Revert KEX rewriting

A truncated part of #445

configure.ac

@@ -13,7 +13,7 @@
 # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 # OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-AC_INIT([OpenSSH],[Portable],[[email protected]])
+AC_INIT([OpenSSH], [Portable], [[email protected]])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([ssh.c])
 

dh.c

@@ -36,11 +36,6 @@
 
 #include <openssl/bn.h>
 #include <openssl/dh.h>
-#include <openssl/evp.h>
-#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
-#include <openssl/core_names.h>
-#include <openssl/param_build.h>
-#endif
 
 #include "dh.h"
 #include "pathnames.h"
@@ -288,103 +283,6 @@ dh_pub_is_valid(const DH *dh, const BIGNUM *dh_pub)
 int
 dh_gen_key(DH *dh, int need)
 {
-#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
-	const BIGNUM *dh_p, *dh_g;
-	BIGNUM *pub_key = NULL, *priv_key = NULL;
-	EVP_PKEY *pkey = NULL;
-  	EVP_PKEY_CTX *ctx = NULL;
-  	OSSL_PARAM_BLD *param_bld = NULL;
-  	OSSL_PARAM *params = NULL;
-	int pbits, r = 0;
-
-	DH_get0_pqg(dh, &dh_p, NULL, &dh_g);
-
-	if (need < 0 || dh_p == NULL ||
-	    (pbits = BN_num_bits(dh_p)) <= 0 ||
-	    need > INT_MAX / 2 || 2 * need > pbits)
-		return SSH_ERR_INVALID_ARGUMENT;
-	if (need < 256)
-		need = 256;
-
-	if ((param_bld = OSSL_PARAM_BLD_new()) == NULL ||
-	    (ctx = EVP_PKEY_CTX_new_from_name(NULL, "DH", NULL)) == NULL) {
-		OSSL_PARAM_BLD_free(param_bld);
-		return SSH_ERR_ALLOC_FAIL;
-	}
-
-	if (OSSL_PARAM_BLD_push_BN(param_bld,
-	        OSSL_PKEY_PARAM_FFC_P, dh_p) != 1 ||
-	    OSSL_PARAM_BLD_push_BN(param_bld,
-	        OSSL_PKEY_PARAM_FFC_G, dh_g) != 1) {
-		error_f("Could not set p,q,g parameters");
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	/*
-	 * Pollard Rho, Big step/Little Step attacks are O(sqrt(n)),
-	 * so double requested need here.
-	 */
-	if (OSSL_PARAM_BLD_push_int(param_bld,
-	        OSSL_PKEY_PARAM_DH_PRIV_LEN,
-		MINIMUM(need * 2, pbits - 1)) != 1 ||
-	    (params = OSSL_PARAM_BLD_to_param(param_bld)) == NULL) {
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	if (EVP_PKEY_fromdata_init(ctx) != 1) {
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	if (EVP_PKEY_fromdata(ctx, &pkey,
-	        EVP_PKEY_KEY_PARAMETERS, params) != 1) {
-		error_f("Failed key generation");
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-
-	/* reuse context for key generation */
-	EVP_PKEY_CTX_free(ctx);
-	ctx = NULL;
-
-	if ((ctx = EVP_PKEY_CTX_new_from_pkey(NULL, pkey, NULL)) == NULL ||
-	    EVP_PKEY_keygen_init(ctx) != 1) {
-		error_f("Could not create or init context");
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	if (EVP_PKEY_generate(ctx, &pkey) != 1) {
-		error_f("Could not generate keys");
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	if (EVP_PKEY_public_check(ctx) != 1) {
-		error_f("The public key is incorrect");
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-
-	if (EVP_PKEY_get_bn_param(pkey, OSSL_PKEY_PARAM_PUB_KEY,
-	    &pub_key) != 1 ||
-	    EVP_PKEY_get_bn_param(pkey, OSSL_PKEY_PARAM_PRIV_KEY,
-	    &priv_key) != 1 ||
-	    DH_set0_key(dh, pub_key, priv_key) != 1) {
-		error_f("Could not set pub/priv keys to DH struct");
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-
-	/* transferred */
-	pub_key = NULL;
-	priv_key = NULL;
-out:
-	OSSL_PARAM_free(params);
-	OSSL_PARAM_BLD_free(param_bld);
-	EVP_PKEY_CTX_free(ctx);
-	EVP_PKEY_free(pkey);
-	BN_clear_free(pub_key);
-	BN_clear_free(priv_key);
-	return r;
-#else
 	int pbits;
 	const BIGNUM *dh_p, *pub_key;
 
@@ -409,7 +307,6 @@ dh_gen_key(DH *dh, int need)
 	if (!dh_pub_is_valid(dh, pub_key))
 		return SSH_ERR_INVALID_FORMAT;
 	return 0;
-#endif
 }
 
 DH *

kex.c

@@ -784,7 +784,9 @@ kex_free(struct kex *kex)
 
