Annotation of src/usr.bin/ssh/dh.c, Revision 1.70
1.70 ! djm 1: /* $OpenBSD: dh.c,v 1.69 2018/11/09 02:56:22 djm Exp $ */
1.1 provos 2: /*
3: * Copyright (c) 2000 Niels Provos. All rights reserved.
4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: *
14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24: */
1.39 stevesk 25:
1.70 ! djm 26: #include <stdio.h>
! 27: #include <stdlib.h>
! 28: #include <string.h>
! 29: #include <limits.h>
1.1 provos 30:
31: #include <openssl/bn.h>
32: #include <openssl/dh.h>
1.38 stevesk 33:
1.59 dtucker 34: #include <errno.h>
1.1 provos 35: #include "dh.h"
1.5 markus 36: #include "pathnames.h"
1.6 markus 37: #include "log.h"
38: #include "misc.h"
1.54 markus 39: #include "ssherr.h"
1.1 provos 40:
1.17 itojun 41: static int
1.1 provos 42: parse_prime(int linenum, char *line, struct dhgroup *dhg)
43: {
44: char *cp, *arg;
45: char *strsize, *gen, *prime;
1.35 deraadt 46: const char *errstr = NULL;
1.47 djm 47: long long n;
1.1 provos 48:
1.51 markus 49: dhg->p = dhg->g = NULL;
1.1 provos 50: cp = line;
1.32 djm 51: if ((arg = strdelim(&cp)) == NULL)
52: return 0;
1.1 provos 53: /* Ignore leading whitespace */
54: if (*arg == '\0')
55: arg = strdelim(&cp);
1.22 markus 56: if (!arg || !*arg || *arg == '#')
1.1 provos 57: return 0;
58:
59: /* time */
60: if (cp == NULL || *arg == '\0')
1.50 djm 61: goto truncated;
1.1 provos 62: arg = strsep(&cp, " "); /* type */
63: if (cp == NULL || *arg == '\0')
1.50 djm 64: goto truncated;
1.47 djm 65: /* Ensure this is a safe prime */
66: n = strtonum(arg, 0, 5, &errstr);
1.50 djm 67: if (errstr != NULL || n != MODULI_TYPE_SAFE) {
68: error("moduli:%d: type is not %d", linenum, MODULI_TYPE_SAFE);
1.47 djm 69: goto fail;
1.50 djm 70: }
1.1 provos 71: arg = strsep(&cp, " "); /* tests */
72: if (cp == NULL || *arg == '\0')
1.50 djm 73: goto truncated;
1.47 djm 74: /* Ensure prime has been tested and is not composite */
75: n = strtonum(arg, 0, 0x1f, &errstr);
76: if (errstr != NULL ||
1.50 djm 77: (n & MODULI_TESTS_COMPOSITE) || !(n & ~MODULI_TESTS_COMPOSITE)) {
78: error("moduli:%d: invalid moduli tests flag", linenum);
1.47 djm 79: goto fail;
1.50 djm 80: }
1.1 provos 81: arg = strsep(&cp, " "); /* tries */
82: if (cp == NULL || *arg == '\0')
1.50 djm 83: goto truncated;
1.47 djm 84: n = strtonum(arg, 0, 1<<30, &errstr);
1.50 djm 85: if (errstr != NULL || n == 0) {
86: error("moduli:%d: invalid primality trial count", linenum);
1.1 provos 87: goto fail;
1.50 djm 88: }
1.1 provos 89: strsize = strsep(&cp, " "); /* size */
90: if (cp == NULL || *strsize == '\0' ||
1.48 grunk 91: (dhg->size = (int)strtonum(strsize, 0, 64*1024, &errstr)) == 0 ||
1.50 djm 92: errstr) {
93: error("moduli:%d: invalid prime length", linenum);
1.1 provos 94: goto fail;
1.50 djm 95: }
1.9 provos 96: /* The whole group is one bit larger */
97: dhg->size++;
1.1 provos 98: gen = strsep(&cp, " "); /* gen */
99: if (cp == NULL || *gen == '\0')
1.50 djm 100: goto truncated;
1.1 provos 101: prime = strsep(&cp, " "); /* prime */
1.50 djm 102: if (cp != NULL || *prime == '\0') {
103: truncated:
104: error("moduli:%d: truncated", linenum);
1.1 provos 105: goto fail;
