From 22c74419e2c258319bc723351876604b3304604b Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 4 Mar 2021 20:22:03 +0100 Subject: Adding upstream version 2.0.0+debian. Signed-off-by: Daniel Baumann --- plugins/cryptopan/cryptopan.c | 475 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 475 insertions(+) create mode 100644 plugins/cryptopan/cryptopan.c (limited to 'plugins/cryptopan/cryptopan.c') diff --git a/plugins/cryptopan/cryptopan.c b/plugins/cryptopan/cryptopan.c new file mode 100644 index 0000000..2e439af --- /dev/null +++ b/plugins/cryptopan/cryptopan.c @@ -0,0 +1,475 @@ +/* + * 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. + */ + +/* + * Crypto-PAn encryption based on submitted extension by David Stott (Lucent) + * https://www.cc.gatech.edu/computing/Networking/projects/cryptopan/lucent.shtml + */ + +#include "config.h" + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "dnscap_common.h" + +#if defined(HAVE_LIBCRYPTO) && defined(HAVE_OPENSSL_CONF_H) && defined(HAVE_OPENSSL_ERR_H) && defined(HAVE_OPENSSL_EVP_H) +#include +#include +#include +#define USE_OPENSSL 1 +#endif + +static set_iaddr_t cryptopan_set_iaddr = 0; + +static logerr_t* logerr; +static int only_clients = 0, only_servers = 0, dns_port = 53, encrypt_v6 = 0, decrypt = 0; +static unsigned char key[16]; +static unsigned char iv[16]; +static unsigned char pad[16]; +#ifdef USE_OPENSSL +static EVP_CIPHER_CTX* ctx = 0; +#endif + +enum plugin_type cryptopan_type() +{ + return plugin_filter; +} + +void usage(const char* msg) +{ + fprintf(stderr, "cryptopan.so usage error: %s\n", msg); + exit(1); +} + +void cryptopan_usage() +{ + fprintf(stderr, + "\ncryptopan.so options:\n" + "\t-? print these instructions and exit\n" + "\t-k A 16 character long key\n" + "\t-K Read the 16 first bytes from file and use as key\n" + "\t-i A 16 character long Initialisation Vector (IV)\n" + "\t-I Read the 16 first bytes from file and use as IV\n" + "\t-a A 16 character long padding\n" + "\t-A Read the 16 first bytes from file and use as padding\n" + "\t-D Decrypt IP addresses\n" + "\t-c Only en/de-crypt clients (port != 53)\n" + "\t-s Only en/de-crypt servers (port == 53)\n" + "\t-p Set port for -c/-s, default 53\n" + "\t-6 En/de-crypt IPv6 addresses, not default or recommended\n"); +} + +void cryptopan_extension(int ext, void* arg) +{ + switch (ext) { + case DNSCAP_EXT_SET_IADDR: + cryptopan_set_iaddr = (set_iaddr_t)arg; + break; + } +} + +void cryptopan_getopt(int* argc, char** argv[]) +{ + int c, got_key = 0, got_iv = 0, got_pad = 0; + unsigned long ul; + char* p; + + while ((c = getopt(*argc, *argv, "?k:K:i:I:a:A:Dcsp:6")) != 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 'a': + if (strlen(optarg) != 16) { + usage("padding must be 16 characters long"); + } + memcpy(pad, optarg, 16); + got_pad = 1; + break; + case 'A': { + int fd; + ssize_t r; + if ((fd = open(optarg, O_RDONLY)) < 0) { + perror("open()"); + usage("unable to open padding file"); + } + if ((r = read(fd, pad, 16)) < 0) { + perror("read()"); + usage("unable to read from padding file"); + } + if (r != 16) { + usage("unable to read 16 bytes from padding file"); + } + close(fd); + got_pad = 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 '6': + encrypt_v6 = 1; + break; + case '?': + cryptopan_usage(); + if (!optopt || optopt == '?') { + exit(0); + } + // fallthrough + default: + exit(1); + } + } + + if (!got_key || !got_iv || !got_pad) { + usage("must have key (-k/-K), IV (-i/-I) and padding (-a/-A)"); + } + +#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, 1)) { + unsigned long e = ERR_get_error(); + fprintf(stderr, "%s:%s:%s\n", 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); + { + unsigned char outbuf[16 + EVP_MAX_BLOCK_LENGTH]; + int outlen = 0; + + if (!EVP_CipherUpdate(ctx, outbuf, &outlen, pad, 16)) { + fprintf(stderr, "cryptopan.so: error encrypting padding: %s\n", ERR_reason_error_string(ERR_get_error())); + exit(1); + } + if (outlen != 16) { + fprintf(stderr, "cryptopan.so: error encrypted padding is not 16 bytes\n"); + exit(1); + } + memcpy(&pad, outbuf, 16); + } +#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 cryptopan_start(logerr_t* a_logerr) +{ + logerr = a_logerr; + return 0; +} + +void cryptopan_stop() +{ +#ifdef USE_OPENSSL + EVP_CIPHER_CTX_free(ctx); + ctx = 0; +#endif +} + +int cryptopan_open(my_bpftimeval ts) +{ + return 0; +} + +int cryptopan_close(my_bpftimeval ts) +{ + return 0; +} + +#ifdef USE_OPENSSL +struct input { + union { + unsigned char input[16]; + uint32_t ui32; + } u; +}; +struct