Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2000 Niels Provos. All rights reserved. |
| 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * 1. Redistributions of source code must retain the above copyright |
| 8 | * notice, this list of conditions and the following disclaimer. |
| 9 | * 2. Redistributions in binary form must reproduce the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer in the |
| 11 | * documentation and/or other materials provided with the distribution. |
| 12 | * |
| 13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 23 | */ |
| 24 | |
| 25 | #include "includes.h" |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 26 | |
| 27 | #include "xmalloc.h" |
| 28 | |
| 29 | #include <openssl/bn.h> |
| 30 | #include <openssl/dh.h> |
| 31 | #include <openssl/evp.h> |
| 32 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 33 | #include "buffer.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 34 | #include "cipher.h" |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 35 | #include "kex.h" |
| 36 | #include "dh.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 37 | #include "pathnames.h" |
| 38 | #include "log.h" |
| 39 | #include "misc.h" |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 40 | |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 41 | static int |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 42 | parse_prime(int linenum, char *line, struct dhgroup *dhg) |
| 43 | { |
| 44 | char *cp, *arg; |
| 45 | char *strsize, *gen, *prime; |
| 46 | |
| 47 | cp = line; |
| 48 | arg = strdelim(&cp); |
| 49 | /* Ignore leading whitespace */ |
| 50 | if (*arg == '\0') |
| 51 | arg = strdelim(&cp); |
Ben Lindstrom | 04f9af7 | 2002-07-04 00:03:56 +0000 | [diff] [blame] | 52 | if (!arg || !*arg || *arg == '#') |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 53 | return 0; |
| 54 | |
| 55 | /* time */ |
| 56 | if (cp == NULL || *arg == '\0') |
| 57 | goto fail; |
| 58 | arg = strsep(&cp, " "); /* type */ |
| 59 | if (cp == NULL || *arg == '\0') |
| 60 | goto fail; |
| 61 | arg = strsep(&cp, " "); /* tests */ |
| 62 | if (cp == NULL || *arg == '\0') |
| 63 | goto fail; |
| 64 | arg = strsep(&cp, " "); /* tries */ |
| 65 | if (cp == NULL || *arg == '\0') |
| 66 | goto fail; |
| 67 | strsize = strsep(&cp, " "); /* size */ |
| 68 | if (cp == NULL || *strsize == '\0' || |
| 69 | (dhg->size = atoi(strsize)) == 0) |
| 70 | goto fail; |
Ben Lindstrom | df22139 | 2001-03-29 00:36:16 +0000 | [diff] [blame] | 71 | /* The whole group is one bit larger */ |
| 72 | dhg->size++; |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 73 | gen = strsep(&cp, " "); /* gen */ |
| 74 | if (cp == NULL || *gen == '\0') |
| 75 | goto fail; |
| 76 | prime = strsep(&cp, " "); /* prime */ |
| 77 | if (cp != NULL || *prime == '\0') |
| 78 | goto fail; |
| 79 | |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 80 | if ((dhg->g = BN_new()) == NULL) |
| 81 | fatal("parse_prime: BN_new failed"); |
| 82 | if ((dhg->p = BN_new()) == NULL) |
| 83 | fatal("parse_prime: BN_new failed"); |
Ben Lindstrom | 206941f | 2001-04-15 14:27:16 +0000 | [diff] [blame] | 84 | if (BN_hex2bn(&dhg->g, gen) == 0) |
Damien Miller | 23e526e | 2001-03-30 10:47:43 +1000 | [diff] [blame] | 85 | goto failclean; |
| 86 | |
Ben Lindstrom | 206941f | 2001-04-15 14:27:16 +0000 | [diff] [blame] | 87 | if (BN_hex2bn(&dhg->p, prime) == 0) |
Damien Miller | 23e526e | 2001-03-30 10:47:43 +1000 | [diff] [blame] | 88 | goto failclean; |
| 89 | |
| 90 | if (BN_num_bits(dhg->p) != dhg->size) |
| 91 | goto failclean; |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 92 | |