1.50 djm 106: }
1.1 provos 107:
1.54 markus 108: if ((dhg->g = BN_new()) == NULL ||
109: (dhg->p = BN_new()) == NULL) {
110: error("parse_prime: BN_new failed");
111: goto fail;
112: }
1.50 djm 113: if (BN_hex2bn(&dhg->g, gen) == 0) {
114: error("moduli:%d: could not parse generator value", linenum);
115: goto fail;
116: }
117: if (BN_hex2bn(&dhg->p, prime) == 0) {
118: error("moduli:%d: could not parse prime value", linenum);
119: goto fail;
120: }
121: if (BN_num_bits(dhg->p) != dhg->size) {
122: error("moduli:%d: prime has wrong size: actual %d listed %d",
123: linenum, BN_num_bits(dhg->p), dhg->size - 1);
124: goto fail;
125: }
126: if (BN_cmp(dhg->g, BN_value_one()) <= 0) {
127: error("moduli:%d: generator is invalid", linenum);
128: goto fail;
129: }
130: return 1;
1.10 provos 131:
1.1 provos 132: fail:
1.63 jsing 133: BN_clear_free(dhg->g);
134: BN_clear_free(dhg->p);
1.50 djm 135: dhg->g = dhg->p = NULL;
136: return 0;
1.1 provos 137: }
138:
139: DH *
1.9 provos 140: choose_dh(int min, int wantbits, int max)
1.1 provos 141: {
142: FILE *f;
1.64 markus 143: char *line = NULL;
144: size_t linesize = 0;
145: int best, bestcount, which, linenum;
1.1 provos 146: struct dhgroup dhg;
147:
1.59 dtucker 148: if ((f = fopen(_PATH_DH_MODULI, "r")) == NULL) {
1.62 dtucker 149: logit("WARNING: could not open %s (%s), using fixed modulus",
1.59 dtucker 150: _PATH_DH_MODULI, strerror(errno));
1.57 dtucker 151: return (dh_new_group_fallback(max));
1.1 provos 152: }
153:
154: linenum = 0;
155: best = bestcount = 0;
1.64 markus 156: while (getline(&line, &linesize, f) != -1) {
1.1 provos 157: linenum++;
158: if (!parse_prime(linenum, line, &dhg))
159: continue;
1.19 markus 160: BN_clear_free(dhg.g);
161: BN_clear_free(dhg.p);
1.1 provos 162:
1.9 provos 163: if (dhg.size > max || dhg.size < min)
164: continue;
165:
166: if ((dhg.size > wantbits && dhg.size < best) ||
167: (dhg.size > best && best < wantbits)) {
1.1 provos 168: best = dhg.size;
169: bestcount = 0;
170: }
171: if (dhg.size == best)
172: bestcount++;
173: }
1.64 markus 174: free(line);
175: line = NULL;
176: linesize = 0;
1.16 provos 177: rewind(f);
1.1 provos 178:
179: if (bestcount == 0) {
1.16 provos 180: fclose(f);
1.59 dtucker 181: logit("WARNING: no suitable primes in %s", _PATH_DH_MODULI);
1.57 dtucker 182: return (dh_new_group_fallback(max));
1.1 provos 183: }
1.68 millert 184: which = arc4random_uniform(bestcount);
1.1 provos 185:
186: linenum = 0;
1.68 millert 187: bestcount = 0;
1.64 markus 188: while (getline(&line, &linesize, f) != -1) {
1.68 millert 189: linenum++;
1.1 provos 190: if (!parse_prime(linenum, line, &dhg))
1.9 provos 191: continue;
1.13 markus 192: if ((dhg.size > max || dhg.size < min) ||
193: dhg.size != best ||
1.68 millert 194: bestcount++ != which) {
1.19 markus 195: BN_clear_free(dhg.g);
196: BN_clear_free(dhg.p);
1.1 provos 197: continue;
198: }
199: break;
200: }
1.64 markus 201: free(line);
202: line = NULL;
1.1 provos 203: fclose(f);
1.68 millert 204: if (bestcount != which + 1) {
205: logit("WARNING: selected prime disappeared in %s, giving up",
206: _PATH_DH_MODULI);
