2 * Secure Remote Password 6a implementation
3 * https://github.com/est31/csrp-gmp
5 * The MIT License (MIT)
7 * Copyright (c) 2010, 2013 Tom Cocagne, 2015 est31 <MTest31@outlook.com>
9 * Permission is hereby granted, free of charge, to any person obtaining a copy of
10 * this software and associated documentation files (the "Software"), to deal in
11 * the Software without restriction, including without limitation the rights to
12 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
13 * of the Software, and to permit persons to whom the Software is furnished to do
14 * so, subject to the following conditions:
16 * The above copyright notice and this permission notice shall be included in all
17 * copies or substantial portions of the Software.
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
44 #if USE_SYSTEM_GMP || defined (__ANDROID__) || defined (ANDROID)
50 #include <util/sha2.h>
53 //#define CSRP_USE_SHA1
54 #define CSRP_USE_SHA256
56 #define srp_dbg_data(data, datalen, prevtext) ;
57 /*void srp_dbg_data(unsigned char * data, size_t datalen, char * prevtext)
61 for (i = 0; i < datalen; i++)
63 printf("%02X", data[i]);
68 static int g_initialized = 0;
70 #define RAND_BUFF_MAX 128
71 static unsigned int g_rand_idx;
72 static unsigned char g_rand_buff[RAND_BUFF_MAX];
74 void *(*srp_alloc)(size_t) = &malloc;
75 void *(*srp_realloc)(void *, size_t) = &realloc;
76 void (*srp_free)(void *) = &free;
79 void srp_set_memory_functions(
80 void *(*new_srp_alloc)(size_t),
81 void *(*new_srp_realloc)(void *, size_t),
82 void (*new_srp_free)(void *))
84 srp_alloc = new_srp_alloc;
85 srp_realloc = new_srp_realloc;
86 srp_free = new_srp_free;
100 /* All constants here were pulled from Appendix A of RFC 5054 */
101 static struct NGHex global_Ng_constants[] = {
103 "EEAF0AB9ADB38DD69C33F80AFA8FC5E86072618775FF3C0B9EA2314C"
104 "9C256576D674DF7496EA81D3383B4813D692C6E0E0D5D8E250B98BE4"
105 "8E495C1D6089DAD15DC7D7B46154D6B6CE8EF4AD69B15D4982559B29"
106 "7BCF1885C529F566660E57EC68EDBC3C05726CC02FD4CBF4976EAA9A"
107 "FD5138FE8376435B9FC61D2FC0EB06E3",
110 "AC6BDB41324A9A9BF166DE5E1389582FAF72B6651987EE07FC319294"
111 "3DB56050A37329CBB4A099ED8193E0757767A13DD52312AB4B03310D"
112 "CD7F48A9DA04FD50E8083969EDB767B0CF6095179A163AB3661A05FB"
113 "D5FAAAE82918A9962F0B93B855F97993EC975EEAA80D740ADBF4FF74"
114 "7359D041D5C33EA71D281E446B14773BCA97B43A23FB801676BD207A"
115 "436C6481F1D2B9078717461A5B9D32E688F87748544523B524B0D57D"
116 "5EA77A2775D2ECFA032CFBDBF52FB3786160279004E57AE6AF874E73"
117 "03CE53299CCC041C7BC308D82A5698F3A8D0C38271AE35F8E9DBFBB6"
118 "94B5C803D89F7AE435DE236D525F54759B65E372FCD68EF20FA7111F"
122 "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08"
123 "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B"
124 "302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9"
125 "A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6"
126 "49286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8"
127 "FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D"
128 "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C"
129 "180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF695581718"
130 "3995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D"
