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authorAdam Langley <agl@google.com>2015-01-22 14:27:53 -0800
committerAdam Langley <agl@google.com>2015-01-30 16:52:14 -0800
commitd9e397b599b13d642138480a28c14db7a136bf05 (patch)
tree34bab61dc4ce323b123ad4614dbc07e86ea2f9ef /src/crypto/dh/dh_impl.c
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Initial commit of BoringSSL for Android.
Diffstat (limited to 'src/crypto/dh/dh_impl.c')
-rw-r--r--src/crypto/dh/dh_impl.c324
1 files changed, 324 insertions, 0 deletions
diff --git a/src/crypto/dh/dh_impl.c b/src/crypto/dh/dh_impl.c
new file mode 100644
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+++ b/src/crypto/dh/dh_impl.c
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+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ *
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to. The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code. The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ *
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * "This product includes cryptographic software written by
+ * Eric Young (eay@cryptsoft.com)"
+ * The word 'cryptographic' can be left out if the rouines from the library
+ * being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from
+ * the apps directory (application code) you must include an acknowledgement:
+ * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed. i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.] */
+
+#include <openssl/dh.h>
+
+#include <openssl/bn.h>
+#include <openssl/err.h>
+
+#include "internal.h"
+
+#define OPENSSL_DH_MAX_MODULUS_BITS 10000
+
+static int generate_parameters(DH *ret, int prime_bits, int generator, BN_GENCB *cb) {
+ /* We generate DH parameters as follows
+ * find a prime q which is prime_bits/2 bits long.
+ * p=(2*q)+1 or (p-1)/2 = q
+ * For this case, g is a generator if
+ * g^((p-1)/q) mod p != 1 for values of q which are the factors of p-1.
+ * Since the factors of p-1 are q and 2, we just need to check
+ * g^2 mod p != 1 and g^q mod p != 1.
+ *
+ * Having said all that,
+ * there is another special case method for the generators 2, 3 and 5.
+ * for 2, p mod 24 == 11
+ * for 3, p mod 12 == 5 <<<<< does not work for safe primes.
+ * for 5, p mod 10 == 3 or 7
+ *
+ * Thanks to Phil Karn <karn@qualcomm.com> for the pointers about the
+ * special generators and for answering some of my questions.
+ *
+ * I've implemented the second simple method :-).
+ * Since DH should be using a safe prime (both p and q are prime),
+ * this generator function can take a very very long time to run.
+ */
+
+ /* Actually there is no reason to insist that 'generator' be a generator.
+ * It's just as OK (and in some sense better) to use a generator of the
+ * order-q subgroup.
+ */
+
+ BIGNUM *t1, *t2;
+ int g, ok = 0;
+ BN_CTX *ctx = NULL;
+
+ ctx = BN_CTX_new();
+ if (ctx == NULL) {
+ goto err;
+ }
+ BN_CTX_start(ctx);
+ t1 = BN_CTX_get(ctx);
+ t2 = BN_CTX_get(ctx);
+ if (t1 == NULL || t2 == NULL) {
+ goto err;
+ }
+
+ /* Make sure 'ret' has the necessary elements */
+ if (!ret->p && ((ret->p = BN_new()) == NULL)) {
+ goto err;
+ }
+ if (!ret->g && ((ret->g = BN_new()) == NULL)) {
+ goto err;
+ }
+
+ if (generator <= 1) {
+ OPENSSL_PUT_ERROR(DH, generate_parameters, DH_R_BAD_GENERATOR);
+ goto err;
+ }
+ if (generator == DH_GENERATOR_2) {
+ if (!BN_set_word(t1, 24)) {
+ goto err;
+ }
+ if (!BN_set_word(t2, 11)) {
+ goto err;
+ }
+ g = 2;
+ } else if (generator == DH_GENERATOR_5) {
+ if (!BN_set_word(t1, 10)) {
+ goto err;
+ }
+ if (!BN_set_word(t2, 3)) {
+ goto err;
+ }
+ /* BN_set_word(t3,7); just have to miss
+ * out on these ones :-( */
