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Commit 566a117a authored by David Howells's avatar David Howells
Browse files

PKCS#7: Make the signature a pointer rather than embedding it 



Point to the public_key_signature struct from the pkcs7_signed_info struct
rather than embedding it.  This makes the code consistent with the X.509
signature handling and makes it possible to have a common cleanup function.

We also save a copy of the digest in the signature without sharing the
memory with the crypto layer metadata.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 77d0910d

crypto/asymmetric_keys/pkcs7_parser.c

+23 −15
Original line number Diff line number Diff line
@@ -44,9 +44,7 @@ struct pkcs7_parse_context { 
static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo)

{

	if (sinfo) {

		kfree(sinfo->sig.s);

		kfree(sinfo->sig.digest);

		kfree(sinfo->signing_cert_id);

		public_key_signature_free(sinfo->sig);

		kfree(sinfo);

	}

}
@@ -125,6 +123,10 @@ struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen) 
	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;
@@ -150,6 +152,7 @@ struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen) 
		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);
@@ -218,25 +221,26 @@ int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen, 


	switch (ctx->last_oid) {

	case OID_md4:

		ctx->sinfo->sig.hash_algo = "md4";

		ctx->sinfo->sig->hash_algo = "md4";

		break;

	case OID_md5:

		ctx->sinfo->sig.hash_algo = "md5";

		ctx->sinfo->sig->hash_algo = "md5";

		break;

	case OID_sha1:

		ctx->sinfo->sig.hash_algo = "sha1";

		ctx->sinfo->sig->hash_algo = "sha1";

		break;

	case OID_sha256:

		ctx->sinfo->sig.hash_algo = "sha256";

		ctx->sinfo->sig->hash_algo = "sha256";

		break;

	case OID_sha384:

		ctx->sinfo->sig.hash_algo = "sha384";

		ctx->sinfo->sig->hash_algo = "sha384";

		break;

	case OID_sha512:

		ctx->sinfo->sig.hash_algo = "sha512";

		ctx->sinfo->sig->hash_algo = "sha512";

		break;

	case OID_sha224:

		ctx->sinfo->sig.hash_algo = "sha224";

		ctx->sinfo->sig->hash_algo = "sha224";

		break;

	default:

		printk("Unsupported digest algo: %u\n", ctx->last_oid);

		return -ENOPKG;
@@ -255,7 +259,7 @@ int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen, 


	switch (ctx->last_oid) {

	case OID_rsaEncryption:

		ctx->sinfo->sig.pkey_algo = "rsa";

		ctx->sinfo->sig->pkey_algo = "rsa";

		break;

	default:

		printk("Unsupported pkey algo: %u\n", ctx->last_oid);
@@ -615,11 +619,11 @@ int pkcs7_sig_note_signature(void *context, size_t hdrlen, 
{

	struct pkcs7_parse_context *ctx = context;



	ctx->sinfo->sig.s = kmemdup(value, vlen, GFP_KERNEL);

	if (!ctx->sinfo->sig.s)

	ctx->sinfo->sig->s = kmemdup(value, vlen, GFP_KERNEL);

	if (!ctx->sinfo->sig->s)

		return -ENOMEM;



	ctx->sinfo->sig.s_size = vlen;

	ctx->sinfo->sig->s_size = vlen;

	return 0;

}
@@ -655,12 +659,16 @@ int pkcs7_note_signed_info(void *context, size_t hdrlen, 


	pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data);



	sinfo->signing_cert_id = kid;

	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;

}

crypto/asymmetric_keys/pkcs7_parser.h

+4 −6
Original line number Diff line number Diff line
@@ -41,19 +41,17 @@ struct pkcs7_signed_info { 
#define	sinfo_has_ms_statement_type	5

	time64_t	signing_time;



	/* Issuing cert serial number and issuer's name [PKCS#7 or CMS ver 1]

	 * or issuing cert's SKID [CMS ver 3].

	 */

	struct asymmetric_key_id *signing_cert_id;



	/* Message signature.

	 *

	 * This contains the generated digest of _either_ the Content Data or

	 * the Authenticated Attributes [RFC2315 9.3].  If the latter, one of

	 * the attributes contains the digest of the the Content Data within

	 * it.

	 *

	 * THis also contains the issuing cert serial number and issuer's name

	 * [PKCS#7 or CMS ver 1] or issuing cert's SKID [CMS ver 3].

	 */

	struct public_key_signature sig;

	struct public_key_signature *sig;

};



struct pkcs7_message {

crypto/asymmetric_keys/pkcs7_trust.c

+2 −2
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, 
				    struct pkcs7_signed_info *sinfo,

				    struct key *trust_keyring)

{

	struct public_key_signature *sig = &sinfo->sig;

	struct public_key_signature *sig = sinfo->sig;

	struct x509_certificate *x509, *last = NULL, *p;

	struct key *key;

	bool trusted;
@@ -105,7 +105,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, 
	 * the signed info directly.