131 "04507A33A85521ABDF1CBA64ECFB850458DBEF0A8AEA71575D060C7D"
132 "B3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D226"
133 "1AD2EE6BF12FFA06D98A0864D87602733EC86A64521F2B18177B200C"
134 "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFC"
135 "E0FD108E4B82D120A92108011A723C12A787E6D788719A10BDBA5B26"
136 "99C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB"
137 "04DE8EF92E8EFC141FBECAA6287C59474E6BC05D99B2964FA090C3A2"
138 "233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD0069127"
139 "D5B05AA993B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934063199"
143 "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08"
144 "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B"
145 "302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9"
146 "A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6"
147 "49286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8"
148 "FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D"
149 "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C"
150 "180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF695581718"
151 "3995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D"
152 "04507A33A85521ABDF1CBA64ECFB850458DBEF0A8AEA71575D060C7D"
153 "B3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D226"
154 "1AD2EE6BF12FFA06D98A0864D87602733EC86A64521F2B18177B200C"
155 "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFC"
156 "E0FD108E4B82D120A92108011A723C12A787E6D788719A10BDBA5B26"
157 "99C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB"
158 "04DE8EF92E8EFC141FBECAA6287C59474E6BC05D99B2964FA090C3A2"
159 "233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD0069127"
160 "D5B05AA993B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934028492"
161 "36C3FAB4D27C7026C1D4DCB2602646DEC9751E763DBA37BDF8FF9406"
162 "AD9E530EE5DB382F413001AEB06A53ED9027D831179727B0865A8918"
163 "DA3EDBEBCF9B14ED44CE6CBACED4BB1BDB7F1447E6CC254B33205151"
164 "2BD7AF426FB8F401378CD2BF5983CA01C64B92ECF032EA15D1721D03"
165 "F482D7CE6E74FEF6D55E702F46980C82B5A84031900B1C9E59E7C97F"
166 "BEC7E8F323A97A7E36CC88BE0F1D45B7FF585AC54BD407B22B4154AA"
167 "CC8F6D7EBF48E1D814CC5ED20F8037E0A79715EEF29BE32806A1D58B"
168 "B7C5DA76F550AA3D8A1FBFF0EB19CCB1A313D55CDA56C9EC2EF29632"
169 "387FE8D76E3C0468043E8F663F4860EE12BF2D5B0B7474D6E694F91E"
170 "6DBE115974A3926F12FEE5E438777CB6A932DF8CD8BEC4D073B931BA"
171 "3BC832B68D9DD300741FA7BF8AFC47ED2576F6936BA424663AAB639C"
172 "5AE4F5683423B4742BF1C978238F16CBE39D652DE3FDB8BEFC848AD9"
173 "22222E04A4037C0713EB57A81A23F0C73473FC646CEA306B4BCBC886"
174 "2F8385DDFA9D4B7FA2C087E879683303ED5BDD3A062B3CF5B3A278A6"
175 "6D2A13F83F44F82DDF310EE074AB6A364597E899A0255DC164F31CC5"
176 "0846851DF9AB48195DED7EA1B1D510BD7EE74D73FAF36BC31ECFA268"
177 "359046F4EB879F924009438B481C6CD7889A002ED5EE382BC9190DA6"
178 "FC026E479558E4475677E9AA9E3050E2765694DFC81F56E880B96E71"
179 "60C980DD98EDD3DFFFFFFFFFFFFFFFFF",
181 {0, 0} /* null sentinel */
184 static void delete_ng(NGConstant *ng)
193 static NGConstant *new_ng(SRP_NGType ng_type, const char *n_hex, const char *g_hex)
195 NGConstant *ng = (NGConstant *)srp_alloc(sizeof(NGConstant));
202 if (ng_type != SRP_NG_CUSTOM) {
203 n_hex = global_Ng_constants[ng_type].n_hex;
