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Diffstat (limited to 'src/util/srp.cpp')
| -rw-r--r-- | src/util/srp.cpp | 1029 |
1 files changed, 1029 insertions, 0 deletions
diff --git a/src/util/srp.cpp b/src/util/srp.cpp new file mode 100644 index 000000000..cc8bac6bb --- /dev/null +++ b/src/util/srp.cpp @@ -0,0 +1,1029 @@ +/* + * Secure Remote Password 6a implementation + * https://github.com/est31/csrp-gmp + * + * The MIT License (MIT) + * + * Copyright (c) 2010, 2013 Tom Cocagne, 2015 est31 <MTest31@outlook.com> + * + * Permission is hereby granted, free of charge, to any person obtaining a copy of + * this software and associated documentation files (the "Software"), to deal in + * the Software without restriction, including without limitation the rights to + * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies + * of the Software, and to permit persons to whom the Software is furnished to do + * so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in all + * copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + * + */ + +#ifdef WIN32 + #include <windows.h> + #include <wincrypt.h> +#else + #include <time.h> +#endif + +#include <stdlib.h> +#include <string.h> +#include <stdio.h> + +#include <config.h> + +#if USE_SYSTEM_GMP || defined (__ANDROID__) || defined (ANDROID) + #include <gmp.h> +#else + #include <gmp/mini-gmp.h> +#endif + +#include <util/sha2.h> + +#include "srp.h" +//#define CSRP_USE_SHA1 +#define CSRP_USE_SHA256 + +#define srp_dbg_data(data, datalen, prevtext) ; +/*void srp_dbg_data(unsigned char * data, size_t datalen, char * prevtext) +{ + printf(prevtext); + size_t i; + for (i = 0; i < datalen; i++) + { + printf("%02X", data[i]); + } + printf("\n"); +}*/ + +static int g_initialized = 0; + +#define RAND_BUFF_MAX 128 +static unsigned int g_rand_idx; +static unsigned char g_rand_buff[RAND_BUFF_MAX]; + +typedef struct +{ + mpz_t N; + mpz_t g; +} NGConstant; + +struct NGHex +{ + const char* n_hex; + const char* g_hex; +}; + +/* All constants here were pulled from Appendix A of RFC 5054 */ +static struct NGHex global_Ng_constants[] = { + { /* 1024 */ + "EEAF0AB9ADB38DD69C33F80AFA8FC5E86072618775FF3C0B9EA2314C9C256576D674DF7496" + "EA81D3383B4813D692C6E0E0D5D8E250B98BE48E495C1D6089DAD15DC7D7B46154D6B6CE8E" + "F4AD69B15D4982559B297BCF1885C529F566660E57EC68EDBC3C05726CC02FD4CBF4976EAA" + "9AFD5138FE8376435B9FC61D2FC0EB06E3", + "2" + }, + { /* 2048 */ + "AC6BDB41324A9A9BF166DE5E1389582FAF72B6651987EE07FC3192943DB56050A37329CBB4" + "A099ED8193E0757767A13DD52312AB4B03310DCD7F48A9DA04FD50E8083969EDB767B0CF60" + "95179A163AB3661A05FBD5FAAAE82918A9962F0B93B855F97993EC975EEAA80D740ADBF4FF" + "747359D041D5C33EA71D281E446B14773BCA97B43A23FB801676BD207A436C6481F1D2B907" + "8717461A5B9D32E688F87748544523B524B0D57D5EA77A2775D2ECFA032CFBDBF52FB37861" + "60279004E57AE6AF874E7303CE53299CCC041C7BC308D82A5698F3A8D0C38271AE35F8E9DB" + "FBB694B5C803D89F7AE435DE236D525F54759B65E372FCD68EF20FA7111F9E4AFF73", + "2" + }, + { /* 4096 */ + "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08" + "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B" + "302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9" + "A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6" + "49286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8" + "FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D" + "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C" + "180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF695581718" + "3995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D" + "04507A33A85521ABDF1CBA64ECFB850458DBEF0A8AEA71575D060C7D" + "B3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D226" + "1AD2EE6BF12FFA06D98A0864D87602733EC86A64521F2B18177B200C" + "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFC" + "E0FD108E4B82D120A92108011A723C12A787E6D788719A10BDBA5B26" + "99C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB" + "04DE8EF92E8EFC141FBECAA6287C59474E6BC05D99B2964FA090C3A2" + "233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD0069127" + "D5B05AA993B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934063199" + "FFFFFFFFFFFFFFFF", + "5" + }, + { /* 8192 */ + "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08" + "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B" + "302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9" + "A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6" + "49286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8" + "FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D" + "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C" + "180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF695581718" + "3995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D" + "04507A33A85521ABDF1CBA64ECFB850458DBEF0A8AEA71575D060C7D" + "B3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D226" + "1AD2EE6BF12FFA06D98A0864D87602733EC86A64521F2B18177B200C" + "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFC" + "E0FD108E4B82D120A92108011A723C12A787E6D788719A10BDBA5B26" + "99C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB" + "04DE8EF92E8EFC141FBECAA6287C59474E6BC05D99B2964FA090C3A2" + "233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD0069127" + "D5B05AA993B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934028492" + "36C3FAB4D27C7026C1D4DCB2602646DEC9751E763DBA37BDF8FF9406" + "AD9E530EE5DB382F413001AEB06A53ED9027D831179727B0865A8918" + "DA3EDBEBCF9B14ED44CE6CBACED4BB1BDB7F1447E6CC254B33205151" + "2BD7AF426FB8F401378CD2BF5983CA01C64B92ECF032EA15D1721D03" + "F482D7CE6E74FEF6D55E702F46980C82B5A84031900B1C9E59E7C97F" + "BEC7E8F323A97A7E36CC88BE0F1D45B7FF585AC54BD407B22B4154AA" + "CC8F6D7EBF48E1D814CC5ED20F8037E0A79715EEF29BE32806A1D58B" + "B7C5DA76F550AA3D8A1FBFF0EB19CCB1A313D55CDA56C9EC2EF29632" + "387FE8D76E3C0468043E8F663F4860EE12BF2D5B0B7474D6E694F91E" + "6DBE115974A3926F12FEE5E438777CB6A932DF8CD8BEC4D073B931BA" + "3BC832B68D9DD300741FA7BF8AFC47ED2576F6936BA424663AAB639C" + "5AE4F5683423B4742BF1C978238F16CBE39D652DE3FDB8BEFC848AD9" + "22222E04A4037C0713EB57A81A23F0C73473FC646CEA306B4BCBC886" + "2F8385DDFA9D4B7FA2C087E879683303ED5BDD3A062B3CF5B3A278A6" + "6D2A13F83F44F82DDF310EE074AB6A364597E899A0255DC164F31CC5" + "0846851DF9AB48195DED7EA1B1D510BD7EE74D73FAF36BC31ECFA268" + "359046F4EB879F924009438B481C6CD7889A002ED5EE382BC9190DA6" + "FC026E479558E4475677E9AA9E3050E2765694DFC81F56E880B96E71" + "60C980DD98EDD3DFFFFFFFFFFFFFFFFF", + "13" + }, + {0,0} /* null sentinel */ +}; + + +static NGConstant *new_ng( SRP_NGType ng_type, const char *n_hex, const char *g_hex ) +{ + NGConstant *ng = (NGConstant *) malloc(sizeof(NGConstant)); + mpz_init(ng->N); + mpz_init(ng->g); + + if (!ng || !ng->N || !ng->g) + return 0; + + if (ng_type != SRP_NG_CUSTOM) { + n_hex = global_Ng_constants[ ng_type ].n_hex; + g_hex = global_Ng_constants[ ng_type ].g_hex; + } + + mpz_set_str(ng->N, n_hex, 16); + mpz_set_str(ng->g, g_hex, 16); + + return ng; +} + +static void delete_ng( NGConstant *ng ) +{ + if (ng) { + mpz_clear(ng->N); + mpz_clear(ng->g); + free(ng); + } +} + + + +typedef union +{ + SHA_CTX sha; + SHA256_CTX sha256; + //SHA512_CTX sha512; +} HashCTX; + + +struct SRPVerifier +{ + SRP_HashAlgorithm hash_alg; + NGConstant *ng; + + char *username; + unsigned char *bytes_B; + int authenticated; + + unsigned char M[SHA512_DIGEST_LENGTH]; + unsigned char H_AMK[SHA512_DIGEST_LENGTH]; + unsigned char session_key[SHA512_DIGEST_LENGTH]; +}; + + +struct SRPUser +{ + SRP_HashAlgorithm hash_alg; + NGConstant *ng; + + mpz_t a; + mpz_t A; + mpz_t S; + + unsigned char *bytes_A; + int authenticated; + + char *username; + char *username_verifier; + unsigned char *password; + size_t password_len; + + unsigned char M[SHA512_DIGEST_LENGTH]; + unsigned char H_AMK[SHA512_DIGEST_LENGTH]; + unsigned char session_key[SHA512_DIGEST_LENGTH]; +}; + + +static int hash_init(SRP_HashAlgorithm alg, HashCTX *c) +{ + switch (alg) { +#ifdef CSRP_USE_SHA1 + case SRP_SHA1: return SHA1_Init(&c->sha); +#endif + /*case SRP_SHA224: return SHA224_Init(&c->sha256);*/ +#ifdef CSRP_USE_SHA256 + case SRP_SHA256: return SHA256_Init(&c->sha256); +#endif + /*case SRP_SHA384: return SHA384_Init(&c->sha512); + case SRP_SHA512: return SHA512_Init(&c->sha512);*/ + default: return -1; + }; +} +static int hash_update( SRP_HashAlgorithm alg, HashCTX *c, const void *data, size_t len ) +{ + switch (alg) { +#ifdef CSRP_USE_SHA1 + case SRP_SHA1: return SHA1_Update(&c->sha, data, len); +#endif + /*case SRP_SHA224: return SHA224_Update(&c->sha256, data, len);*/ +#ifdef CSRP_USE_SHA256 + case SRP_SHA256: return SHA256_Update(&c->sha256, data, len); +#endif + /*case SRP_SHA384: return SHA384_Update( &c->sha512, data, len ); + case SRP_SHA512: return SHA512_Update( &c->sha512, data, len );*/ + default: return -1; + }; +} +static int hash_final( SRP_HashAlgorithm alg, HashCTX *c, unsigned char *md ) +{ + switch (alg) { +#ifdef CSRP_USE_SHA1 + case SRP_SHA1: return SHA1_Final(md, &c->sha); +#endif + /*case SRP_SHA224: return SHA224_Final(md, &c->sha256);*/ +#ifdef CSRP_USE_SHA256 + case SRP_SHA256: return SHA256_Final(md, &c->sha256); +#endif + /*case SRP_SHA384: return SHA384_Final(md, &c->sha512); + case SRP_SHA512: return SHA512_Final(md, &c->sha512);*/ + default: return -1; + }; +} +static unsigned char *hash(SRP_HashAlgorithm alg, const unsigned char *d, size_t n, unsigned char *md) +{ + switch (alg) { +#ifdef CSRP_USE_SHA1 + case SRP_SHA1: return SHA1(d, n, md); +#endif + /*case SRP_SHA224: return SHA224( d, n, md );*/ +#ifdef CSRP_USE_SHA256 + case SRP_SHA256: return SHA256(d, n, md); +#endif + /*case SRP_SHA384: return SHA384( d, n, md ); + case SRP_SHA512: return SHA512( d, n, md );*/ + default: return 0; + }; +} +static size_t hash_length(SRP_HashAlgorithm alg) +{ + switch (alg) { +#ifdef CSRP_USE_SHA1 + case SRP_SHA1: return SHA_DIGEST_LENGTH; +#endif + /*case SRP_SHA224: return SHA224_DIGEST_LENGTH;*/ +#ifdef CSRP_USE_SHA256 + case SRP_SHA256: return SHA256_DIGEST_LENGTH; +#endif + /*case SRP_SHA384: return SHA384_DIGEST_LENGTH; + case SRP_SHA512: return SHA512_DIGEST_LENGTH;*/ + default: return -1; + }; +} + +inline static int mpz_num_bytes(const mpz_t op) +{ + return (mpz_sizeinbase (op, 2) + 7) / 8; +} + +inline static