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>

4 files changed, 97 insertions, 17 deletions

diff --git a/crypto/asymmetric_keys/asym_tpm.c b/crypto/asymmetric_keys/asym_tpm.c
index 402fc34ca044..76d2ce3a1b5b 100644
--- a/crypto/asymmetric_keys/asym_tpm.c
+++ b/crypto/asymmetric_keys/asym_tpm.c
@@ -276,6 +276,10 @@ static int tpm_sign(struct tpm_buf *tb,
 
 	return datalen;
 }
+
+/* Room to fit two u32 zeros for algo id and parameters length. */
+#define SETKEY_PARAMS_SIZE (sizeof(u32) * 2)
+
 /*
  * Maximum buffer size for the BER/DER encoded public key.  The public key
  * is of the form SEQUENCE { INTEGER n, INTEGER e } where n is a maximum 2048
@@ -286,8 +290,9 @@ static int tpm_sign(struct tpm_buf *tb,
  *     - 257 bytes of n
  *   - max 2 bytes for INTEGER e type/length
  *     - 3 bytes of e
+ * - 4+4 of zeros for set_pub_key parameters (SETKEY_PARAMS_SIZE)
  */
-#define PUB_KEY_BUF_SIZE (4 + 4 + 257 + 2 + 3)
+#define PUB_KEY_BUF_SIZE (4 + 4 + 257 + 2 + 3 + SETKEY_PARAMS_SIZE)
 
 /*
  * Provide a part of a description of the key for /proc/keys.
@@ -364,6 +369,8 @@ static uint32_t derive_pub_key(const void *pub_key, uint32_t len, uint8_t *buf)
 	cur = encode_tag_length(cur, 0x02, sizeof(e));
 	memcpy(cur, e, sizeof(e));
 	cur += sizeof(e);
+	/* Zero parameters to satisfy set_pub_key ABI. */
+	memset(cur, 0, SETKEY_PARAMS_SIZE);
 
 	return cur - buf;
 }
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:
diff --git a/crypto/asymmetric_keys/x509.asn1 b/crypto/asymmetric_keys/x509.asn1
index aae0cde414e2..5c9f4e4a5231 100644
--- a/crypto/asymmetric_keys/x509.asn1
+++ b/crypto/asymmetric_keys/x509.asn1
@@ -22,7 +22,7 @@ CertificateSerialNumber ::= INTEGER
 
 AlgorithmIdentifier ::= SEQUENCE {
 	algorithm		OBJECT IDENTIFIER ({ x509_note_OID }),
-	parameters		ANY OPTIONAL
+	parameters		ANY OPTIONAL ({ x509_note_params })
 }
 
 Name ::= SEQUENCE OF RelativeDistinguishedName
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 991f4d735a4e..b2cdf2db1987 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -26,6 +26,9 @@ struct x509_parse_context {
 	const void	*cert_start;		/* Start of cert content */
 	const void	*key;			/* Key data */
 	size_t		key_size;		/* Size of key data */
+	const void	*params;		/* Key parameters */
+	size_t		params_size;		/* Size of key parameters */
+	enum OID	key_algo;		/* Public key algorithm */
 	enum OID	last_oid;		/* Last OID encountered */
 	enum OID	algo_oid;		/* Algorithm OID */
 	unsigned char	nr_mpi;			/* Number of MPIs stored */
@@ -109,6 +112,13 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
 
 	cert->pub->keylen = ctx->key_size;
 
+	cert->pub->params = kmemdup(ctx->params, ctx->params_size, GFP_KERNEL);
+	if (!cert->pub->params)
+		goto error_decode;
+
+	cert->pub->paramlen = ctx->params_size;
+	cert->pub->algo = ctx->key_algo;
+
 	/* Grab the signature bits */
 	ret = x509_get_sig_params(cert);
 	if (ret < 0)
@@ -401,6 +411,27 @@ int x509_note_subject(void *context, size_t hdrlen,
 }
 
 /*
+ * Extract the parameters for the public key
+ */
+int x509_note_params(void *context, size_t hdrlen,
+		     unsigned char tag,
+		     const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+
+	/*
+	 * AlgorithmIdentifier is used three times in the x509, we should skip
+	 * first and ignore third, using second one which is after subject and
+	 * before subjectPublicKey.
+	 */
+	if (!ctx->cert->raw_subject || ctx->key)
+		return 0;
+	ctx->params = value - hdrlen;
+	ctx->params_size = vlen + hdrlen;
+	return 0;
+}
+
+/*
  * Extract the data for the public key algorithm
  */
 int x509_extract_key_data(void *context, size_t hdrlen,