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-rw-r--r--plugins/ipcrypt/ipcrypt.c351
1 files changed, 351 insertions, 0 deletions
diff --git a/plugins/ipcrypt/ipcrypt.c b/plugins/ipcrypt/ipcrypt.c
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--- /dev/null
+++ b/plugins/ipcrypt/ipcrypt.c
@@ -0,0 +1,351 @@
+/*
+ * 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"
+
+static set_iaddr_t ipcrypt_set_iaddr = 0;
+
+static logerr_t* logerr;
+static int only_clients = 0, only_servers = 0, dns_port = 53, iterations = 1, encrypt_v6 = 0, decrypt = 0;
+static uint8_t key[16];
+
+/*
+ * ipcrypt based on Python and Go code at https://github.com/veorq/ipcrypt
+ * by Jean-Philippe Aumasson jeanphilippe.aumasson@gmail.com
+ */
+
+static inline uint8_t rotl(uint8_t b, int r)
+{
+ return (b << r) | (b >> (8 - r));
+}
+
+static inline void permute_fwd(uint8_t* state)
+{
+ state[0] += state[1];
+ state[2] += state[3];
+ state[1] = rotl(state[1], 2) ^ state[0];
+ state[3] = rotl(state[3], 5) ^ state[2];
+ // state[1] ^= state[0];
+ // state[3] ^= state[2];
+ state[0] = rotl(state[0], 4) + state[3];
+ // state[0] += state[3];
+ state[2] += state[1];
+ state[1] = rotl(state[1], 3) ^ state[2];
+ state[3] = rotl(state[3], 7) ^ state[0];
+ // state[1] ^= state[2];
+ // state[3] ^= state[0];
+ state[2] = rotl(state[2], 4);
+}
+
+static inline void permute_bwd(uint8_t* state)
+{
+ state[2] = rotl(state[2], 4);
+ state[1] ^= state[2];
+ state[3] ^= state[0];
+ state[1] = rotl(state[1], 5);
+ state[3] = rotl(state[3], 1);
+ state[0] -= state[3];
+ state[2] -= state[1];
+ state[0] = rotl(state[0], 4);
+ state[1] ^= state[0];
+ state[3] ^= state[2];
+ state[1] = rotl(state[1], 6);
+ state[3] = rotl(state[3], 3);
+ state[0] -= state[1];
+ state[2] -= state[3];
+}
+
+static inline void xor4(uint8_t* x, uint8_t* y)
+{
+ *(uint32_t*)x ^= *(uint32_t*)y;
+ // x[0] ^= y[0];
+ // x[1] ^= y[1];
+ // x[2] ^= y[2];
+ // x[3] ^= y[3];
+}
+
+static inline void _encrypt(uint8_t* ip)
+{
+ int i = iterations;
+ for (; i; i--) {
+ xor4(ip, key);
+ permute_fwd(ip);
+ xor4(ip, &key[4]);
+ permute_fwd(ip);
+ xor4(ip, &key[8]);
+ permute_fwd(ip);
+ xor4(ip, &key[12]);
+ }
+}
+
+static inline void _decrypt(uint8_t* ip)
+{
+ int i = iterations;
+ for (; i; i--) {
+ xor4(ip, &key[12]);
+ permute_bwd(ip);
+ xor4(ip, &key[8]);
+ permute_bwd(ip);
+ xor4(ip, &key[4]);
+ permute_bwd(ip);
+ xor4(ip, key);
+ }
+}
+
+enum plugin_type ipcrypt_type()
+{
+ return plugin_filter;
+}
+
+void usage(const char* msg)
+{
+ fprintf(stderr, "ipcrypt.so usage error: %s\n", msg);
+ exit(1);
+}
+
+void ipcrypt_usage()
+{
+ fprintf(stderr,
+ "\nipcrypt.so options:\n"
+ "\t-? print these instructions and exit\n"
+ "\t-k <key> A 16 character long key\n"
