crypto: ecrdsa - Migrate to sig_alg backend

A sig_alg backend has just been introduced with the intent of moving all
asymmetric sign/verify algorithms to it one by one.

Migrate ecrdsa.c to the new backend.

One benefit of the new API is the use of kernel buffers instead of
sglists, which avoids the overhead of copying signature and digest
sglists back into kernel buffers. ecrdsa.c is thus simplified quite
a bit.

Signed-off-by: Lukas Wunner <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

crypto/Kconfig

···
 config CRYPTO_ECRDSA
 	tristate "EC-RDSA (Elliptic Curve Russian Digital Signature Algorithm)"
 	select CRYPTO_ECC
-	select CRYPTO_AKCIPHER
+	select CRYPTO_SIG
 	select CRYPTO_STREEBOG
 	select OID_REGISTRY
 	select ASN1

crypto/ecrdsa.c

···
 
 #include <linux/module.h>
 #include <linux/crypto.h>
+#include <crypto/sig.h>
 #include <crypto/streebog.h>
-#include <crypto/internal/akcipher.h>
 #include <crypto/internal/ecc.h>
-#include <crypto/akcipher.h>
+#include <crypto/internal/sig.h>
 #include <linux/oid_registry.h>
-#include <linux/scatterlist.h>
 #include "ecrdsa_params.asn1.h"
 #include "ecrdsa_pub_key.asn1.h"
 #include "ecrdsa_defs.h"
···
 	}
 }
 
-static int ecrdsa_verify(struct akcipher_request *req)
+static int ecrdsa_verify(struct crypto_sig *tfm,
+			 const void *src, unsigned int slen,
+			 const void *digest, unsigned int dlen)
 {
-	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
-	struct ecrdsa_ctx *ctx = akcipher_tfm_ctx(tfm);
-	unsigned char sig[ECRDSA_MAX_SIG_SIZE];
-	unsigned char digest[STREEBOG512_DIGEST_SIZE];
-	unsigned int ndigits = req->dst_len / sizeof(u64);
+	struct ecrdsa_ctx *ctx = crypto_sig_ctx(tfm);
+	unsigned int ndigits = dlen / sizeof(u64);
 	u64 r[ECRDSA_MAX_DIGITS]; /* witness (r) */
 	u64 _r[ECRDSA_MAX_DIGITS]; /* -r */
 	u64 s[ECRDSA_MAX_DIGITS]; /* second part of sig (s) */
···
 	 */
 	if (!ctx->curve ||
 	    !ctx->digest ||
-	    !req->src ||
+	    !src ||
+	    !digest ||
 	    !ctx->pub_key.x ||
-	    req->dst_len != ctx->digest_len ||
-	    req->dst_len != ctx->curve->g.ndigits * sizeof(u64) ||
+	    dlen != ctx->digest_len ||
+	    dlen != ctx->curve->g.ndigits * sizeof(u64) ||
 	    ctx->pub_key.ndigits != ctx->curve->g.ndigits ||
-	    req->dst_len * 2 != req->src_len ||
-	    WARN_ON(req->src_len > sizeof(sig)) ||
-	    WARN_ON(req->dst_len > sizeof(digest)))
+	    dlen * 2 != slen ||
+	    WARN_ON(slen > ECRDSA_MAX_SIG_SIZE) ||
+	    WARN_ON(dlen > STREEBOG512_DIGEST_SIZE))
 		return -EBADMSG;
 
-	sg_copy_to_buffer(req->src, sg_nents_for_len(req->src, req->src_len),
-			  sig, req->src_len);
-	sg_pcopy_to_buffer(req->src,
-			   sg_nents_for_len(req->src,
-					    req->src_len + req->dst_len),
-			   digest, req->dst_len, req->src_len);
-
-	vli_from_be64(s, sig, ndigits);
-	vli_from_be64(r, sig + ndigits * sizeof(u64), ndigits);
+	vli_from_be64(s, src, ndigits);
+	vli_from_be64(r, src + ndigits * sizeof(u64), ndigits);
 
 	/* Step 1: verify that 0 < r < q, 0 < s < q */
 	if (vli_is_zero(r, ndigits) ||
···
 }
 
