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-rw-r--r--src/core/wee-crypto.c402
1 files changed, 402 insertions, 0 deletions
diff --git a/src/core/wee-crypto.c b/src/core/wee-crypto.c
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+++ b/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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