#include #include #include #include #include #include #include #include /*****************************************************************************/ /* Begin SRP Header */ /*****************************************************************************/ struct SRPVerifier; struct SRPUser; typedef enum { SRP_NG_1024, SRP_NG_2048, SRP_NG_4096, SRP_NG_8192, SRP_NG_CUSTOM } SRP_NGType; typedef enum { SRP_SHA1, SRP_SHA224, SRP_SHA256, SRP_SHA384, SRP_SHA512 } SRP_HashAlgorithm; /* This library will automatically seed the OpenSSL random number generator * using cryptographically sound random data on Windows & Linux. If this is * undesirable behavior or the host OS does not provide a /dev/urandom file, * this function may be called to seed the random number generator with * alternate data. * * Passing a null pointer to this function will cause this library to skip * seeding the random number generator. * * Notes: * * This function is optional on Windows & Linux. * * * This function is mandatory on all other platforms. Although it * will appear to work on other platforms, this library uses the current * time of day to seed the random number generator. This is well known to * be insecure. * * * When using this function, ensure the provided random data is * cryptographically strong. */ void srp_random_seed( const unsigned char * random_data, int data_length ); /* Out: bytes_s, len_s, bytes_v, len_v * * The caller is responsible for freeing the memory allocated for bytes_s and bytes_v * * The n_hex and g_hex parameters should be 0 unless SRP_NG_CUSTOM is used for ng_type. * If provided, they must contain ASCII text of the hexidecimal notation. */ void srp_create_salted_verification_key( SRP_HashAlgorithm alg, SRP_NGType ng_type, 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, const char * n_hex, const char * g_hex ); /* Out: bytes_B, len_B. * * On failure, bytes_B will be set to NULL and len_B will be set to 0 * * The n_hex and g_hex parameters should be 0 unless SRP_NG_CUSTOM is used for ng_type */ struct SRPVerifier * srp_verifier_new( SRP_HashAlgorithm alg, SRP_NGType ng_type, 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, const char * n_hex, const char * g_hex ); void srp_verifier_delete( struct SRPVerifier * ver ); int srp_verifier_is_authenticated( struct SRPVerifier * ver ); const char * srp_verifier_get_username( struct SRPVerifier * ver ); /* key_length may be null */ const unsigned char * srp_verifier_get_session_key( struct SRPVerifier * ver, int * key_length ); int srp_verifier_get_session_key_length( struct SRPVerifier * ver ); /* user_M must be exactly srp_verifier_get_session_key_length() bytes in size */ void srp_verifier_verify_session( struct SRPVerifier * ver, const unsigned char * user_M, const unsigned char ** bytes_HAMK ); /*******************************************************************************/ /* The n_hex and g_hex parameters should be 0 unless SRP_NG_CUSTOM is used for ng_type */ struct SRPUser * srp_user_new( SRP_HashAlgorithm alg, SRP_NGType ng_type, const char * username, const unsigned char * bytes_password, int len_password, const char * n_hex, const char * g_hex ); void srp_user_delete( struct SRPUser * usr ); int srp_user_is_authenticated( struct SRPUser * usr); const char * srp_user_get_username( struct SRPUser * usr ); /* key_length may be null */ const unsigned char * srp_user_get_session_key( struct SRPUser * usr, int * key_length ); int srp_user_get_session_key_length( struct SRPUser * usr ); /* 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 ); /* Output: bytes_M, len_M (len_M may be null and will always be * srp_user_get_session_key_length() bytes in size) */ 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 ); /* bytes_HAMK must be exactly srp_user_get_session_key_length() bytes in size */ void srp_user_verify_session( struct SRPUser * usr, const unsigned char * bytes_HAMK ); /*****************************************************************************/ /* Begin SRP Library */ /*****************************************************************************/ static int g_initialized = 0; 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[] = { { /* 1024 */ "EEAF0AB9ADB38DD69C33F80AFA8FC5E86072618775FF3C0B9EA2314C9C256576D674DF7496" "EA81D3383B4813D692C6E0E0D5D8E250B98BE48E495C1D6089DAD15DC7D7B46154D6B6CE8E" "F4AD69B15D4982559B297BCF1885C529F566660E57EC68EDBC3C05726CC02FD4CBF4976EAA" "9AFD5138FE8376435B9FC61D2FC0EB06E3", "2" }, { /* 2048 */ "AC6BDB41324A9A9BF166DE5E1389582FAF72B6651987EE07FC3192943DB56050A37329CBB4" "A099ED8193E0757767A13DD52312AB4B03310DCD7F48A9DA04FD50E8083969EDB767B0CF60" "95179A163AB3661A05FBD5FAAAE82918A9962F0B93B855F97993EC975EEAA80D740ADBF4FF" "747359D041D5C33EA71D281E446B14773BCA97B43A23FB801676BD207A436C6481F1D2B907" "8717461A5B9D32E688F87748544523B524B0D57D5EA77A2775D2ECFA032CFBDBF52FB37861" "60279004E57AE6AF874E7303CE53299CCC041C7BC308D82A5698F3A8D0C38271AE35F8E9DB" "FBB694B5C803D89F7AE435DE236D525F54759B65E372FCD68EF20FA7111F9E4AFF73", "2" }, {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}, {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}, {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 = BN_new(); ng->g = BN_new(); if ( ng_type != SRP_NG_CUSTOM ) { n_hex = global_Ng_constants[ ng_type ].n_hex; g_hex = global_Ng_constants[ ng_type ].g_hex; } BN_hex2bn( &ng->N, n_hex ); BN_hex2bn( &ng->g, g_hex ); return ng; } static void delete_ng( NGConstant * ng ) { BN_free( ng->N ); BN_free( ng->g ); ng->N = 0; ng->g = 0; free(ng); } typedef union { SHA_CTX sha; SHA256_CTX sha256; SHA512_CTX sha512; } HashCTX; 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 int hash_init( SRP_HashAlgorithm alg, HashCTX *c ) { switch (alg) { case SRP_SHA1 : return SHA1_Init( &c->sha ); case SRP_SHA224: return SHA224_Init( &c->sha256 ); case SRP_SHA256: return SHA256_Init( &c->sha256 ); 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) { case SRP_SHA1 : return SHA1_Update( &c->sha, data, len ); case SRP_SHA224: return SHA224_Update( &c->sha256, data, len ); case SRP_SHA256: return SHA256_Update( &c->sha256, data, len ); 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) { case SRP_SHA1 : return SHA1_Final( md, &c->sha ); case SRP_SHA224: return SHA224_Final( md, &c->sha256 ); case SRP_SHA256: return SHA256_Final( md, &c->sha256 ); 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) { case SRP_SHA1 : return SHA1( d, n, md ); case SRP_SHA224: return SHA224( d, n, md ); case SRP_SHA256: return SHA256( d, n, md ); case SRP_SHA384: return SHA384( d, n, md ); case SRP_SHA512: return SHA512( d, n, md ); default: return 0; }; } static int hash_length( SRP_HashAlgorithm alg ) { switch (alg) { case SRP_SHA1 : return SHA_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 = BN_num_bytes(n1); int len_n2 = BN_num_bytes(n2); int nbytes = len_n1 + len_n2; unsigned char * bin = (unsigned char *) malloc( nbytes ); BN_bn2bin(n1, bin); BN_bn2bin(n2, bin + len_n1); hash( alg, bin, nbytes, buff ); free(bin); return BN_bin2bn(buff, hash_length(alg), NULL); } 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 = BN_num_bytes(n); int nbytes = len_n + len_bytes; unsigned char * bin = (unsigned char *) malloc( nbytes ); BN_bn2bin(n, bin); memcpy( bin + len_n, bytes, len_bytes ); hash( alg, bin, nbytes, buff ); free(bin); return BN_bin2bn(buff, hash_length(alg), NULL); } 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 = BN_num_bytes(n); unsigned char * n_bytes = (unsigned char *) malloc( len ); BN_bn2bin(n, n_bytes); 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 = BN_num_bytes(n); unsigned char * bin = (unsigned char *) malloc( nbytes ); BN_bn2bin(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 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 ); } /* Python module calls random_seed during module initialization */ #define init_random() /*********************************************************************************************************** * * Exported Functions * ***********************************************************************************************************/ void srp_random_seed( const unsigned char * random_data, int data_length ) { g_initialized = 1; if (random_data) RAND_seed( random_data, data_length ); } void srp_create_salted_verification_key( SRP_HashAlgorithm alg, SRP_NGType ng_type, 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, const char * n_hex, const char * g_hex ) { BIGNUM * s = BN_new(); BIGNUM * v = BN_new(); BIGNUM * x = 0; BN_CTX * ctx = BN_CTX_new(); NGConstant * ng = new_ng( ng_type, n_hex, g_hex ); init_random(); /* Only happens once */ BN_rand(s, 32, -1, 0); x = calculate_x( alg, s, username, password, len_password ); BN_mod_exp(v, ng->g, x, ng->N, ctx); *len_s = BN_num_bytes(s); *len_v = BN_num_bytes(v); *bytes_s = (const unsigned char *) malloc( *len_s ); *bytes_v = (const unsigned char *) malloc( *len_v ); BN_bn2bin(s, (unsigned char *) *bytes_s); BN_bn2bin(v, (unsigned char *) *bytes_v); delete_ng( ng ); BN_free(s); BN_free(v); BN_free(x); 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( SRP_HashAlgorithm alg, SRP_NGType ng_type, 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, const char * n_hex, const char * g_hex ) { BIGNUM *s = BN_bin2bn(bytes_s, len_s, NULL); BIGNUM *v = BN_bin2bn(bytes_v, len_v, NULL); BIGNUM *A = BN_bin2bn(bytes_A, len_A, NULL); BIGNUM *u = 0; BIGNUM *B = BN_new(); BIGNUM *S = BN_new(); BIGNUM *b = BN_new(); BIGNUM *k = 0; BIGNUM *tmp1 = BN_new(); BIGNUM *tmp2 = BN_new(); BN_CTX *ctx = BN_CTX_new(); int ulen = strlen(username) + 1; NGConstant *ng = new_ng( ng_type, n_hex, g_hex ); struct SRPVerifier * ver = (struct SRPVerifier *) malloc( sizeof(struct SRPVerifier) ); init_random(); /* Only happens once */ ver->username = (char *) malloc( ulen ); ver->hash_alg = alg; ver->ng = ng; memcpy( (char*)ver->username, username, ulen ); ver->authenticated = 0; /* SRP-6a safety check */ BN_mod(tmp1, A, ng->N, ctx); if ( !BN_is_zero(tmp1) ) { BN_rand(b, 256, -1, 0); k = H_nn(alg, ng->N, ng->g); /* B = kv + g^b */ BN_mul(tmp1, k, v, ctx); BN_mod_exp(tmp2, ng->g, b, ng->N, ctx); BN_add(B, tmp1, tmp2); u = H_nn(alg, A, B); /* S = (A *(v^u)) ^ b */ BN_mod_exp(tmp1, v, u, ng->N, ctx); BN_mul(tmp2, A, tmp1, ctx); BN_mod_exp(S, tmp2, b, ng->N, ctx); hash_num(alg, S, ver->session_key); calculate_M( alg, ng, ver->M, username, s, A, B, ver->session_key ); calculate_H_AMK( alg, ver->H_AMK, A, ver->M, ver->session_key ); *len_B = BN_num_bytes(B); *bytes_B = malloc( *len_B ); BN_bn2bin( B, (unsigned char *) *bytes_B ); ver->bytes_B = *bytes_B; } else { *len_B = 0; *bytes_B = NULL; } BN_free(s); BN_free(v); BN_free(A); if (u) BN_free(u); if (k) BN_free(k); BN_free(B); BN_free(S); BN_free(b); BN_free(tmp1); BN_free(tmp2); BN_CTX_free(ctx); return ver; } void srp_verifier_delete( struct SRPVerifier * ver ) { delete_ng( ver->ng ); free( (char *) ver->username ); free( (unsigned char *) ver->bytes_B ); 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( SRP_HashAlgorithm alg, SRP_NGType ng_type, const char * username, const unsigned char * bytes_password, int len_password, const char * n_hex, const char * g_hex ) { struct SRPUser *usr = (struct SRPUser *) malloc( sizeof(struct SRPUser) ); int ulen = strlen(username) + 1; init_random(); /* Only happens once */ usr->hash_alg = alg; usr->ng = new_ng( ng_type, n_hex, g_hex ); usr->a = BN_new(); usr->A = BN_new(); usr->S = BN_new(); usr->username = (const char *) malloc(ulen); usr->password = (const unsigned char *) malloc(len_password); usr->password_len = len_password; memcpy((char *)usr->username, username, ulen); memcpy((char *)usr->password, bytes_password, len_password); usr->authenticated = 0; usr->bytes_A = 0; return usr; } void srp_user_delete( struct SRPUser * usr ) { BN_free( usr->a ); BN_free( usr->A ); BN_free( usr->S ); delete_ng( usr->ng ); free((char *)usr->username); free((char *)usr->password); if (usr->bytes_A) free( (char *)usr->bytes_A ); 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 ) { BN_CTX *ctx = BN_CTX_new(); BN_rand(usr->a, 256, -1, 0); BN_mod_exp(usr->A, usr->ng->g, usr->a, usr->ng->N, ctx); BN_CTX_free(ctx); *len_A = BN_num_bytes(usr->A); *bytes_A = malloc( *len_A ); BN_bn2bin( usr->A, (unsigned char *) *bytes_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 *s = BN_bin2bn(bytes_s, len_s, NULL); BIGNUM *B = BN_bin2bn(bytes_B, len_B, NULL); BIGNUM *u = 0; BIGNUM *x = 0; BIGNUM *k = 0; BIGNUM *v = BN_new(); BIGNUM *tmp1 = BN_new(); BIGNUM *tmp2 = BN_new(); BIGNUM *tmp3 = BN_new(); BN_CTX *ctx = BN_CTX_new(); u = H_nn(usr->hash_alg, usr->A, B); x = calculate_x( usr->hash_alg, s, usr->username, usr->password, usr->password_len ); k = H_nn(usr->hash_alg, usr->ng->N, usr->ng->g); /* SRP-6a safety check */ if ( !BN_is_zero(B) && !BN_is_zero(u) ) { BN_mod_exp(v, usr->ng->g, x, usr->ng->N, ctx); /* S = (B - k*(g^x)) ^ (a + ux) */ BN_mul(tmp1, u, x, ctx); BN_add(tmp2, usr->a, tmp1); /* tmp2 = (a + ux) */ BN_mod_exp(tmp1, usr->ng->g, x, usr->ng->N, ctx); BN_mul(tmp3, k, tmp1, ctx); /* tmp3 = k*(g^x) */ BN_sub(tmp1, B, tmp3); /* tmp1 = (B - K*(g^x)) */ BN_mod_exp(usr->S, tmp1, tmp2, usr->ng->N, ctx); 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; } BN_free(s); BN_free(B); BN_free(u); BN_free(x); BN_free(k); BN_free(v); BN_free(tmp1); BN_free(tmp2); BN_free(tmp3); BN_CTX_free(ctx); } 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; } /****************************************************************************** * * Python Module * *****************************************************************************/ typedef struct { PyObject_HEAD struct SRPVerifier * ver; const unsigned char * bytes_B; const unsigned char * bytes_s; int len_B; int len_s; }PyVerifier; typedef struct { PyObject_HEAD struct SRPUser * usr; }PyUser; static void ver_dealloc( PyVerifier * self ) { if ( self->ver != NULL ) srp_verifier_delete( self->ver ); if ( self->bytes_s != NULL ) free( (char *)self->bytes_s ); self->ob_type->tp_free( (PyObject *) self ); } static void usr_dealloc( PyUser * self ) { if ( self->usr != NULL ) srp_user_delete( self->usr ); self->ob_type->tp_free( (PyObject *) self ); } static PyObject * ver_new(PyTypeObject *type, PyObject *args, PyObject *kwds) { PyVerifier *self = (PyVerifier *) type->tp_alloc(type, 0); if (!self) return NULL; self->ver = NULL; self->bytes_B = NULL; self->bytes_s = NULL; self->len_B = 0; self->len_s = 0; return (PyObject *) self; } static PyObject * usr_new(PyTypeObject *type, PyObject *args, PyObject *kwds) { PyUser *self = (PyUser *) type->tp_alloc(type, 0); if (!self) return NULL; self->usr = NULL; return (PyObject *) self; } static int ver_init( PyVerifier *self, PyObject *args, PyObject *kwds ) { const char *username; const unsigned char *bytes_s, *bytes_v, *bytes_A; int len_s, len_v, len_A; int hash_alg = SRP_SHA1; int ng_type = SRP_NG_2048; const char *n_hex = 0; const char *g_hex = 0; static char * kwnames[] = { "username", "bytes_s", "bytes_v", "bytes_A", "hash_alg", "ng_type", "n_hex", "g_hex", NULL }; if ( self->ver != NULL ) { PyErr_SetString(PyExc_TypeError, "Type cannot be re-initialized"); return -1; } if ( ! PyArg_ParseTupleAndKeywords(args, kwds, "st#t#t#|iiss", kwnames, &username, &bytes_s, &len_s, &bytes_v, &len_v, &bytes_A, &len_A, &hash_alg, &ng_type, &n_hex, &g_hex ) ) { return -1; } if ( hash_alg < SRP_SHA1 || hash_alg > SRP_SHA512 ) { PyErr_SetString(PyExc_ValueError, "Invalid Hash Algorithm"); return -1; } if ( ng_type < SRP_NG_1024 || ng_type > SRP_NG_CUSTOM ) { PyErr_SetString(PyExc_ValueError, "Invalid Prime Number Constant"); return -1; } if ( ng_type == SRP_NG_CUSTOM && ( !n_hex || !g_hex ) ) { PyErr_SetString(PyExc_ValueError, "Both n_hex and g_hex are required when ng_type = NG_CUSTOM"); return -1; } /* The srp_verifier_new command is computationally intensive. Allowing multiple, * simultaneous calls here will speed things up for multi-cpu machines */ Py_BEGIN_ALLOW_THREADS self->ver = srp_verifier_new( (SRP_HashAlgorithm) hash_alg, (SRP_NGType) ng_type, username, bytes_s, len_s, bytes_v, len_v, bytes_A, len_A, &self->bytes_B, &self->len_B, n_hex, g_hex ); Py_END_ALLOW_THREADS if ( self->bytes_B == NULL ) { PyErr_SetString(PyExc_Exception, "SRP-6a safety check violated"); return -1; } self->bytes_s = malloc( len_s ); self->len_s = len_s; memcpy( (char *)self->bytes_s, bytes_s, len_s ); return 0; } static int usr_init( PyUser *self, PyObject *args, PyObject *kwds ) { const char *username = 0; const unsigned char *bytes_password = 0; int len_password = 0; int hash_alg = SRP_SHA1; int ng_type = SRP_NG_2048; const char *n_hex = 0; const char *g_hex = 0; static char * kwnames[] = { "username", "password", "hash_alg", "ng_type", "n_hex", "g_hex", NULL }; if ( self->usr != NULL ) { PyErr_SetString(PyExc_TypeError, "Type cannot be re-initialized"); return -1; } if ( ! PyArg_ParseTupleAndKeywords(args, kwds, "st#|iiss", kwnames, &username, &bytes_password, &len_password, &hash_alg, &ng_type, &n_hex, &g_hex) ) { return -1; } if ( hash_alg < SRP_SHA1 || hash_alg > SRP_SHA512 ) { PyErr_SetString(PyExc_ValueError, "Invalid Hash Algorithm"); return -1; } if ( ng_type < SRP_NG_1024 || ng_type > SRP_NG_CUSTOM ) { PyErr_SetString(PyExc_ValueError, "Invalid Prime Number Constant"); return -1; } if ( ng_type == SRP_NG_CUSTOM && ( !n_hex || !g_hex ) ) { PyErr_SetString(PyExc_ValueError, "Both n_hex and g_hex are required when ng_type = NG_CUSTOM"); return -1; } self->usr = srp_user_new( (SRP_HashAlgorithm) hash_alg, (SRP_NGType) ng_type, username, bytes_password, len_password, n_hex, g_hex ); return 0; } static PyObject * ver_is_authenticated( PyVerifier * self ) { if ( self->ver == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } if ( srp_verifier_is_authenticated(self->ver) ) Py_RETURN_TRUE; else Py_RETURN_FALSE; } static PyObject * usr_is_authenticated( PyUser * self ) { if ( self->usr == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } if ( srp_user_is_authenticated(self->usr) ) Py_RETURN_TRUE; else Py_RETURN_FALSE; } static PyObject * ver_get_username( PyVerifier * self ) { if ( self->ver == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } return PyString_FromString( srp_verifier_get_username(self->ver) ); } static PyObject * usr_get_username( PyUser * self ) { if ( self->usr == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } return PyString_FromString( srp_user_get_username(self->usr) ); } static PyObject * ver_get_session_key( PyVerifier * self ) { if ( self->ver == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } if ( srp_verifier_is_authenticated(self->ver) ) { int key_len; const char * u = (const char *)srp_verifier_get_session_key(self->ver, &key_len); return PyString_FromStringAndSize(u, key_len); } else Py_RETURN_NONE; } static PyObject * usr_get_session_key( PyUser * self ) { if ( self->usr == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } if ( srp_user_is_authenticated(self->usr) ) { int key_len; const char * u = (const char *) srp_user_get_session_key(self->usr, &key_len); return PyString_FromStringAndSize(u, key_len); } else Py_RETURN_NONE; } static PyObject * ver_get_challenge( PyVerifier * self ) { if ( self->ver == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } if ( self->bytes_B == NULL ) { PyErr_SetString(PyExc_Exception, "SRP-6a security check failed"); return NULL; } return Py_BuildValue("s#s#", self->bytes_s, self->len_s, self->bytes_B, self->len_B); } static PyObject * ver_verify_session( PyVerifier * self, PyObject * args ) { const unsigned char * bytes_M; const unsigned char * bytes_HAMK; int len_M; if ( self->ver == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } if ( ! PyArg_ParseTuple(args, "t#", &bytes_M, &len_M) ) { return NULL; } if ( len_M != srp_verifier_get_session_key_length( self->ver ) ) Py_RETURN_NONE; srp_verifier_verify_session( self->ver, bytes_M, &bytes_HAMK ); if ( bytes_HAMK == NULL ) Py_RETURN_NONE; else return PyString_FromStringAndSize((const char *) bytes_HAMK, srp_verifier_get_session_key_length( self->ver )); } static PyObject * usr_start_authentication( PyUser * self ) { const char * username; const unsigned char * bytes_A; int len_A; if ( self->usr == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } srp_user_start_authentication( self->usr, &username, &bytes_A, &len_A ); return Py_BuildValue("ss#", username, bytes_A, len_A); } static PyObject * usr_process_challenge( PyUser * self, PyObject * args ) { const unsigned char * bytes_s, *bytes_B; int len_s, len_B, len_M; const unsigned char * bytes_M; if ( self->usr == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } if ( ! PyArg_ParseTuple(args, "t#t#", &bytes_s, &len_s, &bytes_B, &len_B) ) { return NULL; } /* The srp_user_process_challenge command is computationally intensive. * Allowing multiple, simultaneous calls here will speed things up on * multi-cpu machines. */ Py_BEGIN_ALLOW_THREADS srp_user_process_challenge( self->usr, bytes_s, len_s, bytes_B, len_B, &bytes_M, &len_M ); Py_END_ALLOW_THREADS if (bytes_M == NULL) Py_RETURN_NONE; else return PyString_FromStringAndSize((const char *) bytes_M, len_M); } static PyObject * usr_verify_session( PyUser * self, PyObject * args ) { const unsigned char * bytes_HAMK; int len_HAMK; if ( self->usr == NULL ) { PyErr_SetString(PyExc_Exception, "Type not initialized"); return NULL; } if ( ! PyArg_ParseTuple(args, "t#", &bytes_HAMK, &len_HAMK) ) { return NULL; } if ( len_HAMK == srp_user_get_session_key_length( self->usr ) ) srp_user_verify_session( self->usr, bytes_HAMK ); Py_RETURN_NONE; } static PyObject * py_create_salted_verification_key( PyObject *self, PyObject *args, PyObject *kwds ) { PyObject *ret; const char *username; const unsigned char *bytes_password, *bytes_s, *bytes_v; int len_password, len_s, len_v; int hash_alg = SRP_SHA1; int ng_type = SRP_NG_2048; const char *n_hex = 0; const char *g_hex = 0; static char * kwnames[] = { "username", "password", "hash_alg", "ng_type", "n_hex", "g_hex", NULL }; if ( ! PyArg_ParseTupleAndKeywords(args, kwds, "st#|iiss", kwnames, &username, &bytes_password, &len_password, &hash_alg, &ng_type, &n_hex, &g_hex) ) return NULL; if ( hash_alg < SRP_SHA1 || hash_alg > SRP_SHA512 ) { PyErr_SetString(PyExc_ValueError, "Invalid Hash Algorithm"); return NULL; } if ( ng_type < SRP_NG_1024 || ng_type > SRP_NG_CUSTOM ) { PyErr_SetString(PyExc_ValueError, "Invalid Prime Number Constant"); return NULL; } if ( ng_type == SRP_NG_CUSTOM && ( !n_hex || !g_hex ) ) { PyErr_SetString(PyExc_ValueError, "Both n_hex and g_hex are required when ng_type = NG_CUSTOM"); return NULL; } srp_create_salted_verification_key( (SRP_HashAlgorithm) hash_alg, (SRP_NGType) ng_type, username, bytes_password, len_password, &bytes_s, &len_s, &bytes_v, &len_v, n_hex, g_hex ); ret = Py_BuildValue("s#s#", bytes_s, len_s, bytes_v, len_v); free((char*)bytes_s); free((char*)bytes_v); return ret; } /***********************************************************************************/ static PyMethodDef PyVerifier_methods[] = { {"authenticated", (PyCFunction) ver_is_authenticated, METH_NOARGS, PyDoc_STR("Returns boolean indicating whether the session is " "authenticated or not") }, {"get_username", (PyCFunction) ver_get_username, METH_NOARGS, PyDoc_STR("Returns the username the Verifier instance is bound to.") }, {"get_session_key", (PyCFunction) ver_get_session_key, METH_NOARGS, PyDoc_STR("Returns the session key for an authenticated session. " "Returns None if the session is not authenticated.") }, {"get_challenge", (PyCFunction) ver_get_challenge, METH_NOARGS, PyDoc_STR("Returns: (s,B) or None. The salt & challenge that " "should be sent to the user or None if the SRP-6a " "safety check fails.") }, {"verify_session", (PyCFunction) ver_verify_session, METH_VARARGS, PyDoc_STR("Verifies the user based on their reply to " "the challenge") }, {NULL} /* Sentinel */ }; static PyMethodDef PyUser_methods[] = { {"authenticated", (PyCFunction) usr_is_authenticated, METH_NOARGS, PyDoc_STR("Returns boolean indicating whether the session is " "authenticated or not") }, {"get_username", (PyCFunction) usr_get_username, METH_NOARGS, PyDoc_STR("Returns the username the User instance is bound to.") }, {"get_session_key", (PyCFunction) usr_get_session_key, METH_NOARGS, PyDoc_STR("Returns the session key for an authenticated session. " "Returns None if the session is not authenticated.") }, {"start_authentication", (PyCFunction) usr_start_authentication, METH_NOARGS, PyDoc_STR("Returns (username,A). The username and initial " "authentication challenge to send to the verifier") }, {"process_challenge", (PyCFunction) usr_process_challenge, METH_VARARGS, PyDoc_STR("Returns the reply to send to the server or None if the " "SRP-6a safety check fails") }, {"verify_session", (PyCFunction) usr_verify_session, METH_VARARGS, PyDoc_STR("Verifies the server based on its reply to the users " "challenge response") }, {NULL} /* Sentinel */ }; static PyMethodDef srp_module_methods[] = { {"create_salted_verification_key", (PyCFunction) py_create_salted_verification_key, METH_VARARGS | METH_KEYWORDS, PyDoc_STR("Returns (s,v): Generates a salt & verifier for the " "given username and password") }, {NULL} /* Sentinel */ }; static PyTypeObject PyVerifier_Type = { PyVarObject_HEAD_INIT(NULL, 0) "srp._srp.Verifier", /*tp_name*/ sizeof(PyVerifier), /*tp_basicsize*/ 0, /*tp_itemsize*/ /* methods */ (destructor)ver_dealloc, /*tp_dealloc*/ 0, /*tp_print*/ 0, /*tp_getattr*/ 0, /*tp_setattr*/ 0, /*tp_compare*/ 0, /*tp_repr*/ 0, /*tp_as_number*/ 0, /*tp_as_sequence*/ 0, /*tp_as_mapping*/ 0, /*tp_hash*/ 0, /*tp_call*/ 0, /*tp_str*/ 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ Py_TPFLAGS_DEFAULT, /*tp_flags*/ "SRP-6a verfier", /*tp_doc*/ 0, /*tp_traverse*/ 0, /*tp_clear*/ 0, /*tp_richcompare*/ 0, /*tp_weaklistoffset*/ 0, /*tp_iter*/ 0, /*tp_iternext*/ PyVerifier_methods, /*tp_methods*/ 0, /*tp_members*/ 0, /*tp_getset*/ 0, /*tp_base*/ 0, /*tp_dict*/ 0, /*tp_descr_get*/ 0, /*tp_descr_set*/ 0, /*tp_dictoffset*/ (initproc)ver_init, /*tp_init*/ 0, /*tp_alloc*/ ver_new, /*tp_new*/ 0, /*tp_free*/ 0, /*tp_is_gc*/ }; static PyTypeObject PyUser_Type = { PyVarObject_HEAD_INIT(NULL, 0) "srp._srp.User", /*tp_name*/ sizeof(PyUser), /*tp_basicsize*/ 0, /*tp_itemsize*/ /* methods */ (destructor)usr_dealloc, /*tp_dealloc*/ 0, /*tp_print*/ 0, /*tp_getattr*/ 0, /*tp_setattr*/ 0, /*tp_compare*/ 0, /*tp_repr*/ 0, /*tp_as_number*/ 0, /*tp_as_sequence*/ 0, /*tp_as_mapping*/ 0, /*tp_hash*/ 0, /*tp_call*/ 0, /*tp_str*/ 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ Py_TPFLAGS_DEFAULT, /*tp_flags*/ "SRP-6a User", /*tp_doc*/ 0, /*tp_traverse*/ 0, /*tp_clear*/ 0, /*tp_richcompare*/ 0, /*tp_weaklistoffset*/ 0, /*tp_iter*/ 0, /*tp_iternext*/ PyUser_methods, /*tp_methods*/ 0, /*tp_members*/ 0, /*tp_getset*/ 0, /*tp_base*/ 0, /*tp_dict*/ 0, /*tp_descr_get*/ 0, /*tp_descr_set*/ 0, /*tp_dictoffset*/ (initproc)usr_init, /*tp_init*/ 0, /*tp_alloc*/ usr_new, /*tp_new*/ 0, /*tp_free*/ 0, /*tp_is_gc*/ }; PyMODINIT_FUNC init_srp(void) { int init_ok = 0; PyObject *m = NULL; PyObject *os = NULL; PyObject *py_urandom = NULL; os = PyImport_ImportModule("os"); if (os == NULL) return; py_urandom = PyObject_GetAttrString(os, "urandom"); if ( py_urandom && PyCallable_Check(py_urandom) ) { PyObject *args = Py_BuildValue("(i)", 32); if ( args ) { PyObject *randstr = PyObject_CallObject(py_urandom, args); if ( randstr && PyString_Check(randstr)) { char *buff = NULL; Py_ssize_t slen = 0; if (!PyString_AsStringAndSize(randstr, &buff, &slen)) { srp_random_seed( (const unsigned char *)buff, slen ); init_ok = 1; } } Py_XDECREF(randstr); } Py_XDECREF(args); } Py_XDECREF(os); Py_XDECREF(py_urandom); if (!init_ok) { PyErr_SetString(PyExc_ImportError, "Initialization failed"); return; } if (PyType_Ready(&PyVerifier_Type) < 0 || PyType_Ready(&PyUser_Type) < 0) return; m = Py_InitModule3("srp._srp", srp_module_methods,"SRP-6a implementation"); if (m == NULL) return; Py_INCREF(&PyVerifier_Type); Py_INCREF(&PyUser_Type); PyModule_AddObject(m, "Verifier", (PyObject*) &PyVerifier_Type ); PyModule_AddObject(m, "User", (PyObject*) &PyUser_Type ); PyModule_AddIntConstant(m, "NG_1024", SRP_NG_1024); PyModule_AddIntConstant(m, "NG_2048", SRP_NG_2048); PyModule_AddIntConstant(m, "NG_4096", SRP_NG_4096); PyModule_AddIntConstant(m, "NG_8192", SRP_NG_8192); PyModule_AddIntConstant(m, "NG_CUSTOM", SRP_NG_CUSTOM); PyModule_AddIntConstant(m, "SHA1", SRP_SHA1); PyModule_AddIntConstant(m, "SHA224", SRP_SHA224); PyModule_AddIntConstant(m, "SHA256", SRP_SHA256); PyModule_AddIntConstant(m, "SHA384", SRP_SHA384); PyModule_AddIntConstant(m, "SHA512", SRP_SHA512); }