libressl/0059-gost-support-specifying-old-or-new-KEG-derivation-fo.patch

From cd0eec15fae54c7ca1b11109f85503b3cfb02217 Mon Sep 17 00:00:00 2001
From: Dmitry Baryshkov <dbaryshkov@gmail.com>
Date: Wed, 8 Apr 2020 21:27:04 +0300
Subject: [PATCH 59/87] gost: support specifying old or new (KEG) derivation
 format

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
---
 src/lib/libcrypto/gost/gost.h              |  4 ++
 src/lib/libcrypto/gost/gostr341001_pmeth.c | 68 +++++++++++++++++++++-
 2 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/src/lib/libcrypto/gost/gost.h b/src/lib/libcrypto/gost/gost.h
index 6a2b60670..694906b76 100644
--- a/src/lib/libcrypto/gost/gost.h
+++ b/src/lib/libcrypto/gost/gost.h
@@ -229,6 +229,7 @@ size_t GOST_KEY_get_size(const GOST_KEY * r);
 #define EVP_PKEY_CTRL_GOST_SET_DIGEST	(EVP_PKEY_ALG_CTRL+3)
 #define EVP_PKEY_CTRL_GOST_GET_DIGEST	(EVP_PKEY_ALG_CTRL+4)
 #define EVP_PKEY_CTRL_GOST_ENC_FORMAT	(EVP_PKEY_ALG_CTRL+5)
+#define EVP_PKEY_CTRL_GOST_DERIVE_FORMAT	(EVP_PKEY_ALG_CTRL+6)
 
 #define GOST_SIG_FORMAT_SR_BE	0
 #define GOST_SIG_FORMAT_RS_LE	1
@@ -237,6 +238,9 @@ size_t GOST_KEY_get_size(const GOST_KEY * r);
 #define GOST_ENC_FORMAT_PSKEY_MAGMA	1 /* CMS, TLS CTR-OMAC, Magma-encoded */
 #define GOST_ENC_FORMAT_PSKEY_KUZNYECHIK	2 /* CMS, TLS CTR-OMAC, Kuznyechik-encoded */
 
+#define GOST_DERIVE_FORMAT_4490	0 /* RFC 4490, TLS CNT-IMIT */
+#define GOST_DERIVE_FORMAT_KEG	1 /* CMS, TLS CTR-OMAC */
+
 /* BEGIN ERROR CODES */
 /* The following lines are auto generated by the script mkerr.pl. Any changes
  * made after this point may be overwritten when the script is next run.
diff --git a/src/lib/libcrypto/gost/gostr341001_pmeth.c b/src/lib/libcrypto/gost/gostr341001_pmeth.c
index 07ca4d3a3..e21101ddc 100644
--- a/src/lib/libcrypto/gost/gostr341001_pmeth.c
+++ b/src/lib/libcrypto/gost/gostr341001_pmeth.c
@@ -137,6 +137,7 @@ struct gost_pmeth_data {
 	int peer_key_used;
 	int sig_format;
 	int enc_format;
+	int derive_format;
 };
 
 static int
@@ -468,8 +469,8 @@ err:
 	return ret;
 }
 
-int
-pkey_gost01_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
+static int
+pkey_gost01_derive_4490(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
 {
 	/*
 	 * Public key of peer in the ctx field peerkey
@@ -504,6 +505,38 @@ pkey_gost01_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
 	return 1;
 }
 
+static int
+pkey_gost01_derive_keg(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
+{
+	/*
+	 * Public key of peer in the ctx field peerkey
+	 * Our private key in the ctx pkey
+	 * ukm is in the algorithm specific context data
+	 */
+	EVP_PKEY *my_key = EVP_PKEY_CTX_get0_pkey(ctx);
+	EVP_PKEY *peer_key = EVP_PKEY_CTX_get0_peerkey(ctx);
+	struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
+
+	if (data->shared_ukm == NULL) {
+		GOSTerror(GOST_R_UKM_NOT_SET);
+		return 0;
+	}
+
+	if (key == NULL) {
+		*keylen = 64;
+		return 64;
+	}
+
+	if (!gost_keg(peer_key, my_key, data->digest_nid, data->shared_ukm, key)) {
+		GOSTerror(GOST_R_ERROR_COMPUTING_SHARED_KEY);
+		return 0;
+	}
+
+	*keylen = 64;
+
+	return 1;
+}
+
 int
 pkey_gost01_encrypt_4490(EVP_PKEY_CTX *pctx, unsigned char *out, size_t *out_len,
     const unsigned char *key, size_t key_len)
@@ -816,6 +849,21 @@ pkey_gost01_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *out_len,
 	}
 }
 
+int
+pkey_gost01_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
+{
+	struct gost_pmeth_data *pctx = EVP_PKEY_CTX_get_data(ctx);
+
+	switch (pctx->derive_format) {
+	case GOST_DERIVE_FORMAT_4490:
+		return pkey_gost01_derive_4490(ctx, key, keylen);
+	case GOST_DERIVE_FORMAT_KEG:
+		return pkey_gost01_derive_keg(ctx, key, keylen);
+	default:
+		return -1;
+	}
+}
+
 static int
 pkey_gost01_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
 {
@@ -911,6 +959,22 @@ pkey_gost01_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
 		pctx->enc_format = p1;
 		return 1;
 		break;
+	case EVP_PKEY_CTRL_GOST_DERIVE_FORMAT:
+		switch (p1) {
+		case GOST_DERIVE_FORMAT_4490:
+			/* All keys are supported */
+			break;
+		case GOST_DERIVE_FORMAT_KEG:
+			if (pctx->digest_nid != NID_id_tc26_gost3411_2012_256 &&
+			    pctx->digest_nid != NID_id_tc26_gost3411_2012_512)
+				return 0;
+			break;
+		default:
+			return 0;
+		}
+		pctx->derive_format = p1;
+		return 1;
+		break;
 	default:
 		return -2;
 	}
-- 
2.17.1