 #ifdef WITH_OPENSSL
 	DH_free(kex->dh);
-	EVP_PKEY_free(kex->pkey);
+#ifdef OPENSSL_HAS_ECC
+	EC_KEY_free(kex->ec_client_key);
+#endif /* OPENSSL_HAS_ECC */
 #endif /* WITH_OPENSSL */
 	for (mode = 0; mode < MODE_MAX; mode++) {
 		kex_free_newkeys(kex->newkeys[mode]);

kex.h

@@ -33,15 +33,19 @@
 # include <openssl/bn.h>
 # include <openssl/dh.h>
 # include <openssl/ecdsa.h>
-# include <openssl/evp.h>
-#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
-# include <openssl/core_names.h>
-# include <openssl/param_build.h>
-#endif
+# ifdef OPENSSL_HAS_ECC
+#  include <openssl/ec.h>
+# else /* OPENSSL_HAS_ECC */
+#  define EC_KEY	void
+#  define EC_GROUP	void
+#  define EC_POINT	void
+# endif /* OPENSSL_HAS_ECC */
 #else /* WITH_OPENSSL */
 # define DH		void
 # define BIGNUM		void
-# define EVP_PKEY	void
+# define EC_KEY		void
+# define EC_GROUP	void
+# define EC_POINT	void
 #endif /* WITH_OPENSSL */
 
 #define KEX_COOKIE_LEN	16
@@ -167,7 +171,8 @@ struct kex {
 	/* kex specific state */
 	DH	*dh;			/* DH */
 	u_int	min, max, nbits;	/* GEX */
-	EVP_PKEY *pkey; /* ECDH */
+	EC_KEY	*ec_client_key;		/* ECDH */
+	const EC_GROUP *ec_group;	/* ECDH */
 	u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 + KEM */
 	u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */
 	u_char sntrup761_client_key[crypto_kem_sntrup761_SECRETKEYBYTES]; /* KEM */
@@ -256,4 +261,10 @@ int	kexc25519_shared_key_ext(const u_char key[CURVE25519_SIZE],
 void	dump_digest(const char *, const u_char *, int);
 #endif
 
+#if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC)
+# undef EC_KEY
+# undef EC_GROUP
+# undef EC_POINT
+#endif
+
 #endif

kexdh.c

@@ -35,12 +35,6 @@
 
 #include "openbsd-compat/openssl-compat.h"
 #include <openssl/dh.h>
-#include <openssl/err.h>
-#include <openssl/evp.h>
-#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
-#include <openssl/core_names.h>
-#include <openssl/param_build.h>
-#endif
 
 #include "sshkey.h"
 #include "kex.h"
@@ -79,16 +73,9 @@ int
 kex_dh_compute_key(struct kex *kex, BIGNUM *dh_pub, struct sshbuf *out)
 {
 	BIGNUM *shared_secret = NULL;
-	const BIGNUM *pub, *priv, *p, *q, *g;
-	EVP_PKEY *pkey = NULL, *dh_pkey = NULL;
-	EVP_PKEY_CTX *ctx = NULL;
 	u_char *kbuf = NULL;
 	size_t klen = 0;
-	int r = 0;
-#if (OPENSSL_VERSION_NUMBER < 0x30000000L)
-	DH *dh_peer = NULL;
-	BIGNUM *copy_p = NULL, *copy_q = NULL, *copy_g = NULL, *copy_pub = NULL;
-#endif
+	int kout, r;
 
