527 lines
11 KiB
C
527 lines
11 KiB
C
/*-
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* Copyright (c) 2011 Ed Schouten <ed@kumina.nl>
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* All rights reserved.
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*
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* Portions of this software were developed under sponsorship from Snow
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* B.V., the Netherlands.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <assert.h>
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#include <fcntl.h>
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#include <resolv.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <openssl/md5.h>
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static pid_t other;
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static void
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die(int exitcode)
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{
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kill(other, SIGTERM);
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exit(exitcode);
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}
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static void
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usage(void)
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{
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fprintf(stderr, "usage: wsproxy minport maxport\n");
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exit(1);
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}
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static int
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pgetc(FILE *fp)
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{
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int ret;
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ret = fgetc(fp);
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if (ret == EOF)
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die(0);
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return (ret);
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}
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#if 0 /* UTF-8 */
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static void
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pputc(FILE *fp, unsigned char ch)
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{
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int ret;
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ret = fputc(ch, fp);
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if (ret == EOF)
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die(0);
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}
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static void
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decode(FILE *in, int outfd)
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{
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FILE *out;
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int ch;
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unsigned char och;
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out = fdopen(outfd, "w");
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if (out == NULL) {
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perror("fdopen");
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die(1);
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}
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for (;;) {
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/* Frame header. */
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ch = pgetc(in);
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if (ch != 0x00) {
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fprintf(stderr, "malformed frame header received\n");
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die(1);
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}
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for (;;) {
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/* Frame trailer. */
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ch = pgetc(in);
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if (ch == EOF)
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die(0);
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if (ch == 0xff) {
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fflush(out);
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break;
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}
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/* UTF-8 character, only allowing points 0 to 255. */
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if (ch < 0x80)
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och = ch;
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else if ((ch & 0xf3) == 0xc0) {
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och = ch << 6;
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ch = pgetc(in);
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if ((ch & 0xc0) != 0x80)
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goto malformed;
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och |= ch & 0x3f;
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} else
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goto malformed;
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pputc(out, och);
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}
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}
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malformed:
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fprintf(stderr, "malformed UTF-8 sequence received\n");
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die(1);
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}
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static int
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encode(int in, int out)
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{
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unsigned char inbuf[512];
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unsigned char outbuf[sizeof inbuf * 2 + 2];
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unsigned char *op;
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ssize_t len, i;
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for (;;) {
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len = read(in, inbuf, sizeof inbuf);
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if (len == -1) {
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perror("read");
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die(1);
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} else if (len == 0)
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die(0);
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op = outbuf;
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/* Frame header. */
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*op++ = 0x00;
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for (i = 0; i < len; i++) {
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/* Encode data as UTF-8. */
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if (inbuf[i] < 0x80)
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*op++ = inbuf[i];
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else {
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*op++ = 0xc0 | (inbuf[i] >> 6);
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*op++ = 0x80 | (inbuf[i] & 0x3f);
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}
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}
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/* Frame trailer. */
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*op++ = 0xff;
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assert(op <= outbuf + sizeof outbuf);
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len = write(out, outbuf, op - outbuf);
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if (len == -1) {
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perror("write");
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die(1);
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} else if (len != op - outbuf)
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die(0);
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}
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}
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#else /* base64 */
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static void
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putb64(FILE *out, char *inb, size_t *inblen)
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{
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char inbuf[5] = { 0 };
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unsigned char outbuf[3];
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ssize_t outbuflen;
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if (*inblen == 0)
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return;
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assert(*inblen <= 4);
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memcpy(inbuf, inb, *inblen);
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outbuflen = b64_pton(inbuf, outbuf, sizeof outbuf);
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if (outbuflen <= 0) {
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fprintf(stderr, "invalid Base64 data\n");
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die(1);
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}
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if (fwrite(outbuf, outbuflen, 1, out) != 1) {
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perror("fwrite");
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die(1);
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}
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*inblen = 0;
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}
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static void
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decode(FILE *in, int outfd)
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{
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FILE *out;
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int ch;
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char inb[4];
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size_t inblen = 0;