204 g_hex = global_Ng_constants[ng_type].g_hex;
208 rv = mpz_set_str(ng->N, n_hex, 16);
209 rv = rv | mpz_set_str(ng->g, g_hex, 16);
222 // SHA512_CTX sha512;
226 SRP_HashAlgorithm hash_alg;
230 unsigned char *bytes_B;
233 unsigned char M[SHA512_DIGEST_LENGTH];
234 unsigned char H_AMK[SHA512_DIGEST_LENGTH];
235 unsigned char session_key[SHA512_DIGEST_LENGTH];
239 SRP_HashAlgorithm hash_alg;
246 unsigned char *bytes_A;
250 char *username_verifier;
251 unsigned char *password;
254 unsigned char M[SHA512_DIGEST_LENGTH];
255 unsigned char H_AMK[SHA512_DIGEST_LENGTH];
256 unsigned char session_key[SHA512_DIGEST_LENGTH];
260 static int hash_init(SRP_HashAlgorithm alg, HashCTX *c)
264 case SRP_SHA1: return SHA1_Init(&c->sha);
267 case SRP_SHA224: return SHA224_Init(&c->sha256);
269 #ifdef CSRP_USE_SHA256
270 case SRP_SHA256: return SHA256_Init(&c->sha256);
273 case SRP_SHA384: return SHA384_Init(&c->sha512);
274 case SRP_SHA512: return SHA512_Init(&c->sha512);
279 static int hash_update( SRP_HashAlgorithm alg, HashCTX *c, const void *data, size_t len )
283 case SRP_SHA1: return SHA1_Update(&c->sha, data, len);
286 case SRP_SHA224: return SHA224_Update(&c->sha256, data, len);
288 #ifdef CSRP_USE_SHA256
289 case SRP_SHA256: return SHA256_Update(&c->sha256, data, len);
292 case SRP_SHA384: return SHA384_Update(&c->sha512, data, len);
293 case SRP_SHA512: return SHA512_Update(&c->sha512, data, len);
298 static int hash_final( SRP_HashAlgorithm alg, HashCTX *c, unsigned char *md )
302 case SRP_SHA1: return SHA1_Final(md, &c->sha);
305 case SRP_SHA224: return SHA224_Final(md, &c->sha256);
307 #ifdef CSRP_USE_SHA256
308 case SRP_SHA256: return SHA256_Final(md, &c->sha256);
311 case SRP_SHA384: return SHA384_Final(md, &c->sha512);
312 case SRP_SHA512: return SHA512_Final(md, &c->sha512);
317 static unsigned char *hash(SRP_HashAlgorithm alg, const unsigned char *d, size_t n, unsigned char *md)
321 case SRP_SHA1: return SHA1(d, n, md);
324 case SRP_SHA224: return SHA224( d, n, md );
326 #ifdef CSRP_USE_SHA256
327 case SRP_SHA256: return SHA256(d, n, md);
330 case SRP_SHA384: return SHA384( d, n, md );
331 case SRP_SHA512: return SHA512( d, n, md );
336 static size_t hash_length(SRP_HashAlgorithm alg)
340 case SRP_SHA1: return SHA_DIGEST_LENGTH;
343 case SRP_SHA224: return SHA224_DIGEST_LENGTH;
345 #ifdef CSRP_USE_SHA256
346 case SRP_SHA256: return SHA256_DIGEST_LENGTH;
349 case SRP_SHA384: return SHA384_DIGEST_LENGTH;
350 case SRP_SHA512: return SHA512_DIGEST_LENGTH;
357 inline static int mpz_num_bytes(const mpz_t op)
359 return (mpz_sizeinbase(op, 2) + 7) / 8;
362 inline static void mpz_to_bin(const mpz_t op, unsigned char *to)
364 mpz_export(to, NULL, 1, 1, 1, 0, op);
367 inline static void mpz_from_bin(const unsigned char *s, size_t len, mpz_t ret)
369 mpz_import(ret, len, 1, 1, 1, 0, s);
372 // set op to (op1 * op2) mod d, using tmp for the calculation
373 inline static void mpz_mulm(
374 mpz_t op, const mpz_t op1, const mpz_t op2, const mpz_t d, mpz_t tmp)
376 mpz_mul(tmp, op1, op2);
380 // set op to (op1 + op2) mod d, using tmp for the calculation
381 inline static void mpz_addm(
382 mpz_t op, const mpz_t op1, const mpz_t op2, const mpz_t d, mpz_t tmp)
384 mpz_add(tmp, op1, op2);
388 // set op to (op1 - op2) mod d, using tmp for the calculation
