remove most uses of BN_CTX

We weren't following the rules re BN_CTX_start/BN_CTX_end and the places
we were using it didn't benefit from its use anyway. ok dtucker@

4 files changed, 47 insertions, 82 deletions

diff --git a/usr.bin/ssh/moduli.c b/usr.bin/ssh/moduli.c
index 4fa79dc10a1..7ab64e28cdf 100644
--- a/usr.bin/ssh/moduli.c
+++ b/usr.bin/ssh/moduli.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: moduli.c,v 1.36 2019/10/04 03:26:58 dtucker Exp $ */
+/* $OpenBSD: moduli.c,v 1.37 2019/11/15 06:00:20 djm Exp $ */
 /*
  * Copyright 1994 Phil Karn <karn@qualcomm.com>
  * Copyright 1996-1998, 2003 William Allen Simpson <wsimpson@greendragon.com>
@@ -572,7 +572,6 @@ prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
     char *checkpoint_file, unsigned long start_lineno, unsigned long num_lines)
 {
 	BIGNUM *q, *p, *a;
-	BN_CTX *ctx;
 	char *cp, *lp;
 	u_int32_t count_in = 0, count_out = 0, count_possible = 0;
 	u_int32_t generator_known, in_tests, in_tries, in_type, in_size;
@@ -596,8 +595,6 @@ prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
 		fatal("BN_new failed");
 	if ((q = BN_new()) == NULL)
 		fatal("BN_new failed");
-	if ((ctx = BN_CTX_new()) == NULL)
-		fatal("BN_CTX_new failed");
 
 	debug2("%.24s Final %u Miller-Rabin trials (%x generator)",
 	    ctime(&time_start), trials, generator_wanted);
@@ -747,7 +744,7 @@ prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
 		 * that p is also prime. A single pass will weed out the
 		 * vast majority of composite q's.
 		 */
-		is_prime = BN_is_prime_ex(q, 1, ctx, NULL);
+		is_prime = BN_is_prime_ex(q, 1, NULL, NULL);
 		if (is_prime < 0)
 			fatal("BN_is_prime_ex failed");
 		if (is_prime == 0) {
@@ -763,7 +760,7 @@ prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
 		 * will show up on the first Rabin-Miller iteration so it
 		 * doesn't hurt to specify a high iteration count.
 		 */
-		is_prime = BN_is_prime_ex(p, trials, ctx, NULL);
+		is_prime = BN_is_prime_ex(p, trials, NULL, NULL);
 		if (is_prime < 0)
 			fatal("BN_is_prime_ex failed");
 		if (is_prime == 0) {
@@ -773,7 +770,7 @@ prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
 		debug("%10u: p is almost certainly prime", count_in);
 
 		/* recheck q more rigorously */
-		is_prime = BN_is_prime_ex(q, trials - 1, ctx, NULL);
+		is_prime = BN_is_prime_ex(q, trials - 1, NULL, NULL);
 		if (is_prime < 0)
 			fatal("BN_is_prime_ex failed");
 		if (is_prime == 0) {
@@ -796,7 +793,6 @@ prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
 	free(lp);
 	BN_free(p);
 	BN_free(q);
-	BN_CTX_free(ctx);
 
 	if (checkpoint_file != NULL)
 		unlink(checkpoint_file);
diff --git a/usr.bin/ssh/sk-usbhid.c b/usr.bin/ssh/sk-usbhid.c
index 35aafa74af9..08231550811 100644
--- a/usr.bin/ssh/sk-usbhid.c
+++ b/usr.bin/ssh/sk-usbhid.c
@@ -278,15 +278,13 @@ pack_public_key_ecdsa(fido_cred_t *cred, struct sk_enroll_response *response)
 	BIGNUM *x = NULL, *y = NULL;
 	EC_POINT *q = NULL;
 	EC_GROUP *g = NULL;
-	BN_CTX *bn_ctx = NULL;
 	int ret = -1;
 
 	response->public_key = NULL;
 	response->public_key_len = 0;
 
