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Diffstat (limited to 'plugins/anonaes128/anonaes128.c')
| -rw-r--r-- | plugins/anonaes128/anonaes128.c | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/plugins/anonaes128/anonaes128.c b/plugins/anonaes128/anonaes128.c new file mode 100644 index 0000000..340bb71 --- /dev/null +++ b/plugins/anonaes128/anonaes128.c @@ -0,0 +1,344 @@ +/* + * Copyright (c) 2018-2021, OARC, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. Neither the name of the copyright holder nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER + * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include "config.h" + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <sys/socket.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> + +#include "dnscap_common.h" + +#if defined(HAVE_LIBCRYPTO) && defined(HAVE_OPENSSL_CONF_H) && defined(HAVE_OPENSSL_ERR_H) && defined(HAVE_OPENSSL_EVP_H) +#include <openssl/conf.h> +#include <openssl/evp.h> +#include <openssl/err.h> +#define USE_OPENSSL 1 +#endif + +static set_iaddr_t anonaes128_set_iaddr = 0; + +static logerr_t* logerr; +static int only_clients = 0, only_servers = 0, dns_port = 53, encrypt_v4 = 0, decrypt = 0; +static unsigned char key[16]; +static unsigned char iv[16]; +#ifdef USE_OPENSSL +static EVP_CIPHER_CTX* ctx = 0; +#endif + +enum plugin_type anonaes128_type() +{ + return plugin_filter; +} + +void usage(const char* msg) +{ + fprintf(stderr, "anonaes128.so usage error: %s\n", msg); + exit(1); +} + +void anonaes128_usage() +{ + fprintf(stderr, + "\nanonaes128.so options:\n" + "\t-? print these instructions and exit\n" + "\t-k <key> A 16 character long key\n" + "\t-K <file> Read the 16 first bytes from file and use as key\n" + "\t-i <key> A 16 character long Initialisation Vector (IV)\n" + "\t-I <file> Read the 16 first bytes from file and use as IV\n" + "\t-D Decrypt IPv6 addresses\n" + "\t-c Only en/de-crypt clients (port != 53)\n" + "\t-s Only en/de-crypt servers (port == 53)\n" + "\t-p <port> Set port for -c/-s, default 53\n" + "\t-4 Encrypt IPv4 addresses, not default or recommended\n"); +} + +void anonaes128_extension(int ext, void* arg) +{ + switch (ext) { + case DNSCAP_EXT_SET_IADDR: + anonaes128_set_iaddr = (set_iaddr_t)arg; + break; + } +} + +void anonaes128_getopt(int* argc, char** argv[]) +{ + int c, got_key = 0, got_iv = 0; + unsigned long ul; + char* p; + + while ((c = getopt(*argc, *argv, "?k:K:i:I:Dcsp:4")) != EOF) { + switch (c) { + case 'k': + if (strlen(optarg) != 16) { + usage("key must be 16 characters long"); + } + memcpy(key, optarg, 16); + got_key = 1; + break; + case 'K': { + int fd; + ssize_t r; + if ((fd = open(optarg, O_RDONLY)) < 0) { + perror("open()"); + usage("unable to open key file"); + } + if ((r = read(fd, key, 16)) < 0) { + perror("read()"); + usage("unable to read from key file"); + } + if (r != 16) { + usage("unable to read 16 bytes from key file"); + } + close(fd); + got_key = 1; + break; + } + case 'i': + if (strlen(optarg) != 16) { + usage("IV must be 16 characters long"); + } + memcpy(iv, optarg, 16); + got_iv = 1; + break; + case 'I': { + int fd; + ssize_t r; + if ((fd = open(optarg, O_RDONLY)) < 0) { + perror("open()"); + usage("unable to open IV file"); + } + if ((r = read(fd, iv, 16)) < 0) { + perror("read()"); + usage("unable to read from IV file"); + } + if (r != 16) { + usage("unable to read 16 bytes from IV file"); + } + close(fd); + got_iv = 1; + break; + } + case 'D': + decrypt = 1; + break; + case 'c': + only_clients = 1; + break; + case 's': + only_servers = 1; + break; + case 'p': + ul = strtoul(optarg, &p, 0); + if (*p != '\0' || ul < 1U || ul > 65535U) + usage("port must be an integer 1..65535"); + dns_port = (unsigned)ul; + break; + case '4': + encrypt_v4 = 1; + break; + case '?': + anonaes128_usage(); + if (!optopt || optopt == '?') { + exit(0); + } + // fallthrough + default: + exit(1); + } + } + + if (!got_key || !got_iv) { + usage("must have key (-k/-K) and IV (-i/-I)"); + } + if (decrypt && encrypt_v4) { + usage("decryption (-D) can not be done for IPv4 addresses (-4)"); + } + +#ifdef USE_OPENSSL + if (!