1.57 dtucker 207: return (dh_new_group_fallback(max));
1.54 markus 208: }
1.1 provos 209:
210: return (dh_new_group(dhg.g, dhg.p));
1.11 markus 211: }
212:
1.30 djm 213: /* diffie-hellman-groupN-sha1 */
1.11 markus 214:
215: int
1.67 djm 216: dh_pub_is_valid(const DH *dh, const BIGNUM *dh_pub)
1.11 markus 217: {
218: int i;
219: int n = BN_num_bits(dh_pub);
220: int bits_set = 0;
1.36 djm 221: BIGNUM *tmp;
1.67 djm 222: const BIGNUM *dh_p;
1.11 markus 223:
1.67 djm 224: DH_get0_pqg(dh, &dh_p, NULL, NULL);
225:
226: if (BN_is_negative(dh_pub)) {
1.45 ray 227: logit("invalid public DH value: negative");
1.11 markus 228: return 0;
229: }
1.36 djm 230: if (BN_cmp(dh_pub, BN_value_one()) != 1) { /* pub_exp <= 1 */
231: logit("invalid public DH value: <= 1");
232: return 0;
233: }
234:
1.45 ray 235: if ((tmp = BN_new()) == NULL) {
236: error("%s: BN_new failed", __func__);
237: return 0;
238: }
1.67 djm 239: if (!BN_sub(tmp, dh_p, BN_value_one()) ||
1.36 djm 240: BN_cmp(dh_pub, tmp) != -1) { /* pub_exp > p-2 */
241: BN_clear_free(tmp);
242: logit("invalid public DH value: >= p-1");
243: return 0;
244: }
245: BN_clear_free(tmp);
246:
1.11 markus 247: for (i = 0; i <= n; i++)
248: if (BN_is_bit_set(dh_pub, i))
249: bits_set++;
1.67 djm 250: debug2("bits set: %d/%d", bits_set, BN_num_bits(dh_p));
1.11 markus 251:
1.58 djm 252: /*
253: * if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial
254: */
255: if (bits_set < 4) {
256: logit("invalid public DH value (%d/%d)",
1.67 djm 257: bits_set, BN_num_bits(dh_p));
1.58 djm 258: return 0;
259: }
260: return 1;
1.11 markus 261: }
262:
1.54 markus 263: int
1.11 markus 264: dh_gen_key(DH *dh, int need)
265: {
1.53 djm 266: int pbits;
1.67 djm 267: const BIGNUM *dh_p, *pub_key;
268:
269: DH_get0_pqg(dh, &dh_p, NULL, NULL);
1.11 markus 270:
1.67 djm 271: if (need < 0 || dh_p == NULL ||
272: (pbits = BN_num_bits(dh_p)) <= 0 ||
1.56 djm 273: need > INT_MAX / 2 || 2 * need > pbits)
1.54 markus 274: return SSH_ERR_INVALID_ARGUMENT;
1.58 djm 275: if (need < 256)
276: need = 256;
277: /*
278: * Pollard Rho, Big step/Little Step attacks are O(sqrt(n)),
279: * so double requested need here.
280: */
1.67 djm 281: if (!DH_set_length(dh, MINIMUM(need * 2, pbits - 1)))
282: return SSH_ERR_LIBCRYPTO_ERROR;
283:
284: if (DH_generate_key(dh) == 0)
1.54 markus 285: return SSH_ERR_LIBCRYPTO_ERROR;
1.67 djm 286: DH_get0_key(dh, &pub_key, NULL);
287: if (!dh_pub_is_valid(dh, pub_key))
288: return SSH_ERR_INVALID_FORMAT;
1.54 markus 289: return 0;
1.11 markus 290: }
291:
292: DH *
293: dh_new_group_asc(const char *gen, const char *modulus)
294: {
295: DH *dh;
1.67 djm 296: BIGNUM *dh_p = NULL, *dh_g = NULL;
1.11 markus 297:
1.18 markus 298: if ((dh = DH_new()) == NULL)
1.54 markus 299: return NULL;
1.67 djm 300: if (BN_hex2bn(&dh_p, modulus) == 0 ||
301: BN_hex2bn(&dh_g, gen) == 0)
302: goto fail;
303: if (!DH_set0_pqg(dh, dh_p, NULL, dh_g))
304: goto fail;
305: return dh;
306: fail:
307: DH_free(dh);
308: BN_clear_free(dh_p);
309: BN_clear_free(dh_g);
310: return NULL;
1.11 markus 311: }
312:
313: /*
314: * This just returns the group, we still need to generate the exchange
315: * value.