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out = fdopen(outfd, "w");
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if (out == NULL) {
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perror("fdopen");
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die(1);
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}
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for (;;) {
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/* Frame header. */
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ch = pgetc(in);
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if (ch != 0x00) {
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fprintf(stderr, "malformed frame header received\n");
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die(1);
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}
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for (;;) {
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ch = pgetc(in);
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if (ch == EOF) {
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putb64(out, inb, &inblen);
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die(0);
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}
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/* Frame trailer. */
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if (ch == 0xff) {
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putb64(out, inb, &inblen);
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if (fflush(out) == -1) {
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perror("fflush");
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die(1);
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}
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break;
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}
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if (!((ch >= 'A' && ch <= 'Z') ||
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(ch >= 'a' && ch <= 'z') ||
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(ch >= '0' && ch <= '9') ||
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ch == '+' || ch == '/' || ch == '=')) {
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fprintf(stderr,
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"non-Base64 character received\n");
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die(1);
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}
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/* Base64 character. */
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inb[inblen++] = ch;
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if (inblen == sizeof inb)
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putb64(out, inb, &inblen);
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}
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}
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}
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static int
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encode(int in, int out)
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{
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unsigned char inbuf[512];
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char outbuf[sizeof inbuf * 2 + 2];
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ssize_t len, wlen;
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for (;;) {
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len = read(in, inbuf, sizeof inbuf);
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if (len == -1) {
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perror("read");
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die(1);
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} else if (len == 0)
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die(0);
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/* Frame header. */
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outbuf[0] = 0x00;
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/* Encode data as Base64. */
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len = b64_ntop(inbuf, len, outbuf + 1, sizeof outbuf - 1) + 1;
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assert(len >= 1);
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/* Frame footer. */
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outbuf[len++] = 0xff;
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wlen = write(out, outbuf, len);
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if (wlen == -1) {
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perror("write");
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die(1);
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} else if (wlen != len)
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die(0);
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}
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}
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#endif
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static char *
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do_strndup(const char *str, size_t n)
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{
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size_t len;
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char *copy;
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for (len = 0; len < n && str[len]; len++)
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continue;
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if ((copy = malloc(len + 1)) == NULL)
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return (NULL);
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memcpy(copy, str, len);
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copy[len] = '\0';
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return (copy);
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}
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static char *
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parsestring(const char *in)
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{
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size_t len;
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len = strlen(in);
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if (len > 0 && in[len - 1] == '\n')
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len--;
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if (len > 0 && in[len - 1] == '\r')
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len--;
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if (len == 0)
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return (NULL);
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return (do_strndup(in, len));
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}
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static uint32_t
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parsehdrkey(const char *key)
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{
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uint32_t sum = 0, spaces = 0;
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for (; *key != '\0'; key++) {
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if (*key >= '0' && *key <= '9')
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sum = sum * 10 + *key - '0';
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else if (*key == ' ')
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spaces++;
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}
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return (spaces == 0 ? 0 : sum / spaces);
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}
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static void
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calcresponse(uint32_t key1, uint32_t key2, const char *key3, char *out)
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{
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MD5_CTX c;
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char in[16];
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in[0] = key1 >> 24;
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in[1] = key1 >> 16;
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in[2] = key1 >> 8;
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in[3] = key1;
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in[4] = key2 >> 24;
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in[5] = key2 >> 16;
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in[6] = key2 >> 8;
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in[7] = key2;
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memcpy(in + 8, key3, 8);
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MD5_Init(&c);
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MD5_Update(&c, (void *)in, sizeof in);
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MD5_Final((void *)out, &c);
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}
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static void
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eat_flash_magic(void)
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{
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static const char flash_magic[] = "<policy-file-request/>";
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ssize_t i;
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int ch;
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for (i = 0; i < sizeof flash_magic - 1; i++) {
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ch = getchar();
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if (ch == EOF) {
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perror("getc");
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exit(1);
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}
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/* Not a Flash applet. Roll back. */
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if (ch != flash_magic[i]) {
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ungetc(ch, stdin);
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while (--i >= 0)
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ungetc(flash_magic[i], stdin);
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return;
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}
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}
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printf("<cross-domain-policy>"