 #ifdef DEBUG_KEXDH
 	fprintf(stderr, "dh_pub= ");
@@ -103,113 +90,24 @@ kex_dh_compute_key(struct kex *kex, BIGNUM *dh_pub, struct sshbuf *out)
 		r = SSH_ERR_MESSAGE_INCOMPLETE;
 		goto out;
 	}
-
-#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
-	DH_get0_key(kex->dh, &pub, &priv);
-	DH_get0_pqg(kex->dh, &p, &q, &g);
-	/* import key */
-	r = kex_create_evp_dh(&pkey, p, q, g, pub, priv);
-	if (r != 0) {
-		error_f("Could not create EVP_PKEY for dh");
-		ERR_print_errors_fp(stderr);
-		goto out;
-	}
-	/* import peer key
-	 * the parameters should be the same as with pkey
-	 */
-	r = kex_create_evp_dh(&dh_pkey, p, q, g, dh_pub, NULL);
-	if (r != 0) {
-		error_f("Could not import peer key for dh");
-		ERR_print_errors_fp(stderr);
-		goto out;
-	}
-#else
-	DH_get0_pqg(kex->dh, &p, &q, &g);
-	if ((pkey = EVP_PKEY_new()) == NULL) {
-		r = SSH_ERR_ALLOC_FAIL;
-		goto out;
-	}
-
-	if (EVP_PKEY_set1_DH(pkey, kex->dh) != 1) {
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-
-	if ((dh_peer = DH_new()) == NULL) {
-		r = SSH_ERR_ALLOC_FAIL;
-		goto out;
-	}
-
-	copy_p = BN_dup(p);
-	copy_q = BN_dup(q);
-	copy_g = BN_dup(g);
-	if (DH_set0_pqg(dh_peer, copy_p, copy_q, copy_g) != 1) {
-		BN_free(copy_p);
-		BN_free(copy_q);
-		BN_free(copy_g);
-		DH_free(dh_peer);
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	copy_p = copy_q = copy_g = NULL;
-
-	copy_pub = BN_dup(dh_pub);
-	if (DH_set0_key(dh_peer, copy_pub, NULL) != 1) {
-		BN_free(copy_pub);
-		DH_free(dh_peer);
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	copy_pub = NULL;
-
-	if ((dh_pkey = EVP_PKEY_new()) == NULL) {
-		DH_free(dh_peer);
-		r = SSH_ERR_ALLOC_FAIL;
-		goto out;
-	}
-
-	if (EVP_PKEY_set1_DH(dh_pkey, dh_peer) != 1) {
-		DH_free(dh_peer);
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	DH_free(dh_peer);
-#endif
-
-	if ((ctx = EVP_PKEY_CTX_new(pkey, NULL)) == NULL) {
-		error_f("Could not init EVP_PKEY_CTX for dh");
-		ERR_print_errors_fp(stderr);
-		r = SSH_ERR_ALLOC_FAIL;
-		goto out;
-	}
-	if (EVP_PKEY_derive_init(ctx) != 1 ||
-	    EVP_PKEY_derive_set_peer(ctx, dh_pkey) != 1 ||
-	    EVP_PKEY_derive(ctx, NULL, &klen) != 1) {
-		error_f("Could not get key size");
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
+	klen = DH_size(kex->dh);
 	if ((kbuf = malloc(klen)) == NULL ||
 	    (shared_secret = BN_new()) == NULL) {
 		r = SSH_ERR_ALLOC_FAIL;
 		goto out;
 	}
-	if (EVP_PKEY_derive(ctx, kbuf, &klen) != 1 ||
-	    BN_bin2bn(kbuf, klen, shared_secret) == NULL) {
-		error_f("Could not derive key");
+	if ((kout = DH_compute_key(kbuf, dh_pub, kex->dh)) < 0 ||
+	    BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
 		r = SSH_ERR_LIBCRYPTO_ERROR;
 		goto out;
 	}
 #ifdef DEBUG_KEXDH
-	dump_digest("shared secret", kbuf, klen);
+	dump_digest("shared secret", kbuf, kout);
 #endif
 	r = sshbuf_put_bignum2(out, shared_secret);
  out:
 	freezero(kbuf, klen);
 	BN_clear_free(shared_secret);
-	EVP_PKEY_free(pkey);
-	EVP_PKEY_free(dh_pkey);
-	EVP_PKEY_CTX_free(ctx);
 	return r;
 }
 
@@ -302,48 +200,4 @@ kex_dh_dec(struct kex *kex, const struct sshbuf *dh_blob,
 	sshbuf_free(buf);
 	return r;
 }
-#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
-/* 
- * Creates an EVP_PKEY from the given parameters and keys.
- * The private key can be omitted.
- */
-int
-kex_create_evp_dh(EVP_PKEY **pkey, const BIGNUM *p, const BIGNUM *q,
-    const BIGNUM *g, const BIGNUM *pub, const BIGNUM *priv)
-{
-	OSSL_PARAM_BLD *param_bld = NULL;
-	EVP_PKEY_CTX *ctx = NULL;
-	int r = 0;
-
-	/* create EVP_PKEY-DH key */
-	if ((ctx = EVP_PKEY_CTX_new_from_name(NULL, "DH", NULL)) == NULL ||
-	    (param_bld = OSSL_PARAM_BLD_new()) == NULL) {
-		error_f("EVP_PKEY_CTX or PARAM_BLD init failed");
-		r = SSH_ERR_ALLOC_FAIL;
-		goto out;
-	}
-	if (OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_FFC_P, p) != 1 ||
-	    OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_FFC_Q, q) != 1 ||
-	    OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_FFC_G, g) != 1 ||
-	    OSSL_PARAM_BLD_push_BN(param_bld,
-	        OSSL_PKEY_PARAM_PUB_KEY, pub) != 1) {
-		error_f("Failed pushing params to OSSL_PARAM_BLD");
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	if (priv != NULL &&
-	    OSSL_PARAM_BLD_push_BN(param_bld,
-	        OSSL_PKEY_PARAM_PRIV_KEY, priv) != 1) {
-		error_f("Failed pushing private key to OSSL_PARAM_BLD");
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-		goto out;
-	}
-	if ((*pkey = sshkey_create_evp(param_bld, ctx)) == NULL)
-		r = SSH_ERR_LIBCRYPTO_ERROR;
-out:
-	OSSL_PARAM_BLD_free(param_bld);
-	EVP_PKEY_CTX_free(ctx);
-	return r;
-}
-#endif
 #endif /* WITH_OPENSSL */