Darren Tucker | fc113c9 | 2004-02-29 20:12:33 +1100 | [diff] [blame] | 93 | if (BN_is_zero(dhg->g) || BN_is_one(dhg->g)) |
| 94 | goto failclean; |
| 95 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 96 | return (1); |
Damien Miller | 23e526e | 2001-03-30 10:47:43 +1000 | [diff] [blame] | 97 | |
| 98 | failclean: |
Damien Miller | 9ef95dd | 2002-01-22 23:10:33 +1100 | [diff] [blame] | 99 | BN_clear_free(dhg->g); |
| 100 | BN_clear_free(dhg->p); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 101 | fail: |
Ben Lindstrom | 6df8ef4 | 2001-03-05 07:47:23 +0000 | [diff] [blame] | 102 | error("Bad prime description in line %d", linenum); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 103 | return (0); |
| 104 | } |
| 105 | |
| 106 | DH * |
Ben Lindstrom | df22139 | 2001-03-29 00:36:16 +0000 | [diff] [blame] | 107 | choose_dh(int min, int wantbits, int max) |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 108 | { |
| 109 | FILE *f; |
Darren Tucker | c56c7ef | 2004-02-29 20:13:34 +1100 | [diff] [blame] | 110 | char line[4096]; |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 111 | int best, bestcount, which; |
| 112 | int linenum; |
| 113 | struct dhgroup dhg; |
| 114 | |
Ben Lindstrom | 93a29e0 | 2001-06-25 04:13:25 +0000 | [diff] [blame] | 115 | if ((f = fopen(_PATH_DH_MODULI, "r")) == NULL && |
| 116 | (f = fopen(_PATH_DH_PRIMES, "r")) == NULL) { |
Damien Miller | f675fc4 | 2004-06-15 10:30:09 +1000 | [diff] [blame] | 117 | logit("WARNING: %s does not exist, using fixed modulus", |
| 118 | _PATH_DH_MODULI); |
| 119 | return (dh_new_group14()); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 120 | } |
| 121 | |
| 122 | linenum = 0; |
| 123 | best = bestcount = 0; |
| 124 | while (fgets(line, sizeof(line), f)) { |
| 125 | linenum++; |
| 126 | if (!parse_prime(linenum, line, &dhg)) |
| 127 | continue; |
Damien Miller | 9ef95dd | 2002-01-22 23:10:33 +1100 | [diff] [blame] | 128 | BN_clear_free(dhg.g); |
| 129 | BN_clear_free(dhg.p); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 130 | |
Ben Lindstrom | df22139 | 2001-03-29 00:36:16 +0000 | [diff] [blame] | 131 | if (dhg.size > max || dhg.size < min) |
| 132 | continue; |
| 133 | |
| 134 | if ((dhg.size > wantbits && dhg.size < best) || |
| 135 | (dhg.size > best && best < wantbits)) { |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 136 | best = dhg.size; |
| 137 | bestcount = 0; |
| 138 | } |
| 139 | if (dhg.size == best) |
| 140 | bestcount++; |
| 141 | } |
Ben Lindstrom | af73880 | 2001-06-25 04:18:59 +0000 | [diff] [blame] | 142 | rewind(f); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 143 | |
| 144 | if (bestcount == 0) { |
Ben Lindstrom | af73880 | 2001-06-25 04:18:59 +0000 | [diff] [blame] | 145 | fclose(f); |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 146 | logit("WARNING: no suitable primes in %s", _PATH_DH_PRIMES); |
Darren Tucker | 9a2bd11 | 2004-08-12 22:40:59 +1000 | [diff] [blame] | 147 | return (dh_new_group14()); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 148 | } |
| 149 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 150 | linenum = 0; |
| 151 | which = arc4random() % bestcount; |
| 152 | while (fgets(line, sizeof(line), f)) { |
| 153 | if (!parse_prime(linenum, line, &dhg)) |
| 154 | continue; |
Ben Lindstrom | 5ba23b3 | 2001-04-05 02:05:21 +0000 | [diff] [blame] | 155 | if ((dhg.size > max || dhg.size < min) || |
| 156 | dhg.size != best || |
| 157 | linenum++ != which) { |
Damien Miller | 9ef95dd | 2002-01-22 23:10:33 +1100 | [diff] [blame] | 158 | BN_clear_free(dhg.g); |
| 159 | BN_clear_free(dhg.p); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 160 | continue; |
| 161 | } |
| 162 | break; |
| 163 | } |
