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luban-lite/bsp/examples/test-mbedtls-csrp/srp.c
刘可亮 3e10f578d3 v1.2.2
2025-10-21 13:59:50 +08:00

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/*
* Secure Remote Password 6a implementation based on mbedtls.
*
* Copyright (c) 2017 Johannes Schriewer
* https://github.com/dunkelstern/mbedtls-csrp
*
* Copyright (c) 2015 Dieter Wimberger
* https://github.com/dwimberger/mbedtls-csrp
*
* Derived from:
* Copyright (c) 2010 Tom Cocagne. All rights reserved.
* https://github.com/cocagne/csrp
*
* The MIT License (MIT)
*
* Copyright (c) 2015 Tom Cocagne, Dieter Wimberger
*
* 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.
*
*/
#include <time.h>
#include <stdlib.h>
#include <string.h>
#include "mbedtls/bignum.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/sha1.h"
#include "mbedtls/sha256.h"
#include "mbedtls/sha512.h"
#include "srp.h"
static int g_initialized = 0;
static mbedtls_entropy_context entropy_ctx;
static mbedtls_ctr_drbg_context ctr_drbg_ctx;
static mbedtls_mpi * RR;
typedef struct
{
BIGNUM *N;
BIGNUM *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[] = {
{ /* 512 */
"D66AAFE8E245F9AC245A199F62CE61AB8FA90A4D80C71CD2ADFD0B9DA163B29F2A34AFBDB3B"
"1B5D0102559CE63D8B6E86B0AA59C14E79D4AA62D1748E4249DF3",
"2"
},
{ /* 768 */
"B344C7C4F8C495031BB4E04FF8F84EE95008163940B9558276744D91F7CC9F402653BE7147F"
"00F576B93754BCDDF71B636F2099E6FFF90E79575F3D0DE694AFF737D9BE9713CEF8D837ADA"
"6380B1093E94B6A529A8C6C2BE33E0867C60C3262B",
"2"
},
{ /* 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) );
ng->N = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
ng->g = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(ng->N);
mbedtls_mpi_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;
}
mbedtls_mpi_read_string( ng->N, 16, n_hex);
mbedtls_mpi_read_string( ng->g, 16, g_hex);
return ng;
}
static void delete_ng( NGConstant * ng )
{
if (ng)
{
mbedtls_mpi_free( ng->N );
mbedtls_mpi_free( ng->g );
free(ng->N);
free(ng->g);
free(ng);
}
}
typedef union
{
mbedtls_sha1_context sha;
mbedtls_sha256_context sha256;
mbedtls_sha512_context sha512;
} HashCTX;
struct SRPSession
{
SRP_HashAlgorithm hash_alg;
NGConstant *ng;
};
struct SRPVerifier
{
SRP_HashAlgorithm hash_alg;
NGConstant *ng;
const char * username;
const 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;
BIGNUM *a;
BIGNUM *A;
BIGNUM *S;
const unsigned char * bytes_A;
int authenticated;
const char * username;
const unsigned char * password;
int password_len;
unsigned char M [SHA512_DIGEST_LENGTH];
unsigned char H_AMK [SHA512_DIGEST_LENGTH];
unsigned char session_key [SHA512_DIGEST_LENGTH];
};
static void hash_init( SRP_HashAlgorithm alg, HashCTX *c )
{
switch (alg)
{
case SRP_SHA1 : mbedtls_sha1_init( &c->sha );
case SRP_SHA256: mbedtls_sha256_init( &c->sha256 );
case SRP_SHA512: mbedtls_sha512_init( &c->sha512 );
default:
return;
};
}
#if 0
static void hash_start( SRP_HashAlgorithm alg, HashCTX *c )
{
switch (alg)
{
case SRP_SHA1 : mbedtls_sha1_starts( &c->sha );
case SRP_SHA224: mbedtls_sha256_starts( &c->sha256, 1 );
