New upstream version 13~git1505328970.9c1c35c5upstream/13_git1505328970.9c1c35c5

1 files changed, 156 insertions, 244 deletions

diff --git a/Cryptlib/OpenSSL/crypto/bn/bn_prime.c b/Cryptlib/OpenSSL/crypto/bn/bn_prime.c
index 7103acfe..4dab3bba 100644
--- a/Cryptlib/OpenSSL/crypto/bn/bn_prime.c
+++ b/Cryptlib/OpenSSL/crypto/bn/bn_prime.c
@@ -1,18 +1,125 @@
-/*
- * WARNING: do not edit!
- * Generated by crypto/bn/bn_prime.pl
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+/* crypto/bn/bn_prime.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.]
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
+ *
+ * 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 above 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 acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED 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 OpenSSL PROJECT OR
+ * ITS 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.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
  *
- * Licensed under the OpenSSL license (the "License").  You may not use
- * this file except in compliance with the License.  You can obtain a copy
- * in the file LICENSE in the source distribution or at
- * https://www.openssl.org/source/license.html
  */
 
 #include <stdio.h>
 #include <time.h>
-#include "internal/cryptlib.h"
+#include "cryptlib.h"
 #include "bn_lcl.h"
+#include <openssl/rand.h>
+
+/*
+ * NB: these functions have been "upgraded", the deprecated versions (which
+ * are compatibility wrappers using these functions) are in bn_depr.c. -
+ * Geoff
+ */
 
 /*
  * The quick sieve algorithm approach to weeding out primes is Philip
@@ -25,56 +132,11 @@ static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
                    const BIGNUM *a1_odd, int k, BN_CTX *ctx,
                    BN_MONT_CTX *mont);
 static int probable_prime(BIGNUM *rnd, int bits, prime_t *mods);
-static int probable_prime_dh_safe(BIGNUM *rnd, int bits,
-                                  const BIGNUM *add, const BIGNUM *rem,
-                                  BN_CTX *ctx);
-
-static const int prime_offsets[480] = {
-    13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83,
-    89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163,
-    167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 221, 223, 227, 229,
-    233, 239, 241, 247, 251, 257, 263, 269, 271, 277, 281, 283, 289, 293,
-    299, 307, 311, 313, 317, 323, 331, 337, 347, 349, 353, 359, 361, 367,
-    373, 377, 379, 383, 389, 391, 397, 401, 403, 409, 419, 421, 431, 433,
-    437, 439, 443, 449, 457, 461, 463, 467, 479, 481, 487, 491, 493, 499,
-    503, 509, 521, 523, 527, 529, 533, 541, 547, 551, 557, 559, 563, 569,
-    571, 577, 587, 589, 593, 599, 601, 607, 611, 613, 617, 619, 629, 631,
-    641, 643, 647, 653, 659, 661, 667, 673, 677, 683, 689, 691, 697, 701,
-    703, 709, 713, 719, 727, 731, 733, 739, 743, 751, 757, 761, 767, 769,
-    773, 779, 787, 793, 797, 799, 809, 811, 817, 821, 823, 827, 829, 839,
-    841, 851, 853, 857, 859, 863, 871, 877, 881, 883, 887, 893, 899, 901,
-    907, 911, 919, 923, 929, 937, 941, 943, 947, 949, 953, 961, 967, 971,
-    977, 983, 989, 991, 997, 1003, 1007, 1009, 1013, 1019, 1021, 1027, 1031,
-    1033, 1037, 1039, 1049, 1051, 1061, 1063, 1069, 1073, 1079, 1081, 1087,
-    1091, 1093, 1097, 1103, 1109, 1117, 1121, 1123, 1129, 1139, 1147, 1151,
-    1153, 1157, 1159, 1163, 1171, 1181, 1187, 1189, 1193, 1201, 1207, 1213,
-    1217, 1219, 1223, 1229, 1231, 1237, 1241, 1247, 1249, 1259, 1261, 1271,
-    1273, 1277, 1279, 1283, 1289, 1291, 1297, 1301, 1303, 1307, 1313, 1319,
-    1321, 1327, 1333, 1339, 1343, 1349, 1357, 1361, 1363, 1367, 1369, 1373,
-    1381, 1387, 1391, 1399, 1403, 1409, 1411, 1417, 1423, 1427, 1429, 1433,
-    1439, 1447, 1451, 1453, 1457, 1459, 1469, 1471, 1481, 1483, 1487, 1489,
-    1493, 1499, 1501, 1511, 1513, 1517, 1523, 1531, 1537, 1541, 1543, 1549,
-    1553, 1559, 1567, 1571, 1577, 1579, 1583, 1591, 1597, 1601, 1607, 1609,
-    1613, 1619, 1621, 1627, 1633, 1637, 1643, 1649, 1651, 1657, 1663, 1667,
-    1669, 1679, 1681, 1691, 1693, 1697, 1699, 1703, 1709, 1711, 1717, 1721,
-    1723, 1733, 1739, 1741, 1747, 1751, 1753, 1759, 1763, 1769, 1777, 1781,
-    1783, 1787, 1789, 1801, 1807, 1811, 1817, 1819, 1823, 1829, 1831, 1843,
-    1847, 1849, 1853, 1861, 1867, 1871, 1873, 1877, 1879, 1889, 1891, 1901,
-    1907, 1909, 1913, 1919, 1921, 1927, 1931, 1933, 1937, 1943, 1949, 1951,
-    1957, 1961, 1963, 1973, 1979, 1987, 1993, 1997, 1999, 2003, 2011, 2017,
-    2021, 2027, 2029, 2033, 2039, 2041, 2047, 2053, 2059, 2063, 2069, 2071,
-    2077, 2081, 2083, 2087, 2089, 2099, 2111, 2113, 2117, 2119, 2129, 2131,
-    2137, 2141, 2143, 2147, 2153, 2159, 2161, 2171, 2173, 2179, 2183, 2197,
-    2201, 2203, 2207, 2209, 2213, 2221, 2227, 2231, 2237, 2239, 2243, 2249,
-    2251, 2257, 2263, 2267, 2269, 2273, 2279, 2281, 2287, 2291, 2293, 2297,
-    2309, 2311
-};
-
-static const int prime_offset_count = 480;
-static const int prime_multiplier = 2310;
-static const int prime_multiplier_bits = 11; /* 2^|prime_multiplier_bits| <=
-                                              * |prime_multiplier| */
-static const int first_prime_index = 5;
+static int probable_prime_dh(BIGNUM *rnd, int bits,
+                             const BIGNUM *add, const BIGNUM *rem,
+                             BN_CTX *ctx);
+static int probable_prime_dh_safe(BIGNUM *rnd, int bits, const BIGNUM *add,
+                                  const BIGNUM *rem, BN_CTX *ctx);
 