| 164 | fclose(f); |
Ben Lindstrom | 5ba23b3 | 2001-04-05 02:05:21 +0000 | [diff] [blame] | 165 | if (linenum != which+1) |
| 166 | fatal("WARNING: line %d disappeared in %s, giving up", |
| 167 | which, _PATH_DH_PRIMES); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 168 | |
| 169 | return (dh_new_group(dhg.g, dhg.p)); |
| 170 | } |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 171 | |
Damien Miller | f675fc4 | 2004-06-15 10:30:09 +1000 | [diff] [blame] | 172 | /* diffie-hellman-groupN-sha1 */ |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 173 | |
| 174 | int |
| 175 | dh_pub_is_valid(DH *dh, BIGNUM *dh_pub) |
| 176 | { |
| 177 | int i; |
| 178 | int n = BN_num_bits(dh_pub); |
| 179 | int bits_set = 0; |
| 180 | |
| 181 | if (dh_pub->neg) { |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 182 | logit("invalid public DH value: negativ"); |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 183 | return 0; |
| 184 | } |
| 185 | for (i = 0; i <= n; i++) |
| 186 | if (BN_is_bit_set(dh_pub, i)) |
| 187 | bits_set++; |
Ben Lindstrom | 1f53083 | 2002-12-23 02:03:02 +0000 | [diff] [blame] | 188 | debug2("bits set: %d/%d", bits_set, BN_num_bits(dh->p)); |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 189 | |
| 190 | /* if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial */ |
| 191 | if (bits_set > 1 && (BN_cmp(dh_pub, dh->p) == -1)) |
| 192 | return 1; |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 193 | logit("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p)); |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 194 | return 0; |
| 195 | } |
| 196 | |
| 197 | void |
| 198 | dh_gen_key(DH *dh, int need) |
| 199 | { |
Darren Tucker | effc84c | 2004-02-29 20:15:08 +1100 | [diff] [blame] | 200 | int i, bits_set, tries = 0; |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 201 | |
| 202 | if (dh->p == NULL) |
| 203 | fatal("dh_gen_key: dh->p == NULL"); |
Darren Tucker | c0815c9 | 2003-09-22 21:05:50 +1000 | [diff] [blame] | 204 | if (need > INT_MAX / 2 || 2 * need >= BN_num_bits(dh->p)) |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 205 | fatal("dh_gen_key: group too small: %d (2*need %d)", |
| 206 | BN_num_bits(dh->p), 2*need); |
| 207 | do { |
| 208 | if (dh->priv_key != NULL) |
Damien Miller | 9ef95dd | 2002-01-22 23:10:33 +1100 | [diff] [blame] | 209 | BN_clear_free(dh->priv_key); |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 210 | if ((dh->priv_key = BN_new()) == NULL) |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 211 | fatal("dh_gen_key: BN_new failed"); |
| 212 | /* generate a 2*need bits random private exponent */ |
Damien Miller | 6d6c5d2 | 2002-03-07 12:58:42 +1100 | [diff] [blame] | 213 | if (!BN_rand(dh->priv_key, 2*need, 0, 0)) |
| 214 | fatal("dh_gen_key: BN_rand failed"); |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 215 | if (DH_generate_key(dh) == 0) |
| 216 | fatal("DH_generate_key"); |
Darren Tucker | effc84c | 2004-02-29 20:15:08 +1100 | [diff] [blame] | 217 | for (i = 0, bits_set = 0; i <= BN_num_bits(dh->priv_key); i++) |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 218 | if (BN_is_bit_set(dh->priv_key, i)) |
| 219 | bits_set++; |
Ben Lindstrom | 1f53083 | 2002-12-23 02:03:02 +0000 | [diff] [blame] | 220 | debug2("dh_gen_key: priv key bits set: %d/%d", |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 221 | bits_set, BN_num_bits(dh->priv_key)); |
| 222 | if (tries++ > 10) |
| 223 | fatal("dh_gen_key: too many bad keys: giving up"); |
| 224 | } while (!dh_pub_is_valid(dh, dh->pub_key)); |
| 225 | } |
| 226 | |
| 227 | DH * |
| 228 | dh_new_group_asc(const char *gen, const char *modulus) |