case SRP_SHA256: mbedtls_sha256_starts( &c->sha256, 0 );
case SRP_SHA384: mbedtls_sha512_starts( &c->sha512, 1 );
case SRP_SHA512: mbedtls_sha512_starts( &c->sha512, 0 );
default:
return;
};
}
#endif
static void hash_update( SRP_HashAlgorithm alg, HashCTX *c, const void *data, size_t len )
{
switch (alg)
{
case SRP_SHA1 : mbedtls_sha1_update( &c->sha, data, len ); break;
case SRP_SHA224: mbedtls_sha256_update( &c->sha256, data, len ); break;
case SRP_SHA256: mbedtls_sha256_update( &c->sha256, data, len ); break;
case SRP_SHA384: mbedtls_sha512_update( &c->sha512, data, len ); break;
case SRP_SHA512: mbedtls_sha512_update( &c->sha512, data, len ); break;
default:
return;
};
}
static void hash_final( SRP_HashAlgorithm alg, HashCTX *c, unsigned char *md )
{
switch (alg)
{
case SRP_SHA1 : mbedtls_sha1_finish( &c->sha, md ); break;
case SRP_SHA224: mbedtls_sha256_finish( &c->sha256, md ); break;
case SRP_SHA256: mbedtls_sha256_finish( &c->sha256, md ); break;
case SRP_SHA384: mbedtls_sha512_finish( &c->sha512, md ); break;
case SRP_SHA512: mbedtls_sha512_finish( &c->sha512, md ); break;
default:
return;
};
}
static void hash( SRP_HashAlgorithm alg, const unsigned char *d, size_t n, unsigned char *md )
{
switch (alg)
{
case SRP_SHA1 : mbedtls_sha1( d, n, md ); break;
case SRP_SHA224: mbedtls_sha256( d, n, md, 1); break;
case SRP_SHA256: mbedtls_sha256( d, n, md, 0); break;
case SRP_SHA384: mbedtls_sha512( d, n, md, 1 ); break;
case SRP_SHA512: mbedtls_sha512( d, n, md, 0 ); break;
default:
return;
};
}
static int hash_length( SRP_HashAlgorithm alg )
{
switch (alg)
{
case SRP_SHA1 : return SHA1_DIGEST_LENGTH;
case SRP_SHA224: return SHA224_DIGEST_LENGTH;
case SRP_SHA256: return SHA256_DIGEST_LENGTH;
case SRP_SHA384: return SHA384_DIGEST_LENGTH;
case SRP_SHA512: return SHA512_DIGEST_LENGTH;
default:
return -1;
};
}
static BIGNUM * H_nn( SRP_HashAlgorithm alg, const BIGNUM * n1, const BIGNUM * n2 )
{
unsigned char buff[ SHA512_DIGEST_LENGTH ];
int len_n1 = mbedtls_mpi_size(n1);
int len_n2 = mbedtls_mpi_size(n2);
int nbytes = len_n1 + len_n2;
unsigned char * bin = (unsigned char *) malloc( nbytes );
if (!bin)
return 0;
mbedtls_mpi_write_binary( n1, bin, len_n1 );
mbedtls_mpi_write_binary( n2, bin+len_n1, len_n2 );
hash( alg, bin, nbytes, buff );
free(bin);
BIGNUM * bn;
bn = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(bn);
mbedtls_mpi_read_binary( bn, buff, hash_length(alg) );
return bn;
}
static BIGNUM * H_ns( SRP_HashAlgorithm alg, const BIGNUM * n, const unsigned char * bytes, int len_bytes )
{
unsigned char buff[ SHA512_DIGEST_LENGTH ];
int len_n = mbedtls_mpi_size(n);
int nbytes = len_n + len_bytes;
unsigned char * bin = (unsigned char *) malloc( nbytes );
if (!bin)
return 0;
mbedtls_mpi_write_binary( n, bin, len_n );
memcpy( bin + len_n, bytes, len_bytes );
hash( alg, bin, nbytes, buff );
free(bin);
BIGNUM * bn;
bn = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(bn);
mbedtls_mpi_read_binary( bn, buff, hash_length(alg) );
return bn;
}
static BIGNUM * calculate_x( SRP_HashAlgorithm alg, const BIGNUM * salt, const char * username, const unsigned char * password, int password_len )