(ctx = EVP_CIPHER_CTX_new())) { + usage("unable to create openssl cipher context"); + } + if (!EVP_CipherInit_ex(ctx, EVP_aes_128_ecb(), NULL, key, iv, decrypt ? 0 : 1)) { + unsigned long e = ERR_get_error(); + fprintf(stderr, "%s:%s:%s", ERR_lib_error_string(e), ERR_func_error_string(e), ERR_reason_error_string(e)); + usage("unable to initialize AES128 cipher"); + } + EVP_CIPHER_CTX_set_padding(ctx, 0); +#else + usage("no openssl support built in, can't encrypt IP addresses"); +#endif + + if (only_clients && only_servers) { + usage("-c and -s options are mutually exclusive"); + } +} + +int anonaes128_start(logerr_t* a_logerr) +{ + logerr = a_logerr; + return 0; +} + +void anonaes128_stop() +{ +#ifdef USE_OPENSSL + EVP_CIPHER_CTX_free(ctx); + ctx = 0; +#endif +} + +int anonaes128_open(my_bpftimeval ts) +{ + return 0; +} + +int anonaes128_close(my_bpftimeval ts) +{ + return 0; +} + +int anonaes128_filter(const char* descr, iaddr* from, iaddr* to, uint8_t proto, unsigned flags, + unsigned sport, unsigned dport, my_bpftimeval ts, + const u_char* pkt_copy, const unsigned olen, + const u_char* payload, const unsigned payloadlen) +{ +#ifdef USE_OPENSSL + unsigned char outbuf[16 + EVP_MAX_BLOCK_LENGTH]; + int outlen = 0; + + for (;;) { + if (only_clients && sport == dns_port) { + from = 0; + break; + } + if (only_servers && sport != dns_port) { + from = 0; + break; + } + + switch (from->af) { + case AF_INET6: + if (!EVP_CipherUpdate(ctx, outbuf, &outlen, (unsigned char*)&from->u.a6, 16)) { + logerr("anonaes128.so: error en/de-crypting IP address: %s", ERR_reason_error_string(ERR_get_error())); + exit(1); + } + if (outlen != 16) { + logerr("anonaes128.so: error en/de-crypted output is not 16 bytes"); + exit(1); + } + memcpy(&from->u.a6, outbuf, 16); + break; + case AF_INET: + if (encrypt_v4) { + memcpy(((uint8_t*)&from->u.a6) + 4, &from->u.a4, 4); + memcpy(((uint8_t*)&from->u.a6) + 8, &from->u.a4, 4); + memcpy(((uint8_t*)&from->u.a6) + 12, &from->u.a4, 4); + + if (!EVP_CipherUpdate(ctx, outbuf, &outlen, (unsigned char*)&from->u.a6, 16)) { + logerr("anonaes128.so: error en/de-crypting IP address: %s", ERR_reason_error_string(ERR_get_error())); + exit(1); + } + if (outlen != 16) { + logerr("anonaes128.so: error en/de-crypted output is not 16 bytes"); + exit(1); + } + memcpy(&from->u.a4, outbuf, 4); + break; + } + default: + from = 0; + break; + } + break; + } + + for (;;) { + if (only_clients && dport == dns_port) { + to = 0; + break; + } + if (only_servers && dport != dns_port) { + to = 0; + break; + } + + switch (to->af) { + case AF_INET6: + if (!EVP_CipherUpdate(ctx, outbuf, &outlen, (unsigned char*)&to->u.a6, 16)) { + logerr("anonaes128.so: error en/de-crypting IP address: %s", ERR_reason_error_string(ERR_get_error())); + exit(1); + } + if (outlen != 16) { + logerr("anonaes128.so: error en/de-crypted output is not 16 bytes"); + exit(1); + } + memcpy(&to->u.a6, outbuf, 16); + break; + case AF_INET: + if (encrypt_v4) { + memcpy(((uint8_t*)&to->u.a6) + 4, &to->u.a4, 4); + memcpy(((uint8_t*)&to->u.a6) + 8, &to->u.a4, 4); + memcpy(((uint8_t*)&to->u.a6) + 12, &to->u.a4, 4); + + if (!EVP_CipherUpdate(ctx, outbuf, &outlen, (unsigned char*)&to->u.a6, 16)) { + logerr("anonaes128.so: error en/de-crypting IP address: %s", ERR_reason_error_string(ERR_get_error())); + exit(1); + } + if (outlen != 16) { + logerr("anonaes128.so: error en/de-crypted output is not 16 bytes"); + exit(1); + } + memcpy(&to->u.a4, outbuf, 4); + break; + } + default: + to = 0; + break; + } + break; + } + + if (anonaes128_set_iaddr && (from || to)) { + anonaes128_set_iaddr(from, to); + } +#endif + return 0; +} |