/*-

 * Copyright (c) 2020 Yuquan Wang

 *

 * 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.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <stdarg.h>

#include <usrsctp.h>

#include "../programs/programs_helper.h"

#define FUZZ_B_RESERVED1          (1 << 0)

#define SACK_FLAG                 (1 << 1)

#define FUZZ_B_RESERVED3            (1 << 2)

#define FUZZ_B_RESERVED4            (1 << 3)

#define NR_SACK_FLAG                (1 << 4)

#define FUZZ_B_RESERVED5            (1 << 5)

#define I_DATA_FLAG                 (1 << 6)

#define FUZZ_B_RESERVED6            (1 << 7)

#define fuzzer_printf(...)

#define BUFFER_SIZE 4096

#define COMMON_HEADER_SIZE 12

#define SCTP_INTERLEAVING_SUPPORTED 0x00001206

#define SEND_DATA_SIZE 4096

static uint32_t assoc_vtag = 0;

static void

handle_upcall(struct socket *sock, void *arg, int flgs)

{

  fuzzer_printf("handle_upcall()\n");

  int events = usrsctp_get_events(sock);

  while (events & SCTP_EVENT_READ) {

    struct sctp_recvv_rn rn;

    ssize_t n;

    struct sockaddr_in addr;

    char *buf = calloc(1, BUFFER_SIZE);

    int flags = 0;

    socklen_t len = (socklen_t)sizeof(struct sockaddr_in);

    unsigned int infotype = 0;

    socklen_t infolen = sizeof(struct sctp_recvv_rn);

    memset(&rn, 0, sizeof(struct sctp_recvv_rn));

    n = usrsctp_recvv(sock, buf, BUFFER_SIZE, (struct sockaddr *) &addr, &len, (void *)&rn, &infolen, &infotype, &flags);

    fuzzer_printf("usrsctp_recvv() - returned %zd\n", n);

    if (flags & MSG_NOTIFICATION) {

      fuzzer_printf("NOTIFICATION received\n");

#ifdef FUZZ_VERBOSE

      handle_notification((union sctp_notification *)buf, n);

#endif // FUZZ_VERBOSE

    } else {

      fuzzer_printf("DATA received\n");

    }

    free(buf);

    if (n <= 0) {

      break;

    }

    events = usrsctp_get_events(sock);

  }

}

static int

conn_output(void *addr, void *buf, size_t length, uint8_t tos, uint8_t set_df)

{

  struct sctp_init_chunk *init_chunk;

  const char *init_chunk_first_bytes = "\x13\x88\x13\x89\x00\x00\x00\x00\x00\x00\x00\x00\x01";

  // Looking for the outgoing VTAG.

  // length >= (COMMON_HEADER_SIZE + 16 (min size of INIT))

  // If the common header has no VTAG (all zero), we're assuming it carries an INIT

  if ((length >= (COMMON_HEADER_SIZE + 16)) && (memcmp(buf, init_chunk_first_bytes, COMMON_HEADER_SIZE) == 0)) {

    init_chunk = (struct sctp_init_chunk*) ((char *)buf + sizeof(struct sctp_common_header));

    fuzzer_printf("Found outgoing INIT, extracting VTAG : %u\n", init_chunk->initiate_tag);

    assoc_vtag = init_chunk->initiate_tag;

  }

  return (0);

}

int

initialize_fuzzer(void) {

  usrsctp_init(0, conn_output, NULL);

  usrsctp_enable_crc32c_offload();

#ifdef SCTP_DEBUG

  usrsctp_sysctl_set_sctp_debug_on(SCTP_DEBUG_ALL);

#endif // SCTP_DEBUG

  usrsctp_register_address((void *)1);

  usrsctp_sysctl_set_sctp_pktdrop_enable(1);

  usrsctp_sysctl_set_sctp_nrsack_enable(1);

  fuzzer_printf("usrsctp initialized\n");

  return (1);

}

int

LLVMFuzzerTestOneInput(const uint8_t* data, size_t data_size)