{
unsigned char ucp_hash[SHA512_DIGEST_LENGTH];
HashCTX ctx;
hash_init( alg, &ctx );
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( alg, salt, ucp_hash, hash_length(alg) );
}
static void update_hash_n( SRP_HashAlgorithm alg, HashCTX *ctx, const BIGNUM * n )
{
unsigned long len = mbedtls_mpi_size(n);
unsigned char * n_bytes = (unsigned char *) malloc( len );
if (!n_bytes)
return;
mbedtls_mpi_write_binary( n, n_bytes, len );
hash_update(alg, ctx, n_bytes, len);
free(n_bytes);
}
static void hash_num( SRP_HashAlgorithm alg, const BIGNUM * n, unsigned char * dest )
{
int nbytes = mbedtls_mpi_size(n);
unsigned char * bin = (unsigned char *) malloc( nbytes );
if(!bin)
return;
mbedtls_mpi_write_binary( n, bin, nbytes );
hash( alg, bin, nbytes, dest );
free(bin);
}
static void calculate_M( SRP_HashAlgorithm alg, NGConstant *ng, unsigned char * dest, const char * I, const BIGNUM * s,
const BIGNUM * A, const BIGNUM * 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;
int i = 0;
int 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 );
update_hash_n( alg, &ctx, s );
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 BIGNUM * 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 );
}
static void init_random()
{
if (g_initialized)
return;
mbedtls_entropy_init( &entropy_ctx );
mbedtls_ctr_drbg_init( &ctr_drbg_ctx );
unsigned char hotBits[128] = {
82, 42, 71, 87, 124, 241, 30, 1, 54, 239, 240, 121, 89, 9, 151, 11, 60,
226, 142, 47, 115, 157, 100, 126, 242, 132, 46, 12, 56, 197, 194, 76,
198, 122, 90, 241, 255, 43, 120, 209, 69, 21, 195, 212, 100, 251, 18,
111, 30, 238, 24, 199, 238, 236, 138, 225, 45, 15, 42, 83, 114, 132,
165, 141, 32, 185, 167, 100, 131, 23, 236, 9, 11, 51, 130, 136, 97, 161,
36, 174, 129, 234, 2, 54, 119, 184, 70, 103, 118, 109, 122, 15, 24, 23,
166, 203, 102, 160, 77, 100, 17, 4, 132, 138, 215, 204, 109, 245, 122,
9, 184, 89, 70, 247, 125, 97, 213, 240, 85, 243, 91, 226, 127, 64, 136,
37, 154, 232
};
mbedtls_ctr_drbg_seed(
&ctr_drbg_ctx,
mbedtls_entropy_func,
&entropy_ctx,
hotBits,
128
);
RR = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(RR);
g_initialized = 1;
}
/***********************************************************************************************************
*
* Exported Functions
*
***********************************************************************************************************/
struct SRPSession * srp_session_new( SRP_HashAlgorithm alg,
SRP_NGType ng_type,
const char * n_hex, const char * g_hex)
{
struct SRPSession * session;
session = (struct SRPSession *)malloc(sizeof(struct SRPSession));
memset(session, 0, sizeof(struct SRPSession));
session->hash_alg = alg;
session->ng = new_ng( ng_type, n_hex, g_hex );
return session;
}
void srp_session_delete(struct SRPSession *session)
{
delete_ng( session->ng );
free(session);
}
void srp_random_seed( const unsigned char * random_data, int data_length )
{
g_initialized = 1;
if( mbedtls_ctr_drbg_seed( &ctr_drbg_ctx, mbedtls_entropy_func, &entropy_ctx,
(const unsigned char *) random_data,
data_length ) != 0 )
{
return;