+ g = 5;
+ } else {
+ /* in the general case, don't worry if 'generator' is a
+ * generator or not: since we are using safe primes,
+ * it will generate either an order-q or an order-2q group,
+ * which both is OK */
+ if (!BN_set_word(t1, 2)) {
+ goto err;
+ }
+ if (!BN_set_word(t2, 1)) {
+ goto err;
+ }
+ g = generator;
+ }
+
+ if (!BN_generate_prime_ex(ret->p, prime_bits, 1, t1, t2, cb)) {
+ goto err;
+ }
+ if (!BN_GENCB_call(cb, 3, 0)) {
+ goto err;
+ }
+ if (!BN_set_word(ret->g, g)) {
+ goto err;
+ }
+ ok = 1;
+
+err:
+ if (!ok) {
+ OPENSSL_PUT_ERROR(DH, generate_parameters, ERR_R_BN_LIB);
+ }
+
+ if (ctx != NULL) {
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ }
+ return ok;
+}
+
+static int generate_key(DH *dh) {
+ int ok = 0;
+ int generate_new_key = 0;
+ unsigned l;
+ BN_CTX *ctx;
+ BN_MONT_CTX *mont = NULL;
+ BIGNUM *pub_key = NULL, *priv_key = NULL;
+ BIGNUM local_priv;
+
+ ctx = BN_CTX_new();
+ if (ctx == NULL) {
+ goto err;
+ }
+
+ if (dh->priv_key == NULL) {
+ priv_key = BN_new();
+ if (priv_key == NULL) {
+ goto err;
+ }
+ generate_new_key = 1;
+ } else {
+ priv_key = dh->priv_key;
+ }
+
+ if (dh->pub_key == NULL) {
+ pub_key = BN_new();
+ if (pub_key == NULL) {
+ goto err;
+ }
+ } else {
+ pub_key = dh->pub_key;
+ }
+
+ mont =
+ BN_MONT_CTX_set_locked(&dh->method_mont_p, CRYPTO_LOCK_DH, dh->p, ctx);
+ if (!mont) {
+ goto err;
+ }
+
+ if (generate_new_key) {
+ if (dh->q) {
+ do {
+ if (!BN_rand_range(priv_key, dh->q)) {
+ goto err;
+ }
+ } while (BN_is_zero(priv_key) || BN_is_one(priv_key));
+ } else {
+ /* secret exponent length */
+ DH_check_standard_parameters(dh);
+ l = dh->priv_length ? dh->priv_length : BN_num_bits(dh->p) - 1;
+ if (!BN_rand(priv_key, l, 0, 0)) {
+ goto err;
+ }
+ }
+ }
+
+ BN_with_flags(&local_priv, priv_key, BN_FLG_CONSTTIME);
+ if (!BN_mod_exp_mont(pub_key, dh->g, &local_priv, dh->p, ctx, mont)) {
+ goto err;
+ }
+
+ dh->pub_key = pub_key;
+ dh->priv_key = priv_key;
+ ok = 1;
+
+err:
+ if (ok != 1) {
+ OPENSSL_PUT_ERROR(DH, generate_key, ERR_R_BN_LIB);
+ }
+
+ if (pub_key != NULL && dh->pub_key == NULL) {
+ BN_free(pub_key);
+ }
+ if (priv_key != NULL && dh->priv_key == NULL) {
+ BN_free(priv_key);
+ }
+ BN_CTX_free(ctx);
+ return ok;
+}
+
+static int compute_key(DH *dh, unsigned char *out, const BIGNUM *pub_key) {
+ BN_CTX *ctx = NULL;
+ BN_MONT_CTX *mont = NULL;
+ BIGNUM *shared_key;
+ int ret = -1;
+ int check_result;
+ BIGNUM local_priv;
+
+ if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
+ OPENSSL_PUT_ERROR(DH, compute_key, DH_R_MODULUS_TOO_LARGE);
+ goto err;
+ }
+
+ ctx = BN_CTX_new();
+ if (ctx == NULL) {
+ goto err;
+ }
+ BN_CTX_start(ctx);
+ shared_key = BN_CTX_get(ctx);
+ if (shared_key == NULL) {
+ goto err;
+ }
+
+ if (dh->priv_key == NULL) {
+ OPENSSL_PUT_ERROR(DH, compute_key, DH_R_NO_PRIVATE_VALUE);
+ goto err;
+ }
+
+ mont =
+ BN_MONT_CTX_set_locked(&dh->method_mont_p, CRYPTO_LOCK_DH, dh->p, ctx);
+ if (!mont) {
+ goto err;
+ }
+
+ if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) {
+ OPENSSL_PUT_ERROR(DH, compute_key, DH_R_INVALID_PUBKEY);
+ goto err;
+ }
+
+ BN_with_flags(&local_priv, dh->priv_key, BN_FLG_CONSTTIME);
+ if (!BN_mod_exp_mont(shared_key, pub_key, &local_priv, dh->p, ctx,
+ mont)) {
+ OPENSSL_PUT_ERROR(DH, compute_key, ERR_R_BN_LIB);
+ goto err;
+ }
+
+ ret = BN_bn2bin(shared_key, out);
+
+err:
+ if (ctx != NULL) {
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ }
+
+ return ret;
+}
+
+const struct dh_method DH_default_method = {
+ {
+ 0 /* references */,
+ 1 /* is_static */,
+ },
+ NULL /* app_data */,
+ NULL /* init */,
+ NULL /* finish */,
+ generate_parameters,
+ generate_key,
+ compute_key,
+};