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weechat/src/core/wee-crypto.c

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/*
* wee-crypto.c - cryptographic functions
*
* Copyright (C) 2020 Sébastien Helleu <flashcode@flashtux.org>
*
* This file is part of WeeChat, the extensible chat client.
*
* WeeChat is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* WeeChat is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with WeeChat. If not, see <https://www.gnu.org/licenses/>.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <time.h>
#include <math.h>
#include <gcrypt.h>
#include "weechat.h"
#include "wee-crypto.h"
#include "wee-config-file.h"
#include "wee-hashtable.h"
#include "wee-string.h"
#include "../plugins/plugin.h"
char *weecrypto_hash_algo_string[] = {
"crc32",
"md5",
"sha1",
"sha224", "sha256", "sha384", "sha512",
"sha3-224", "sha3-256", "sha3-384", "sha3-512",
NULL,
};
int weecrypto_hash_algo[] = {
GCRY_MD_CRC32,
GCRY_MD_MD5,
GCRY_MD_SHA1,
GCRY_MD_SHA224, GCRY_MD_SHA256, GCRY_MD_SHA384, GCRY_MD_SHA512,
GCRY_MD_SHA3_224, GCRY_MD_SHA3_256, GCRY_MD_SHA3_384, GCRY_MD_SHA3_512,
};
/*
* Returns the hash algorithm with the name, or GCRY_MD_NONE if not found.
*/
int
weecrypto_get_hash_algo (const char *hash_algo)
{
int i;
if (!hash_algo)
return GCRY_MD_NONE;
for (i = 0; weecrypto_hash_algo_string[i]; i++)
{
if (strcmp (weecrypto_hash_algo_string[i], hash_algo) == 0)
return weecrypto_hash_algo[i];
}
return GCRY_MD_NONE;
}
/*
* Computes hash of data using the given algorithm.
*
* The hash size depends on the algorithm, common ones are:
*
* GCRY_MD_CRC32 32 bits == 4 bytes
* GCRY_MD_MD5 128 bits == 16 bytes
* GCRY_MD_SHA1 160 bits == 20 bytes
* GCRY_MD_SHA224 224 bits == 28 bytes
* GCRY_MD_SHA256 256 bits == 32 bytes
* GCRY_MD_SHA384 384 bits == 48 bytes
* GCRY_MD_SHA512 512 bits == 64 bytes
* GCRY_MD_SHA3_224 224 bits == 28 bytes
* GCRY_MD_SHA3_256 256 bits == 32 bytes
* GCRY_MD_SHA3_384 384 bits == 48 bytes
* GCRY_MD_SHA3_512 512 bits == 64 bytes
*
* The result hash is stored in "hash" (the buffer must be large enough).
*
* If hash_size is not NULL, the length of hash is stored in *hash_size
* (in bytes).
*
* Returns 1 if OK, 0 if error.
*/
int
weecrypto_hash (const void *data, int data_size, int hash_algo,
void *hash, int *hash_size)
{
gcry_md_hd_t *hd_md;
int rc, hd_md_opened, algo_size;
unsigned char *ptr_hash;
rc = 0;
hd_md = NULL;
hd_md_opened = 0;
if (!hash)
goto hash_end;
if (hash_size)
*hash_size = 0;
if (!data || (data_size < 1))
goto hash_end;
hd_md = malloc (sizeof (gcry_md_hd_t));
if (!hd_md)
goto hash_end;
if (gcry_md_open (hd_md, hash_algo, 0) != 0)
goto hash_end;
hd_md_opened = 1;
gcry_md_write (*hd_md, data, data_size);
ptr_hash = gcry_md_read (*hd_md, hash_algo);
if (!ptr_hash)
goto hash_end;
algo_size = gcry_md_get_algo_dlen (hash_algo);
memcpy (hash, ptr_hash, algo_size);
if (hash_size)
*hash_size = algo_size;
rc = 1;
hash_end:
if (hd_md)
{
if (hd_md_opened)
gcry_md_close (*hd_md);
free (hd_md);
}
return rc;
}
/*
* Computes PKCS#5 Passphrase Based Key Derivation Function number 2 (PBKDF2)
* hash of data.
*
* The hash size depends on the algorithm, common ones are:
*
* GCRY_MD_SHA1 160 bits == 20 bytes
* GCRY_MD_SHA256 256 bits == 32 bytes
* GCRY_MD_SHA512 512 bits == 64 bytes
*
* The result hash is stored in "hash" (the buffer must be large enough).
*
* If hash_size is not NULL, the length of hash is stored in *hash_size
* (in bytes).
*
* Returns 1 if OK, 0 if error.
