139 lines
3.6 KiB
C
139 lines
3.6 KiB
C
/**
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* sesimos - secure, simple, modern web server
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* @brief WebSocket reverse proxy
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* @file src/lib/websocket.c
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* @author Lorenz Stechauner
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* @date 2022-08-16
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*/
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#include "../logger.h"
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#include "websocket.h"
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#include "utils.h"
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#include <string.h>
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#include <openssl/sha.h>
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static const char ws_key_uuid[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
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int ws_calc_accept_key(const char *key, char *accept_key) {
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if (key == NULL || accept_key == NULL)
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return -1;
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char input[256] = "";
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unsigned char output[SHA_DIGEST_LENGTH];
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strcat(input, key);
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strcat(input, ws_key_uuid);
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if (SHA1((unsigned char *) input, strlen(input), output) == NULL) {
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return -2;
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}
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base64_encode(output, sizeof(output), accept_key, NULL);
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return 0;
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}
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int ws_recv_frame_header(sock *s, ws_frame *frame) {
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unsigned char buf[12];
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long ret = sock_recv(s, buf, 2, 0);
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if (ret < 0) {
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error("Unable to receive from socket");
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return -1;
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} else if (ret != 2) {
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error("Unable to receive 2 bytes from socket");
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return -2;
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}
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unsigned short bits = (buf[0] << 8) | buf[1];
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frame->f_fin = (bits >> 15) & 1;
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frame->f_rsv1 = (bits >> 14) & 1;
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frame->f_rsv2 = (bits >> 13) & 1;
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frame->f_rsv3 = (bits >> 12) & 1;
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frame->opcode = (bits >> 8) & 0xF;
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frame->f_mask = (bits >> 7) & 1;
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unsigned short len = (bits & 0x7F);
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int remaining = frame->f_mask ? 4 : 0;
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if (len == 126) {
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remaining += 2;
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} else if (len == 127) {
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remaining += 8;
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}
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ret = sock_recv(s, buf, remaining, 0);
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if (ret < 0) {
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error("Unable to receive from socket");
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return -1;
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} else if (ret != remaining) {
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error("Unable to receive correct number of bytes from socket");
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return -2;
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}
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if (len == 126) {
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frame->len = (((unsigned long) buf[0]) << 8) | ((unsigned long) buf[1]);
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} else if (len == 127) {
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frame->len =
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(((unsigned long) buf[0]) << 56) |
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(((unsigned long) buf[1]) << 48) |
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(((unsigned long) buf[2]) << 40) |
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(((unsigned long) buf[3]) << 32) |
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(((unsigned long) buf[4]) << 24) |
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(((unsigned long) buf[5]) << 16) |
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(((unsigned long) buf[6]) << 8) |
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(((unsigned long) buf[7]) << 0);
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} else {
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frame->len = len;
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}
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if (frame->f_mask) memcpy(frame->masking_key, buf + (remaining - 4), 4);
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return 0;
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}
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int ws_send_frame_header(sock *s, ws_frame *frame) {
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unsigned char buf[14], *ptr = buf;
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unsigned short len;
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if (frame->len > 0x7FFF) {
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len = 127;
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} else if (frame->len > 125) {
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len = 126;
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} else {
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len = frame->len;
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}
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unsigned short bits =
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(frame->f_fin << 15) |
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(frame->f_rsv1 << 14) |
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(frame->f_rsv2 << 13) |
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(frame->f_rsv3 << 12) |
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(frame->opcode << 8) |
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(frame->f_mask << 7) |
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len;
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ptr++[0] = bits >> 8;
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ptr++[0] = bits & 0xFF;
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if (len >= 126) {
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for (int i = (len == 126 ? 2 : 8) - 1; i >= 0; i--)
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ptr++[0] = (unsigned char) ((frame->len >> (i * 8)) & 0xFF);
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}
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if (frame->f_mask) {
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memcpy(ptr, frame->masking_key, 4);
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ptr += 4;
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}
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long ret = sock_send(s, buf, ptr - buf, frame->len != 0 ? MSG_MORE : 0);
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if (ret < 0) {
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error("Unable to send to socket");
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return -1;
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} else if (ret != ptr - buf) {
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error("Unable to send to socket");
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return -2;
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}
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return 0;
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}
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