Annotation of src/usr.bin/ssh/dh.c, Revision 1.68
1.68 ! millert 1: /* $OpenBSD: dh.c,v 1.67 2018/09/13 02:08:33 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:
1.1 provos 26:
27: #include <openssl/bn.h>
28: #include <openssl/dh.h>
1.38 stevesk 29:
1.59 dtucker 30: #include <errno.h>
1.41 stevesk 31: #include <stdio.h>
1.40 stevesk 32: #include <stdlib.h>
1.38 stevesk 33: #include <string.h>
1.55 deraadt 34: #include <limits.h>
1.1 provos 35:
36: #include "dh.h"
1.5 markus 37: #include "pathnames.h"
1.6 markus 38: #include "log.h"
39: #include "misc.h"
1.54 markus 40: #include "ssherr.h"
1.1 provos 41:
1.17 itojun 42: static int
1.1 provos 43: parse_prime(int linenum, char *line, struct dhgroup *dhg)
44: {
45: char *cp, *arg;
46: char *strsize, *gen, *prime;
1.35 deraadt 47: const char *errstr = NULL;
1.47 djm 48: long long n;
1.1 provos 49:
1.51 markus 50: dhg->p = dhg->g = NULL;
1.1 provos 51: cp = line;
1.32 djm 52: if ((arg = strdelim(&cp)) == NULL)
53: return 0;
1.1 provos 54: /* Ignore leading whitespace */
55: if (*arg == '\0')
56: arg = strdelim(&cp);
1.22 markus 57: if (!arg || !*arg || *arg == '#')
1.1 provos 58: return 0;
59:
60: /* time */
61: if (cp == NULL || *arg == '\0')
1.50 djm 62: goto truncated;
1.1 provos 63: arg = strsep(&cp, " "); /* type */
64: if (cp == NULL || *arg == '\0')
1.50 djm 65: goto truncated;
1.47 djm 66: /* Ensure this is a safe prime */
67: n = strtonum(arg, 0, 5, &errstr);
1.50 djm 68: if (errstr != NULL || n != MODULI_TYPE_SAFE) {
69: error("moduli:%d: type is not %d", linenum, MODULI_TYPE_SAFE);
1.47 djm 70: goto fail;
1.50 djm 71: }
1.1 provos 72: arg = strsep(&cp, " "); /* tests */
73: if (cp == NULL || *arg == '\0')
1.50 djm 74: goto truncated;
1.47 djm 75: /* Ensure prime has been tested and is not composite */
76: n = strtonum(arg, 0, 0x1f, &errstr);
77: if (errstr != NULL ||
1.50 djm 78: (n & MODULI_TESTS_COMPOSITE) || !(n & ~MODULI_TESTS_COMPOSITE)) {
79: error("moduli:%d: invalid moduli tests flag", linenum);
1.47 djm 80: goto fail;
1.50 djm 81: }
1.1 provos 82: arg = strsep(&cp, " "); /* tries */
83: if (cp == NULL || *arg == '\0')
1.50 djm 84: goto truncated;
1.47 djm 85: n = strtonum(arg, 0, 1<<30, &errstr);
1.50 djm 86: if (errstr != NULL || n == 0) {
87: error("moduli:%d: invalid primality trial count", linenum);
1.1 provos 88: goto fail;
1.50 djm 89: }
1.1 provos 90: strsize = strsep(&cp, " "); /* size */
91: if (cp == NULL || *strsize == '\0' ||
1.48 grunk 92: (dhg->size = (int)strtonum(strsize, 0, 64*1024, &errstr)) == 0 ||
1.50 djm 93: errstr) {
94: error("moduli:%d: invalid prime length", linenum);
1.1 provos 95: goto fail;
1.50 djm 96: }
1.9 provos 97: /* The whole group is one bit larger */
98: dhg->size++;
1.1 provos 99: gen = strsep(&cp, " "); /* gen */
100: if (cp == NULL || *gen == '\0')
1.50 djm 101: goto truncated;
1.1 provos 102: prime = strsep(&cp, " "); /* prime */
1.50 djm 103: if (cp != NULL || *prime == '\0') {
104: truncated:
105: error("moduli:%d: truncated", linenum);
1.1 provos 106: goto fail;
1.50 djm 107: }
1.1 provos 108:
1.54 markus 109: if ((dhg->g = BN_new()) == NULL ||
