1 /* 2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 #include <stdio.h> 11 #include <stdlib.h> 12 #include <string.h> 13 14 #include "../e_os.h" 15 16 #include <openssl/bio.h> 17 #include <openssl/bn.h> 18 #include <openssl/rand.h> 19 #include <openssl/err.h> 20 21 #define NUM_BITS (BN_BITS2 * 4) 22 23 static const char rnd_seed[] = 24 "string to make the random number generator think it has entropy"; 25 26 /* 27 * Test that r == 0 in test_exp_mod_zero(). Returns one on success, 28 * returns zero and prints debug output otherwise. 29 */ 30 static int a_is_zero_mod_one(const char *method, const BIGNUM *r, 31 const BIGNUM *a) { 32 if (!BN_is_zero(r)) { 33 fprintf(stderr, "%s failed:\n", method); 34 fprintf(stderr, "a ** 0 mod 1 = r (should be 0)\n"); 35 fprintf(stderr, "a = "); 36 BN_print_fp(stderr, a); 37 fprintf(stderr, "\nr = "); 38 BN_print_fp(stderr, r); 39 fprintf(stderr, "\n"); 40 return 0; 41 } 42 return 1; 43 } 44 45 /* 46 * test_exp_mod_zero tests that x**0 mod 1 == 0. It returns zero on success. 47 */ 48 static int test_exp_mod_zero(void) 49 { 50 BIGNUM *a = NULL, *p = NULL, *m = NULL; 51 BIGNUM *r = NULL; 52 BN_ULONG one_word = 1; 53 BN_CTX *ctx = BN_CTX_new(); 54 int ret = 1, failed = 0; 55 56 m = BN_new(); 57 if (!m) 58 goto err; 59 BN_one(m); 60 61 a = BN_new(); 62 if (!a) 63 goto err; 64 BN_one(a); 65 66 p = BN_new(); 67 if (!p) 68 goto err; 69 BN_zero(p); 70 71 r = BN_new(); 72 if (!r) 73 goto err; 74 75 if (!BN_rand(a, 1024, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY)) 76 goto err; 77 78 if (!BN_mod_exp(r, a, p, m, ctx)) 79 goto err; 80 81 if (!a_is_zero_mod_one("BN_mod_exp", r, a)) 82 failed = 1; 83 84 if (!BN_mod_exp_recp(r, a, p, m, ctx)) 85 goto err; 86 87 if (!a_is_zero_mod_one("BN_mod_exp_recp", r, a)) 88 failed = 1; 89 90 if (!BN_mod_exp_simple(r, a, p, m, ctx)) 91 goto err; 92 93 if (!a_is_zero_mod_one("BN_mod_exp_simple", r, a)) 94 failed = 1; 95 96 if (!BN_mod_exp_mont(r, a, p, m, ctx, NULL)) 97 goto err; 98 99 if (!a_is_zero_mod_one("BN_mod_exp_mont", r, a)) 100 failed = 1; 101 102 if (!BN_mod_exp_mont_consttime(r, a, p, m, ctx, NULL)) { 103 goto err; 104 } 105 106 if (!a_is_zero_mod_one("BN_mod_exp_mont_consttime", r, a)) 107 failed = 1; 108 109 /* 110 * A different codepath exists for single word multiplication 111 * in non-constant-time only. 112 */ 113 if (!BN_mod_exp_mont_word(r, one_word, p, m, ctx, NULL)) 114 goto err; 115 116 if (!BN_is_zero(r)) { 117 fprintf(stderr, "BN_mod_exp_mont_word failed:\n"); 118 fprintf(stderr, "1 ** 0 mod 1 = r (should be 0)\n"); 119 fprintf(stderr, "r = "); 120 BN_print_fp(stderr, r); 121 fprintf(stderr, "\n"); 122 return 0; 123 } 124 125 ret = failed; 126 127 err: 128 BN_free(r); 129 BN_free(a); 130 BN_free(p); 131 BN_free(m); 132 BN_CTX_free(ctx); 133 134 return ret; 135 } 136 137 int main(int argc, char *argv[]) 138 { 139 BN_CTX *ctx; 140 BIO *out = NULL; 141 int i, ret; 142 unsigned char c; 143 BIGNUM *r_mont, *r_mont_const, *r_recp, *r_simple, *a, *b, *m; 144 145 /* 146 * Seed or BN_rand may fail, and we don't even check its return 147 * value (which we should) 148 */ 149 RAND_seed(rnd_seed, sizeof(rnd_seed)); 150 151 ctx = BN_CTX_new(); 152 if (ctx == NULL) 153 EXIT(1); 154 r_mont = BN_new(); 155 r_mont_const = BN_new(); 156 r_recp = BN_new(); 157 r_simple = BN_new(); 158 a = BN_new(); 159 b = BN_new(); 160 m = BN_new(); 161 if ((r_mont == NULL) || (r_recp == NULL) || (a == NULL) || (b == NULL)) 162 goto err; 163 164 out = BIO_new(BIO_s_file()); 165 166 if (out == NULL) 167 EXIT(1); 168 BIO_set_fp(out, stdout, BIO_NOCLOSE | BIO_FP_TEXT); 169 170 for (i = 0; i < 200; i++) { 171 RAND_bytes(&c, 1); 172 c = (c % BN_BITS) - BN_BITS2; 173 BN_rand(a, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY); 174 175 RAND_bytes(&c, 1); 176 c = (c % BN_BITS) - BN_BITS2; 177 BN_rand(b, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY); 178 179 RAND_bytes(&c, 1); 180 c = (c % BN_BITS) - BN_BITS2; 181 BN_rand(m, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD); 182 183 BN_mod(a, a, m, ctx); 184 BN_mod(b, b, m, ctx); 185 186 ret = BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL); 187 if (ret <= 0) { 188 printf("BN_mod_exp_mont() problems\n"); 189 ERR_print_errors(out); 190 EXIT(1); 191 } 192 193 ret = BN_mod_exp_recp(r_recp, a, b, m, ctx); 194 if (ret <= 0) { 195 printf("BN_mod_exp_recp() problems\n"); 196 ERR_print_errors(out); 197 EXIT(1); 198 } 199 200 ret = BN_mod_exp_simple(r_simple, a, b, m, ctx); 201 if (ret <= 0) { 202 printf("BN_mod_exp_simple() problems\n"); 203 ERR_print_errors(out); 204 EXIT(1); 205 } 206 207 ret = BN_mod_exp_mont_consttime(r_mont_const, a, b, m, ctx, NULL); 208 if (ret <= 0) { 209 printf("BN_mod_exp_mont_consttime() problems\n"); 210 ERR_print_errors(out); 211 EXIT(1); 212 } 213 214 if (BN_cmp(r_simple, r_mont) == 0 215 && BN_cmp(r_simple, r_recp) == 0 216 && BN_cmp(r_simple, r_mont_const) == 0) { 217 printf("."); 218 fflush(stdout); 219 } else { 220 if (BN_cmp(r_simple, r_mont) != 0) 221 printf("\nsimple and mont results differ\n"); 222 if (BN_cmp(r_simple, r_mont_const) != 0) 223 printf("\nsimple and mont const time results differ\n"); 224 if (BN_cmp(r_simple, r_recp) != 0) 225 printf("\nsimple and recp results differ\n"); 226 227 printf("a (%3d) = ", BN_num_bits(a)); 228 BN_print(out, a); 229 printf("\nb (%3d) = ", BN_num_bits(b)); 230 BN_print(out, b); 231 printf("\nm (%3d) = ", BN_num_bits(m)); 232 BN_print(out, m); 233 printf("\nsimple ="); 234 BN_print(out, r_simple); 235 printf("\nrecp ="); 236 BN_print(out, r_recp); 237 printf("\nmont ="); 238 BN_print(out, r_mont); 239 printf("\nmont_ct ="); 240 BN_print(out, r_mont_const); 241 printf("\n"); 242 EXIT(1); 243 } 244 } 245 BN_free(r_mont); 246 BN_free(r_mont_const); 247 BN_free(r_recp); 248 BN_free(r_simple); 249 BN_free(a); 250 BN_free(b); 251 BN_free(m); 252 BN_CTX_free(ctx); 253 254 if (test_exp_mod_zero() != 0) 255 goto err; 256 257 #ifndef OPENSSL_NO_CRYPTO_MDEBUG 258 if (CRYPTO_mem_leaks(out) <= 0) 259 goto err; 260 #endif 261 BIO_free(out); 262 printf("\n"); 263 264 printf("done\n"); 265 266 EXIT(0); 267 err: 268 ERR_print_errors(out); 269 EXIT(1); 270 } 271