/* * irc-sasl.c - SASL authentication with IRC server * * Copyright (C) 2003-2019 Sébastien Helleu * * 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 . */ #include #include #include #include #include #include #ifdef HAVE_GNUTLS #include #if LIBGNUTLS_VERSION_NUMBER >= 0x020a01 /* 2.10.1 */ #include #endif /* LIBGNUTLS_VERSION_NUMBER >= 0x020a01 */ #endif /* HAVE_GNUTLS */ #include "../weechat-plugin.h" #include "irc.h" #include "irc-sasl.h" #include "irc-server.h" /* * these names are sent to the IRC server (as upper case), so they must be * valid values for the AUTHENTICATE command (example: "AUTHENTICATE PLAIN") */ char *irc_sasl_mechanism_string[IRC_NUM_SASL_MECHANISMS] = { "plain", "ecdsa-nist256p-challenge", "external", "dh-blowfish", "dh-aes" }; /* * Builds answer for SASL authentication, using mechanism "PLAIN". * * Note: result must be freed after use. */ char * irc_sasl_mechanism_plain (const char *sasl_username, const char *sasl_password) { char *string, *answer_base64; int length_username, length; answer_base64 = NULL; length_username = strlen (sasl_username); length = ((length_username + 1) * 2) + strlen (sasl_password) + 1; string = malloc (length); if (string) { snprintf (string, length, "%s|%s|%s", sasl_username, sasl_username, sasl_password); string[length_username] = '\0'; string[(length_username * 2) + 1] = '\0'; answer_base64 = malloc (length * 4); if (answer_base64) { if (weechat_string_base_encode (64, string, length - 1, answer_base64) < 0) { free (answer_base64); answer_base64 = NULL; } } free (string); } return answer_base64; } /* * Returns the content of file with SASL key. * * Note: result must be freed after use. */ char * irc_sasl_get_key_content (struct t_irc_server *server, const char *sasl_key) { const char *weechat_dir; char *key_path1, *key_path2, *content; if (!sasl_key) return NULL; content = NULL; weechat_dir = weechat_info_get ("weechat_dir", ""); key_path1 = weechat_string_replace (sasl_key, "%h", weechat_dir); key_path2 = (key_path1) ? weechat_string_expand_home (key_path1) : NULL; if (key_path2) content = weechat_file_get_content (key_path2); if (!content) { weechat_printf ( server->buffer, _("%s%s: unable to read private key in file \"%s\""), weechat_prefix ("error"), IRC_PLUGIN_NAME, (key_path2) ? key_path2 : ((key_path1) ? key_path1 : sasl_key)); } if (key_path1) free (key_path1); if (key_path2) free (key_path2); return content; } /* * Builds answer for SASL authentication, using mechanism * "ECDSA-NIST256P-CHALLENGE". * * Note: result must be freed after use. */ char * irc_sasl_mechanism_ecdsa_nist256p_challenge (struct t_irc_server *server, const char *data_base64, const char *sasl_username, const char *sasl_key) { #if defined(HAVE_GNUTLS) && (LIBGNUTLS_VERSION_NUMBER >= 0x030015) /* 3.0.21 */ char *data, *string, *answer_base64; int length_data, length_username, length, ret; char *str_privkey; gnutls_x509_privkey_t x509_privkey; gnutls_privkey_t privkey; gnutls_datum_t filedatum, decoded_data, signature; #if LIBGNUTLS_VERSION_NUMBER >= 0x030300 /* 3.3.0 */ gnutls_ecc_curve_t curve; gnutls_datum_t x, y, k; char *pubkey, *pubkey_base64; #endif /* LIBGNUTLS_VERSION_NUMBER >= 0x030300 */ answer_base64 = NULL; string = NULL; if (strcmp (data_base64, "+") == 0) { /* send "username" + '\0' + "username" */ answer_base64 = NULL; length_username = strlen (sasl_username); length = length_username + 1 + length_username; string = malloc (length + 1); if (string) { snprintf (string, length + 1, "%s|%s", sasl_username, sasl_username); string[length_username] = '\0'; } } else { /* sign the challenge with the private key and return the result */ /* decode the challenge */ data = malloc (strlen (data_base64) + 1); if (!data) return NULL; length_data = weechat_string_base_decode (64, data_base64, data); /* read file with private key */ str_privkey = irc_sasl_get_key_content (server, sasl_key); if (!str_privkey) { free (data); return NULL; } /* import key */ gnutls_x509_privkey_init (&x509_privkey); gnutls_privkey_init (&privkey); filedatum.data = (unsigned char *)str_privkey; filedatum.size = strlen (str_privkey); ret = gnutls_x509_privkey_import (x509_privkey, &filedatum, GNUTLS_X509_FMT_PEM); free (str_privkey); if (ret != GNUTLS_E_SUCCESS) { weechat_printf ( server->buffer, _("%sgnutls: invalid private key file: error %d %s"), weechat_prefix ("error"), ret, gnutls_strerror (ret)); gnutls_x509_privkey_deinit (x509_privkey); gnutls_privkey_deinit (privkey); free (data); return NULL; } #if LIBGNUTLS_VERSION_NUMBER >= 0x030300 /* 3.3.0 */ /* read raw values in key, to display public key */ ret = gnutls_x509_privkey_export_ecc_raw (x509_privkey, &curve, &x, &y, &k); if (ret == GNUTLS_E_SUCCESS) { pubkey = malloc (x.size + 1); if (pubkey) { pubkey[0] = (y.data[y.size - 1] & 1) ? 0x03 : 0x02; memcpy (pubkey + 1, x.data, x.size); pubkey_base64 = malloc ((x.size + 1 + 1) * 4); if (pubkey_base64) { if (weechat_string_base_encode (64, pubkey, x.size + 1, pubkey_base64) >= 0) { weechat_printf ( server->buffer, _("%s%s: signing the challenge with ECC public " "key: %s"), weechat_prefix ("network"), IRC_PLUGIN_NAME, pubkey_base64); } free (pubkey_base64); } free (pubkey); } gnutls_free (x.data); gnutls_free (y.data); gnutls_free (k.data); } #endif /* LIBGNUTLS_VERSION_NUMBER >= 0x030300 */ /* import private key in an abstract key structure */ ret = gnutls_privkey_import_x509 (privkey, x509_privkey, 0); /* gnutls >= 2.11.0 */ if (ret != GNUTLS_E_SUCCESS) { weechat_printf ( server->buffer, _("%sgnutls: unable to import the private key: error %d %s"), weechat_prefix ("error"), ret, gnutls_strerror (ret)); gnutls_x509_privkey_deinit (x509_privkey); gnutls_privkey_deinit (privkey); free (data); return NULL; } decoded_data.data = (unsigned char *)data; decoded_data.size = length_data; ret = gnutls_privkey_sign_hash (privkey, GNUTLS_DIG_SHA256, 0, /* gnutls >= 2.11.0 */ &decoded_data, &signature); if (ret != GNUTLS_E_SUCCESS) { weechat_printf ( server->buffer, _("%sgnutls: unable to sign the hashed data: error %d %s"), weechat_prefix ("error"), ret, gnutls_strerror (ret)); gnutls_x509_privkey_deinit (x509_privkey); gnutls_privkey_deinit (privkey); free (data); return NULL; } gnutls_x509_privkey_deinit (x509_privkey); gnutls_privkey_deinit (privkey); string = malloc (signature.size); if (string) memcpy (string, signature.data, signature.size); length = signature.size; gnutls_free (signature.data); free (data); } if (string && (length > 0)) { answer_base64 = malloc ((length + 1) * 4); if (answer_base64) { if (weechat_string_base_encode (64, string, length, answer_base64) < 0) { free (answer_base64); answer_base64 = NULL; } } free (string); string = NULL; } if (string) free (string); return answer_base64; #else /* no gnutls or gnutls < 3.0.21 */ /* make C compiler happy */ (void) data_base64; (void) sasl_username; (void) sasl_key; weechat_printf (server->buffer, _("%sgnutls: version >= 3.0.21 is required for SASL " "\"ecdsa-nist256p-challenge\""), weechat_prefix ("error")); return NULL; #endif /* defined(HAVE_GNUTLS) && (LIBGNUTLS_VERSION_NUMBER >= 0x030015) */ } /* * Reads key sent by server (Diffie-Hellman key exchange). * * Returns: * 1: OK * 0: error */ int irc_sasl_dh (const char *data_base64, unsigned char **public_bin, unsigned char **secret_bin, int *length_key) { char *data; unsigned char *ptr_data; int length_data, size, num_bits_prime_number, rc; size_t num_written; gcry_mpi_t data_prime_number, data_generator_number, data_server_pub_key; gcry_mpi_t pub_key, priv_key, secret_mpi; rc = 0; data = NULL; data_prime_number = NULL; data_generator_number = NULL; data_server_pub_key = NULL; pub_key = NULL; priv_key = NULL; secret_mpi = NULL; /* decode data */ data = malloc (strlen (data_base64) + 1); if (!data) goto dhend; length_data = weechat_string_base_decode (64, data_base64, data); ptr_data = (unsigned char *)data; /* extract prime number */ size = ntohs ((((unsigned int)ptr_data[1]) << 8) | ptr_data[0]); ptr_data += 2; length_data -= 2; if (size > length_data) goto dhend; data_prime_number = gcry_mpi_new (size * 8); gcry_mpi_scan (&data_prime_number, GCRYMPI_FMT_USG, ptr_data, size, NULL); num_bits_prime_number = gcry_mpi_get_nbits (data_prime_number); if (num_bits_prime_number == 0 || INT_MAX - 7 < num_bits_prime_number) goto dhend; ptr_data += size; length_data -= size; /* extract generator number */ size = ntohs ((((unsigned int)ptr_data[1]) << 8) | ptr_data[0]); ptr_data += 2; length_data -= 2; if (size > length_data) goto dhend; data_generator_number = gcry_mpi_new (size * 8); gcry_mpi_scan (&data_generator_number, GCRYMPI_FMT_USG, ptr_data, size, NULL); ptr_data += size; length_data -= size; /* extract server-generated public key */ size = ntohs ((((unsigned int)ptr_data[1]) << 8) | ptr_data[0]); ptr_data += 2; length_data -= 2; if (size > length_data) goto dhend; data_server_pub_key = gcry_mpi_new (size * 8); gcry_mpi_scan (&data_server_pub_key, GCRYMPI_FMT_USG, ptr_data, size, NULL); /* generate keys */ pub_key = gcry_mpi_new (num_bits_prime_number); priv_key = gcry_mpi_new (num_bits_prime_number); gcry_mpi_randomize (priv_key, num_bits_prime_number, GCRY_STRONG_RANDOM); /* pub_key = (g ^ priv_key) % p */ gcry_mpi_powm (pub_key, data_generator_number, priv_key, data_prime_number); /* compute secret_bin */ *length_key = (num_bits_prime_number + 7) / 8; *secret_bin = malloc (*length_key); secret_mpi = gcry_mpi_new (num_bits_prime_number); /* secret_mpi = (y ^ priv_key) % p */ gcry_mpi_powm (secret_mpi, data_server_pub_key, priv_key, data_prime_number); gcry_mpi_print (GCRYMPI_FMT_USG, *secret_bin, *length_key, &num_written, secret_mpi); /* create public_bin */ *public_bin = malloc (*length_key); gcry_mpi_print (GCRYMPI_FMT_USG, *public_bin, *length_key, &num_written, pub_key); rc = 1; dhend: if (data) free (data); if (data_prime_number) gcry_mpi_release (data_prime_number); if (data_generator_number) gcry_mpi_release (data_generator_number); if (data_server_pub_key) gcry_mpi_release (data_server_pub_key); if (pub_key) gcry_mpi_release (pub_key); if (priv_key) gcry_mpi_release (priv_key); if (secret_mpi) gcry_mpi_release (secret_mpi); return rc; } /* * Builds answer for SASL authentication, using mechanism "DH-BLOWFISH". * * Argument data_base64 is a concatenation of 3 strings, each string is composed * of 2 bytes (length of string), followed by content of string: * 1. a prime number * 2. a generator number * 3. server-generated public key * * Note: result must be freed after use. */ char * irc_sasl_mechanism_dh_blowfish (const char *data_base64, const char *sasl_username, const char *sasl_password) { char *answer, *ptr_answer, *answer_base64; unsigned char *password_clear, *password_crypted; int length_key, length_username, length_password, length_answer; unsigned char *public_bin, *secret_bin; gcry_cipher_hd_t gcrypt_handle; password_clear = NULL; password_crypted = NULL; answer = NULL; answer_base64 = NULL; secret_bin = NULL; public_bin = NULL; if (!irc_sasl_dh (data_base64, &public_bin, &secret_bin, &length_key)) goto bfend; /* create password buffers (clear and crypted) */ length_password = strlen (sasl_password) + ((8 - (strlen (sasl_password) % 8)) % 8); password_clear = malloc (length_password); password_crypted = malloc (length_password); memset (password_clear, 0, length_password); memset (password_crypted, 0, length_password); memcpy (password_clear, sasl_password, strlen (sasl_password)); /* crypt password using blowfish */ if (gcry_cipher_open (&gcrypt_handle, GCRY_CIPHER_BLOWFISH, GCRY_CIPHER_MODE_ECB, 0) != 0) goto bfend; if (gcry_cipher_setkey (gcrypt_handle, secret_bin, length_key) != 0) goto bfend; if (gcry_cipher_encrypt (gcrypt_handle, password_crypted, length_password, password_clear, length_password) != 0) goto bfend; gcry_cipher_close (gcrypt_handle); /* * build answer for server, it is concatenation of: * 1. key length (2 bytes) * 2. public key ('length_key' bytes) * 3. sasl_username ('length_username'+1 bytes) * 4. encrypted password ('length_password' bytes) */ length_username = strlen (sasl_username) + 1; length_answer = 2 + length_key + length_username + length_password; answer = malloc (length_answer); ptr_answer = answer; *((unsigned int *)ptr_answer) = htons (length_key); ptr_answer += 2; memcpy (ptr_answer, public_bin, length_key); ptr_answer += length_key; memcpy (ptr_answer, sasl_username, length_username); ptr_answer += length_username; memcpy (ptr_answer, password_crypted, length_password); /* encode answer to base64 */ answer_base64 = malloc ((length_answer + 1) * 4); if (answer_base64) { if (weechat_string_base_encode (64, answer, length_answer, answer_base64) < 0) { free (answer_base64); answer_base64 = NULL; } } bfend: if (secret_bin) free (secret_bin); if (public_bin) free (public_bin); if (password_clear) free (password_clear); if (password_crypted) free (password_crypted); if (answer) free (answer); return answer_base64; } /* * Builds answer for SASL authentication, using mechanism "DH-AES". * * Argument data_base64 is a concatenation of 3 strings, each string is composed * of 2 bytes (length of string), followed by content of string: * 1. a prime number * 2. a generator number * 3. server-generated public key * * Note: result must be freed after use. */ char * irc_sasl_mechanism_dh_aes (const char *data_base64, const char *sasl_username, const char *sasl_password) { char *answer, *ptr_answer, *answer_base64; unsigned char *ptr_userpass, *userpass_clear, *userpass_crypted; int length_key, length_answer; int length_username, length_password, length_userpass; unsigned char *public_bin, *secret_bin; char iv[16]; int cipher_algo; gcry_cipher_hd_t gcrypt_handle; userpass_clear = NULL; userpass_crypted = NULL; answer = NULL; answer_base64 = NULL; secret_bin = NULL; public_bin = NULL; if (irc_sasl_dh (data_base64, &public_bin, &secret_bin, &length_key) == 0) goto aesend; /* Select cipher algorithm: key length * 8 = cipher bit size */ switch (length_key) { case 32: cipher_algo = GCRY_CIPHER_AES256; break; case 24: cipher_algo = GCRY_CIPHER_AES192; break; case 16: cipher_algo = GCRY_CIPHER_AES128; break; default: /* Invalid bit length */ goto aesend; } /* Generate the IV */ gcry_randomize (iv, sizeof (iv), GCRY_STRONG_RANDOM); /* create user/pass buffers (clear and crypted) */ length_username = strlen (sasl_username) + 1; length_password = strlen (sasl_password) + 1; length_userpass = length_username + length_password + ((16 - ((length_username + length_password) % 16)) % 16); ptr_userpass = userpass_clear = malloc (length_userpass); userpass_crypted = malloc (length_userpass); memset (userpass_clear, 0, length_password); memset (userpass_crypted, 0, length_password); memcpy (ptr_userpass, sasl_username, length_username); ptr_userpass += length_username; memcpy (ptr_userpass, sasl_password, length_password); /* crypt password using AES in CBC mode */ if (gcry_cipher_open (&gcrypt_handle, cipher_algo, GCRY_CIPHER_MODE_CBC, 0) != 0) goto aesend; if (gcry_cipher_setkey (gcrypt_handle, secret_bin, length_key) != 0) goto aesend; if (gcry_cipher_setiv (gcrypt_handle, iv, sizeof (iv)) != 0) goto aesend; if (gcry_cipher_encrypt (gcrypt_handle, userpass_crypted, length_userpass, userpass_clear, length_userpass) != 0) goto aesend; gcry_cipher_close (gcrypt_handle); /* * build answer for server, it is concatenation of: * 1. key length (2 bytes) * 2. public key ('length_key' bytes) * 3. IV (sizeof (iv) bytes) * 4. encrypted password ('length_userpass' bytes) */ length_answer = 2 + length_key + sizeof (iv) + length_userpass; answer = malloc (length_answer); ptr_answer = answer; *((unsigned int *)ptr_answer) = htons (length_key); ptr_answer += 2; memcpy (ptr_answer, public_bin, length_key); ptr_answer += length_key; memcpy (ptr_answer, iv, sizeof (iv)); ptr_answer += sizeof (iv); memcpy (ptr_answer, userpass_crypted, length_userpass); /* encode answer to base64 */ answer_base64 = malloc ((length_answer + 1) * 4); if (answer_base64) { if (weechat_string_base_encode (64, answer, length_answer, answer_base64) < 0) { free (answer_base64); answer_base64 = NULL; } } aesend: if (secret_bin) free (secret_bin); if (public_bin) free (public_bin); if (userpass_clear) free (userpass_clear); if (userpass_crypted) free (userpass_crypted); if (answer) free (answer); return answer_base64; }