-	if ((bn_ctx = BN_CTX_new()) == NULL ||
-	    (x = BN_CTX_get(bn_ctx)) == NULL ||
-	    (y = BN_CTX_get(bn_ctx)) == NULL ||
+	if ((x = BN_new()) == NULL ||
+	    (y = BN_new()) == NULL ||
 	    (g = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1)) == NULL ||
 	    (q = EC_POINT_new(g)) == NULL) {
 		skdebug(__func__, "libcrypto setup failed");
@@ -307,12 +305,12 @@ pack_public_key_ecdsa(fido_cred_t *cred, struct sk_enroll_response *response)
 		skdebug(__func__, "BN_bin2bn failed");
 		goto out;
 	}
-	if (EC_POINT_set_affine_coordinates_GFp(g, q, x, y, bn_ctx) != 1) {
+	if (EC_POINT_set_affine_coordinates_GFp(g, q, x, y, NULL) != 1) {
 		skdebug(__func__, "EC_POINT_set_affine_coordinates_GFp failed");
 		goto out;
 	}
 	response->public_key_len = EC_POINT_point2oct(g, q,
-	    POINT_CONVERSION_UNCOMPRESSED, NULL, 0, bn_ctx);
+	    POINT_CONVERSION_UNCOMPRESSED, NULL, 0, NULL);
 	if (response->public_key_len == 0 || response->public_key_len > 2048) {
 		skdebug(__func__, "bad pubkey length %zu",
 		    response->public_key_len);
@@ -323,7 +321,7 @@ pack_public_key_ecdsa(fido_cred_t *cred, struct sk_enroll_response *response)
 		goto out;
 	}
 	if (EC_POINT_point2oct(g, q, POINT_CONVERSION_UNCOMPRESSED,
-	    response->public_key, response->public_key_len, bn_ctx) == 0) {
+	    response->public_key, response->public_key_len, NULL) == 0) {
 		skdebug(__func__, "EC_POINT_point2oct failed");
 		goto out;
 	}
@@ -337,7 +335,8 @@ pack_public_key_ecdsa(fido_cred_t *cred, struct sk_enroll_response *response)
 	}
 	EC_POINT_free(q);
 	EC_GROUP_free(g);
-	BN_CTX_free(bn_ctx);
+	BN_clear_free(x);
+	BN_clear_free(y);
 	return ret;
 }
 
diff --git a/usr.bin/ssh/sshbuf-getput-crypto.c b/usr.bin/ssh/sshbuf-getput-crypto.c
index fa91a8abd26..e3e71ba0cf2 100644
--- a/usr.bin/ssh/sshbuf-getput-crypto.c
+++ b/usr.bin/ssh/sshbuf-getput-crypto.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sshbuf-getput-crypto.c,v 1.7 2019/01/21 09:54:11 djm Exp $	*/
+/*	$OpenBSD: sshbuf-getput-crypto.c,v 1.8 2019/11/15 06:00:20 djm Exp $	*/
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -146,23 +146,17 @@ int
 sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g)
 {
 	u_char d[SSHBUF_MAX_ECPOINT];
-	BN_CTX *bn_ctx;
 	size_t len;
 	int ret;
 
-	if ((bn_ctx = BN_CTX_new()) == NULL)
-		return SSH_ERR_ALLOC_FAIL;
 	if ((len = EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
-	    NULL, 0, bn_ctx)) > SSHBUF_MAX_ECPOINT) {
-		BN_CTX_free(bn_ctx);
+	    NULL, 0, NULL)) > SSHBUF_MAX_ECPOINT) {
 		return SSH_ERR_INVALID_ARGUMENT;
 	}
 	if (EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
-	    d, len, bn_ctx) != len) {
-		BN_CTX_free(bn_ctx);
+	    d, len, NULL) != len) {
 		return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
 	}
-	BN_CTX_free(bn_ctx);
 	ret = sshbuf_put_string(buf, d, len);
 	explicit_bzero(d, len);
 	return ret;
diff --git a/usr.bin/ssh/sshkey.c b/usr.bin/ssh/sshkey.c
index 7a138fe3130..abad883b27a 100644
--- a/usr.bin/ssh/sshkey.c
+++ b/usr.bin/ssh/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.92 2019/11/13 22:00:21 markus Exp $ */
+/* $OpenBSD: sshkey.c,v 1.93 2019/11/15 06:00:20 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
@@ -677,7 +677,6 @@ int
 sshkey_equal_public(const struct sshkey *a, const struct sshkey *b)
 {
 #ifdef WITH_OPENSSL
-	BN_CTX *bnctx;
 	const BIGNUM *rsa_e_a, *rsa_n_a;
 	const BIGNUM *rsa_e_b, *rsa_n_b;
 	const BIGNUM *dsa_p_a, *dsa_q_a, *dsa_g_a, *dsa_pub_key_a;
@@ -723,17 +722,12 @@ sshkey_equal_public(const struct sshkey *a, const struct sshkey *b)
 		    EC_KEY_get0_public_key(a->ecdsa) == NULL ||
 		    EC_KEY_get0_public_key(b->ecdsa) == NULL)
 			return 0;
-		if ((bnctx = BN_CTX_new()) == NULL)
-			return 0;
 		if (EC_GROUP_cmp(EC_KEY_get0_group(a->ecdsa),
-		    EC_KEY_get0_group(b->ecdsa), bnctx) != 0 ||
+		    EC_KEY_get0_group(b->ecdsa), NULL) != 0 ||
 		    EC_POINT_cmp(EC_KEY_get0_group(a->ecdsa),
 		    EC_KEY_get0_public_key(a->ecdsa),
-		    EC_KEY_get0_public_key(b->ecdsa), bnctx) != 0) {
-			BN_CTX_free(bnctx);
+		    EC_KEY_get0_public_key(b->ecdsa), NULL) != 0)
 			return 0;
-		}
-		BN_CTX_free(bnctx);
 		return 1;
 #endif /* WITH_OPENSSL */
 	case KEY_ED25519_SK:
@@ -1623,7 +1617,6 @@ sshkey_ecdsa_key_to_nid(EC_KEY *k)
 	};
 	int nid;
 	u_int i;
-	BN_CTX *bnctx;
 	const EC_GROUP *g = EC_KEY_get0_group(k);
 
