upstream: 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@

OpenBSD-Commit-ID: ea9ba6c0d2e6f6adfe00b309a8f41842fe12fc7a

4 files changed, 47 insertions, 84 deletions

diff --git a/moduli.c b/moduli.c
index 4f6f8da8d..8dd36b1cf 100644
--- a/moduli.c
+++ b/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>
@@ -578,7 +578,6 @@ 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;
@@ -602,8 +601,6 @@ 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);
@@ -753,7 +750,7 @@ 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) {
@@ -769,7 +766,7 @@ 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) {
@@ -779,7 +776,7 @@ 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) {
@@ -802,7 +799,6 @@ 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/sk-usbhid.c b/sk-usbhid.c
index 180f2eab9..d008b0a9a 100644
--- a/sk-usbhid.c
+++ b/sk-usbhid.c
@@ -282,15 +282,13 @@ 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");
@@ -311,12 +309,12 @@ 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);
@@ -327,7 +325,7 @@ 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;
         }
@@ -341,7 +339,8 @@ 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/sshbuf-getput-crypto.c b/sshbuf-getput-crypto.c
index ecbfa550f..2e61d3bcd 100644
--- a/sshbuf-getput-crypto.c
+++ b/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
  *
@@ -154,23 +154,17 @@ 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/sshkey.c b/sshkey.c
index 8db947436..40e764dd4 100644
--- a/sshkey.c
+++ b/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.
@@ -706,9 +706,6 @@ sshkey_equal_public(const struct sshkey *a, const struct sshkey *b)
         const BIGNUM *rsa_e_b, *rsa_n_b;
         const BIGNUM *dsa_p_a, *dsa_q_a, *dsa_g_a, *dsa_pub_key_a;
         const BIGNUM *dsa_p_b, *dsa_q_b, *dsa_g_b, *dsa_pub_key_b;
-# if defined(OPENSSL_HAS_ECC)
-        BN_CTX *bnctx;
-# endif /* OPENSSL_HAS_ECC */
 #endif /* WITH_OPENSSL */
 
         if (a == NULL || b == NULL ||
@@ -751,17 +748,12 @@ 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 /* OPENSSL_HAS_ECC */
 #endif /* WITH_OPENSSL */
@@ -1659,7 +1651,6 @@ 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);
 
         /*
@@ -1672,18 +1663,13 @@ 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);
@@ -3788,9 +3774,8 @@ 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;
 
         /*
@@ -3801,10 +3786,6 @@ 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.
@@ -3817,18 +3798,18 @@ 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;
         }
@@ -3841,7 +3822,7 @@ 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;
         }
@@ -3857,7 +3838,10 @@ 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;
 }
@@ -3865,22 +3849,16 @@ 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;
         }
@@ -3897,47 +3875,43 @@ 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