 int BN_GENCB_call(BN_GENCB *cb, int a, int b)
 {
@@ -108,20 +170,9 @@ int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe,
     prime_t *mods = NULL;
     int checks = BN_prime_checks_for_size(bits);
 
-    if (bits < 2) {
-        /* There are no prime numbers this small. */
-        BNerr(BN_F_BN_GENERATE_PRIME_EX, BN_R_BITS_TOO_SMALL);
-        return 0;
-    } else if (bits == 2 && safe) {
-        /* The smallest safe prime (7) is three bits. */
-        BNerr(BN_F_BN_GENERATE_PRIME_EX, BN_R_BITS_TOO_SMALL);
-        return 0;
-    }
-
-    mods = OPENSSL_zalloc(sizeof(*mods) * NUMPRIMES);
+    mods = OPENSSL_malloc(sizeof(*mods) * NUMPRIMES);
     if (mods == NULL)
         goto err;
-
     ctx = BN_CTX_new();
     if (ctx == NULL)
         goto err;
@@ -139,11 +190,11 @@ int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe,
             if (!probable_prime_dh_safe(ret, bits, add, rem, ctx))
                 goto err;
         } else {
-            if (!bn_probable_prime_dh(ret, bits, add, rem, ctx))
+            if (!probable_prime_dh(ret, bits, add, rem, ctx))
                 goto err;
         }
     }
-
+    /* if (BN_mod_word(ret,(BN_ULONG)3) == 1) goto loop; */
     if (!BN_GENCB_call(cb, 0, c1++))
         /* aborted */
         goto err;
@@ -184,9 +235,10 @@ int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe,
     found = 1;
  err:
     OPENSSL_free(mods);
-    if (ctx != NULL)
+    if (ctx != NULL) {
         BN_CTX_end(ctx);
-    BN_CTX_free(ctx);
+        BN_CTX_free(ctx);
+    }
     bn_check_top(ret);
     return found;
 }
@@ -218,13 +270,9 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
         /* a is even => a is prime if and only if a == 2 */
         return BN_is_word(a, 2);
     if (do_trial_division) {
-        for (i = 1; i < NUMPRIMES; i++) {
-            BN_ULONG mod = BN_mod_word(a, primes[i]);
-            if (mod == (BN_ULONG)-1)
-                goto err;
-            if (mod == 0)
+        for (i = 1; i < NUMPRIMES; i++)
+            if (BN_mod_word(a, primes[i]) == 0)
                 return 0;
-        }
         if (!BN_GENCB_call(cb, 1, -1))
             goto err;
     }
@@ -300,88 +348,12 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
         if (ctx_passed == NULL)
             BN_CTX_free(ctx);
     }
-    BN_MONT_CTX_free(mont);
+    if (mont != NULL)
+        BN_MONT_CTX_free(mont);
 