389 inline static void mpz_subm(
390 mpz_t op, const mpz_t op1, const mpz_t op2, const mpz_t d, mpz_t tmp)
392 mpz_sub(tmp, op1, op2);
396 static SRP_Result H_nn(
397 mpz_t result, SRP_HashAlgorithm alg, const mpz_t N, const mpz_t n1, const mpz_t n2)
399 unsigned char buff[SHA512_DIGEST_LENGTH];
400 size_t len_N = mpz_num_bytes(N);
401 size_t len_n1 = mpz_num_bytes(n1);
402 size_t len_n2 = mpz_num_bytes(n2);
403 size_t nbytes = len_N + len_N;
404 unsigned char *bin = (unsigned char *)srp_alloc(nbytes);
405 if (!bin) return SRP_ERR;
406 if (len_n1 > len_N || len_n2 > len_N) {
410 memset(bin, 0, nbytes);
411 mpz_to_bin(n1, bin + (len_N - len_n1));
412 mpz_to_bin(n2, bin + (len_N + len_N - len_n2));
413 hash(alg, bin, nbytes, buff);
415 mpz_from_bin(buff, hash_length(alg), result);
419 static SRP_Result H_ns(mpz_t result, SRP_HashAlgorithm alg, const unsigned char *n,
420 size_t len_n, const unsigned char *bytes, size_t len_bytes)
422 unsigned char buff[SHA512_DIGEST_LENGTH];
423 size_t nbytes = len_n + len_bytes;
424 unsigned char *bin = (unsigned char *)srp_alloc(nbytes);
425 if (!bin) return SRP_ERR;
426 memcpy(bin, n, len_n);
427 memcpy(bin + len_n, bytes, len_bytes);
428 hash(alg, bin, nbytes, buff);
430 mpz_from_bin(buff, hash_length(alg), result);
434 static int calculate_x(mpz_t result, SRP_HashAlgorithm alg, const unsigned char *salt,
435 size_t salt_len, const char *username, const unsigned char *password,
438 unsigned char ucp_hash[SHA512_DIGEST_LENGTH];
440 hash_init(alg, &ctx);
442 srp_dbg_data((char *)username, strlen(username), "Username for x: ");
443 srp_dbg_data((char *)password, password_len, "Password for x: ");
444 hash_update(alg, &ctx, username, strlen(username));
445 hash_update(alg, &ctx, ":", 1);
446 hash_update(alg, &ctx, password, password_len);
448 hash_final(alg, &ctx, ucp_hash);
450 return H_ns(result, alg, salt, salt_len, ucp_hash, hash_length(alg));
453 static SRP_Result update_hash_n(SRP_HashAlgorithm alg, HashCTX *ctx, const mpz_t n)
455 size_t len = mpz_num_bytes(n);
456 unsigned char *n_bytes = (unsigned char *)srp_alloc(len);
457 if (!n_bytes) return SRP_ERR;
458 mpz_to_bin(n, n_bytes);
459 hash_update(alg, ctx, n_bytes, len);
464 static SRP_Result hash_num(SRP_HashAlgorithm alg, const mpz_t n, unsigned char *dest)
466 int nbytes = mpz_num_bytes(n);
467 unsigned char *bin = (unsigned char *)srp_alloc(nbytes);
468 if (!bin) return SRP_ERR;
470 hash(alg, bin, nbytes, dest);
475 static SRP_Result calculate_M(SRP_HashAlgorithm alg, NGConstant *ng, unsigned char *dest,
476 const char *I, const unsigned char *s_bytes, size_t s_len, const mpz_t A,
477 const mpz_t B, const unsigned char *K)
479 unsigned char H_N[SHA512_DIGEST_LENGTH];
480 unsigned char H_g[SHA512_DIGEST_LENGTH];
481 unsigned char H_I[SHA512_DIGEST_LENGTH];
482 unsigned char H_xor[SHA512_DIGEST_LENGTH];
485 size_t hash_len = hash_length(alg);
487 if (!hash_num(alg, ng->N, H_N)) return SRP_ERR;
488 if (!hash_num(alg, ng->g, H_g)) return SRP_ERR;
490 hash(alg, (const unsigned char *)I, strlen(I), H_I);
492 for (i = 0; i < hash_len; i++)
493 H_xor[i] = H_N[i] ^ H_g[i];
495 hash_init(alg, &ctx);
497 hash_update(alg, &ctx, H_xor, hash_len);
498 hash_update(alg, &ctx, H_I, hash_len);