| 229 | { |
| 230 | DH *dh; |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 231 | |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 232 | if ((dh = DH_new()) == NULL) |
| 233 | fatal("dh_new_group_asc: DH_new"); |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 234 | |
Ben Lindstrom | 206941f | 2001-04-15 14:27:16 +0000 | [diff] [blame] | 235 | if (BN_hex2bn(&dh->p, modulus) == 0) |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 236 | fatal("BN_hex2bn p"); |
Ben Lindstrom | 206941f | 2001-04-15 14:27:16 +0000 | [diff] [blame] | 237 | if (BN_hex2bn(&dh->g, gen) == 0) |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 238 | fatal("BN_hex2bn g"); |
| 239 | |
| 240 | return (dh); |
| 241 | } |
| 242 | |
| 243 | /* |
| 244 | * This just returns the group, we still need to generate the exchange |
| 245 | * value. |
| 246 | */ |
| 247 | |
| 248 | DH * |
| 249 | dh_new_group(BIGNUM *gen, BIGNUM *modulus) |
| 250 | { |
| 251 | DH *dh; |
| 252 | |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 253 | if ((dh = DH_new()) == NULL) |
| 254 | fatal("dh_new_group: DH_new"); |
Damien Miller | 9709f90 | 2001-03-30 10:50:10 +1000 | [diff] [blame] | 255 | dh->p = modulus; |
| 256 | dh->g = gen; |
| 257 | |
| 258 | return (dh); |
| 259 | } |
| 260 | |
| 261 | DH * |
| 262 | dh_new_group1(void) |
| 263 | { |
| 264 | static char *gen = "2", *group1 = |
| 265 | "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1" |
| 266 | "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD" |
| 267 | "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245" |
| 268 | "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED" |
| 269 | "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE65381" |
| 270 | "FFFFFFFF" "FFFFFFFF"; |
| 271 | |
| 272 | return (dh_new_group_asc(gen, group1)); |
| 273 | } |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 274 | |
Damien Miller | f675fc4 | 2004-06-15 10:30:09 +1000 | [diff] [blame] | 275 | DH * |
| 276 | dh_new_group14(void) |
| 277 | { |
| 278 | static char *gen = "2", *group14 = |
| 279 | "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1" |
| 280 | "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD" |
| 281 | "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245" |
| 282 | "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED" |
| 283 | "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D" |
| 284 | "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F" |
| 285 | "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D" |
| 286 | "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B" |
| 287 | "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9" |
| 288 | "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510" |
| 289 | "15728E5A" "8AACAA68" "FFFFFFFF" "FFFFFFFF"; |
| 290 | |
| 291 | return (dh_new_group_asc(gen, group14)); |
| 292 | } |
| 293 | |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 294 | /* |
| 295 | * Estimates the group order for a Diffie-Hellman group that has an |
| 296 | * attack complexity approximately the same as O(2**bits). Estimate |
| 297 | * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3))) |
| 298 | */ |
| 299 | |
| 300 | int |
| 301 | dh_estimate(int bits) |
| 302 | { |
| 303 | |
Damien Miller | 8975ddf | 2003-12-17 16:33:53 +1100 | [diff] [blame] | 304 | if (bits <= 128) |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 305 | return (1024); /* O(2**86) */ |
Damien Miller | 8975ddf | 2003-12-17 16:33:53 +1100 | [diff] [blame] | 306 | if (bits <= 192) |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 307 | return (2048); /* O(2**116) */ |
| 308 | return (4096); /* O(2**156) */ |
| 309 | } |