void mpz_to_bin(const mpz_t op, unsigned char *to) +{ + mpz_export(to, NULL, 1, 1, 1, 0, op); +} + +inline static void mpz_from_bin(const unsigned char *s, size_t len, mpz_t ret) +{ + mpz_import(ret, len, 1, 1, 1, 0, s); +} + +// set op to (op1 * op2) mod d, using tmp for the calculation +inline static void mpz_mulm(mpz_t op, const mpz_t op1, const mpz_t op2, const mpz_t d, mpz_t tmp) +{ + mpz_mul(tmp, op1, op2); + mpz_mod(op, tmp, d); +} + +// set op to (op1 + op2) mod d, using tmp for the calculation +inline static void mpz_addm( mpz_t op, const mpz_t op1, const mpz_t op2, const mpz_t d, mpz_t tmp ) +{ + mpz_add(tmp, op1, op2); + mpz_mod(op, tmp, d); +} + +// set op to (op1 - op2) mod d, using tmp for the calculation +inline static void mpz_subm(mpz_t op, const mpz_t op1, const mpz_t op2, const mpz_t d, mpz_t tmp) +{ + mpz_sub(tmp, op1, op2); + mpz_mod(op, tmp, d); +} + +static int H_nn(mpz_t result, SRP_HashAlgorithm alg, const mpz_t N, const mpz_t n1, const mpz_t n2) +{ + unsigned char buff[SHA512_DIGEST_LENGTH]; + size_t len_N = mpz_num_bytes(N); + size_t len_n1 = mpz_num_bytes(n1); + size_t len_n2 = mpz_num_bytes(n2); + size_t nbytes = len_N + len_N; + unsigned char *bin = (unsigned char *) malloc(nbytes); + if (!bin) + return 0; + if (len_n1 > len_N || len_n2 > len_N) { + free(bin); + return 0; + } + memset(bin, 0, nbytes); + mpz_to_bin(n1, bin + (len_N - len_n1)); + mpz_to_bin(n2, bin + (len_N + len_N - len_n2)); + hash( alg, bin, nbytes, buff ); + free(bin); + mpz_from_bin(buff, hash_length(alg), result); + return 1; +} + +static int H_ns(mpz_t result, SRP_HashAlgorithm alg, const unsigned char *n, size_t len_n, const unsigned char *bytes, size_t len_bytes) +{ + unsigned char buff[SHA512_DIGEST_LENGTH]; + size_t nbytes = len_n + len_bytes; + unsigned char *bin = (unsigned char *) malloc(nbytes); + if (!bin) + return 0; + memcpy(bin, n, len_n); + memcpy(bin + len_n, bytes, len_bytes); + hash(alg, bin, nbytes, buff); + free(bin); + mpz_from_bin(buff, hash_length(alg), result); + return 1; +} + +static int calculate_x(mpz_t result, SRP_HashAlgorithm alg, const unsigned char *salt, size_t salt_len, const char *username, const unsigned char *password, size_t password_len) +{ + unsigned char ucp_hash[SHA512_DIGEST_LENGTH]; + HashCTX ctx; + hash_init(alg, &ctx); + + srp_dbg_data((char*) username, strlen(username), "Username for x: "); + srp_dbg_data((char*) password, password_len, "Password for x: "); + hash_update(alg, &ctx, username, strlen(username)); + hash_update(alg, &ctx, ":", 1); + hash_update(alg, &ctx, password, password_len); + + hash_final(alg, &ctx, ucp_hash); + + return H_ns(result, alg, salt, salt_len, ucp_hash, hash_length(alg)); +} + +static void update_hash_n(SRP_HashAlgorithm alg, HashCTX *ctx, const mpz_t n) +{ + size_t len = mpz_num_bytes(n); + unsigned char* n_bytes = (unsigned char *) malloc(len); + if (!n_bytes) + return; + mpz_to_bin(n, n_bytes); + hash_update(alg, ctx, n_bytes, len); + free(n_bytes); +} + +static void hash_num( SRP_HashAlgorithm alg, const mpz_t n, unsigned char *dest ) +{ + int nbytes = mpz_num_bytes(n); + unsigned char *bin = (unsigned char *) malloc(nbytes); + if(!bin) + return; + mpz_to_bin(n, bin); + hash(alg, bin, nbytes, dest); + free(bin); +} + +static void calculate_M(SRP_HashAlgorithm alg, NGConstant *ng, unsigned char *dest, + const char *I, const unsigned char *s_bytes, size_t s_len, + const mpz_t