	 */

	key = x509_request_asymmetric_key(trust_keyring,

					  sinfo->signing_cert_id,

					  sinfo->sig->auth_ids[0],

					  NULL,

					  false);

	if (!IS_ERR(key)) {

crypto/asymmetric_keys/pkcs7_verify.c

+26 −25
Original line number Diff line number Diff line
@@ -25,34 +25,36 @@ 
static int pkcs7_digest(struct pkcs7_message *pkcs7,

			struct pkcs7_signed_info *sinfo)

{

	struct public_key_signature *sig = sinfo->sig;

	struct crypto_shash *tfm;

	struct shash_desc *desc;

	size_t digest_size, desc_size;

	void *digest;

	size_t desc_size;

	int ret;



	kenter(",%u,%s", sinfo->index, sinfo->sig.hash_algo);

	kenter(",%u,%s", sinfo->index, sinfo->sig->hash_algo);



	if (!sinfo->sig.hash_algo)

	if (!sinfo->sig->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(sinfo->sig.hash_algo, 0, 0);

	tfm = crypto_alloc_shash(sinfo->sig->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);

	sig->digest_size = crypto_shash_digestsize(tfm);



	ret = -ENOMEM;

	digest = kzalloc(ALIGN(digest_size, __alignof__(*desc)) + desc_size,

			 GFP_KERNEL);

	if (!digest)

	sig->digest = kmalloc(sig->digest_size, GFP_KERNEL);

	if (!sig->digest)

		goto error_no_desc;



	desc = kzalloc(desc_size, GFP_KERNEL);

	if (!desc)

		goto error_no_desc;



	desc = PTR_ALIGN(digest + digest_size, __alignof__(*desc));

	desc->tfm   = tfm;

	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
@@ -60,10 +62,11 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7, 
	ret = crypto_shash_init(desc);

	if (ret < 0)

		goto error;

	ret = crypto_shash_finup(desc, pkcs7->data, pkcs7->data_len, digest);

	ret = crypto_shash_finup(desc, pkcs7->data, pkcs7->data_len,

				 sig->digest);

	if (ret < 0)

		goto error;

	pr_devel("MsgDigest = [%*ph]\n", 8, digest);

	pr_devel("MsgDigest = [%*ph]\n", 8, sig->digest);



	/* However, if there are authenticated attributes, there must be a

	 * message digest attribute amongst them which corresponds to the
@@ -78,14 +81,15 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7, 
			goto error;

		}



		if (sinfo->msgdigest_len != sinfo->sig.digest_size) {

		if (sinfo->msgdigest_len != 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) {

		if (memcmp(sig->digest, sinfo->msgdigest,

			   sinfo->msgdigest_len) != 0) {

			pr_debug("Sig %u: Message digest doesn't match\n",

				 sinfo->index);

			ret = -EKEYREJECTED;
@@ -97,7 +101,7 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7, 
		 * convert the attributes from a CONT.0 into a SET before we

		 * hash it.

		 */

		memset(digest, 0, sinfo->sig.digest_size);

		memset(sig->digest, 0, sig->digest_size);



		ret = crypto_shash_init(desc);

		if (ret < 0)
@@ -107,17 +111,14 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7, 
		if (ret < 0)

			goto error;

		ret = crypto_shash_finup(desc, sinfo->authattrs,

					 sinfo->authattrs_len, digest);

					 sinfo->authattrs_len, sig->digest);

		if (ret < 0)

			goto error;

		pr_devel("AADigest = [%*ph]\n", 8, digest);

		pr_devel("AADigest = [%*ph]\n", 8, sig->digest);

	}



	sinfo->sig.digest = digest;

	digest = NULL;



error:

	kfree(digest);

	kfree(desc);

error_no_desc:

	crypto_free_shash(tfm);

	kleave(" = %d", ret);
@@ -144,12 +145,12 @@ static int pkcs7_find_key(struct pkcs7_message *pkcs7, 
		 * 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))

		if (!asymmetric_key_id_same(x509->id, sinfo->sig->auth_ids[0]))

			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) {

		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;
@@ -164,7 +165,7 @@ static int pkcs7_find_key(struct pkcs7_message *pkcs7, 
	 */

	pr_debug("Sig %u: Issuing X.509 cert not found (#%*phN)\n",

		 sinfo->index,

		 sinfo->signing_cert_id->len, sinfo->signing_cert_id->data);

		 sinfo->sig->auth_ids[0]->len, sinfo->sig->auth_ids[0]->data);

	return 0;

}
@@ -334,7 +335,7 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7, 
	}



	/* Verify the PKCS#7 binary against the key */

	ret = public_key_verify_signature(sinfo->signer->pub, &sinfo->sig);

	ret = public_key_verify_signature(sinfo->signer->pub, sinfo->sig);

	if (ret < 0)

		return ret;