     return (ret);
 }
 
-int bn_probable_prime_dh_retry(BIGNUM *rnd, int bits, BN_CTX *ctx)
-{
-    int i;
-    int ret = 0;
-
- loop:
-    if (!BN_rand(rnd, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
-        goto err;
-
-    /* we now have a random number 'rand' to test. */
-
-    for (i = 1; i < NUMPRIMES; i++) {
-        /* check that rnd is a prime */
-        BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]);
-        if (mod == (BN_ULONG)-1)
-            goto err;
-        if (mod <= 1) {
-            goto loop;
-        }
-    }
-    ret = 1;
-
- err:
-    bn_check_top(rnd);
-    return (ret);
-}
-
-int bn_probable_prime_dh_coprime(BIGNUM *rnd, int bits, BN_CTX *ctx)
-{
-    int i;
-    BIGNUM *offset_index;
-    BIGNUM *offset_count;
-    int ret = 0;
-
-    OPENSSL_assert(bits > prime_multiplier_bits);
-
-    BN_CTX_start(ctx);
-    if ((offset_index = BN_CTX_get(ctx)) == NULL)
-        goto err;
-    if ((offset_count = BN_CTX_get(ctx)) == NULL)
-        goto err;
-
-    if (!BN_add_word(offset_count, prime_offset_count))
-        goto err;
-
- loop:
-    if (!BN_rand(rnd, bits - prime_multiplier_bits,
-                 BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
-        goto err;
-    if (BN_is_bit_set(rnd, bits))
-        goto loop;
-    if (!BN_rand_range(offset_index, offset_count))
-        goto err;
-
-    if (!BN_mul_word(rnd, prime_multiplier)
-        || !BN_add_word(rnd, prime_offsets[BN_get_word(offset_index)]))
-        goto err;
-
-    /* we now have a random number 'rand' to test. */
-
-    /* skip coprimes */
-    for (i = first_prime_index; i < NUMPRIMES; i++) {
-        /* check that rnd is a prime */
-        BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]);
-        if (mod == (BN_ULONG)-1)
-            goto err;
-        if (mod <= 1)
-            goto loop;
-    }
-    ret = 1;
-
- err:
-    BN_CTX_end(ctx);
-    bn_check_top(rnd);
-    return ret;
-}
-
 static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
                    const BIGNUM *a1_odd, int k, BN_CTX *ctx,
                    BN_MONT_CTX *mont)
@@ -412,87 +384,37 @@ static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
 static int probable_prime(BIGNUM *rnd, int bits, prime_t *mods)
 {
     int i;
-    BN_ULONG delta;
-    BN_ULONG maxdelta = BN_MASK2 - primes[NUMPRIMES - 1];
-    char is_single_word = bits <= BN_BITS2;
+    BN_ULONG delta, maxdelta;
 