499 hash_update(alg, &ctx, s_bytes, s_len);
500 if (!update_hash_n(alg, &ctx, A)) return SRP_ERR;
501 if (!update_hash_n(alg, &ctx, B)) return SRP_ERR;
502 hash_update(alg, &ctx, K, hash_len);
504 hash_final(alg, &ctx, dest);
508 static SRP_Result calculate_H_AMK(SRP_HashAlgorithm alg, unsigned char *dest,
509 const mpz_t A, const unsigned char *M, const unsigned char *K)
513 hash_init(alg, &ctx);
515 if (!update_hash_n(alg, &ctx, A)) return SRP_ERR;
516 hash_update(alg, &ctx, M, hash_length(alg));
517 hash_update(alg, &ctx, K, hash_length(alg));
519 hash_final(alg, &ctx, dest);
523 static SRP_Result fill_buff()
535 if (!CryptAcquireContext(&wctx, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
537 if (!CryptGenRandom(wctx, sizeof(g_rand_buff), (BYTE *)g_rand_buff)) return SRP_ERR;
538 if (!CryptReleaseContext(wctx, 0)) return SRP_ERR;
541 fp = fopen("/dev/urandom", "r");
543 if (!fp) return SRP_ERR;
545 if (fread(g_rand_buff, sizeof(g_rand_buff), 1, fp) != 1) { fclose(fp); return SRP_ERR; }
546 if (fclose(fp)) return SRP_ERR;
551 static SRP_Result mpz_fill_random(mpz_t num)
553 // was call: BN_rand(num, 256, -1, 0);
554 if (RAND_BUFF_MAX - g_rand_idx < 32)
555 if (fill_buff() != SRP_OK) return SRP_ERR;
556 mpz_from_bin((const unsigned char *)(&g_rand_buff[g_rand_idx]), 32, num);
561 static SRP_Result init_random()
563 if (g_initialized) return SRP_OK;
564 SRP_Result ret = fill_buff();
565 g_initialized = (ret == SRP_OK);
569 #define srp_dbg_num(num, text) ;
570 /*void srp_dbg_num(mpz_t num, char * prevtext)
572 int len_num = mpz_num_bytes(num);
573 char *bytes_num = (char*) srp_alloc(len_num);
574 mpz_to_bin(num, (unsigned char *) bytes_num);
575 srp_dbg_data(bytes_num, len_num, prevtext);
580 /***********************************************************************************************************
584 ***********************************************************************************************************/
587 SRP_Result srp_create_salted_verification_key( SRP_HashAlgorithm alg,
588 SRP_NGType ng_type, const char *username_for_verifier,
589 const unsigned char *password, size_t len_password,
590 unsigned char **bytes_s, size_t *len_s,
591 unsigned char **bytes_v, size_t *len_v,
592 const char *n_hex, const char *g_hex )
594 SRP_Result ret = SRP_OK;
596 mpz_t v; mpz_init(v);
597 mpz_t x; mpz_init(x);
600 NGConstant *ng = new_ng(ng_type, n_hex, g_hex);
602 if (!ng) goto error_and_exit;
604 if (init_random() != SRP_OK) /* Only happens once */
607 if (*bytes_s == NULL) {
608 size_t size_to_fill = 16;
609 *len_s = size_to_fill;
610 if (RAND_BUFF_MAX - g_rand_idx < size_to_fill)
611 if (fill_buff() != SRP_OK) goto error_and_exit;
612 *bytes_s = (unsigned char *)srp_alloc(size_to_fill);
613 if (!*bytes_s) goto error_and_exit;
614 memcpy(*bytes_s, &g_rand_buff + g_rand_idx, size_to_fill);
615 g_rand_idx += size_to_fill;
619 x, alg, *bytes_s, *len_s, username_for_verifier, password, len_password))
622 srp_dbg_num(x, "Server calculated x: ");
624 mpz_powm(v, ng->g, x, ng->N);
626 *len_v = mpz_num_bytes(v);
628 *bytes_v = (unsigned char *)srp_alloc(*len_v);
630 if (!*bytes_v) goto error_and_exit;
632 mpz_to_bin(v, *bytes_v);
641 goto cleanup_and_exit;
646 /* Out: bytes_B, len_B.