110: (dhg->p = BN_new()) == NULL) {
111: error("parse_prime: BN_new failed");
112: goto fail;
113: }
1.50 djm 114: if (BN_hex2bn(&dhg->g, gen) == 0) {
115: error("moduli:%d: could not parse generator value", linenum);
116: goto fail;
117: }
118: if (BN_hex2bn(&dhg->p, prime) == 0) {
119: error("moduli:%d: could not parse prime value", linenum);
120: goto fail;
121: }
122: if (BN_num_bits(dhg->p) != dhg->size) {
123: error("moduli:%d: prime has wrong size: actual %d listed %d",
124: linenum, BN_num_bits(dhg->p), dhg->size - 1);
125: goto fail;
126: }
127: if (BN_cmp(dhg->g, BN_value_one()) <= 0) {
128: error("moduli:%d: generator is invalid", linenum);
129: goto fail;
130: }
131: return 1;
1.10 provos 132:
1.1 provos 133: fail:
1.63 jsing 134: BN_clear_free(dhg->g);
135: BN_clear_free(dhg->p);
1.50 djm 136: dhg->g = dhg->p = NULL;
137: return 0;
1.1 provos 138: }
139:
140: DH *
1.9 provos 141: choose_dh(int min, int wantbits, int max)
1.1 provos 142: {
143: FILE *f;
1.64 markus 144: char *line = NULL;
145: size_t linesize = 0;
146: int best, bestcount, which, linenum;
1.1 provos 147: struct dhgroup dhg;
148:
1.59 dtucker 149: if ((f = fopen(_PATH_DH_MODULI, "r")) == NULL) {
1.62 dtucker 150: logit("WARNING: could not open %s (%s), using fixed modulus",
1.59 dtucker 151: _PATH_DH_MODULI, strerror(errno));
1.57 dtucker 152: return (dh_new_group_fallback(max));
1.1 provos 153: }
154:
155: linenum = 0;
156: best = bestcount = 0;
1.64 markus 157: while (getline(&line, &linesize, f) != -1) {
1.1 provos 158: linenum++;
159: if (!parse_prime(linenum, line, &dhg))
160: continue;
1.19 markus 161: BN_clear_free(dhg.g);
162: BN_clear_free(dhg.p);
1.1 provos 163:
1.9 provos 164: if (dhg.size > max || dhg.size < min)
165: continue;
166:
167: if ((dhg.size > wantbits && dhg.size < best) ||
168: (dhg.size > best && best < wantbits)) {
1.1 provos 169: best = dhg.size;
170: bestcount = 0;
171: }
172: if (dhg.size == best)
173: bestcount++;
174: }
1.64 markus 175: free(line);
176: line = NULL;
177: linesize = 0;
1.16 provos 178: rewind(f);
1.1 provos 179:
180: if (bestcount == 0) {
1.16 provos 181: fclose(f);
1.59 dtucker 182: logit("WARNING: no suitable primes in %s", _PATH_DH_MODULI);
1.57 dtucker 183: return (dh_new_group_fallback(max));
1.1 provos 184: }
1.68 ! millert 185: which = arc4random_uniform(bestcount);
1.1 provos 186:
187: linenum = 0;
1.68 ! millert 188: bestcount = 0;
1.64 markus 189: while (getline(&line, &linesize, f) != -1) {
1.68 ! millert 190: linenum++;
1.1 provos 191: if (!parse_prime(linenum, line, &dhg))
1.9 provos 192: continue;
1.13 markus 193: if ((dhg.size > max || dhg.size < min) ||
194: dhg.size != best ||
1.68 ! millert 195: bestcount++ != which) {
1.19 markus 196: BN_clear_free(dhg.g);
197: BN_clear_free(dhg.p);
1.1 provos 198: continue;
199: }
200: break;
201: }
1.64 markus 202: free(line);
203: line = NULL;
1.1 provos 204: fclose(f);
1.68 ! millert 205: if (bestcount != which + 1) {
! 206: logit("WARNING: selected prime disappeared in %s, giving up",
! 207: _PATH_DH_MODULI);
1.57 dtucker 208: return (dh_new_group_fallback(max));