 /* Parse BER encoded subjectPublicKey. */
-static int ecrdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
+static int ecrdsa_set_pub_key(struct crypto_sig *tfm, const void *key,
 			      unsigned int keylen)
 {
-	struct ecrdsa_ctx *ctx = akcipher_tfm_ctx(tfm);
+	struct ecrdsa_ctx *ctx = crypto_sig_ctx(tfm);
 	unsigned int ndigits;
 	u32 algo, paramlen;
 	u8 *params;
···
 	return 0;
 }
 
-static unsigned int ecrdsa_max_size(struct crypto_akcipher *tfm)
+static unsigned int ecrdsa_max_size(struct crypto_sig *tfm)
 {
-	struct ecrdsa_ctx *ctx = akcipher_tfm_ctx(tfm);
+	struct ecrdsa_ctx *ctx = crypto_sig_ctx(tfm);
 
 	/*
 	 * Verify doesn't need any output, so it's just informational
···
 	return ctx->pub_key.ndigits * sizeof(u64);
 }
 
-static void ecrdsa_exit_tfm(struct crypto_akcipher *tfm)
+static void ecrdsa_exit_tfm(struct crypto_sig *tfm)
 {
 }
 
-static struct akcipher_alg ecrdsa_alg = {
+static struct sig_alg ecrdsa_alg = {
 	.verify		= ecrdsa_verify,
 	.set_pub_key	= ecrdsa_set_pub_key,
 	.max_size	= ecrdsa_max_size,
···
 
 static int __init ecrdsa_mod_init(void)
 {
-	return crypto_register_akcipher(&ecrdsa_alg);
+	return crypto_register_sig(&ecrdsa_alg);
 }
 
 static void __exit ecrdsa_mod_fini(void)
 {
-	crypto_unregister_akcipher(&ecrdsa_alg);
+	crypto_unregister_sig(&ecrdsa_alg);
 }
 
 module_init(ecrdsa_mod_init);

crypto/testmgr.c

···
 		}
 	}, {
 		.alg = "ecrdsa",
-		.test = alg_test_akcipher,
+		.test = alg_test_sig,
 		.suite = {
-			.akcipher = __VECS(ecrdsa_tv_template)
+			.sig = __VECS(ecrdsa_tv_template)
 		}
 	}, {
 		.alg = "essiv(authenc(hmac(sha256),cbc(aes)),sha256)",

crypto/testmgr.h

···
 /*
  * EC-RDSA test vectors are generated by gost-engine.
  */
-static const struct akcipher_testvec ecrdsa_tv_template[] = {
+static const struct sig_testvec ecrdsa_tv_template[] = {
 	{
 	.key =
 	"\x04\x40\xd5\xa7\x77\xf9\x26\x2f\x8c\xbd\xcc\xe3\x1f\x01\x94\x05"
···
 	"\x79\xd2\x76\x64\xa3\xbd\x66\x10\x79\x05\x5a\x06\x42\xec\xb9\xc9",
 	.m_size = 32,
 	.public_key_vec = true,
-	.siggen_sigver_test = true,
 	},
 	{
 	.key =
···
 	"\x11\x23\x4a\x70\x43\x52\x7a\x68\x11\x65\x45\x37\xbb\x25\xb7\x40",
 	.m_size = 32,
 	.public_key_vec = true,
-	.siggen_sigver_test = true,
 	},
 	{
 	.key =
···
 	"\x9f\x16\xc6\x1c\xb1\x3f\x84\x41\x69\xec\x34\xfd\xf1\xf9\xa3\x39",
 	.m_size = 32,
 	.public_key_vec = true,
-	.siggen_sigver_test = true,
 	},
 	{
 	.key =
···
 	"\xa8\xf6\x80\x01\xb9\x27\xac\xd8\x45\x96\x66\xa1\xee\x48\x08\x3f",
 	.m_size = 64,
 	.public_key_vec = true,
-	.siggen_sigver_test = true,
 	},
 	{
 	.key =
···
 	"\x6d\xf4\xd2\x45\xc2\x83\xa0\x42\x95\x05\x9d\x89\x8e\x0a\xca\xcc",
 	.m_size = 64,
 	.public_key_vec = true,
-	.siggen_sigver_test = true,
 	},
 };