*/
int
weecrypto_hash_pbkdf2 (const void *data, int data_size, int hash_subalgo,
const void *salt, int salt_size, int iterations,
void *hash, int *hash_size)
{
int rc, algo_size;
rc = 0;
if (!hash)
goto hash_pbkdf2_end;
if (hash_size)
*hash_size = 0;
if (!data || (data_size < 1) || !salt || (salt_size < 1)
|| (iterations < 1))
{
goto hash_pbkdf2_end;
}
algo_size = gcry_md_get_algo_dlen (hash_subalgo);
if (gcry_kdf_derive (data, data_size, GCRY_KDF_PBKDF2, hash_subalgo,
salt, salt_size, iterations,
algo_size, hash) != 0)
{
goto hash_pbkdf2_end;
}
if (hash_size)
*hash_size = algo_size;
rc = 1;
hash_pbkdf2_end:
return rc;
}
/*
* Generates a Time-based One-Time Password (TOTP), as described
* in the RFC 6238.
*
* Returns:
* 1: OK
* 0: error
*/
int
weecrypto_totp_generate_internal (const char *secret, int length_secret,
uint64_t moving_factor, int digits,
char *result)
{
gcry_md_hd_t hd_md;
uint64_t moving_factor_swapped;
unsigned char *ptr_hash;
char hash[20];
int offset, length;
unsigned long bin_code;
if (gcry_md_open (&hd_md, GCRY_MD_SHA1, GCRY_MD_FLAG_HMAC) != 0)
return 0;
if (gcry_md_setkey (hd_md, secret, length_secret) != 0)
{
gcry_md_close (hd_md);
return 0;
}
moving_factor_swapped = (moving_factor >> 56)
| ((moving_factor << 40) & 0x00FF000000000000)
| ((moving_factor << 24) & 0x0000FF0000000000)
| ((moving_factor << 8) & 0x000000FF00000000)
| ((moving_factor >> 8) & 0x00000000FF000000)
| ((moving_factor >> 24) & 0x0000000000FF0000)
| ((moving_factor >> 40) & 0x000000000000FF00)
| (moving_factor << 56);
gcry_md_write (hd_md,
&moving_factor_swapped, sizeof (moving_factor_swapped));
ptr_hash = gcry_md_read (hd_md, GCRY_MD_SHA1);
if (!ptr_hash)
{
gcry_md_close (hd_md);
return 0;
}
memcpy (hash, ptr_hash, sizeof (hash));
gcry_md_close (hd_md);
offset = hash[19] & 0xf;
bin_code = (hash[offset] & 0x7f) << 24
| (hash[offset+1] & 0xff) << 16
| (hash[offset+2] & 0xff) << 8
| (hash[offset+3] & 0xff);
bin_code %= (unsigned long)(pow (10, digits));
length = snprintf (result, digits + 1, "%.*lu", digits, bin_code);
if (length != digits)
return 0;
return 1;
}
/*
* Generates a Time-based One-Time Password (TOTP), as described
* in the RFC 6238.
*
* Returns the password as string, NULL if error.
*
* Note: result must be freed after use.
*/
char *
weecrypto_totp_generate (const char *secret_base32, time_t totp_time,
int digits)
{
char *result, *secret;
int length_secret, rc;
uint64_t moving_factor;
secret = NULL;
result = NULL;
if (!secret_base32 || !secret_base32[0]
|| (digits < WEECRYPTO_TOTP_MIN_DIGITS)
|| (digits > WEECRYPTO_TOTP_MAX_DIGITS))
{
goto error;
}
secret = malloc ((strlen (secret_base32) * 4) + 16 + 1);
if (!secret)
goto error;
length_secret = string_base32_decode (secret_base32, secret);
if (length_secret < 0)
goto error;
result = malloc (digits + 1);
if (!result)
goto error;
if (totp_time == 0)
totp_time = time (NULL);
moving_factor = totp_time / 30;
rc = weecrypto_totp_generate_internal (secret, length_secret,
moving_factor, digits, result);
if (!rc)
goto error;
free (secret);
return result;
error:
if (secret)
free (secret);
if (result)
free (result);
return NULL;
}
/*
* Validates a Time-based One-Time Password (TOTP).
*
* Returns:
* 1: OTP is OK
* 0: OTP is invalid
*/
int
weecrypto_totp_validate (const char *secret_base32, time_t totp_time,
int window, const char *otp)
{
char *secret, str_otp[16];
int length_secret, digits, rc, otp_ok;
uint64_t i, moving_factor;
secret = NULL;
if (!secret_base32 || !secret_base32[0] || (window < 0) || !otp || !otp[0])
goto error;
digits = strlen (otp);
if ((digits < WEECRYPTO_TOTP_MIN_DIGITS)
|| (digits > WEECRYPTO_TOTP_MAX_DIGITS))
{
goto error;
}
secret = malloc (strlen (secret_base32) + 1);
if (!secret)
goto error;
length_secret = string_base32_decode (secret_base32, secret);
if (length_secret < 0)
goto error;
if (totp_time == 0)
totp_time = time (NULL);
moving_factor = totp_time / 30;
otp_ok = 0;
for (i = moving_factor - window; i <= moving_factor + window; i++)
{
rc = weecrypto_totp_generate_internal (secret, length_secret,
i, digits, str_otp);
if (rc && (strcmp (str_otp, otp) == 0))
{
otp_ok = 1;
break;
}
}
free (secret);
return otp_ok;
error:
if (secret)
free (secret);
return 0;
}
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