A, const mpz_t B, const unsigned char *K) +{ + unsigned char H_N[SHA512_DIGEST_LENGTH]; + unsigned char H_g[SHA512_DIGEST_LENGTH]; + unsigned char H_I[SHA512_DIGEST_LENGTH]; + unsigned char H_xor[SHA512_DIGEST_LENGTH]; + HashCTX ctx; + size_t i = 0; + size_t hash_len = hash_length(alg); + + hash_num(alg, ng->N, H_N); + hash_num(alg, ng->g, H_g); + + hash(alg, (const unsigned char *)I, strlen(I), H_I); + + + for (i = 0; i < hash_len; i++ ) + H_xor[i] = H_N[i] ^ H_g[i]; + + hash_init(alg, &ctx); + + hash_update(alg, &ctx, H_xor, hash_len); + hash_update(alg, &ctx, H_I, hash_len); + hash_update(alg, &ctx, s_bytes, s_len); + update_hash_n(alg, &ctx, A); + update_hash_n(alg, &ctx, B); + hash_update(alg, &ctx, K, hash_len); + + hash_final(alg, &ctx, dest); +} + +static void calculate_H_AMK(SRP_HashAlgorithm alg, unsigned char *dest, const mpz_t A, const unsigned char *M, const unsigned char *K) +{ + HashCTX ctx; + + hash_init(alg, &ctx); + + update_hash_n(alg, &ctx, A); + hash_update(alg, &ctx, M, hash_length(alg)); + hash_update(alg, &ctx, K, hash_length(alg)); + + hash_final(alg, &ctx, dest); +} + + +struct srp_pcgrandom { + unsigned long long int m_state; + unsigned long long int m_inc; +}; typedef struct srp_pcgrandom srp_pcgrandom; + +static unsigned long int srp_pcgrandom_next(srp_pcgrandom *r) +{ + unsigned long long int oldstate = r->m_state; + r->m_state = oldstate * 6364136223846793005ULL + r->m_inc; + + unsigned long int xorshifted = ((oldstate >> 18u) ^ oldstate) >> 27u; + unsigned long int rot = oldstate >> 59u; + return (xorshifted >> rot) | (xorshifted << ((-rot) & 31)); +} + +static void srp_pcgrandom_seed(srp_pcgrandom *r, unsigned long long int state, + unsigned long long int seq) +{ + r->m_state = 0U; + r->m_inc = (seq << 1u) | 1u; + srp_pcgrandom_next(r); + r->m_state += state; + srp_pcgrandom_next(r); +} + + +static int fill_buff() +{ + g_rand_idx = 0; + +#ifdef WIN32 + HCRYPTPROV wctx; +#else + FILE *fp = 0; +#endif + +#ifdef WIN32 + + CryptAcquireContext(&wctx, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT); + CryptGenRandom(wctx, sizeof(g_rand_buff), (BYTE*) g_rand_buff); + CryptReleaseContext(wctx, 0); + + return 1; + +#else + fp = fopen("/dev/urandom", "r"); + + if (fp) { + fread(g_rand_buff, sizeof(g_rand_buff), 1, fp); + fclose(fp); + } else { + srp_pcgrandom *r = (srp_pcgrandom *) malloc(sizeof(srp_pcgrandom)); + srp_pcgrandom_seed(r, time(NULL) ^ clock(), 0xda3e39cb94b95bdbULL); + size_t i = 0; + for (i = 0; i < RAND_BUFF_MAX; i++) { + g_rand_buff[i] = srp_pcgrandom_next(r); + } + } +#endif + return 1; +} + +static void mpz_fill_random(mpz_t num) +{ + // was call: BN_rand(num, 256, -1, 0); + if (RAND_BUFF_MAX - g_rand_idx < 32) + fill_buff(); + mpz_from_bin((const unsigned char *) (&g_rand_buff[g_rand_idx]), 32, num); + g_rand_idx += 32; +} + +static void init_random() +{ + if (g_initialized) + return; + g_initialized = fill_buff(); +} + +#define srp_dbg_num(num, text) ; +/*void srp_dbg_num(mpz_t num, char * prevtext) +{ + int len_num = mpz_num_bytes(num); + char *bytes_num = (char*) malloc(len_num); + mpz_to_bin(num, (unsigned char *) bytes_num); + srp_dbg_data(bytes_num, len_num, prevtext); + free(bytes_num); + +}*/ + +/*********************************************************************************************************** + * + * Exported Functions + * + ***********************************************************************************************************/ + +void srp_create_salted_verification_key( SRP_HashAlgorithm alg, + SRP_NGType ng_type, const char *username_for_verifier, + const unsigned char *password, size_t len_password, + unsigned char **bytes_s, size_t *len_s, + unsigned char **bytes_v, size_t *len_v, + const char *n_hex, const char *g_hex ) +{ + mpz_t v; mpz_init(v); + mpz_t x; mpz_init(x); + NGConstant *ng = new_ng(ng_type, n_hex, g_hex); + + if(!ng) + goto cleanup_and_exit; + + if (*bytes_s == NULL) { + *len_s = 16; + if (RAND_BUFF_MAX - g_rand_idx < 16) + fill_buff(); + *bytes_s = (unsigned char*)malloc(sizeof(char) * 16); + memcpy(*bytes_s, &g_rand_buff + g_rand_idx, sizeof(char) * 16); + g_rand_idx += 16; + } + + + if (!calculate_x(x, alg, *bytes_s, *len_s, username_for_verifier, + password, len_password)) + goto cleanup_and_exit; + + srp_dbg_num(x, "Server calculated x: "); + + mpz_powm(v, ng->g, x, ng->N); + + *len_v = mpz_num_bytes(v); + + *bytes_v = (unsigned char*)malloc(*len_v); + + if (!bytes_v) + goto cleanup_and_exit; + + mpz_to_bin(v, *bytes_v); + +cleanup_and_exit: + delete_ng( ng ); + mpz_clear(v); + mpz_clear(x); +} + + + +/* Out: bytes_B, len_B. + * + * On failure, bytes_B will be set to NULL and len_B will be set to 0 + */ +struct SRPVerifier *srp_verifier_new(SRP_HashAlgorithm alg, + SRP_NGType ng_type, const char *username, + const unsigned char *bytes_s, size_t len_s, + const unsigned char *bytes_v, size_t len_v, + const unsigned char *bytes_A, size_t len_A, + const unsigned char *bytes_b, size_t len_b, + unsigned char **bytes_B, size_t *len_B, + const char *n_hex, const char *g_hex ) +{ + mpz_t v; mpz_init(v); mpz_from_bin(bytes_v, len_v, v); + mpz_t A; mpz_init(A); mpz_from_bin(bytes_A, len_A, A); + mpz_t u; mpz_init(u); + mpz_t B; mpz_init(B); + mpz_t S; mpz_init(S); + mpz_t b; mpz_init(b); + mpz_t k; mpz_init(k); + mpz_t tmp1; mpz_init(tmp1); + mpz_t tmp2; mpz_init(tmp2); + mpz_t tmp3; mpz_init(tmp3); + size_t ulen = strlen(username) + 1; + NGConstant *ng = new_ng(ng_type, n_hex, g_hex); + struct SRPVerifier *ver = 0; + + *len_B = 0; + *bytes_B = 0; + + if (!ng) + goto cleanup_and_exit; + + ver = (struct SRPVerifier *) malloc( sizeof(struct SRPVerifier) ); + + if (!ver) + goto cleanup_and_exit; + + init_random(); /* Only happens once */ + + ver->username = (char *) malloc(ulen); + ver->hash_alg = alg; + ver->ng = ng; + + if (!ver->username) { + free(ver); + ver = 0; + goto cleanup_and_exit; + } + + memcpy((char*)ver->username, username, ulen); + + ver->authenticated = 0; + + /* SRP-6a safety check */ + mpz_mod(tmp1, A, ng->N); + if (mpz_sgn(tmp1) != 0) { + if (bytes_b) { + mpz_from_bin(bytes_b, len_b, b); + } else { + mpz_fill_random(b); + } + + if (!H_nn(k, alg, ng->N, ng->N, ng->g)) { + free(ver); + ver = 0; + goto cleanup_and_exit; + } + + /* B = kv + g^b */ + mpz_mulm(tmp1, k, v, ng->N, tmp3); + mpz_powm(tmp2, ng->g, b, ng->N); + mpz_addm(B, tmp1, tmp2, ng->N, tmp3); + + if (!H_nn(u, alg, ng->N, A, B)) { + free(ver); + ver = 0; + goto cleanup_and_exit; + } + + srp_dbg_num(u, "Server calculated u: "); + + /* S = (A *(v^u)) ^ b */ + mpz_powm(tmp1, v, u, ng->N); + mpz_mulm(tmp2, A, tmp1, ng->N, tmp3); + mpz_powm(S, tmp2, b, ng->N); + + hash_num(alg, S, ver->session_key); + + calculate_M(alg, ng, ver->M, username, bytes_s, len_s, A, B, ver->session_key); + calculate_H_AMK(alg, ver->H_AMK, A, ver->M, ver->session_key); + + *len_B = mpz_num_bytes(B); + *bytes_B = (unsigned char*)malloc(*len_B); + + if (!