1.54 markus 209: }
1.1 provos 210:
211: return (dh_new_group(dhg.g, dhg.p));
1.11 markus 212: }
213:
1.30 djm 214: /* diffie-hellman-groupN-sha1 */
1.11 markus 215:
216: int
1.67 djm 217: dh_pub_is_valid(const DH *dh, const BIGNUM *dh_pub)
1.11 markus 218: {
219: int i;
220: int n = BN_num_bits(dh_pub);
221: int bits_set = 0;
1.36 djm 222: BIGNUM *tmp;
1.67 djm 223: const BIGNUM *dh_p;
1.11 markus 224:
1.67 djm 225: DH_get0_pqg(dh, &dh_p, NULL, NULL);
226:
227: if (BN_is_negative(dh_pub)) {
1.45 ray 228: logit("invalid public DH value: negative");
1.11 markus 229: return 0;
230: }
1.36 djm 231: if (BN_cmp(dh_pub, BN_value_one()) != 1) { /* pub_exp <= 1 */
232: logit("invalid public DH value: <= 1");
233: return 0;
234: }
235:
1.45 ray 236: if ((tmp = BN_new()) == NULL) {
237: error("%s: BN_new failed", __func__);
238: return 0;
239: }
1.67 djm 240: if (!BN_sub(tmp, dh_p, BN_value_one()) ||
1.36 djm 241: BN_cmp(dh_pub, tmp) != -1) { /* pub_exp > p-2 */
242: BN_clear_free(tmp);
243: logit("invalid public DH value: >= p-1");
244: return 0;
245: }
246: BN_clear_free(tmp);
247:
1.11 markus 248: for (i = 0; i <= n; i++)
249: if (BN_is_bit_set(dh_pub, i))
250: bits_set++;
1.67 djm 251: debug2("bits set: %d/%d", bits_set, BN_num_bits(dh_p));
1.11 markus 252:
1.58 djm 253: /*
254: * if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial
255: */
256: if (bits_set < 4) {
257: logit("invalid public DH value (%d/%d)",
1.67 djm 258: bits_set, BN_num_bits(dh_p));
1.58 djm 259: return 0;
260: }
261: return 1;
1.11 markus 262: }
263:
1.54 markus 264: int
1.11 markus 265: dh_gen_key(DH *dh, int need)
266: {
1.53 djm 267: int pbits;
1.67 djm 268: const BIGNUM *dh_p, *pub_key;
269:
270: DH_get0_pqg(dh, &dh_p, NULL, NULL);
1.11 markus 271:
1.67 djm 272: if (need < 0 || dh_p == NULL ||
273: (pbits = BN_num_bits(dh_p)) <= 0 ||
1.56 djm 274: need > INT_MAX / 2 || 2 * need > pbits)
1.54 markus 275: return SSH_ERR_INVALID_ARGUMENT;
1.58 djm 276: if (need < 256)
277: need = 256;
278: /*
279: * Pollard Rho, Big step/Little Step attacks are O(sqrt(n)),
280: * so double requested need here.
281: */
1.67 djm 282: if (!DH_set_length(dh, MINIMUM(need * 2, pbits - 1)))
283: return SSH_ERR_LIBCRYPTO_ERROR;
284:
285: if (DH_generate_key(dh) == 0)
1.54 markus 286: return SSH_ERR_LIBCRYPTO_ERROR;
1.67 djm 287: DH_get0_key(dh, &pub_key, NULL);
288: if (!dh_pub_is_valid(dh, pub_key))
289: return SSH_ERR_INVALID_FORMAT;
1.54 markus 290: return 0;
1.11 markus 291: }
292:
293: DH *
294: dh_new_group_asc(const char *gen, const char *modulus)
295: {
296: DH *dh;
1.67 djm 297: BIGNUM *dh_p = NULL, *dh_g = NULL;
1.11 markus 298:
1.18 markus 299: if ((dh = DH_new()) == NULL)
1.54 markus 300: return NULL;
1.67 djm 301: if (BN_hex2bn(&dh_p, modulus) == 0 ||
302: BN_hex2bn(&dh_g, gen) == 0)
303: goto fail;
304: if (!DH_set0_pqg(dh, dh_p, NULL, dh_g))
305: goto fail;
306: return dh;
307: fail:
308: DH_free(dh);
309: BN_clear_free(dh_p);
310: BN_clear_free(dh_g);
311: return NULL;
1.11 markus 312: }
313:
314: /*
315: * This just returns the group, we still need to generate the exchange
316: * value.