}
}
void srp_create_salted_verification_key( struct SRPSession *session,
const char * username,
const unsigned char * password, int len_password,
const unsigned char ** bytes_s, int * len_s,
const unsigned char ** bytes_v, int * len_v)
{
BIGNUM * s;
BIGNUM * v;
BIGNUM * x = 0;
s = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(s);
v = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(v);
if( !session || !s || !v )
goto cleanup_and_exit;
init_random(); /* Only happens once */
mbedtls_mpi_fill_random( s, 32,
&mbedtls_ctr_drbg_random,
&ctr_drbg_ctx );
x = calculate_x( session->hash_alg, s, username, password, len_password );
if( !x )
goto cleanup_and_exit;
mbedtls_mpi_exp_mod(v, session->ng->g, x, session->ng->N, RR);
*len_s = mbedtls_mpi_size(s);
*len_v = mbedtls_mpi_size(v);
*bytes_s = (const unsigned char *) malloc( *len_s );
*bytes_v = (const unsigned char *) malloc( *len_v );
if (!bytes_s || !bytes_v)
goto cleanup_and_exit;
mbedtls_mpi_write_binary( s, (unsigned char *)*bytes_s, *len_s );
mbedtls_mpi_write_binary( v, (unsigned char *)*bytes_v, *len_v );
cleanup_and_exit:
mbedtls_mpi_free(s);
free(s);
mbedtls_mpi_free(v);
free(v);
mbedtls_mpi_free(x);
free(x);
//TODO: BN_CTX_free(ctx);
}
/* 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( struct SRPSession *session,
const char *username,
const unsigned char * bytes_s, int len_s,
const unsigned char * bytes_v, int len_v,
const unsigned char * bytes_A, int len_A,
const unsigned char ** bytes_B, int * len_B)
{
BIGNUM *s;
s = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(s);
mbedtls_mpi_read_binary(s, bytes_s, len_s);
BIGNUM *v;
v = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(v);
mbedtls_mpi_read_binary(v, bytes_v, len_v);
BIGNUM *A;
A = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(A);
mbedtls_mpi_read_binary(A, bytes_A, len_A);
BIGNUM *u = 0;
BIGNUM *B;
B = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(B);
BIGNUM *S;
S = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(S);
BIGNUM *b;
b = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(b);
BIGNUM *k = 0;
BIGNUM *tmp1;
tmp1 = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(tmp1);
BIGNUM *tmp2;
tmp2 = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(tmp2);
int ulen = strlen(username) + 1;
struct SRPVerifier *ver = 0;
ver = (struct SRPVerifier *) malloc( sizeof(struct SRPVerifier) );
*len_B = 0;
*bytes_B = 0;
if( !session || !B || !S || !b || !tmp1 || !tmp2 || !ver ) {
goto cleanup_and_exit;
}
init_random(); /* Only happens once */
ver->hash_alg = session->hash_alg;
ver->ng = session->ng;
ver->username = (char *) malloc( ulen ); // FIXME
if (!ver->username)
{
free(ver);
ver = 0;
goto cleanup_and_exit;
}
memcpy( (char*)ver->username, username, ulen );
ver->authenticated = 0;
/* SRP-6a safety check */
mbedtls_mpi_mod_mpi( tmp1, A, session->ng->N );
if ( mbedtls_mpi_cmp_int( tmp1, 0 ) != 0)
{
mbedtls_mpi_fill_random( b, 256,
&mbedtls_ctr_drbg_random,
&ctr_drbg_ctx );
k = H_nn(session->hash_alg, session->ng->N, session->ng->g);
/* B = kv + g^b */
mbedtls_mpi_mul_mpi( tmp1, k, v);