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"<allow-access-from domain=\"*\" to-ports=\"*\"/>"
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"</cross-domain-policy>\n");
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exit(0);
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}
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int
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main(int argc, char *argv[])
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{
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union {
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struct sockaddr sa;
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struct sockaddr_in sa_in;
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struct sockaddr_in6 sa_in6;
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} sa;
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char line[512], key3[8], response[16], *host = NULL, *origin = NULL;
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unsigned long minport, maxport, port;
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uint32_t key1 = 0, key2 = 0;
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socklen_t salen;
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pid_t pid;
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int fd, monitoring = 0, s;
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/* Squelch stderr when it is a socket. */
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if (!isatty(STDERR_FILENO)) {
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fd = open("/dev/null", O_WRONLY);
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if (fd == -1) {
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perror("open");
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return (1);
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}
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if (fd != STDERR_FILENO) {
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dup2(fd, STDERR_FILENO);
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close(fd);
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}
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}
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if (argc != 3)
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usage();
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minport = strtoul(argv[1], NULL, 10);
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maxport = strtoul(argv[2], NULL, 10);
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if (1 > minport || minport > maxport || maxport > 65535)
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usage();
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eat_flash_magic();
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/* GET / header. */
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if (fgets(line, sizeof line, stdin) == NULL) {
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perror("fgets");
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return (1);
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}
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if (strncmp(line, "GET /", 5) != 0) {
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fprintf(stderr, "malformed HTTP header received\n");
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return (1);
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}
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if (strncmp(line, "GET /wsproxy-monitoring/ ", 25) == 0)
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monitoring = 1;
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port = strtoul(line + 5, NULL, 10);
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if (!monitoring && (port < minport || port > maxport)) {
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fprintf(stderr, "port not allowed\n");
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return (1);
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}
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/* Parse HTTP headers. */
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do {
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if (fgets(line, sizeof line, stdin) == NULL) {
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fprintf(stderr, "partial HTTP header received\n");
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return (1);
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}
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if (strncasecmp(line, "Host: ", 6) == 0) {
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host = parsestring(line + 6);
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} else if (strncasecmp(line, "Origin: ", 8) == 0) {
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origin = parsestring(line + 8);
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} else if (strncasecmp(line, "Sec-WebSocket-Key1: ", 20) == 0) {
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key1 = parsehdrkey(line + 20);
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} else if (strncasecmp(line, "Sec-WebSocket-Key2: ", 20) == 0) {
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key2 = parsehdrkey(line + 20);
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}
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} while (strcmp(line, "\n") != 0 && strcmp(line, "\r\n") != 0);
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/* Simple monitoring. */
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if (monitoring) {
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printf("HTTP/1.1 200 OK\r\n"
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"Content-Type: text/plain\r\n"
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"\r\n"
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"RUNNING\n");
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return (0);
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}
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/* Eight byte payload. */
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if (fread(key3, sizeof key3, 1, stdin) != 1) {
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fprintf(stderr, "key data missing\n");
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return (1);
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}
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/* Use our own address. Fall back to 127.0.0.1 on failure. */
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salen = sizeof sa;
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if (getsockname(STDIN_FILENO, &sa.sa, &salen) == -1) {
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salen = sizeof sa.sa_in;
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memset(&sa.sa_in, 0, salen);
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sa.sa_in.sin_family = AF_INET;
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sa.sa_in.sin_addr.s_addr = inet_addr("127.0.0.1");
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}
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switch (sa.sa.sa_family) {
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case AF_INET:
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sa.sa_in.sin_port = htons(port);
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break;
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case AF_INET6:
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sa.sa_in6.sin6_port = htons(port);
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break;
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default:
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/* Unknown protocol. */
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fprintf(stderr, "unsupported network protocol\n");
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return (1);
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}
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s = socket(sa.sa.sa_family, SOCK_STREAM, 0);
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if (s == -1) {
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perror("socket");
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return (1);
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}
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if (connect(s, &sa.sa, salen) == -1) {
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perror("connect");
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return (1);
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}
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/* Send HTTP response. */
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calcresponse(key1, key2, key3, response);
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printf("HTTP/1.1 101 WebSocket Protocol Handshake\r\n"
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"Upgrade: WebSocket\r\n"
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"Connection: Upgrade\r\n"
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"Sec-WebSocket-Origin: %s\r\n"
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"Sec-WebSocket-Location: ws://%s/%lu\r\n"
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"Sec-WebSocket-Protocol: base64\r\n\r\n", origin, host, port);
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fwrite(response, sizeof response, 1, stdout);
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fflush(stdout);
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/* Spawn child process for bi-directional pipe. */
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pid = fork();
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if (pid == -1) {
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perror("fork");
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return (1);
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} else if (pid == 0) {
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other = getppid();
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decode(stdin, s);
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} else {
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other = pid;
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encode(s, STDOUT_FILENO);
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}
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assert(0);
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}
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