  again:
-    if (!BN_rand(rnd, bits, BN_RAND_TOP_TWO, BN_RAND_BOTTOM_ODD))
+    if (!BN_rand(rnd, bits, 1, 1))
         return (0);
-    /* we now have a random number 'rnd' to test. */
-    for (i = 1; i < NUMPRIMES; i++) {
-        BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]);
-        if (mod == (BN_ULONG)-1)
-            return 0;
-        mods[i] = (prime_t) mod;
-    }
-    /*
-     * If bits is so small that it fits into a single word then we
-     * additionally don't want to exceed that many bits.
-     */
-    if (is_single_word) {
-        BN_ULONG size_limit;
-
-        if (bits == BN_BITS2) {
-            /*
-             * Shifting by this much has undefined behaviour so we do it a
-             * different way
-             */
-            size_limit = ~((BN_ULONG)0) - BN_get_word(rnd);
-        } else {
-            size_limit = (((BN_ULONG)1) << bits) - BN_get_word(rnd) - 1;
-        }
-        if (size_limit < maxdelta)
-            maxdelta = size_limit;
-    }
+    /* we now have a random number 'rand' to test. */
+    for (i = 1; i < NUMPRIMES; i++)
+        mods[i] = (prime_t) BN_mod_word(rnd, (BN_ULONG)primes[i]);
+    maxdelta = BN_MASK2 - primes[NUMPRIMES - 1];
     delta = 0;
- loop:
-    if (is_single_word) {
-        BN_ULONG rnd_word = BN_get_word(rnd);
-
-        /*-
-         * In the case that the candidate prime is a single word then
-         * we check that:
-         *   1) It's greater than primes[i] because we shouldn't reject
-         *      3 as being a prime number because it's a multiple of
-         *      three.
-         *   2) That it's not a multiple of a known prime. We don't
-         *      check that rnd-1 is also coprime to all the known
-         *      primes because there aren't many small primes where
-         *      that's true.
+ loop:for (i = 1; i < NUMPRIMES; i++) {
+        /*
+         * check that rnd is not a prime and also that gcd(rnd-1,primes) == 1
+         * (except for 2)
          */
-        for (i = 1; i < NUMPRIMES && primes[i] < rnd_word; i++) {
-            if ((mods[i] + delta) % primes[i] == 0) {
-                delta += 2;
-                if (delta > maxdelta)
-                    goto again;
-                goto loop;
-            }
-        }
-    } else {
-        for (i = 1; i < NUMPRIMES; i++) {
-            /*
-             * check that rnd is not a prime and also that gcd(rnd-1,primes)
-             * == 1 (except for 2)
-             */
-            if (((mods[i] + delta) % primes[i]) <= 1) {
-                delta += 2;
-                if (delta > maxdelta)
-                    goto again;
-                goto loop;
-            }
+        if (((mods[i] + delta) % primes[i]) <= 1) {
+            delta += 2;
+            if (delta > maxdelta)
+                goto again;
+            goto loop;
         }
     }
     if (!BN_add_word(rnd, delta))
         return (0);
-    if (BN_num_bits(rnd) != bits)
-        goto again;
     bn_check_top(rnd);
     return (1);
 }
 
-int bn_probable_prime_dh(BIGNUM *rnd, int bits,
-                         const BIGNUM *add, const BIGNUM *rem, BN_CTX *ctx)
+static int probable_prime_dh(BIGNUM *rnd, int bits,
+                             const BIGNUM *add, const BIGNUM *rem,
+                             BN_CTX *ctx)
 {
     int i, ret = 0;
     BIGNUM *t1;
@@ -501,7 +423,7 @@ int bn_probable_prime_dh(BIGNUM *rnd, int bits,
     if ((t1 = BN_CTX_get(ctx)) == NULL)
         goto err;
 
-    if (!BN_rand(rnd, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
+    if (!BN_rand(rnd, bits, 0, 1))
         goto err;
 
     /* we need ((rnd-rem) % add) == 0 */
@@ -520,20 +442,15 @@ int bn_probable_prime_dh(BIGNUM *rnd, int bits,
 
     /* we now have a random number 'rand' to test. */
 
- loop:
-    for (i = 1; i < NUMPRIMES; i++) {
+ loop:for (i = 1; i < NUMPRIMES; i++) {
         /* check that rnd is a prime */
-        BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]);
-        if (mod == (BN_ULONG)-1)
-            goto err;
-        if (mod <= 1) {
+        if (BN_mod_word(rnd, (BN_ULONG)primes[i]) <= 1) {
             if (!BN_add(rnd, rnd, add))
                 goto err;
             goto loop;
         }
     }
     ret = 1;
-
  err:
     BN_CTX_end(ctx);
     bn_check_top(rnd);
@@ -557,7 +474,7 @@ static int probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd,
     if (!BN_rshift1(qadd, padd))
         goto err;
 
-    if (!BN_rand(q, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
+    if (!BN_rand(q, bits, 0, 1))
         goto err;
 
     /* we need ((rnd-rem) % add) == 0 */
@@ -581,17 +498,13 @@ static int probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd,
     if (!BN_add_word(p, 1))
         goto err;
 
- loop:
-    for (i = 1; i < NUMPRIMES; i++) {
+ loop:for (i = 1; i < NUMPRIMES; i++) {
         /* check that p and q are prime */
         /*
          * check that for p and q gcd(p-1,primes) == 1 (except for 2)
          */
-        BN_ULONG pmod = BN_mod_word(p, (BN_ULONG)primes[i]);
-        BN_ULONG qmod = BN_mod_word(q, (BN_ULONG)primes[i]);
-        if (pmod == (BN_ULONG)-1 || qmod == (BN_ULONG)-1)
-            goto err;
-        if (pmod == 0 || qmod == 0) {
+        if ((BN_mod_word(p, (BN_ULONG)primes[i]) == 0) ||
+            (BN_mod_word(q, (BN_ULONG)primes[i]) == 0)) {
             if (!BN_add(p, p, padd))
                 goto err;
             if (!BN_add(q, q, qadd))
@@ -600,7 +513,6 @@ static int probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd,
         }
     }
     ret = 1;
-
  err:
     BN_CTX_end(ctx);
     bn_check_top(p);