[RFC PATCH 5/7] PKCS#7: Make the signature a pointer rather than embedding it
From: David Howells
Date: Mon Feb 29 2016 - 13:22:19 EST
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: David Howells <dhowells@xxxxxxxxxx>
---
crypto/asymmetric_keys/pkcs7_parser.c | 38 +++++++++++++++----------
crypto/asymmetric_keys/pkcs7_parser.h | 10 +++---
crypto/asymmetric_keys/pkcs7_trust.c | 4 +--
crypto/asymmetric_keys/pkcs7_verify.c | 51 +++++++++++++++++----------------
4 files changed, 55 insertions(+), 48 deletions(-)
diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c
index 40de03f49ff8..835701613125 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.c
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -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 @@ out:
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;
}
diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h
index a66b19ebcf47..d5eec31e95b6 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.h
+++ b/crypto/asymmetric_keys/pkcs7_parser.h
@@ -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 {
diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index bf89e006bd07..554200284ea8 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -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)) {
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index d8d8d234874e..1426f03e630b 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -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;