mbedtls_mpi_exp_mod( tmp2, session->ng->g, b, session->ng->N, RR );
mbedtls_mpi_add_mpi( tmp1, tmp1, tmp2 );
mbedtls_mpi_mod_mpi( B, tmp1, session->ng->N );
u = H_nn(session->hash_alg, A, B);
/* S = (A *(v^u)) ^ b */
mbedtls_mpi_exp_mod(tmp1, v, u, session->ng->N, RR);
mbedtls_mpi_mul_mpi(tmp2, A, tmp1);
mbedtls_mpi_exp_mod(S, tmp2, b, session->ng->N, RR);
hash_num(session->hash_alg, S, ver->session_key);
calculate_M( session->hash_alg, session->ng, ver->M, username, s, A, B, ver->session_key );
calculate_H_AMK( session->hash_alg, ver->H_AMK, A, ver->M, ver->session_key );
*len_B = mbedtls_mpi_size(B);
*bytes_B = malloc( *len_B );
if( !*bytes_B )
{
free( (void*) ver->username );
free( ver );
ver = 0;
*len_B = 0;
goto cleanup_and_exit;
}
mbedtls_mpi_write_binary( B, (unsigned char *)*bytes_B, *len_B );
ver->bytes_B = *bytes_B;
}
cleanup_and_exit:
mbedtls_mpi_free(s);
free(s);
mbedtls_mpi_free(v);
free(v);
mbedtls_mpi_free(A);
free(A);
if (u) {mbedtls_mpi_free(u); free(u);}
if (k) {mbedtls_mpi_free(k); free(k);}
mbedtls_mpi_free(B);
free(B);
mbedtls_mpi_free(S);
free(S);
mbedtls_mpi_free(b);
free(b);
mbedtls_mpi_free(tmp1);
free(tmp1);
mbedtls_mpi_free(tmp2);
free(tmp2);
return ver;
}
void srp_verifier_delete( struct SRPVerifier * ver )
{
if (ver)
{
free( (char *) ver->username );
if(ver->bytes_B !=0) {
free( (unsigned char *) 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, int * key_length )
{
if (key_length)
*key_length = hash_length( ver->hash_alg );
return ver->session_key;
}
int 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, const 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( struct SRPSession *session, const char * username,
const unsigned char * bytes_password, int len_password)
{
struct SRPUser *usr = (struct SRPUser *) malloc( sizeof(struct SRPUser) );
int ulen = strlen(username) + 1;
if (!usr)
goto err_exit;
init_random(); /* Only happens once */
usr->hash_alg = session->hash_alg;
usr->ng = session->ng;
usr->a = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
usr->A = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
usr->S = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(usr->a);
mbedtls_mpi_init(usr->A);
mbedtls_mpi_init(usr->S);
if (!usr->ng || !usr->a || !usr->A || !usr->S)
goto err_exit;
usr->username = (const char *) malloc(ulen);
usr->password = (const unsigned char *) malloc(len_password);
usr->password_len = len_password;
if (!usr->username || !usr->password)
goto err_exit;
memcpy((char *)usr->username, username, ulen);
memcpy((char *)usr->password, bytes_password, len_password);
usr->authenticated = 0;
usr->bytes_A = 0;
return usr;
err_exit:
if (usr)
{
mbedtls_mpi_free(usr->a);
mbedtls_mpi_free(usr->A);
mbedtls_mpi_free(usr->S);
if (usr->username)
free((void*)usr->username);
if (usr->password)
{
memset((void*)usr->password, 0, usr->password_len);
free((void*)usr->password);
}
free(usr);
}
return 0;
}
void srp_user_delete( struct SRPUser * usr )
{
if( usr )
{
mbedtls_mpi_free( usr->a );
mbedtls_mpi_free( usr->A );
mbedtls_mpi_free( usr->S );
memset((void*)usr->password, 0, usr->password_len);