 	/*
@@ -1636,18 +1629,13 @@ sshkey_ecdsa_key_to_nid(EC_KEY *k)
 	 */
 	if ((nid = EC_GROUP_get_curve_name(g)) > 0)
 		return nid;
-	if ((bnctx = BN_CTX_new()) == NULL)
-		return -1;
 	for (i = 0; nids[i] != -1; i++) {
-		if ((eg = EC_GROUP_new_by_curve_name(nids[i])) == NULL) {
-			BN_CTX_free(bnctx);
+		if ((eg = EC_GROUP_new_by_curve_name(nids[i])) == NULL)
 			return -1;
-		}
-		if (EC_GROUP_cmp(g, eg, bnctx) == 0)
+		if (EC_GROUP_cmp(g, eg, NULL) == 0)
 			break;
 		EC_GROUP_free(eg);
 	}
-	BN_CTX_free(bnctx);
 	if (nids[i] != -1) {
 		/* Use the group with the NID attached */
 		EC_GROUP_set_asn1_flag(eg, OPENSSL_EC_NAMED_CURVE);
@@ -3725,9 +3713,8 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
 int
 sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
 {
-	BN_CTX *bnctx;
 	EC_POINT *nq = NULL;
-	BIGNUM *order, *x, *y, *tmp;
+	BIGNUM *order = NULL, *x = NULL, *y = NULL, *tmp = NULL;
 	int ret = SSH_ERR_KEY_INVALID_EC_VALUE;
 
 	/*
@@ -3738,10 +3725,6 @@ sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
 	 * EC_POINT_oct2point then the caller will need to explicitly check.
 	 */
 
-	if ((bnctx = BN_CTX_new()) == NULL)
-		return SSH_ERR_ALLOC_FAIL;
-	BN_CTX_start(bnctx);
-
 	/*
 	 * We shouldn't ever hit this case because bignum_get_ecpoint()
 	 * refuses to load GF2m points.
@@ -3754,18 +3737,18 @@ sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
 	if (EC_POINT_is_at_infinity(group, public))
 		goto out;
 
-	if ((x = BN_CTX_get(bnctx)) == NULL ||
-	    (y = BN_CTX_get(bnctx)) == NULL ||
-	    (order = BN_CTX_get(bnctx)) == NULL ||
-	    (tmp = BN_CTX_get(bnctx)) == NULL) {
+	if ((x = BN_new()) == NULL ||
+	    (y = BN_new()) == NULL ||
+	    (order = BN_new()) == NULL ||
+	    (tmp = BN_new()) == NULL) {
 		ret = SSH_ERR_ALLOC_FAIL;
 		goto out;
 	}
 