output { + union { + unsigned char outbuf[16 + EVP_MAX_BLOCK_LENGTH]; + uint32_t ui32; + } u; +}; +static inline void _encrypt(uint32_t* in) +{ + struct input input; + struct output output; + int outlen = 0, pos; + uint32_t orig, result = 0, pad4b, mask = 0; + + memcpy(input.u.input, pad, 16); + orig = ntohl(*in); + memcpy(&pad4b, pad, 4); + + // First pass with padding only + + input.u.ui32 = htonl(pad4b); + + if (!EVP_CipherUpdate(ctx, output.u.outbuf, &outlen, input.u.input, 16)) { + fprintf(stderr, "cryptopan.so: error encrypting: %s\n", ERR_reason_error_string(ERR_get_error())); + exit(1); + } + if (outlen != 16) { + fprintf(stderr, "cryptopan.so: error encrypted result is not 16 bytes\n"); + exit(1); + } + + result |= ntohl(output.u.ui32) & 0x80000000; + mask >>= 1; + mask |= 0x80000000; + + for (pos = 1; pos < 32; pos++) { + input.u.ui32 = htonl(((pad4b << pos) | (pad4b >> (32 - pos))) ^ (orig & mask)); + + if (!EVP_CipherUpdate(ctx, output.u.outbuf, &outlen, input.u.input, 16)) { + fprintf(stderr, "cryptopan.so: error encrypting: %s\n", ERR_reason_error_string(ERR_get_error())); + exit(1); + } + if (outlen != 16) { + fprintf(stderr, "cryptopan.so: error encrypted result is not 16 bytes\n"); + exit(1); + } + + result |= (ntohl(output.u.ui32) & 0x80000000) >> pos; + mask >>= 1; + mask |= 0x80000000; + } + + *in = htonl(result ^ orig); +} + +static inline void _decrypt(uint32_t* in) +{ + struct input input; + struct output output; + int outlen = 0, pos; + uint32_t orig, pad4b, mask = 0; + + memcpy(input.u.input, pad, 16); + orig = ntohl(*in); + memcpy(&pad4b, pad, 4); + + // First pass with padding only + + input.u.ui32 = htonl(pad4b); + + if (!EVP_CipherUpdate(ctx, output.u.outbuf, &outlen, input.u.input, 16)) { + fprintf(stderr, "cryptopan.so: error encrypting: %s\n", ERR_reason_error_string(ERR_get_error())); + exit(1); + } + if (outlen != 16) { + fprintf(stderr, "cryptopan.so: error encrypted result is not 16 bytes\n"); + exit(1); + } + + orig ^= ntohl(output.u.ui32) & 0x80000000; + mask >>= 1; + mask |= 0x80000000; + + for (pos = 1; pos < 32; pos++) { + input.u.ui32 = htonl(((pad4b << pos) | (pad4b >> (32 - pos))) ^ (orig & mask)); + + if (!EVP_CipherUpdate(ctx, output.u.outbuf, &outlen, input.u.input, 16)) { + fprintf(stderr, "cryptopan.so: error encrypting: %s\n", ERR_reason_error_string(ERR_get_error())); + exit(1); + } + if (outlen != 16) { + fprintf(stderr, "cryptopan.so: error encrypted result is not 16 bytes\n"); + exit(1); + } + + orig ^= (ntohl(output.u.ui32) & 0x80000000) >> pos; + mask >>= 1; + mask |= 0x80000000; + } + + *in = htonl(orig); +} +#endif + +int cryptopan_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 + for (;;) { + if (only_clients && sport == dns_port) { + from = 0; + break; + } + if (only_servers && sport != dns_port) { + from = 0; + break; + } + + switch (from->af) { + case AF_INET: + decrypt ? _decrypt((uint32_t*)&from->u.a4) : _encrypt((uint32_t*)&from->u.a4); + break; + case AF_INET6: + if (encrypt_v6) { + if (decrypt) { + _decrypt((uint32_t*)&from->u.a6); + _decrypt(((uint32_t*)&from->u.a6) + 1); // lgtm [cpp/suspicious-pointer-scaling] + _decrypt(((uint32_t*)&from->u.a6) + 2); // lgtm [cpp/suspicious-pointer-scaling] + _decrypt(((uint32_t*)&from->u.a6) + 3); // lgtm [cpp/suspicious-pointer-scaling] + } else { + _encrypt((uint32_t*)&from->u.a6); + _encrypt(((uint32_t*)&from->u.a6) + 1); // lgtm [cpp/suspicious-pointer-scaling] + _encrypt(((uint32_t*)&from->u.a6) + 2); // lgtm [cpp/suspicious-pointer-scaling] + _encrypt(((uint32_t*)&from->u.a6) + 3); // lgtm [cpp/suspicious-pointer-scaling] + } + 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_INET: + decrypt ? _decrypt((uint32_t*)&to->u.a4) : _encrypt((uint32_t*)&to->u.a4); + break; + case AF_INET6: + if (encrypt_v6) { + if (decrypt) { + _decrypt((uint32_t*)&to->u.a6); + _decrypt(((uint32_t*)&to->u.a6) + 1); // lgtm [cpp/suspicious-pointer-scaling] + _decrypt(((uint32_t*)&to->u.a6) + 2); // lgtm [cpp/suspicious-pointer-scaling] + _decrypt(((uint32_t*)&to->u.a6) + 3); // lgtm [cpp/suspicious-pointer-scaling] + } else { + _encrypt((uint32_t*)&to->u.a6); + _encrypt(((uint32_t*)&to->u.a6) + 1); // lgtm [cpp/suspicious-pointer-scaling] + _encrypt(((uint32_t*)&to->u.a6) + 2); // lgtm [cpp/suspicious-pointer-scaling] + _encrypt(((uint32_t*)&to->u.a6) + 3); // lgtm [cpp/suspicious-pointer-scaling] + } + break; + } + default: + to = 0; + break; + } + break; + } + + if (cryptopan_set_iaddr && (from || to)) { + cryptopan_set_iaddr(from, to); + } +#endif + return 0; +} -- cgit v1.2.3