+ "\t-f <file> Read the 16 first bytes from file and use as key\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 <port> Set port for -c/-s, default 53\n"
+ "\t-i <num> Number of en/de-cryption iterations, default 1\n"
+ "\t-6 En/de-crypt IPv6 addresses, not default or recommended\n");
+}
+
+void ipcrypt_extension(int ext, void* arg)
+{
+ switch (ext) {
+ case DNSCAP_EXT_SET_IADDR:
+ ipcrypt_set_iaddr = (set_iaddr_t)arg;
+ break;
+ }
+}
+
+void ipcrypt_getopt(int* argc, char** argv[])
+{
+ int c, got_key = 0;
+ unsigned long ul;
+ char* p;
+
+ while ((c = getopt(*argc, *argv, "?k:f:Dcsp:i: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 'f': {
+ 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 '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 'i':
+ ul = strtoul(optarg, &p, 0);
+ if (*p != '\0' || ul < 1U || ul > 65535U)
+ usage("iterations must be an integer 1..65535");
+ iterations = (unsigned)ul;
+ break;
+ case '6':
+ encrypt_v6 = 1;
+ break;
+ case '?':
+ ipcrypt_usage();
+ if (!optopt || optopt == '?') {
+ exit(0);
+ }
+ // fallthrough
+ default:
+ exit(1);
+ }
+ }
+
+ if (!got_key) {
+ usage("must have -k <key> or -f <file>");
+ }
+
+ if (only_clients && only_servers) {
+ usage("-c and -s options are mutually exclusive");
+ }
+}
+
+int ipcrypt_start(logerr_t* a_logerr)
+{
+ logerr = a_logerr;
+ return 0;
+}
+
+void ipcrypt_stop()
+{
+}
+
+int ipcrypt_open(my_bpftimeval ts)
+{
+ return 0;
+}
+
+int ipcrypt_close(my_bpftimeval ts)
+{
+ return 0;
+}
+
+int ipcrypt_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)
+{
+ 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((uint8_t*)&from->u.a4) : _encrypt((uint8_t*)&from->u.a4);
+ break;
+ case AF_INET6:
+ if (encrypt_v6) {
+ if (decrypt) {
+ _decrypt((uint8_t*)&from->u.a6);
+ _decrypt(((uint8_t*)&from->u.a6) + 4);
+ _decrypt(((uint8_t*)&from->u.a6) + 8);
+ _decrypt(((uint8_t*)&from->u.a6) + 12);
+ } else {
+ _encrypt((uint8_t*)&from->u.a6);
+ _encrypt(((uint8_t*)&from->u.a6) + 4);
+ _encrypt(((uint8_t*)&from->u.a6) + 8);
+ _encrypt(((uint8_t*)&from->u.a6) + 12);
+ }
+ 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((uint8_t*)&to->u.a4) : _encrypt((uint8_t*)&to->u.a4);
+ break;
+ case AF_INET6:
+ if (encrypt_v6) {
+ if (decrypt) {
+ _decrypt((uint8_t*)&to->u.a6);
+ _decrypt(((uint8_t*)&to->u.a6) + 4);
+ _decrypt(((uint8_t*)&to->u.a6) + 8);
+ _decrypt(((uint8_t*)&to->u.a6) + 12);
+ } else {
+ _encrypt((uint8_t*)&to->u.a6);
+ _encrypt(((uint8_t*)&to->u.a6) + 4);
+ _encrypt(((uint8_t*)&to->u.a6) + 8);
+ _encrypt(((uint8_t*)&to->u.a6) + 12);
+ }
+ break;
+ }
+ default:
+ to = 0;
+ break;
+ }
+ break;
+ }
+
+ if (ipcrypt_set_iaddr && (from || to)) {
+ ipcrypt_set_iaddr(from, to);
+ }
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-13 15:13:05 +0000