free((char *)usr->username);
free((char *)usr->password);
if (usr->bytes_A)
free( (char *)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, int * key_length )
{
if (key_length)
*key_length = hash_length( usr->hash_alg );
return usr->session_key;
}
int 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, const char ** username,
const unsigned char ** bytes_A, int * len_A )
{
mbedtls_mpi_fill_random( usr->a, 256, &mbedtls_ctr_drbg_random, &ctr_drbg_ctx);
mbedtls_mpi_exp_mod(usr->A, usr->ng->g, usr->a, usr->ng->N, RR);
*len_A = mbedtls_mpi_size(usr->A);
*bytes_A = malloc( *len_A );
if (!*bytes_A)
{
*len_A = 0;
*bytes_A = 0;
*username = 0;
return;
}
mbedtls_mpi_write_binary( usr->A, (unsigned char *) *bytes_A, *len_A );
usr->bytes_A = *bytes_A;
*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, int len_s,
const unsigned char * bytes_B, int len_B,
const unsigned char ** bytes_M, int * len_M )
{
BIGNUM *u = 0;
BIGNUM *x = 0;
BIGNUM *k = 0;
BIGNUM *s;
s = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(s);
mbedtls_mpi_read_binary(s, bytes_s, len_s);
BIGNUM *B;
B = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(B);
mbedtls_mpi_read_binary(B, bytes_B, len_B);
BIGNUM *v;
v = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(v);
BIGNUM *tmp1;
tmp1 = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(tmp1);
BIGNUM *tmp2;
tmp2 = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(tmp2);
BIGNUM *tmp3;
tmp3 = (mbedtls_mpi *) malloc(sizeof(mbedtls_mpi));
mbedtls_mpi_init(tmp3);
*len_M = 0;
*bytes_M = 0;
if( !s || !B || !v || !tmp1 || !tmp2 || !tmp3 )
goto cleanup_and_exit;
u = H_nn(usr->hash_alg, usr->A, B);
if (!u)
goto cleanup_and_exit;
x = calculate_x( usr->hash_alg, s, usr->username, usr->password, usr->password_len );
if (!x)
goto cleanup_and_exit;
k = H_nn(usr->hash_alg, usr->ng->N, usr->ng->g);
if (!k)
goto cleanup_and_exit;
/* SRP-6a safety check */
if( mbedtls_mpi_cmp_int( B, 0 ) != 0 && mbedtls_mpi_cmp_int( u, 0 ) !=0 )
{
mbedtls_mpi_exp_mod(v, usr->ng->g, x, usr->ng->N, RR);
/* S = (B - k*(g^x)) ^ (a + ux) */
mbedtls_mpi_mul_mpi( tmp1, u, x );
mbedtls_mpi_mod_mpi( tmp1, tmp1, usr->ng->N);
mbedtls_mpi_add_mpi( tmp2, usr->a, tmp1);
mbedtls_mpi_mod_mpi( tmp2, tmp2, usr->ng->N);
/* tmp2 = (a + ux) */
mbedtls_mpi_exp_mod( tmp1, usr->ng->g, x, usr->ng->N, RR);
mbedtls_mpi_mul_mpi( tmp3, k, tmp1 );
mbedtls_mpi_mod_mpi( tmp3, tmp3, usr->ng->N);
/* tmp3 = k*(g^x) */
mbedtls_mpi_sub_mpi(tmp1, B, tmp3);
/* tmp1 = (B - K*(g^x)) */
mbedtls_mpi_exp_mod( usr->S, tmp1, tmp2, usr->ng->N, RR);
hash_num(usr->hash_alg, usr->S, usr->session_key);
calculate_M( usr->hash_alg, usr->ng, usr->M, usr->username, 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:
mbedtls_mpi_free(s);
mbedtls_mpi_free(B);
mbedtls_mpi_free(u);
mbedtls_mpi_free(x);
mbedtls_mpi_free(k);
mbedtls_mpi_free(v);
mbedtls_mpi_free(tmp1);
mbedtls_mpi_free(tmp2);
mbedtls_mpi_free(tmp3);
free(s);
free(B);
free(u);
free(x);
free(k);
free(v);
free(tmp1);
free(tmp2);
free(tmp3);
}
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;
}
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