648 * On failure, bytes_B will be set to NULL and len_B will be set to 0
650 struct SRPVerifier *srp_verifier_new(SRP_HashAlgorithm alg,
651 SRP_NGType ng_type, const char *username,
652 const unsigned char *bytes_s, size_t len_s,
653 const unsigned char *bytes_v, size_t len_v,
654 const unsigned char *bytes_A, size_t len_A,
655 const unsigned char *bytes_b, size_t len_b,
656 unsigned char **bytes_B, size_t *len_B,
657 const char *n_hex, const char *g_hex )
659 mpz_t v; mpz_init(v); mpz_from_bin(bytes_v, len_v, v);
660 mpz_t A; mpz_init(A); mpz_from_bin(bytes_A, len_A, A);
661 mpz_t u; mpz_init(u);
662 mpz_t B; mpz_init(B);
663 mpz_t S; mpz_init(S);
664 mpz_t b; mpz_init(b);
665 mpz_t k; mpz_init(k);
666 mpz_t tmp1; mpz_init(tmp1);
667 mpz_t tmp2; mpz_init(tmp2);
668 mpz_t tmp3; mpz_init(tmp3);
670 size_t ulen = strlen(username) + 1;
671 NGConstant *ng = new_ng(ng_type, n_hex, g_hex);
672 struct SRPVerifier *ver = 0;
677 if (!ng) goto cleanup_and_exit;
679 ver = (struct SRPVerifier *)srp_alloc(sizeof(struct SRPVerifier));
681 if (!ver) goto cleanup_and_exit;
683 if (init_random() != SRP_OK) { /* Only happens once */
686 goto cleanup_and_exit;
689 ver->username = (char *)srp_alloc(ulen);
693 if (!ver->username) {
696 goto cleanup_and_exit;
699 memcpy((char *)ver->username, username, ulen);
701 ver->authenticated = 0;
703 /* SRP-6a safety check */
704 mpz_mod(tmp1, A, ng->N);
705 if (mpz_sgn(tmp1) != 0) {
707 mpz_from_bin(bytes_b, len_b, b);
709 if (!mpz_fill_random(b)) goto ver_cleanup_and_exit;
712 if (!H_nn(k, alg, ng->N, ng->N, ng->g)) goto ver_cleanup_and_exit;
715 mpz_mulm(tmp1, k, v, ng->N, tmp3);
716 mpz_powm(tmp2, ng->g, b, ng->N);
717 mpz_addm(B, tmp1, tmp2, ng->N, tmp3);
719 if (!H_nn(u, alg, ng->N, A, B)) goto ver_cleanup_and_exit;
721 srp_dbg_num(u, "Server calculated u: ");
723 /* S = (A *(v^u)) ^ b */
724 mpz_powm(tmp1, v, u, ng->N);
725 mpz_mulm(tmp2, A, tmp1, ng->N, tmp3);
726 mpz_powm(S, tmp2, b, ng->N);
728 if (!hash_num(alg, S, ver->session_key)) goto ver_cleanup_and_exit;
731 alg, ng, ver->M, username, bytes_s, len_s, A, B, ver->session_key)) {
732 goto ver_cleanup_and_exit;
734 if (!calculate_H_AMK(alg, ver->H_AMK, A, ver->M, ver->session_key)) {
735 goto ver_cleanup_and_exit;
738 *len_B = mpz_num_bytes(B);
739 *bytes_B = (unsigned char *)srp_alloc(*len_B);
743 goto ver_cleanup_and_exit;
746 mpz_to_bin(B, *bytes_B);
748 ver->bytes_B = *bytes_B;
766 ver_cleanup_and_exit:
767 srp_free(ver->username);
770 goto cleanup_and_exit;
773 void srp_verifier_delete(struct SRPVerifier *ver)
777 srp_free(ver->username);
778 srp_free(ver->bytes_B);
779 memset(ver, 0, sizeof(*ver));
784 int srp_verifier_is_authenticated(struct SRPVerifier *ver)
786 return ver->authenticated;
789 const char *srp_verifier_get_username(struct SRPVerifier *ver)
791 return ver->username;
794 const unsigned char *srp_verifier_get_session_key(
795 struct SRPVerifier *ver, size_t *key_length)
797 if (key_length) *key_length = hash_length(ver->hash_alg);
798 return ver->session_key;
801 size_t srp_verifier_get_session_key_length(struct SRPVerifier *ver)
803 return hash_length(ver->hash_alg);
806 /* user_M must be exactly SHA512_DIGEST_LENGTH bytes in size */
807 void srp_verifier_verify_session(
808 struct SRPVerifier *ver, const unsigned char *user_M, unsigned char **bytes_HAMK)
810 if (memcmp(ver->M, user_M, hash_length(ver->hash_alg)) == 0) {
811 ver->authenticated = 1;
812 *bytes_HAMK = ver->H_AMK;
817 /*******************************************************************************/
819 struct SRPUser *srp_user_new(SRP_HashAlgorithm alg, SRP_NGType ng_type,
820 const char *username, const char *username_for_verifier,
821 const unsigned char *bytes_password, size_t len_password, const char *n_hex,
824 struct SRPUser *usr = (struct SRPUser *)srp_alloc(sizeof(struct SRPUser));
825 size_t ulen = strlen(username) + 1;
826 size_t uvlen = strlen(username_for_verifier) + 1;
828 if (!usr) goto err_exit;
830 if (init_random() != SRP_OK) /* Only happens once */
834 usr->ng = new_ng(ng_type, n_hex, g_hex);
840 if (!usr->ng) goto err_exit;
842 usr->username = (char *)srp_alloc(ulen);
843 usr->username_verifier = (char *)srp_alloc(uvlen);
844 usr->password = (unsigned char *)srp_alloc(len_password);
845 usr->password_len = len_password;
847 if (!usr->username || !usr->password || !usr->username_verifier) goto err_exit;
849 memcpy(usr->username, username, ulen);
850 memcpy(usr->username_verifier, username_for_verifier, uvlen);
851 memcpy(usr->password, bytes_password, len_password);
853 usr->authenticated = 0;
864 if (usr->ng) delete_ng(usr->ng);
865 srp_free(usr->username);
866 srp_free(usr->username_verifier);
868 memset(usr->password, 0, usr->password_len);
869 srp_free(usr->password);
877 void srp_user_delete(struct SRPUser *usr)
886 memset(usr->password, 0, usr->password_len);
888 srp_free(usr->username);
889 srp_free(usr->username_verifier);
890 srp_free(usr->password);
892 if (usr->bytes_A) srp_free(usr->bytes_A);
894 memset(usr, 0, sizeof(*usr));
899 int srp_user_is_authenticated(struct SRPUser *usr)
901 return usr->authenticated;
904 const char *srp_user_get_username(struct SRPUser *usr)
906 return usr->username;
909 const unsigned char *srp_user_get_session_key(struct SRPUser *usr, size_t *key_length)
911 if (key_length) *key_length = hash_length(usr->hash_alg);
912 return usr->session_key;
915 size_t srp_user_get_session_key_length(struct SRPUser *usr)