*bytes_B) { + free(ver->username); + free(ver); + ver = 0; + *len_B = 0; + goto cleanup_and_exit; + } + + mpz_to_bin(B, *bytes_B); + + ver->bytes_B = *bytes_B; + } else { + free(ver); + ver = 0; + } + +cleanup_and_exit: + mpz_clear(v); + mpz_clear(A); + mpz_clear(u); + mpz_clear(k); + mpz_clear(B); + mpz_clear(S); + mpz_clear(b); + mpz_clear(tmp1); + mpz_clear(tmp2); + mpz_clear(tmp3); + return ver; +} + + + + +void srp_verifier_delete(struct SRPVerifier *ver) +{ + if (ver) { + delete_ng(ver->ng); + free(ver->username); + free(ver->bytes_B); + memset(ver, 0, sizeof(*ver)); + free(ver); + } +} + + + +int srp_verifier_is_authenticated(struct SRPVerifier *ver) +{ + return ver->authenticated; +} + + +const char *srp_verifier_get_username(struct SRPVerifier *ver) +{ + return ver->username; +} + + +const unsigned char *srp_verifier_get_session_key(struct SRPVerifier *ver, size_t *key_length) +{ + if (key_length) + *key_length = hash_length(ver->hash_alg); + return ver->session_key; +} + + +size_t srp_verifier_get_session_key_length(struct SRPVerifier *ver) +{ + return hash_length(ver->hash_alg); +} + + +/* user_M must be exactly SHA512_DIGEST_LENGTH bytes in size */ +void srp_verifier_verify_session(struct SRPVerifier *ver, const unsigned char *user_M, unsigned char **bytes_HAMK) +{ + if (memcmp(ver->M, user_M, hash_length(ver->hash_alg)) == 0) { + ver->authenticated = 1; + *bytes_HAMK = ver->H_AMK; + } else + *bytes_HAMK = NULL; +} + +/*******************************************************************************/ + +struct SRPUser *srp_user_new(SRP_HashAlgorithm alg, SRP_NGType ng_type, + const char *username, const char *username_for_verifier, + const unsigned char *bytes_password, size_t len_password, + const char *n_hex, const char *g_hex) +{ + struct SRPUser *usr = (struct SRPUser *) malloc(sizeof(struct SRPUser)); + size_t ulen = strlen(username) + 1; + size_t uvlen = strlen(username_for_verifier) + 1; + + if (!usr) + goto err_exit; + + init_random(); /* Only happens once */ + + usr->hash_alg = alg; + usr->ng = new_ng(ng_type, n_hex, g_hex); + + mpz_init(usr->a); + mpz_init(usr->A); + mpz_init(usr->S); + + if (!usr->ng || !usr->a || !usr->A || !usr->S) + goto err_exit; + + usr->username = (char*)malloc(ulen); + usr->username_verifier = (char*)malloc(uvlen); + usr->password = (unsigned char*)malloc(len_password); + usr->password_len = len_password; + + if (!usr->username || !usr->password) + goto err_exit; + + memcpy(usr->username, username, ulen); + memcpy(usr->username_verifier, username_for_verifier, uvlen); + memcpy(usr->password, bytes_password, len_password); + + usr->authenticated = 0; + + usr->bytes_A = 0; + + return usr; + +err_exit: + if (usr) { + mpz_clear(usr->a); + mpz_clear(usr->A); + mpz_clear(usr->S); + if (usr->username) + free(usr->username); + if (usr->username_verifier) + free(usr->username_verifier); + if (usr->password) { + memset(usr->password, 0, usr->password_len); + free(usr->password); + } + free(usr); + } + + return 0; +} + + + +void srp_user_delete(struct SRPUser *usr) +{ + if(usr) { + mpz_clear(usr->a); + mpz_clear(usr->A); + mpz_clear(usr->S); + + delete_ng(usr->ng); + + memset(usr->password, 0, usr->password_len); + + free(usr->username); + free(usr->username_verifier); + free(usr->password); + + if (usr->bytes_A) + free(usr->bytes_A); + + memset(usr, 