--- /dev/null
+/* 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>
+
+
+int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *out_flags) {
+ *out_flags = 0;
+
+ BN_CTX *ctx = BN_CTX_new();
+ if (ctx == NULL) {
+ return 0;
+ }
+ BN_CTX_start(ctx);
+
+ int ok = 0;
+
+ // Check |pub_key| is greater than 1.
+ BIGNUM *tmp = BN_CTX_get(ctx);
+ if (tmp == NULL ||
+ !BN_set_word(tmp, 1)) {
+ goto err;
+ }
+ if (BN_cmp(pub_key, tmp) <= 0) {
+ *out_flags |= DH_CHECK_PUBKEY_TOO_SMALL;
+ }
+
+ // Check |pub_key| is less than |dh->p| - 1.
+ if (!BN_copy(tmp, dh->p) ||
+ !BN_sub_word(tmp, 1)) {
+ goto err;
+ }
+ if (BN_cmp(pub_key, tmp) >= 0) {
+ *out_flags |= DH_CHECK_PUBKEY_TOO_LARGE;
+ }
+
+ if (dh->q != NULL) {
+ // Check |pub_key|^|dh->q| is 1 mod |dh->p|. This is necessary for RFC 5114
+ // groups which are not safe primes but pick a generator on a prime-order
+ // subgroup of size |dh->q|.
+ if (!BN_mod_exp_mont(tmp, pub_key, dh->q, dh->p, ctx, NULL)) {
+ goto err;
+ }
+ if (!BN_is_one(tmp)) {
+ *out_flags |= DH_CHECK_PUBKEY_INVALID;
+ }
+ }
+
+ ok = 1;
+
+err:
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ return ok;
+}
+
+
+int DH_check(const DH *dh, int *out_flags) {
+ // Check that p is a safe prime and if g is 2, 3 or 5, check that it is a
+ // suitable generator where:
+ // for 2, p mod 24 == 11
+ // for 3, p mod 12 == 5
+ // for 5, p mod 10 == 3 or 7
+ // should hold.
+ int ok = 0, r;
+ BN_CTX *ctx = NULL;
+ BN_ULONG l;
+ BIGNUM *t1 = NULL, *t2 = NULL;
+
+ *out_flags = 0;
+ ctx = BN_CTX_new();
+ if (ctx == NULL) {
+ goto err;
+ }
+ BN_CTX_start(ctx);
+ t1 = BN_CTX_get(ctx);
+ if (t1 == NULL) {
+ goto err;
+ }
+ t2 = BN_CTX_get(ctx);
+ if (t2 == NULL) {
+ goto err;
+ }
+
+ if (dh->q) {
+ if (BN_cmp(dh->g, BN_value_one()) <= 0) {
+ *out_flags |= DH_CHECK_NOT_SUITABLE_GENERATOR;
+ } else if (BN_cmp(dh->g, dh->p) >= 0) {
+ *out_flags |= DH_CHECK_NOT_SUITABLE_GENERATOR;
+ } else {
+ // Check g^q == 1 mod p
+ if (!BN_mod_exp_mont(t1, dh->g, dh->q, dh->p, ctx, NULL)) {
+ goto err;
+ }
+ if (!BN_is_one(t1)) {
+ *out_flags |= DH_CHECK_NOT_SUITABLE_GENERATOR;
+ }
+ }
+ r = BN_is_prime_ex(dh->q, BN_prime_checks, ctx, NULL);
+ if (r < 0) {
+ goto err;
+ }
+ if (!r) {
+ *out_flags |= DH_CHECK_Q_NOT_PRIME;
+ }
+ // Check p == 1 mod q i.e. q divides p - 1
+ if (!BN_div(t1, t2, dh->p, dh->q, ctx)) {
+ goto err;
+ }
+ if (!BN_is_one(t2)) {
+ *out_flags |= DH_CHECK_INVALID_Q_VALUE;
+ }
+ if (dh->j && BN_cmp(dh->j, t1)) {
+ *out_flags |= DH_CHECK_INVALID_J_VALUE;
+ }
+ } else if (BN_is_word(dh->g, DH_GENERATOR_2)) {
+ l = BN_mod_word(dh->p, 24);
+ if (l == (BN_ULONG)-1) {
+ goto err;
+ }
+ if (l != 11) {
+ *out_flags |= DH_CHECK_NOT_SUITABLE_GENERATOR;
+ }
+ } else if (BN_is_word(dh->g, DH_GENERATOR_5)) {
+ l = BN_mod_word(dh->p, 10);
+ if (l == (BN_ULONG)-1) {
+ goto err;
+ }
+ if (l != 3 && l != 7) {
+ *out_flags |= DH_CHECK_NOT_SUITABLE_GENERATOR;
+ }
+ } else {
+ *out_flags |= DH_CHECK_UNABLE_TO_CHECK_GENERATOR;
+ }
+
+ r = BN_is_prime_ex(dh->p, BN_prime_checks, ctx, NULL);
+ if (r < 0) {
+ goto err;
+ }
+ if (!r) {
+ *out_flags |= DH_CHECK_P_NOT_PRIME;
+ } else if (!dh->q) {
+ if (!BN_rshift1(t1, dh->p)) {
+ goto err;
+ }
+ r = BN_is_prime_ex(t1, BN_prime_checks, ctx, NULL);
+ if (r < 0) {
+ goto err;
+ }
+ if (!r) {
+ *out_flags |= DH_CHECK_P_NOT_SAFE_PRIME;
+ }
+ }
+ ok = 1;
+
+err:
+ if (ctx != NULL) {
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ }
+ return ok;
+}
git://repos.xcallymotion.com / motion2.git / blobdiff