917 return hash_length(usr->hash_alg);
921 /* Output: username, bytes_A, len_A */
922 SRP_Result srp_user_start_authentication(struct SRPUser *usr, char **username,
923 const unsigned char *bytes_a, size_t len_a,
924 unsigned char **bytes_A, size_t *len_A)
928 mpz_from_bin(bytes_a, len_a, usr->a);
930 if (!mpz_fill_random(usr->a)) goto error_and_exit;
933 mpz_powm(usr->A, usr->ng->g, usr->a, usr->ng->N);
935 *len_A = mpz_num_bytes(usr->A);
936 *bytes_A = (unsigned char *)srp_alloc(*len_A);
938 if (!*bytes_A) goto error_and_exit;
940 mpz_to_bin(usr->A, *bytes_A);
942 usr->bytes_A = *bytes_A;
943 if (username) *username = usr->username;
955 /* Output: bytes_M. Buffer length is SHA512_DIGEST_LENGTH */
956 void srp_user_process_challenge(struct SRPUser *usr,
957 const unsigned char *bytes_s, size_t len_s,
958 const unsigned char *bytes_B, size_t len_B,
959 unsigned char **bytes_M, size_t *len_M)
961 mpz_t B; mpz_init(B); mpz_from_bin(bytes_B, len_B, B);
962 mpz_t u; mpz_init(u);
963 mpz_t x; mpz_init(x);
964 mpz_t k; mpz_init(k);
965 mpz_t v; mpz_init(v);
966 mpz_t tmp1; mpz_init(tmp1);
967 mpz_t tmp2; mpz_init(tmp2);
968 mpz_t tmp3; mpz_init(tmp3);
969 mpz_t tmp4; mpz_init(tmp4);
975 if (!H_nn(u, usr->hash_alg, usr->ng->N, usr->A, B)) goto cleanup_and_exit;
977 srp_dbg_num(u, "Client calculated u: ");
979 if (!calculate_x(x, usr->hash_alg, bytes_s, len_s, usr->username_verifier,
980 usr->password, usr->password_len))
981 goto cleanup_and_exit;
983 srp_dbg_num(x, "Client calculated x: ");
985 if (!H_nn(k, usr->hash_alg, usr->ng->N, usr->ng->N, usr->ng->g))
986 goto cleanup_and_exit;
988 /* SRP-6a safety check */
989 if (mpz_sgn(B) != 0 && mpz_sgn(u) != 0) {
990 mpz_powm(v, usr->ng->g, x, usr->ng->N);
992 srp_dbg_num(v, "Client calculated v: ");
995 /* S = (B - k*(g^x)) ^ (a + ux) */
997 mpz_add(tmp2, usr->a, tmp1); /* tmp2 = (a + ux) */
998 mpz_powm(tmp1, usr->ng->g, x, usr->ng->N); /* tmp1 = g^x */
999 mpz_mulm(tmp3, k, tmp1, usr->ng->N, tmp4); /* tmp3 = k*(g^x) */
1000 mpz_subm(tmp1, B, tmp3, usr->ng->N, tmp4); /* tmp1 = (B - K*(g^x)) */
1001 mpz_powm(usr->S, tmp1, tmp2, usr->ng->N);
1004 if (!hash_num(usr->hash_alg, usr->S, usr->session_key)) goto cleanup_and_exit;
1006 if (!calculate_M(usr->hash_alg, usr->ng, usr->M, usr->username, bytes_s, len_s,
1007 usr->A, B, usr->session_key))
1008 goto cleanup_and_exit;
1009 if (!calculate_H_AMK(usr->hash_alg, usr->H_AMK, usr->A, usr->M, usr->session_key))
1010 goto cleanup_and_exit;
1013 if (len_M) *len_M = hash_length(usr->hash_alg);
1016 if (len_M) *len_M = 0;
1031 void srp_user_verify_session(struct SRPUser *usr, const unsigned char *bytes_HAMK)
1033 if (memcmp(usr->H_AMK, bytes_HAMK, hash_length(usr->hash_alg)) == 0)
1034 usr->authenticated = 1;