0, sizeof(*usr)); + free(usr); + } +} + + + +int srp_user_is_authenticated(struct SRPUser *usr) +{ + return usr->authenticated; +} + + +const char *srp_user_get_username(struct SRPUser *usr) +{ + return usr->username; +} + + +const unsigned char* srp_user_get_session_key(struct SRPUser* usr, size_t* key_length) +{ + if (key_length) + *key_length = hash_length(usr->hash_alg); + return usr->session_key; +} + + +size_t srp_user_get_session_key_length(struct SRPUser *usr) +{ + return hash_length(usr->hash_alg); +} + + +/* Output: username, bytes_A, len_A */ +void srp_user_start_authentication(struct SRPUser *usr, char **username, + const unsigned char *bytes_a, size_t len_a, + unsigned char **bytes_A, size_t *len_A) +{ + if (bytes_a) { + mpz_from_bin(bytes_a, len_a, usr->a); + } else { + mpz_fill_random(usr->a); + } + + mpz_powm(usr->A, usr->ng->g, usr->a, usr->ng->N); + + *len_A = mpz_num_bytes(usr->A); + *bytes_A = (unsigned char*)malloc(*len_A); + + if (!*bytes_A) { + *len_A = 0; + *bytes_A = 0; + *username = 0; + return; + } + + mpz_to_bin(usr->A, *bytes_A); + + usr->bytes_A = *bytes_A; + if (username) + *username = usr->username; +} + + +/* Output: bytes_M. Buffer length is SHA512_DIGEST_LENGTH */ +void srp_user_process_challenge(struct SRPUser *usr, + const unsigned char *bytes_s, size_t len_s, + const unsigned char *bytes_B, size_t len_B, + unsigned char **bytes_M, size_t *len_M) +{ + mpz_t B; mpz_init(B); mpz_from_bin(bytes_B, len_B, B); + mpz_t u; mpz_init(u); + mpz_t x; mpz_init(x); + mpz_t k; mpz_init(k); + mpz_t v; mpz_init(v); + mpz_t tmp1; mpz_init(tmp1); + mpz_t tmp2; mpz_init(tmp2); + mpz_t tmp3; mpz_init(tmp3); + mpz_t tmp4; mpz_init(tmp4); + + *len_M = 0; + *bytes_M = 0; + + if (!H_nn(u, usr->hash_alg, usr->ng->N, usr->A, B)) + goto cleanup_and_exit; + + srp_dbg_num(u, "Client calculated u: "); + + if (!calculate_x(x, usr->hash_alg, bytes_s, len_s, + usr->username_verifier, usr->password, usr->password_len)) + goto cleanup_and_exit; + + srp_dbg_num(x, "Client calculated x: "); + + if (!H_nn(k, usr->hash_alg, usr->ng->N, usr->ng->N, usr->ng->g)) + goto cleanup_and_exit; + + /* SRP-6a safety check */ + if ( mpz_sgn(B) != 0 && mpz_sgn(u) != 0 ) { + mpz_powm(v, usr->ng->g, x, usr->ng->N); + + srp_dbg_num(v, "Client calculated v: "); + + /* S = (B - k*(g^x)) ^ (a + ux) */ + mpz_mul(tmp1, u, x); + mpz_add(tmp2, usr->a, tmp1); /* tmp2 = (a + ux) */ + mpz_powm(tmp1, usr->ng->g, x, usr->ng->N); /* tmp1 = g^x */ + mpz_mulm(tmp3, k, tmp1, usr->ng->N, tmp4); /* tmp3 = k*(g^x) */ + mpz_subm(tmp1, B, tmp3, usr->ng->N, tmp4); /* tmp1 = (B - K*(g^x)) */ + mpz_powm(usr->S, tmp1, tmp2, usr->ng->N); + + hash_num(usr->hash_alg, usr->S, usr->session_key); + + calculate_M( usr->hash_alg, usr->ng, usr->M, usr->username, bytes_s, len_s, usr->A,B, usr->session_key ); + calculate_H_AMK( usr->hash_alg, usr->H_AMK, usr->A, usr->M, usr->session_key ); + + *bytes_M = usr->M; + if (len_M) + *len_M = hash_length( usr->hash_alg ); + } else { + *bytes_M = NULL; + if (len_M) + *len_M = 0; + } + +cleanup_and_exit: + + mpz_clear(B); + mpz_clear(u); + mpz_clear(x); + mpz_clear(k); + mpz_clear(v); + mpz_clear(tmp1); + mpz_clear(tmp2); + mpz_clear(tmp3); + mpz_clear(tmp4); +} + + +void srp_user_verify_session(struct SRPUser *usr, const unsigned char *bytes_HAMK) +{ + if (memcmp(usr->H_AMK, bytes_HAMK, hash_length(usr->hash_alg)) == 0) + usr->authenticated = 1; +} |