317: */
318: DH *
319: dh_new_group(BIGNUM *gen, BIGNUM *modulus)
320: {
321: DH *dh;
322:
1.18 markus 323: if ((dh = DH_new()) == NULL)
1.54 markus 324: return NULL;
1.67 djm 325: if (!DH_set0_pqg(dh, modulus, NULL, gen)) {
326: DH_free(dh);
327: return NULL;
328: }
1.11 markus 329:
1.67 djm 330: return dh;
1.11 markus 331: }
332:
1.60 djm 333: /* rfc2409 "Second Oakley Group" (1024 bits) */
1.11 markus 334: DH *
335: dh_new_group1(void)
336: {
337: static char *gen = "2", *group1 =
338: "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
339: "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
340: "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
341: "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
342: "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE65381"
343: "FFFFFFFF" "FFFFFFFF";
344:
345: return (dh_new_group_asc(gen, group1));
1.30 djm 346: }
347:
1.60 djm 348: /* rfc3526 group 14 "2048-bit MODP Group" */
1.30 djm 349: DH *
350: dh_new_group14(void)
351: {
352: static char *gen = "2", *group14 =
353: "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
354: "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
355: "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
356: "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
357: "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
358: "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
359: "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
360: "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
361: "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
362: "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
363: "15728E5A" "8AACAA68" "FFFFFFFF" "FFFFFFFF";
364:
365: return (dh_new_group_asc(gen, group14));
1.57 dtucker 366: }
367:
1.60 djm 368: /* rfc3526 group 16 "4096-bit MODP Group" */
1.57 dtucker 369: DH *
1.60 djm 370: dh_new_group16(void)
1.57 dtucker 371: {
372: static char *gen = "2", *group16 =
373: "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
374: "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
375: "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
376: "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
377: "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
378: "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
379: "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
380: "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
381: "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
382: "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
383: "15728E5A" "8AAAC42D" "AD33170D" "04507A33" "A85521AB" "DF1CBA64"
384: "ECFB8504" "58DBEF0A" "8AEA7157" "5D060C7D" "B3970F85" "A6E1E4C7"
385: "ABF5AE8C" "DB0933D7" "1E8C94E0" "4A25619D" "CEE3D226" "1AD2EE6B"
386: "F12FFA06" "D98A0864" "D8760273" "3EC86A64" "521F2B18" "177B200C"
387: "BBE11757" "7A615D6C" "770988C0" "BAD946E2" "08E24FA0" "74E5AB31"
388: "43DB5BFC" "E0FD108E" "4B82D120" "A9210801" "1A723C12" "A787E6D7"
389: "88719A10" "BDBA5B26" "99C32718" "6AF4E23C" "1A946834" "B6150BDA"
390: "2583E9CA" "2AD44CE8" "DBBBC2DB" "04DE8EF9" "2E8EFC14" "1FBECAA6"
391: "287C5947" "4E6BC05D" "99B2964F" "A090C3A2" "233BA186" "515BE7ED"
392: "1F612970" "CEE2D7AF" "B81BDD76" "2170481C" "D0069127" "D5B05AA9"
393: "93B4EA98" "8D8FDDC1" "86FFB7DC" "90A6C08F" "4DF435C9" "34063199"
394: "FFFFFFFF" "FFFFFFFF";
395:
1.60 djm 396: return (dh_new_group_asc(gen, group16));
397: }
398:
399: /* rfc3526 group 18 "8192-bit MODP Group" */
400: DH *
401: dh_new_group18(void)
402: {
403: static char *gen = "2", *group16 =
404: "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
405: "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
406: "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
407: "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
408: "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
409: "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
410: "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
411: "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
412: "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
413: "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
414: "15728E5A" "8AAAC42D" "AD33170D" "04507A33" "A85521AB" "DF1CBA64"
415: "ECFB8504" "58DBEF0A" "8AEA7157" "5D060C7D" "B3970F85" "A6E1E4C7"
416: "ABF5AE8C" "DB0933D7" "1E8C94E0" "4A25619D" "CEE3D226" "1AD2EE6B"
417: "F12FFA06" "D98A0864" "D8760273" "3EC86A64" "521F2B18" "177B200C"
418: "BBE11757" "7A615D6C" "770988C0" "BAD946E2" "08E24FA0" "74E5AB31"
419: "43DB5BFC" "E0FD108E" "4B82D120" "A9210801" "1A723C12" "A787E6D7"
420: "88719A10" "BDBA5B26" "99C32718" "6AF4E23C" "1A946834" "B6150BDA"
421: "2583E9CA" "2AD44CE8" "DBBBC2DB" "04DE8EF9" "2E8EFC14" "1FBECAA6"
422: "287C5947" "4E6BC05D" "99B2964F" "A090C3A2" "233BA186" "515BE7ED"
423: "1F612970" "CEE2D7AF" "B81BDD76" "2170481C" "D0069127" "D5B05AA9"
424: "93B4EA98" "8D8FDDC1" "86FFB7DC" "90A6C08F" "4DF435C9" "34028492"
425: "36C3FAB4" "D27C7026" "C1D4DCB2" "602646DE" "C9751E76" "3DBA37BD"
426: "F8FF9406" "AD9E530E" "E5DB382F" "413001AE" "B06A53ED" "9027D831"
427: "179727B0" "865A8918" "DA3EDBEB" "CF9B14ED" "44CE6CBA" "CED4BB1B"
428: "DB7F1447" "E6CC254B" "33205151" "2BD7AF42" "6FB8F401" "378CD2BF"
429: "5983CA01" "C64B92EC" "F032EA15" "D1721D03" "F482D7CE" "6E74FEF6"
430: "D55E702F" "46980C82" "B5A84031" "900B1C9E" "59E7C97F" "BEC7E8F3"
431: "23A97A7E" "36CC88BE" "0F1D45B7" "FF585AC5" "4BD407B2" "2B4154AA"
432: "CC8F6D7E" "BF48E1D8" "14CC5ED2" "0F8037E0" "A79715EE" "F29BE328"
433: "06A1D58B" "B7C5DA76" "F550AA3D" "8A1FBFF0" "EB19CCB1" "A313D55C"
434: "DA56C9EC" "2EF29632" "387FE8D7" "6E3C0468" "043E8F66" "3F4860EE"
435: "12BF2D5B" "0B7474D6" "E694F91E" "6DBE1159" "74A3926F" "12FEE5E4"
436: "38777CB6" "A932DF8C" "D8BEC4D0" "73B931BA" "3BC832B6" "8D9DD300"
437: "741FA7BF" "8AFC47ED" "2576F693" "6BA42466" "3AAB639C" "5AE4F568"
438: "3423B474" "2BF1C978" "238F16CB" "E39D652D" "E3FDB8BE" "FC848AD9"
439: "22222E04" "A4037C07" "13EB57A8" "1A23F0C7" "3473FC64" "6CEA306B"
440: "4BCBC886" "2F8385DD" "FA9D4B7F" "A2C087E8" "79683303" "ED5BDD3A"
441: "062B3CF5" "B3A278A6" "6D2A13F8" "3F44F82D" "DF310EE0" "74AB6A36"
442: "4597E899" "A0255DC1" "64F31CC5" "0846851D" "F9AB4819" "5DED7EA1"
443: "B1D510BD" "7EE74D73" "FAF36BC3" "1ECFA268" "359046F4" "EB879F92"
444: "4009438B" "481C6CD7" "889A002E" "D5EE382B" "C9190DA6" "FC026E47"
445: "9558E447" "5677E9AA" "9E3050E2" "765694DF" "C81F56E8" "80B96E71"
446: "60C980DD" "98EDD3DF" "FFFFFFFF" "FFFFFFFF";
447:
448: return (dh_new_group_asc(gen, group16));
449: }
450:
451: /* Select fallback group used by DH-GEX if moduli file cannot be read. */
452: DH *
453: dh_new_group_fallback(int max)
454: {
455: debug3("%s: requested max size %d", __func__, max);
456: if (max < 3072) {
457: debug3("using 2k bit group 14");
1.57 dtucker 458: return dh_new_group14();
1.60 djm 459: } else if (max < 6144) {
460: debug3("using 4k bit group 16");
461: return dh_new_group16();
1.57 dtucker 462: }
1.60 djm 463: debug3("using 8k bit group 18");
464: return dh_new_group18();
1.12 markus 465: }
466:
467: /*
468: * Estimates the group order for a Diffie-Hellman group that has an
1.52 dtucker 469: * attack complexity approximately the same as O(2**bits).
470: * Values from NIST Special Publication 800-57: Recommendation for Key
471: * Management Part 1 (rev 3) limited by the recommended maximum value
472: * from RFC4419 section 3.
1.12 markus 473: */
1.54 markus 474: u_int
1.12 markus 475: dh_estimate(int bits)
476: {
1.52 dtucker 477: if (bits <= 112)
478: return 2048;
1.26 markus 479: if (bits <= 128)
1.52 dtucker 480: return 3072;
1.26 markus 481: if (bits <= 192)
1.52 dtucker 482: return 7680;
483: return 8192;
1.1 provos 484: }
![[BACK]](/icons/back.gif){kind=icon}
Return to dh.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh