hexchat/plugins/fishlim/fish.c

459 lines
13 KiB
C

/*
Copyright (c) 2010 Samuel Lidén Borell <samuel@kodafritt.se>
Copyright (c) 2019 <bakasura@protonmail.ch>
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.
*/
#ifdef __APPLE__
#define __AVAILABILITYMACROS__
#define DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER
#endif
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/evp.h>
#include <openssl/blowfish.h>
#include <openssl/rand.h>
#include "keystore.h"
#include "fish.h"
#define IB 64
static const char fish_base64[] = "./0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
static const char base64_chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
static const signed char fish_unbase64[256] = {
IB,IB,IB,IB,IB,IB,IB,IB, IB,IB,IB,IB,IB,IB,IB,IB,
IB,IB,IB,IB,IB,IB,IB,IB, IB,IB,IB,IB,IB,IB,IB,IB,
/* ! " # $ % & ' ( ) * + , - . / */
IB,IB,IB,IB,IB,IB,IB,IB, IB,IB,IB,IB,IB,IB, 0, 1,
/* 0 1 2 3 4 5 6 7 8 9 : ; < = > ? */
2, 3, 4, 5, 6, 7, 8, 9, 10,11,IB,IB,IB,IB,IB,IB,
/* @ A B C D E F G H I J K L M N O */
IB,38,39,40,41,42,43,44, 45,46,47,48,49,50,51,52,
/* P Q R S T U V W X Y Z [ \ ] ^ _*/
53,54,55,56,57,58,59,60, 61,62,63,IB,IB,IB,IB,IB,
/* ` a b c d e f g h i j k l m n o */
IB,12,13,14,15,16,17,18, 19,20,21,22,23,24,25,26,
/* p q r s t u v w x y z { | } ~ <del> */
27,28,29,30,31,32,33,34, 35,36,37,IB,IB,IB,IB,IB,
};
/**
* Convert Int to 4 Bytes (Big-endian)
*
* @param int source
* @param char* dest
*/
#define GET_BYTES(dest, source) do { \
*((dest)++) = ((source) >> 24) & 0xFF; \
*((dest)++) = ((source) >> 16) & 0xFF; \
*((dest)++) = ((source) >> 8) & 0xFF; \
*((dest)++) = (source) & 0xFF; \
} while (0);
/**
* Convert 4 Bytes to Int (Big-endian)
*
* @param char* source
* @param int dest
*/
#define GET_LONG(dest, source) do { \
dest = ((uint8_t)*((source)++) << 24); \
dest |= ((uint8_t)*((source)++) << 16); \
dest |= ((uint8_t)*((source)++) << 8); \
dest |= (uint8_t)*((source)++); \
} while (0);
/**
* Encode ECB FiSH Base64
*
* @param [in] message Bytes to encode
* @param [in] message_len Size of bytes to encode
* @return Array of char with encoded string
*/
char *fish_base64_encode(const char *message, size_t message_len) {
BF_LONG left = 0, right = 0;
int i, j;
char *encoded = NULL;
char *end = NULL;
char *msg = NULL;
if (message_len == 0)
return NULL;
/* Each 8-byte block becomes 12 bytes (fish base64 format) and add 1 byte for \0 */
encoded = g_malloc(((message_len - 1) / 8) * 12 + 12 + 1);
end = encoded;
/* Iterate over each 8-byte block (Blowfish block size) */
for (j = 0; j < message_len; j += 8) {
msg = (char *) message;
/* Set left and right longs */
GET_LONG(left, msg);
GET_LONG(right, msg);
for (i = 0; i < 6; ++i) {
*end++ = fish_base64[right & 0x3fu];
right = (right >> 6u);
}
for (i = 0; i < 6; ++i) {
*end++ = fish_base64[left & 0x3fu];
left = (left >> 6u);
}
/* The previous for'd ensure fill all bytes of encoded, we don't need will with zeros */
message += 8;
}
*end = '\0';
return encoded;
}
/**
* Decode ECB FiSH Base64
*
* @param [in] message Base64 encoded string
* @param [out] final_len Real length of message
* @return Array of char with decoded message
*/
char *fish_base64_decode(const char *message, size_t *final_len) {
BF_LONG left, right;
int i;
char *bytes = NULL;
char *msg = NULL;
char *byt = NULL;
size_t message_len;
message_len = strlen(message);
/* Ensure blocks of 12 bytes each one and valid characters */
if (message_len == 0 || message_len % 12 != 0 || strspn(message, fish_base64) != message_len)
return NULL;
/* Each 12 bytes becomes 8-byte block and add 1 byte for \0 */
*final_len = ((message_len - 1) / 12) * 8 + 8 + 1;
(*final_len)--; /* We support binary data */
bytes = (char *) g_malloc0(*final_len);
byt = bytes;
msg = (char *) message;
while (*msg) {
right = 0;
left = 0;
for (i = 0; i < 6; i++) right |= (uint8_t) fish_unbase64[*msg++] << (i * 6u);
for (i = 0; i < 6; i++) left |= (uint8_t) fish_unbase64[*msg++] << (i * 6u);
GET_BYTES(byt, left);
GET_BYTES(byt, right);
}
return bytes;
}
/**
* Encrypt or decrypt data with Blowfish cipher, support binary data.
