X.509: parse public key parameters from x509 for akcipher

Some public key algorithms (like EC-DSA) keep in parameters field
important data such as digest and curve OIDs (possibly more for
different EC-DSA variants). Thus, just setting a public key (as
for RSA) is not enough.

Append parameters into the key stream for akcipher_set_{pub,priv}_key.
Appended data is: (u32) algo OID, (u32) parameters length, parameters
data.

This does not affect current akcipher API nor RSA ciphers (they could
ignore it). Idea of appending parameters to the key stream is by Herbert
Xu.

Cc: David Howells <dhowells@redhat.com>
Cc: Denis Kenzior <denkenz@gmail.com>
Cc: keyrings@vger.kernel.org
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
Reviewed-by: Denis Kenzior <denkenz@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 57 insertions, 15 deletions

diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index 33093b7bcc47..77e0ae7840ff 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -45,6 +45,7 @@ void public_key_free(struct public_key *key)
 {
 	if (key) {
 		kfree(key->key);
+		kfree(key->params);
 		kfree(key);
 	}
 }
@@ -94,6 +95,12 @@ int software_key_determine_akcipher(const char *encoding,
 	return -ENOPKG;
 }
 
+static u8 *pkey_pack_u32(u8 *dst, u32 val)
+{
+	memcpy(dst, &val, sizeof(val));
+	return dst + sizeof(val);
+}
+
 /*
  * Query information about a key.
  */
@@ -103,6 +110,7 @@ static int software_key_query(const struct kernel_pkey_params *params,
 	struct crypto_akcipher *tfm;
 	struct public_key *pkey = params->key->payload.data[asym_crypto];
 	char alg_name[CRYPTO_MAX_ALG_NAME];
+	u8 *key, *ptr;
 	int ret, len;
 
 	ret = software_key_determine_akcipher(params->encoding,
@@ -115,14 +123,22 @@ static int software_key_query(const struct kernel_pkey_params *params,
 	if (IS_ERR(tfm))
 		return PTR_ERR(tfm);
 
+	key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
+		      GFP_KERNEL);
+	if (!key)
+		goto error_free_tfm;
+	memcpy(key, pkey->key, pkey->keylen);
+	ptr = key + pkey->keylen;
+	ptr = pkey_pack_u32(ptr, pkey->algo);
+	ptr = pkey_pack_u32(ptr, pkey->paramlen);
+	memcpy(ptr, pkey->params, pkey->paramlen);
+
 	if (pkey->key_is_private)
-		ret = crypto_akcipher_set_priv_key(tfm,
-						   pkey->key, pkey->keylen);
+		ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
 	else
-		ret = crypto_akcipher_set_pub_key(tfm,
-						  pkey->key, pkey->keylen);
+		ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
 	if (ret < 0)
-		goto error_free_tfm;
+		goto error_free_key;
 
 	len = crypto_akcipher_maxsize(tfm);
 	info->key_size = len * 8;
@@ -137,6 +153,8 @@ static int software_key_query(const struct kernel_pkey_params *params,
 					KEYCTL_SUPPORTS_SIGN);
 	ret = 0;
 
+error_free_key:
+	kfree(key);
 error_free_tfm:
 	crypto_free_akcipher(tfm);
 	pr_devel("<==%s() = %d\n", __func__, ret);
@@ -155,6 +173,7 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
 	struct crypto_wait cwait;
 	struct scatterlist in_sg, out_sg;
 	char alg_name[CRYPTO_MAX_ALG_NAME];
+	char *key, *ptr;
 	int ret;
 
 	pr_devel("==>%s()\n", __func__);
@@ -173,14 +192,23 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
 	if (!req)
 		goto error_free_tfm;
 
+	key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
+		      GFP_KERNEL);
+	if (!key)
+		goto error_free_req;
+
+	memcpy(key, pkey->key, pkey->keylen);
+	ptr = key + pkey->keylen;
+	ptr = pkey_pack_u32(ptr, pkey->algo);
+	ptr = pkey_pack_u32(ptr, pkey->paramlen);
+	memcpy(ptr, pkey->params, pkey->paramlen);
+
 	if (pkey->key_is_private)
-		ret = crypto_akcipher_set_priv_key(tfm,
-						   pkey->key, pkey->keylen);
+		ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
 	else
-		ret = crypto_akcipher_set_pub_key(tfm,
-						  pkey->key, pkey->keylen);
+		ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
 	if (ret)
-		goto error_free_req;
+		goto error_free_key;
 
 	sg_init_one(&in_sg, in, params->in_len);
 	sg_init_one(&out_sg, out, params->out_len);
@@ -210,6 +238,8 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
 	if (ret == 0)
 		ret = req->dst_len;
 
+error_free_key:
+	kfree(key);
 error_free_req:
 	akcipher_request_free(req);
 error_free_tfm:
@@ -229,6 +259,7 @@ int public_key_verify_signature(const struct public_key *pkey,
 	struct akcipher_request *req;
 	struct scatterlist src_sg[2];
 	char alg_name[CRYPTO_MAX_ALG_NAME];
+	char *key, *ptr;
 	int ret;
 
 	pr_devel("==>%s()\n", __func__);
@@ -252,14 +283,23 @@ int public_key_verify_signature(const struct public_key *pkey,
 	if (!req)
 		goto error_free_tfm;
 
+	key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
+		      GFP_KERNEL);
+	if (!key)
+		goto error_free_req;
+
+	memcpy(key, pkey->key, pkey->keylen);
+	ptr = key + pkey->keylen;
+	ptr = pkey_pack_u32(ptr, pkey->algo);
+	ptr = pkey_pack_u32(ptr, pkey->paramlen);
+	memcpy(ptr, pkey->params, pkey->paramlen);
+
 	if (pkey->key_is_private)
-		ret = crypto_akcipher_set_priv_key(tfm,
-						   pkey->key, pkey->keylen);
+		ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
 	else
-		ret = crypto_akcipher_set_pub_key(tfm,
-						  pkey->key, pkey->keylen);
+		ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
 	if (ret)
-		goto error_free_req;
+		goto error_free_key;
 
 	sg_init_table(src_sg, 2);
 	sg_set_buf(&src_sg[0], sig->s, sig->s_size);
@@ -272,6 +312,8 @@ int public_key_verify_signature(const struct public_key *pkey,
 				      crypto_req_done, &cwait);
 	ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
 
+error_free_key:
+	kfree(key);
 error_free_req:
 	akcipher_request_free(req);
 error_free_tfm: