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path: root/builtin/mainmenu/common.lua
Commit message (Collapse)AuthorAge
* Fix core.wrap_text and make its behaviour consistent with the docssfan52017-09-12
| | | | Code based on initial implementation by @dsohler.
* CSM: Document forgotten functionsSmallJoker2017-05-16
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* Use a settings object for the main settingsShadowNinja2017-05-06
| | | | | | | This unifies the settings APIs. This also unifies the sync and async registration APIs, since the async registration API did not support adding non-functions to the API table.
* Multiplayer menu: fix attempt to open nonexistant imagekilbith2017-02-18
| | | | | | | | Since local servers and local favorites have no ping value (these are only provided by the server) we shouldn't load a broken image filename. Fixes #5238
* Serverlist: Add ping indicators (#5164)kilbith2017-02-03
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* Add keyword based search to serverlistred-0012017-01-15
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* Client: disable pre v25 init sending by defaultest312016-08-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Disable the ability to connect to old servers by default to improve password security. If people still want to connect to old (0.4.12 and earlier) servers, they can flip the send_pre_v25_init setting. Add the ability to detect if we've tried to connect to a server which only supports the pre v25 init protocol, and show an apropriate error message. Most times the error will already be catched at the serverlist level, the detection mechanism only acts as last resort, because the "Connection timed out" error message that would be shown otherwise would be very confusing. Automatic "fixing" of this condition is not desired, as it would allow for downgrade attacks. As already 161 of the 167 servers on the serverlist support the new srp based auth protocol (> 96%), the breakage should be minimal. Follow up of commit af30183124d40a969040d7de4b3a487feec466e4 "Add option to not send pre v25 init packet" Also change the pessimistic assumption of masterlist server versions to optimistic, in order to avoid buggy behaviour (favourites not in the serverlist would be denied to connect to, etc).
* Fix mainmenu code downloading the public serverlist twice.Ekdohibs2016-04-22
| | | | | Also, fix a nil error that can happen sometimes in menu_handle_key_up_down
* Mainmenu: Code cleaningkilbith2016-04-20
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* Mainmenu: Unify favorite servers with main serverlistkilbith2016-04-20
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* Mainmenu: Still support favorites if send_pre_v25_init is disabledest312016-04-15
| | | | | | | | | | | | | | | | | | | | | | | @SmallJoker has noted a bug that servers from the (local) main menu favorites list can't be opened. This commit fixes the bug by disabling any main menu based protocol checks for servers from the favorite list. Also, it fixes a second bug that happens when a server from the public serverlist doesn't send its supported protocol versions, most likely because its running a minetest older than commit [1]. Then we have shown an error msg that the server has enforced one specific protocol version. This was most likely not the case. Of course, we can't do anything better than do an assumption on the protocol versions if they are not known. That assumption should however be closest to the most often occuring case as possible. Also, some little cleanups. [1]: 5a0ed780f56a5225b3d7c5f64099586e390e5f39 "Server: announce MIN/MAX protocol version supported to serverlist. Client: check serverlist"
* mainmenu: Tidy up logic in is_server_protocol_compat() (#3997)SmallJoker2016-04-15
| | | Apply de morgan to simplify the logic.
* Add option to not send pre v25 init packetest312016-03-15
| | | | | | | | | | | | | | | | | The legacy init packet (pre v25) sends information about the client's password that a server could use to log in to other servers if the username and password are the same. All the other benefits of SRP of protocol v25 are missed if the legacy init packet is still sent during connection creation. This patch adds an option to not send the v25 init packet. Not sending the v25 packet means breaking compat with pre v25 servers, but as the option is not enabled by default, no servers are affected unless the user explicitly flips the switch. More than 90% of the servers on the serverlist support post v25 protocols. The patch also fixes a bug with greying out of non compliant servers being done wrongly, the min and max params were mixed.
* Faster insertion into tableRui9142016-03-06
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* Better gettext support for protocol version mismatch messagesest312015-10-24
| | | | | Previously, xgettext failed to resolve the dynamic call. Thanks to @JakubVanek for pointing this out.
* Don't do formspec escaping twice for loading descriptionest312015-08-14
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* Set server_announce to world.mt and respect modes when changing subgameSokomine2015-07-02
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* Fix world.mt not written when selecting modeSokomine2015-07-01
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* Fix single click world selectest312015-06-30
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* Fix bugs in mainmenujeanpatrick.guerrero@gmail.com2015-06-30
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* More reliable serverlist behaviourHybridDog2015-06-09
| | | | | -> remember the previously loaded serverlist, and use if new one failed -> show a "loading" serverlist
* Remove duplicate code since 8ca08a850ff2494652aa0ac2daa3d00f03aa4e7aLoic Blot2015-03-25
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* Save creative_mode and enable_damage setting for each world in world.mtfz722015-03-18
| | | | Create Parameters on world initialisation and set settings of old worlds
* Server: announce MIN/MAX protocol version supported to serverlist. Client: ↵est312015-02-18
| | | | | | | check serverlist Client now informs about incompatible servers from the list, this permits to prevent the protocol movements. Server announces its supported protocol versions to master server
* Fix forgotten favourite list image update of simple menusapier2015-01-04
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* Ignore downloaded public serverlist if public_serverlist is falseKahrl2014-12-30
| | | | | Fixes #1807: When the server list finishes downloading, the local server list resets in certain conditions
* Display serverlist flags as iconsKahrl2014-12-13
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* Add formspec toolkit and refactor mainmenu to use itsapier2014-05-16
Fix crash on using cursor keys in client menu without selected server Add support for non fixed size tabviews
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/*
 * 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.
 *
 */

// clang-format off

#include <cstddef>

#ifdef WIN32
	#include <windows.h>
	#include <wincrypt.h>
#else
	#include <ctime>

#endif
// clang-format on

#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cstdint>

#include <config.h>

#if USE_SYSTEM_GMP
	#include <gmp.h>
#else
	#include <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];

void *(*srp_alloc)(size_t) = &malloc;
void *(*srp_realloc)(void *, size_t) = &realloc;
void (*srp_free)(void *) = &free;

// clang-format off
void srp_set_memory_functions(
		void *(*new_srp_alloc)(size_t),
		void *(*new_srp_realloc)(void *, size_t),
		void (*new_srp_free)(void *))
{
	srp_alloc = new_srp_alloc;
	srp_realloc = new_srp_realloc;
	srp_free = new_srp_free;
}
// clang-format on

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 */
		"EEAF0AB9ADB38DD69C33F80AFA8FC5E86072618775FF3C0B9EA2314C"
		"9C256576D674DF7496EA81D3383B4813D692C6E0E0D5D8E250B98BE4"
		"8E495C1D6089DAD15DC7D7B46154D6B6CE8EF4AD69B15D4982559B29"
		"7BCF1885C529F566660E57EC68EDBC3C05726CC02FD4CBF4976EAA9A"
		"FD5138FE8376435B9FC61D2FC0EB06E3",
		"2"},
	{/* 2048 */
		"AC6BDB41324A9A9BF166DE5E1389582FAF72B6651987EE07FC319294"
		"3DB56050A37329CBB4A099ED8193E0757767A13DD52312AB4B03310D"
		"CD7F48A9DA04FD50E8083969EDB767B0CF6095179A163AB3661A05FB"
		"D5FAAAE82918A9962F0B93B855F97993EC975EEAA80D740ADBF4FF74"
		"7359D041D5C33EA71D281E446B14773BCA97B43A23FB801676BD207A"
		"436C6481F1D2B9078717461A5B9D32E688F87748544523B524B0D57D"
		"5EA77A2775D2ECFA032CFBDBF52FB3786160279004E57AE6AF874E73"
		"03CE53299CCC041C7BC308D82A5698F3A8D0C38271AE35F8E9DBFBB6"
		"94B5C803D89F7AE435DE236D525F54759B65E372FCD68EF20FA7111F"
		"9E4AFF73",
		"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 void delete_ng(NGConstant *ng)
{
	if (ng) {
		mpz_clear(ng->N);
		mpz_clear(ng->g);
		srp_free(ng);
	}
}

static NGConstant *new_ng(SRP_NGType ng_type, const char *n_hex, const char *g_hex)
{
	NGConstant *ng = (NGConstant *)srp_alloc(sizeof(NGConstant));

	if (!ng) return 0;

	mpz_init(ng->N);
	mpz_init(ng->g);

	if (ng_type != SRP_NG_CUSTOM) {
		n_hex = global_Ng_constants[ng_type].n_hex;
		g_hex = global_Ng_constants[ng_type].g_hex;
	}

	int rv = 0;
	rv = mpz_set_str(ng->N, n_hex, 16);
	rv = rv | mpz_set_str(ng->g, g_hex, 16);

	if (rv) {
		delete_ng(ng);
		return 0;
	}

	return 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];
};

// clang-format off
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 0;
	};
}
// clang-format on

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 SRP_Result 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 *)srp_alloc(nbytes);
	if (!bin) return SRP_ERR;
	if (len_n1 > len_N || len_n2 > len_N) {
		srp_free(bin);
		return SRP_ERR;
	}
	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);
	srp_free(bin);
	mpz_from_bin(buff, hash_length(alg), result);
	return SRP_OK;
}

static SRP_Result 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 *)srp_alloc(nbytes);
	if (!bin) return SRP_ERR;
	memcpy(bin, n, len_n);
	memcpy(bin + len_n, bytes, len_bytes);
	hash(alg, bin, nbytes, buff);
	srp_free(bin);
	mpz_from_bin(buff, hash_length(alg), result);
	return SRP_OK;
}

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 SRP_Result 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 *)srp_alloc(len);
	if (!n_bytes) return SRP_ERR;
	mpz_to_bin(n, n_bytes);
	hash_update(alg, ctx, n_bytes, len);
	srp_free(n_bytes);
	return SRP_OK;
}

static SRP_Result hash_num(SRP_HashAlgorithm alg, const mpz_t n, unsigned char *dest)
{
	int nbytes = mpz_num_bytes(n);
	unsigned char *bin = (unsigned char *)srp_alloc(nbytes);
	if (!bin) return SRP_ERR;
	mpz_to_bin(n, bin);
	hash(alg, bin, nbytes, dest);
	srp_free(bin);
	return SRP_OK;
}

static SRP_Result 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);

	if (!hash_num(alg, ng->N, H_N)) return SRP_ERR;
	if (!hash_num(alg, ng->g, H_g)) return SRP_ERR;

	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);
	if (!update_hash_n(alg, &ctx, A)) return SRP_ERR;
	if (!update_hash_n(alg, &ctx, B)) return SRP_ERR;
	hash_update(alg, &ctx, K, hash_len);

	hash_final(alg, &ctx, dest);
	return SRP_OK;
}

static SRP_Result 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);

	if (!update_hash_n(alg, &ctx, A)) return SRP_ERR;
	hash_update(alg, &ctx, M, hash_length(alg));
	hash_update(alg, &ctx, K, hash_length(alg));

	hash_final(alg, &ctx, dest);
	return SRP_OK;
}

static SRP_Result fill_buff()
{
	g_rand_idx = 0;

#ifdef WIN32
	HCRYPTPROV wctx;
#else
	FILE *fp = 0;
#endif

#ifdef WIN32

	if (!CryptAcquireContext(&wctx, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
		return SRP_ERR;
	if (!CryptGenRandom(wctx, sizeof(g_rand_buff), (BYTE *)g_rand_buff)) return SRP_ERR;
	if (!CryptReleaseContext(wctx, 0)) return SRP_ERR;

#else
	fp = fopen("/dev/urandom", "r");

	if (!fp) return SRP_ERR;

	if (fread(g_rand_buff, sizeof(g_rand_buff), 1, fp) != 1) { fclose(fp); return SRP_ERR; }
	if (fclose(fp)) return SRP_ERR;
#endif
	return SRP_OK;
}

static SRP_Result mpz_fill_random(mpz_t num)
{
	// was call: BN_rand(num, 256, -1, 0);
	if (RAND_BUFF_MAX - g_rand_idx < 32)
		if (fill_buff() != SRP_OK) return SRP_ERR;
	mpz_from_bin((const unsigned char *)(&g_rand_buff[g_rand_idx]), 32, num);
	g_rand_idx += 32;
	return SRP_OK;
}

static SRP_Result init_random()
{
	if (g_initialized) return SRP_OK;
	SRP_Result ret = fill_buff();
	g_initialized = (ret == SRP_OK);
	return ret;
}

#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*) srp_alloc(len_num);
	mpz_to_bin(num, (unsigned char *) bytes_num);
	srp_dbg_data(bytes_num, len_num, prevtext);
	srp_free(bytes_num);

}*/

/***********************************************************************************************************
 *
 *  Exported Functions
 *
 ***********************************************************************************************************/

// clang-format off
SRP_Result 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 )
{
	SRP_Result ret = SRP_OK;

	mpz_t v; mpz_init(v);
	mpz_t x; mpz_init(x);
	// clang-format on

	NGConstant *ng = new_ng(ng_type, n_hex, g_hex);

	if (!ng) goto error_and_exit;

	if (init_random() != SRP_OK) /* Only happens once */
		goto error_and_exit;

	if (*bytes_s == NULL) {
		size_t size_to_fill = 16;
		*len_s = size_to_fill;
		if (RAND_BUFF_MAX - g_rand_idx < size_to_fill)
			if (fill_buff() != SRP_OK) goto error_and_exit;
		*bytes_s = (unsigned char *)srp_alloc(size_to_fill);
		if (!*bytes_s) goto error_and_exit;
		memcpy(*bytes_s, &g_rand_buff[g_rand_idx], size_to_fill);
		g_rand_idx += size_to_fill;
	}

	if (!calculate_x(
			x, alg, *bytes_s, *len_s, username_for_verifier, password, len_password))
		goto error_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 *)srp_alloc(*len_v);

	if (!*bytes_v) goto error_and_exit;

	mpz_to_bin(v, *bytes_v);

cleanup_and_exit:
	delete_ng(ng);
	mpz_clear(v);
	mpz_clear(x);
	return ret;
error_and_exit:
	ret = SRP_ERR;
	goto cleanup_and_exit;
}

// clang-format off

/* 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);
	// clang-format on
	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 *)srp_alloc(sizeof(struct SRPVerifier));

	if (!ver) goto cleanup_and_exit;

	if (init_random() != SRP_OK) { /* Only happens once */
		srp_free(ver);
		ver = 0;
		goto cleanup_and_exit;
	}

	ver->username = (char *)srp_alloc(ulen);
	ver->hash_alg = alg;
	ver->ng = ng;

	if (!ver->username) {
		srp_free(ver);
		ver = 0;
		goto cleanup_and_exit;
	}

	memcpy(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 {
			if (!mpz_fill_random(b)) goto ver_cleanup_and_exit;
		}

		if (!H_nn(k, alg, ng->N, ng->N, ng->g)) goto ver_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)) goto ver_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);

		if (!hash_num(alg, S, ver->session_key)) goto ver_cleanup_and_exit;

		if (!calculate_M(
				alg, ng, ver->M, username, bytes_s, len_s, A, B, ver->session_key)) {
			goto ver_cleanup_and_exit;
		}
		if (!calculate_H_AMK(alg, ver->H_AMK, A, ver->M, ver->session_key)) {
			goto ver_cleanup_and_exit;
		}

		*len_B = mpz_num_bytes(B);
		*bytes_B = (unsigned char *)srp_alloc(*len_B);

		if (!*bytes_B) {
			*len_B = 0;
			goto ver_cleanup_and_exit;
		}

		mpz_to_bin(B, *bytes_B);

		ver->bytes_B = *bytes_B;
	} else {
		srp_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;
ver_cleanup_and_exit:
	srp_free(ver->username);
	srp_free(ver);
	ver = 0;
	goto cleanup_and_exit;
}

void srp_verifier_delete(struct SRPVerifier *ver)
{
	if (ver) {
		delete_ng(ver->ng);
		srp_free(ver->username);
		srp_free(ver->bytes_B);
		memset(ver, 0, sizeof(*ver));
		srp_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 *)srp_alloc(sizeof(struct SRPUser));
	size_t ulen = strlen(username) + 1;
	size_t uvlen = strlen(username_for_verifier) + 1;

	if (!usr) goto err_exit;

	if (init_random() != SRP_OK) /* Only happens once */
		goto err_exit;

	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) goto err_exit;

	usr->username = (char *)srp_alloc(ulen);
	usr->username_verifier = (char *)srp_alloc(uvlen);
	usr->password = (unsigned char *)srp_alloc(len_password);
	usr->password_len = len_password;

	if (!usr->username || !usr->password || !usr->username_verifier) 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);
		delete_ng(usr->ng);
		srp_free(usr->username);
		srp_free(usr->username_verifier);
		if (usr->password) {
			memset(usr->password, 0, usr->password_len);
			srp_free(usr->password);
		}
		srp_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);

		srp_free(usr->username);
		srp_free(usr->username_verifier);
		srp_free(usr->password);

		if (usr->bytes_A) srp_free(usr->bytes_A);

		memset(usr, 0, sizeof(*usr));
		srp_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);
}

// clang-format off
/* Output: username, bytes_A, len_A */
SRP_Result 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)
{
	// clang-format on
	if (bytes_a) {
		mpz_from_bin(bytes_a, len_a, usr->a);
	} else {
		if (!mpz_fill_random(usr->a)) goto error_and_exit;
	}

	mpz_powm(usr->A, usr->ng->g, usr->a, usr->ng->N);

	*len_A = mpz_num_bytes(usr->A);
	*bytes_A = (unsigned char *)srp_alloc(*len_A);

	if (!*bytes_A) goto error_and_exit;

	mpz_to_bin(usr->A, *bytes_A);

	usr->bytes_A = *bytes_A;
	if (username) *username = usr->username;

	return SRP_OK;

error_and_exit:
	*len_A = 0;
	*bytes_A = 0;
	*username = 0;
	return SRP_ERR;
}

// clang-format off
/* 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);
	// clang-format on

	*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: ");

		// clang-format off
		/* 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);
		// clang-format on

		if (!hash_num(usr->hash_alg, usr->S, usr->session_key)) goto cleanup_and_exit;

		if (!calculate_M(usr->hash_alg, usr->ng, usr->M, usr->username, bytes_s, len_s,
				usr->A, B, usr->session_key))
			goto cleanup_and_exit;
		if (!calculate_H_AMK(usr->hash_alg, usr->H_AMK, usr->A, usr->M, usr->session_key))
			goto cleanup_and_exit;

		*bytes_M = usr->M;
		*len_M = hash_length(usr->hash_alg);
	} else {
		*bytes_M = NULL;
		*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;
}