*
* Good documentation for EVP:
*
* - https://wiki.openssl.org/index.php/EVP_Symmetric_Encryption_and_Decryption
*
* - https://stackoverflow.com/questions/5727646/what-is-the-length-parameter-of-aes-evp-decrypt
*
* - https://stackoverflow.com/questions/26345175/correct-way-to-free-allocate-the-context-in-the-openssl
*
* - https://stackoverflow.com/questions/29874150/working-with-evp-and-openssl-coding-in-c
*
* @param [in] plaintext Bytes to encrypt or decrypt
* @param [in] plaintext_len Size of plaintext
* @param [in] key Bytes of key
* @param [in] keylen Size of key
* @param [in] encode 1 or encrypt 0 for decrypt
* @param [in] mode EVP_CIPH_ECB_MODE or EVP_CIPH_CBC_MODE
* @param [out] ciphertext_len The bytes written
* @return Array of char with data encrypted or decrypted
*/
char *fish_cipher(const char *plaintext, size_t plaintext_len, const char *key, size_t keylen, int encode, int mode, size_t *ciphertext_len) {
EVP_CIPHER_CTX *ctx;
EVP_CIPHER *cipher = NULL;
int bytes_written = 0;
unsigned char *ciphertext = NULL;
unsigned char *iv_ciphertext = NULL;
unsigned char *iv = NULL;
size_t block_size = 0;
*ciphertext_len = 0;
if (plaintext_len == 0 || keylen == 0 || encode < 0 || encode > 1)
return NULL;
block_size = plaintext_len;
if (mode == EVP_CIPH_CBC_MODE) {
if (encode == 1) {
iv = (unsigned char *) g_malloc0(8);
RAND_bytes(iv, 8);
} else {
if (plaintext_len <= 8) /* IV + DATA */
return NULL;
iv = (unsigned char *) plaintext;
block_size -= 8;
plaintext += 8;
plaintext_len -= 8;
}
cipher = (EVP_CIPHER *) EVP_bf_cbc();
} else if (mode == EVP_CIPH_ECB_MODE) {
cipher = (EVP_CIPHER *) EVP_bf_ecb();
}
/* Zero Padding */
if (block_size % 8 != 0) {
block_size = block_size + 8 - (block_size % 8);
}
ciphertext = (unsigned char *) g_malloc0(block_size);
memcpy(ciphertext, plaintext, plaintext_len);
/* Create and initialise the context */
if (!(ctx = EVP_CIPHER_CTX_new()))
return NULL;
/* Initialise the cipher operation only with mode */
if (!EVP_CipherInit_ex(ctx, cipher, NULL, NULL, NULL, encode))
return NULL;
/* Set custom key length */
if (!EVP_CIPHER_CTX_set_key_length(ctx, keylen))
return NULL;
/* Finish the initiation the cipher operation */
if (1 != EVP_CipherInit_ex(ctx, NULL, NULL, (const unsigned char *) key, iv, encode))
return NULL;
/* We will manage this */
EVP_CIPHER_CTX_set_padding(ctx, 0);
/* Do cipher operation */
if (1 != EVP_CipherUpdate(ctx, ciphertext, &bytes_written, ciphertext, block_size))
return NULL;
*ciphertext_len = bytes_written;
/* Finalise the cipher. Further ciphertext bytes may be written at this stage */
if (1 != EVP_CipherFinal_ex(ctx, ciphertext + bytes_written, &bytes_written))
return NULL;
*ciphertext_len += bytes_written;
/* Clean up */
EVP_CIPHER_CTX_free(ctx);
if (mode == EVP_CIPH_CBC_MODE && encode == 1) {
/* Join IV + DATA */
iv_ciphertext = g_malloc0(8 + *ciphertext_len);
memcpy(iv_ciphertext, iv, 8);
memcpy(&iv_ciphertext[8], ciphertext, *ciphertext_len);
*ciphertext_len += 8;
g_free(ciphertext);
g_free(iv);
return (char *) iv_ciphertext;
} else {
return (char *) ciphertext;
}
}
/**
* Return a fish or standard Base64 encoded string with data encrypted
* is binary safe
*
* @param [in] key Bytes of key
* @param [in] keylen Size of key
* @param [in] message Bytes to encrypt
* @param [in] message_len Size of message
* @param [in] mode Chiper mode
* @return Array of char with data encrypted
*/
char *fish_encrypt(const char *key, size_t keylen, const char *message, size_t message_len, enum fish_mode mode) {
size_t ciphertext_len = 0;
char *ciphertext = NULL;
char *b64 = NULL;
if (keylen == 0 || message_len == 0)
return NULL;
ciphertext = fish_cipher(message, message_len, key, keylen, 1, mode, &ciphertext_len);
if (ciphertext == NULL || ciphertext_len == 0)
return NULL;
switch (mode) {
case FISH_CBC_MODE:
b64 = g_base64_encode((const unsigned char *) ciphertext, ciphertext_len);
break;
case FISH_ECB_MODE:
b64 = fish_base64_encode((const char *) ciphertext, ciphertext_len);
}
g_free(ciphertext);
if (b64 == NULL)
return NULL;
return b64;
}
/**
* Return an array of bytes with data decrypted
* is binary safe
*
* @param [in] key Bytes of key
* @param [in] keylen Size of key
* @param [in] data Fish or standard Base64 encoded string
* @param [in] mode Chiper mode
* @param [out] final_len Length of returned array
* @return Array of char with data decrypted
*/
char *fish_decrypt(const char *key, size_t keylen, const char *data, enum fish_mode mode, size_t *final_len) {
size_t ciphertext_len = 0;
char *ciphertext = NULL;
char *plaintext = NULL;
*final_len = 0;
if (keylen == 0 || strlen(data) == 0)
return NULL;
switch (mode) {
case FISH_CBC_MODE:
if (strspn(data, base64_chars) != strlen(data))
return NULL;
ciphertext = (char *) g_base64_decode(data, &ciphertext_len);
break;
case FISH_ECB_MODE:
ciphertext = fish_base64_decode(data, &ciphertext_len);
}
if (ciphertext == NULL || ciphertext_len == 0)
return NULL;
plaintext = fish_cipher(ciphertext, ciphertext_len, key, keylen, 0, mode, final_len);
g_free(ciphertext);
if (*final_len == 0)
return NULL;
return plaintext;
}
/**
* Similar to fish_decrypt, but pad with zeros any after the first zero in the decrypted data
*
* @param [in] key Bytes of key
* @param [in] keylen Size of key
* @param [in] data Fish or standard Base64 encoded string
* @param [in] mode Chiper mode
* @return Array of char with data decrypted
*/
char *fish_decrypt_str(const char *key, size_t keylen, const char *data, enum fish_mode mode) {
char *decrypted = NULL;
char *plaintext_str = NULL;
size_t decrypted_len = 0;
decrypted = fish_decrypt(key, strlen(key), data, mode, &decrypted_len);
if (decrypted == NULL || decrypted_len == 0)
return NULL;
plaintext_str = g_strndup(decrypted, decrypted_len);
g_free(decrypted);
return plaintext_str;
}
/**
* Encrypts a message (see fish_decrypt). The key is searched for in the
* key store.
*/
char *fish_encrypt_for_nick(const char *nick, const char *data, enum fish_mode *omode) {
char *key;
char *encrypted, *encrypted_cbc = NULL;
enum fish_mode mode;
/* Look for key */
key = keystore_get_key(nick, &mode);
if (!key) return NULL;
*omode = mode;
/* Encrypt */
encrypted = fish_encrypt(key, strlen(key), data, strlen(data), mode);
g_free(key);
if (encrypted == NULL || mode == FISH_ECB_MODE)
return encrypted;
/* Add '*' for CBC */
encrypted_cbc = g_strdup_printf("*%s",encrypted);
g_free(encrypted);
return encrypted_cbc;
}
/**
* Decrypts a message (see fish_decrypt). The key is searched for in the
* key store.
*/
char *fish_decrypt_from_nick(const char *nick, const char *data, enum fish_mode *omode) {
char *key;
char *decrypted;
enum fish_mode mode;
/* Look for key */
key = keystore_get_key(nick, &mode);
if (!key) return NULL;
*omode = mode;
if (mode == FISH_CBC_MODE)
++data;
/* Decrypt */
decrypted = fish_decrypt_str(key, strlen(key), data, mode);
g_free(key);
return decrypted;
}