316: */
317: DH *
318: dh_new_group(BIGNUM *gen, BIGNUM *modulus)
319: {
320: DH *dh;
321:
1.18 markus 322: if ((dh = DH_new()) == NULL)
1.54 markus 323: return NULL;
1.67 djm 324: if (!DH_set0_pqg(dh, modulus, NULL, gen)) {
325: DH_free(dh);
326: return NULL;
327: }
1.11 markus 328:
1.67 djm 329: return dh;
1.11 markus 330: }
331:
1.60 djm 332: /* rfc2409 "Second Oakley Group" (1024 bits) */
1.11 markus 333: DH *
334: dh_new_group1(void)
335: {
336: static char *gen = "2", *group1 =
337: "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
338: "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
339: "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
340: "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
341: "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE65381"
342: "FFFFFFFF" "FFFFFFFF";
343:
344: return (dh_new_group_asc(gen, group1));
1.30 djm 345: }
346:
1.60 djm 347: /* rfc3526 group 14 "2048-bit MODP Group" */
1.30 djm 348: DH *
349: dh_new_group14(void)
350: {
351: static char *gen = "2", *group14 =
352: "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
353: "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
354: "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
355: "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
356: "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
357: "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
358: "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
359: "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
360: "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
361: "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
362: "15728E5A" "8AACAA68" "FFFFFFFF" "FFFFFFFF";
363:
364: return (dh_new_group_asc(gen, group14));
1.57 dtucker 365: }
366:
1.60 djm 367: /* rfc3526 group 16 "4096-bit MODP Group" */
1.57 dtucker 368: DH *
1.60 djm 369: dh_new_group16(void)
1.57 dtucker 370: {
371: static char *gen = "2", *group16 =
372: "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
373: "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
374: "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
375: "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
376: "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
377: "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
378: "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
379: "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
380: "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
381: "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
382: "15728E5A" "8AAAC42D" "AD33170D" "04507A33" "A85521AB" "DF1CBA64"
383: "ECFB8504" "58DBEF0A" "8AEA7157" "5D060C7D" "B3970F85" "A6E1E4C7"
384: "ABF5AE8C" "DB0933D7" "1E8C94E0" "4A25619D" "CEE3D226" "1AD2EE6B"
385: "F12FFA06" "D98A0864" "D8760273" "3EC86A64" "521F2B18" "177B200C"
386: "BBE11757" "7A615D6C" "770988C0" "BAD946E2" "08E24FA0" "74E5AB31"
387: "43DB5BFC" "E0FD108E" "4B82D120" "A9210801" "1A723C12" "A787E6D7"
388: "88719A10" "BDBA5B26" "99C32718" "6AF4E23C" "1A946834" "B6150BDA"
389: "2583E9CA" "2AD44CE8" "DBBBC2DB" "04DE8EF9" "2E8EFC14" "1FBECAA6"
390: "287C5947" "4E6BC05D" "99B2964F" "A090C3A2" "233BA186" "515BE7ED"
391: "1F612970" "CEE2D7AF" "B81BDD76" "2170481C" "D0069127" "D5B05AA9"
392: "93B4EA98" "8D8FDDC1" "86FFB7DC" "90A6C08F" "4DF435C9" "34063199"
393: "FFFFFFFF" "FFFFFFFF";
394:
1.60 djm 395: return (dh_new_group_asc(gen, group16));
396: }
397:
398: /* rfc3526 group 18 "8192-bit MODP Group" */
399: DH *
400: dh_new_group18(void)
401: {
1.69 djm 402: static char *gen = "2", *group18 =
1.60 djm 403: "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
404: "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
405: "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
406: "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
407: "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