 	/* log2(x) > log2(order)/2, log2(y) > log2(order)/2 */
-	if (EC_GROUP_get_order(group, order, bnctx) != 1 ||
+	if (EC_GROUP_get_order(group, order, NULL) != 1 ||
 	    EC_POINT_get_affine_coordinates_GFp(group, public,
-	    x, y, bnctx) != 1) {
+	    x, y, NULL) != 1) {
 		ret = SSH_ERR_LIBCRYPTO_ERROR;
 		goto out;
 	}
@@ -3778,7 +3761,7 @@ sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
 		ret = SSH_ERR_ALLOC_FAIL;
 		goto out;
 	}
-	if (EC_POINT_mul(group, nq, NULL, public, order, bnctx) != 1) {
+	if (EC_POINT_mul(group, nq, NULL, public, order, NULL) != 1) {
 		ret = SSH_ERR_LIBCRYPTO_ERROR;
 		goto out;
 	}
@@ -3794,7 +3777,10 @@ sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
 		goto out;
 	ret = 0;
  out:
-	BN_CTX_free(bnctx);
+	BN_clear_free(x);
+	BN_clear_free(y);
+	BN_clear_free(order);
+	BN_clear_free(tmp);
 	EC_POINT_free(nq);
 	return ret;
 }
@@ -3802,22 +3788,16 @@ sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
 int
 sshkey_ec_validate_private(const EC_KEY *key)
 {
-	BN_CTX *bnctx;
-	BIGNUM *order, *tmp;
+	BIGNUM *order = NULL, *tmp = NULL;
 	int ret = SSH_ERR_KEY_INVALID_EC_VALUE;
 
-	if ((bnctx = BN_CTX_new()) == NULL)
-		return SSH_ERR_ALLOC_FAIL;
-	BN_CTX_start(bnctx);
-
-	if ((order = BN_CTX_get(bnctx)) == NULL ||
-	    (tmp = BN_CTX_get(bnctx)) == NULL) {
+	if ((order = BN_new()) == NULL || (tmp = BN_new()) == NULL) {
 		ret = SSH_ERR_ALLOC_FAIL;
 		goto out;
 	}
 
 	/* log2(private) > log2(order)/2 */
-	if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, bnctx) != 1) {
+	if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, NULL) != 1) {
 		ret = SSH_ERR_LIBCRYPTO_ERROR;
 		goto out;
 	}
@@ -3834,47 +3814,43 @@ sshkey_ec_validate_private(const EC_KEY *key)
 		goto out;
 	ret = 0;
  out:
-	BN_CTX_free(bnctx);
+	BN_clear_free(order);
+	BN_clear_free(tmp);
 	return ret;
 }
 
 void
 sshkey_dump_ec_point(const EC_GROUP *group, const EC_POINT *point)
 {
-	BIGNUM *x, *y;
-	BN_CTX *bnctx;
+	BIGNUM *x = NULL, *y = NULL;
 
 	if (point == NULL) {
 		fputs("point=(NULL)\n", stderr);
 		return;
 	}
-	if ((bnctx = BN_CTX_new()) == NULL) {
-		fprintf(stderr, "%s: BN_CTX_new failed\n", __func__);
-		return;
-	}
-	BN_CTX_start(bnctx);
-	if ((x = BN_CTX_get(bnctx)) == NULL ||
-	    (y = BN_CTX_get(bnctx)) == NULL) {
-		fprintf(stderr, "%s: BN_CTX_get failed\n", __func__);
-		return;
+	if ((x = BN_new()) == NULL || (y = BN_new()) == NULL) {
+		fprintf(stderr, "%s: BN_new failed\n", __func__);
+		goto out;
 	}
 	if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
 	    NID_X9_62_prime_field) {
 		fprintf(stderr, "%s: group is not a prime field\n", __func__);
-		return;
+		goto out;
 	}
-	if (EC_POINT_get_affine_coordinates_GFp(group, point, x, y,
-	    bnctx) != 1) {
+	if (EC_POINT_get_affine_coordinates_GFp(group, point,
+	    x, y, NULL) != 1) {
 		fprintf(stderr, "%s: EC_POINT_get_affine_coordinates_GFp\n",
 		    __func__);
-		return;
+		goto out;
 	}
 	fputs("x=", stderr);
 	BN_print_fp(stderr, x);
 	fputs("\ny=", stderr);
 	BN_print_fp(stderr, y);
 	fputs("\n", stderr);
-	BN_CTX_free(bnctx);
+ out:
+	BN_clear_free(x);
+	BN_clear_free(y);
 }
 
 void