1 files changed, 175 insertions, 0 deletions

diff --git a/src/lib/libcrypto/dh/dh_gen.c b/src/lib/libcrypto/dh/dh_gen.c
new file mode 100644
index 0000000000..cfd5b11868
--- /dev/null
+++ b/src/lib/libcrypto/dh/dh_gen.c
@@ -0,0 +1,175 @@
+/* crypto/dh/dh_gen.c */
+/* 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.]
+ */
+
+/* NB: These functions have been upgraded - the previous prototypes are in
+ * dh_depr.c as wrappers to these ones.
+ *  - Geoff
+ */
+
+#include <stdio.h>
+#include "cryptlib.h"
+#include <openssl/bn.h>
+#include <openssl/dh.h>
+
+static int dh_builtin_genparams(DH *ret, int prime_len, int generator, BN_GENCB *cb);
+
+int DH_generate_parameters_ex(DH *ret, int prime_len, int generator, BN_GENCB *cb)
+        {
+        if(ret->meth->generate_params)
+                return ret->meth->generate_params(ret, prime_len, generator, cb);
+        return dh_builtin_genparams(ret, prime_len, generator, cb);
+        }
+
+/* We generate DH parameters as follows
+ * find a prime q which is prime_len/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.
+ */
+static int dh_builtin_genparams(DH *ret, int prime_len, int generator, BN_GENCB *cb)
+        {
+        BIGNUM *t1,*t2;
+        int g,ok= -1;
+        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)
+                {
+                DHerr(DH_F_DH_BUILTIN_GENPARAMS, 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;
+                }
+#if 0 /* does not work for safe primes */
+        else if (generator == DH_GENERATOR_3)
+                {
+                if (!BN_set_word(t1,12)) goto err;
+                if (!BN_set_word(t2,5)) goto err;
+                g=3;
+                }
+#endif
+        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_len,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 == -1)
+                {
+                DHerr(DH_F_DH_BUILTIN_GENPARAMS,ERR_R_BN_LIB);
+                ok=0;
+                }
+
+        if (ctx != NULL)
+                {
+                BN_CTX_end(ctx);
+                BN_CTX_free(ctx);
+                }
+        return ok;
+        }