408: "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
409: "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
410: "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
411: "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
412: "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
413: "15728E5A" "8AAAC42D" "AD33170D" "04507A33" "A85521AB" "DF1CBA64"
414: "ECFB8504" "58DBEF0A" "8AEA7157" "5D060C7D" "B3970F85" "A6E1E4C7"
415: "ABF5AE8C" "DB0933D7" "1E8C94E0" "4A25619D" "CEE3D226" "1AD2EE6B"
416: "F12FFA06" "D98A0864" "D8760273" "3EC86A64" "521F2B18" "177B200C"
417: "BBE11757" "7A615D6C" "770988C0" "BAD946E2" "08E24FA0" "74E5AB31"
418: "43DB5BFC" "E0FD108E" "4B82D120" "A9210801" "1A723C12" "A787E6D7"
419: "88719A10" "BDBA5B26" "99C32718" "6AF4E23C" "1A946834" "B6150BDA"
420: "2583E9CA" "2AD44CE8" "DBBBC2DB" "04DE8EF9" "2E8EFC14" "1FBECAA6"
421: "287C5947" "4E6BC05D" "99B2964F" "A090C3A2" "233BA186" "515BE7ED"
422: "1F612970" "CEE2D7AF" "B81BDD76" "2170481C" "D0069127" "D5B05AA9"
423: "93B4EA98" "8D8FDDC1" "86FFB7DC" "90A6C08F" "4DF435C9" "34028492"
424: "36C3FAB4" "D27C7026" "C1D4DCB2" "602646DE" "C9751E76" "3DBA37BD"
425: "F8FF9406" "AD9E530E" "E5DB382F" "413001AE" "B06A53ED" "9027D831"
426: "179727B0" "865A8918" "DA3EDBEB" "CF9B14ED" "44CE6CBA" "CED4BB1B"
427: "DB7F1447" "E6CC254B" "33205151" "2BD7AF42" "6FB8F401" "378CD2BF"
428: "5983CA01" "C64B92EC" "F032EA15" "D1721D03" "F482D7CE" "6E74FEF6"
429: "D55E702F" "46980C82" "B5A84031" "900B1C9E" "59E7C97F" "BEC7E8F3"
430: "23A97A7E" "36CC88BE" "0F1D45B7" "FF585AC5" "4BD407B2" "2B4154AA"
431: "CC8F6D7E" "BF48E1D8" "14CC5ED2" "0F8037E0" "A79715EE" "F29BE328"
432: "06A1D58B" "B7C5DA76" "F550AA3D" "8A1FBFF0" "EB19CCB1" "A313D55C"
433: "DA56C9EC" "2EF29632" "387FE8D7" "6E3C0468" "043E8F66" "3F4860EE"
434: "12BF2D5B" "0B7474D6" "E694F91E" "6DBE1159" "74A3926F" "12FEE5E4"
435: "38777CB6" "A932DF8C" "D8BEC4D0" "73B931BA" "3BC832B6" "8D9DD300"
436: "741FA7BF" "8AFC47ED" "2576F693" "6BA42466" "3AAB639C" "5AE4F568"
437: "3423B474" "2BF1C978" "238F16CB" "E39D652D" "E3FDB8BE" "FC848AD9"
438: "22222E04" "A4037C07" "13EB57A8" "1A23F0C7" "3473FC64" "6CEA306B"
439: "4BCBC886" "2F8385DD" "FA9D4B7F" "A2C087E8" "79683303" "ED5BDD3A"
440: "062B3CF5" "B3A278A6" "6D2A13F8" "3F44F82D" "DF310EE0" "74AB6A36"
441: "4597E899" "A0255DC1" "64F31CC5" "0846851D" "F9AB4819" "5DED7EA1"
442: "B1D510BD" "7EE74D73" "FAF36BC3" "1ECFA268" "359046F4" "EB879F92"
443: "4009438B" "481C6CD7" "889A002E" "D5EE382B" "C9190DA6" "FC026E47"
444: "9558E447" "5677E9AA" "9E3050E2" "765694DF" "C81F56E8" "80B96E71"
445: "60C980DD" "98EDD3DF" "FFFFFFFF" "FFFFFFFF";
446:
1.69 djm 447: return (dh_new_group_asc(gen, group18));
1.60 djm 448: }
449:
450: /* Select fallback group used by DH-GEX if moduli file cannot be read. */
451: DH *
452: dh_new_group_fallback(int max)
453: {
454: debug3("%s: requested max size %d", __func__, max);
455: if (max < 3072) {
456: debug3("using 2k bit group 14");
1.57 dtucker 457: return dh_new_group14();
1.60 djm 458: } else if (max < 6144) {
459: debug3("using 4k bit group 16");
460: return dh_new_group16();
1.57 dtucker 461: }
1.60 djm 462: debug3("using 8k bit group 18");
463: return dh_new_group18();
1.12 markus 464: }
465:
466: /*
467: * Estimates the group order for a Diffie-Hellman group that has an
1.52 dtucker 468: * attack complexity approximately the same as O(2**bits).
469: * Values from NIST Special Publication 800-57: Recommendation for Key
470: * Management Part 1 (rev 3) limited by the recommended maximum value
471: * from RFC4419 section 3.
1.12 markus 472: */
1.54 markus 473: u_int
1.12 markus 474: dh_estimate(int bits)
475: {
1.52 dtucker 476: if (bits <= 112)
477: return 2048;
1.26 markus 478: if (bits <= 128)
1.52 dtucker 479: return 3072;
1.26 markus 480: if (bits <= 192)
1.52 dtucker 481: return 7680;
482: return 8192;
1.1 provos 483: }
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