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: David Howells <dhowells@redhat.com>
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index d8d8d23..1426f03 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 = PTR_ALIGN(digest + digest_size, __alignof__(*desc));
+ desc = kzalloc(desc_size, GFP_KERNEL);
+ if (!desc)
+ goto error_no_desc;
+
desc->tfm = tfm;
desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
@@ -60,10 +62,11 @@
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 @@
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 @@
* 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 @@
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 @@
* 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 @@
*/
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 @@
}
/* 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;