 message and the
|
|
* signed information block
|
|
*/
|
|
ret = pkcs7_digest(pkcs7, sinfo);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/* Find the key for the signature if there is one */
|
|
ret = pkcs7_find_key(pkcs7, sinfo);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (!sinfo->signer)
|
|
return 0;
|
|
|
|
pr_devel("Using X.509[%u] for sig %u\n",
|
|
sinfo->signer->index, sinfo->index);
|
|
|
|
/* Check that the PKCS#7 signing time is valid according to the X.509
|
|
* certificate. We can't, however, check against the system clock
|
|
* since that may not have been set yet and may be wrong.
|
|
*/
|
|
if (test_bit(sinfo_has_signing_time, &sinfo->aa_set)) {
|
|
if (sinfo->signing_time < sinfo->signer->valid_from ||
|
|
sinfo->signing_time > sinfo->signer->valid_to) {
|
|
pr_warn("Message signed outside of X.509 validity window\n");
|
|
return -EKEYREJECTED;
|
|
}
|
|
}
|
|
|
|
/* Verify the PKCS#7 binary against the key */
|
|
ret = public_key_verify_signature(sinfo->signer->pub, &sinfo->sig);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
pr_devel("Verified signature %u\n", sinfo->index);
|
|
|
|
/* Verify the internal certificate chain */
|
|
return pkcs7_verify_sig_chain(pkcs7, sinfo);
|
|
}
|
|
|
|
/**
|
|
* pkcs7_verify - Verify a PKCS#7 message
|
|
* @pkcs7: The PKCS#7 message to be verified
|
|
* @usage: The use to which the key is being put
|
|
*
|
|
* Verify a PKCS#7 message is internally consistent - that is, the data digest
|
|
* matches the digest in the AuthAttrs and any signature in the message or one
|
|
* of the X.509 certificates it carries that matches another X.509 cert in the
|
|
* message can be verified.
|
|
*
|
|
* This does not look to match the contents of the PKCS#7 message against any
|
|
* external public keys.
|
|
*
|
|
* Returns, in order of descending priority:
|
|
*
|
|
* (*) -EKEYREJECTED if a key was selected that had a usage restriction at
|
|
* odds with the specified usage, or:
|
|
*
|
|
* (*) -EKEYREJECTED if a signature failed to match for which we found an
|
|
* appropriate X.509 certificate, or:
|
|
*
|
|
* (*) -EBADMSG if some part of the message was invalid, or:
|
|
*
|
|
* (*) -ENOPKG if none of the signature chains are verifiable because suitable
|
|
* crypto modules couldn't be found, or:
|
|
*
|
|
* (*) 0 if all the signature chains that don't incur -ENOPKG can be verified
|
|
* (note that a signature chain may be of zero length), or:
|
|
*/
|
|
int pkcs7_verify(struct pkcs7_message *pkcs7,
|
|
enum key_being_used_for usage)
|
|
{
|
|
struct pkcs7_signed_info *sinfo;
|
|
struct x509_certificate *x509;
|
|
int enopkg = -ENOPKG;
|
|
int ret, n;
|
|
|
|
kenter("");
|
|
|
|
switch (usage) {
|
|
case VERIFYING_MODULE_SIGNATURE:
|
|
if (pkcs7->data_type != OID_data) {
|
|
pr_warn("Invalid module sig (not pkcs7-data)\n");
|
|
return -EKEYREJECTED;
|
|
}
|
|
if (pkcs7->have_authattrs) {
|
|
pr_warn("Invalid module sig (has authattrs)\n");
|
|
return -EKEYREJECTED;
|
|
}
|
|
break;
|
|
case VERIFYING_FIRMWARE_SIGNATURE:
|
|
if (pkcs7->data_type != OID_data) {
|
|
pr_warn("Invalid firmware sig (not pkcs7-data)\n");
|
|
return -EKEYREJECTED;
|
|
}
|
|
if (!pkcs7->have_authattrs) {
|
|
pr_warn("Invalid firmware sig (missing authattrs)\n");
|
|
return -EKEYREJECTED;
|
|
}
|
|
break;
|
|
case VERIFYING_KEXEC_PE_SIGNATURE:
|
|
if (pkcs7->data_type != OID_msIndirectData) {
|
|
pr_warn("Invalid kexec sig (not Authenticode)\n");
|
|
return -EKEYREJECTED;
|
|
}
|
|
/* Authattr presence checked in parser */
|
|
break;
|
|
case VERIFYING_UNSPECIFIED_SIGNATURE:
|
|
if (pkcs7->data_type != OID_data) {
|
|
pr_warn("Invalid unspecified sig (not pkcs7-data)\n");
|
|
return -EKEYREJECTED;
|
|
}
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
for (n = 0, x509 = pkcs7->certs; x509; x509 = x509->next, n++) {
|
|
ret = x509_get_sig_params(x509);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
|
|
ret = pkcs7_verify_one(pkcs7, sinfo);
|
|
if (ret < 0) {
|
|
if (ret == -ENOPKG) {
|
|
sinfo->unsupported_crypto = true;
|
|
continue;
|
|
}
|
|
kleave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
enopkg = 0;
|
|
}
|
|
|
|
kleave(" = %d", enopkg);
|
|
return enopkg;
|
|
}
|
|
EXPORT_SYMBOL_GPL(pkcs7_verify);
|
|
|
|
/**
|
|
* pkcs7_supply_detached_data - Supply the data needed to verify a PKCS#7 message
|
|
* @pkcs7: The PKCS#7 message
|
|
* @data: The data to be verified
|
|
* @datalen: The amount of data
|
|
*
|
|
* Supply the detached data needed to verify a PKCS#7 message. Note that no
|
|
* attempt to retain/pin the data is made. That is left to the caller. The
|
|
* data will not be modified by pkcs7_verify() and will not be freed when the
|
|
* PKCS#7 message is freed.
|
|
*
|
|
* Returns -EINVAL if data is already supplied in the message, 0 otherwise.
|
|
*/
|
|
int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7,
|
|
const void *data, size_t datalen)
|
|
{
|
|
if (pkcs7->data) {
|
|
pr_debug("Data already supplied\n");
|
|
return -EINVAL;
|
|
}
|
|
pkcs7->data = data;
|
|
pkcs7->data_len = datalen;
|
|
return 0;
|
|
}
|