{

  static int initialized;

  char *fuzz_packet_buffer;

  size_t fuzz_data_count;

  struct socket *socket_client;

  struct linger so_linger;

  struct sctp_initmsg initmsg;

  struct sctp_event event;

  struct sockaddr_conn sconn;

  struct sctp_common_header* common_header;

  struct sctp_assoc_value assoc_val;

  int result;

  int optval;

  unsigned long i;

  char* send_data_buffer;

  uint16_t event_types[] = {

    SCTP_ASSOC_CHANGE,

    SCTP_PEER_ADDR_CHANGE,

    SCTP_REMOTE_ERROR,

    SCTP_SEND_FAILED,

    SCTP_SHUTDOWN_EVENT,

    SCTP_ADAPTATION_INDICATION,

    SCTP_PARTIAL_DELIVERY_EVENT,

    SCTP_AUTHENTICATION_EVENT,

    SCTP_STREAM_RESET_EVENT,

    SCTP_SENDER_DRY_EVENT,

    SCTP_ASSOC_RESET_EVENT,

    SCTP_STREAM_CHANGE_EVENT,

    SCTP_SEND_FAILED_EVENT

  };

  char fuzz_init_ack[] = "\x13\x89\x13\x88\x49\xa4\xac\xb2\x00\x00\x00\x00\x02\x00\x01\xb4" \

    "\x2b\xe8\x47\x40\x00\x1c\x71\xc7\xff\xff\xff\xff\xed\x69\x58\xec" \

    "\xc0\x06\x00\x08\x00\x00\x07\xc4\x80\x00\x00\x04\xc0\x00\x00\x04" \

    "\x80\x08\x00\x0b\xc0\xc2\x0f\xc1\x80\x82\x40\x00\x80\x02\x00\x24" \

    "\x40\x39\xcf\x32\xd6\x60\xcf\xfa\x3f\x2f\xa9\x52\xed\x2b\xf2\xe6" \

    "\x2f\xb7\x81\x96\xf8\xda\xe9\xa0\x62\x01\x79\xe1\x0d\x5f\x38\xaa" \

    "\x80\x04\x00\x08\x00\x03\x00\x01\x80\x03\x00\x06\x80\xc1\x00\x00" \

    "\x00\x07\x01\x50\x4b\x41\x4d\x45\x2d\x42\x53\x44\x20\x31\x2e\x31" \

    "\x00\x00\x00\x00\x64\xdb\x63\x00\x00\x00\x00\x00\xc9\x76\x03\x00" \

    "\x00\x00\x00\x00\x60\xea\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" \

    "\xb2\xac\xa4\x49\x2b\xe8\x47\x40\xd4\xc9\x79\x52\x00\x00\x00\x00" \

    "\x00\x00\x00\x00\x00\x00\x00\x00\x05\x00\x00\x00\xd4\xc9\x79\x53" \

    "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x05\x00\x00\x00" \

    "\x00\x00\x00\x00\x5a\x76\x13\x89\x01\x00\x00\x00\x00\x00\x00\x00" \

    "\x00\x00\x00\x00\x01\x00\x00\x62\x49\xa4\xac\xb2\x00\x1c\x71\xc7" \

    "\x00\x01\xff\xff\x82\xe6\xc8\x44\x80\x00\x00\x04\xc0\x00\x00\x04" \

    "\x80\x08\x00\x0b\xc0\xc2\x0f\xc1\x80\x82\x40\x00\x80\x02\x00\x24" \

    "\xb6\xbb\xb5\x7f\xbb\x4b\x0e\xb5\x42\xf6\x75\x18\x4f\x79\x0f\x24" \

    "\x1c\x44\x0b\xd6\x62\xa9\x84\xe7\x2c\x3c\x7f\xad\x1b\x67\x81\x57" \

    "\x80\x04\x00\x08\x00\x03\x00\x01\x80\x03\x00\x06\x80\xc1\x00\x00" \

    "\x00\x0c\x00\x06\x00\x05\x00\x00\x02\x00\x01\xb4\x2b\xe8\x47\x40" \

    "\x00\x1c\x71\xc7\x00\x01\xff\xff\xed\x69\x58\xec\xc0\x06\x00\x08" \

    "\x00\x00\x07\xc4\x80\x00\x00\x04\xc0\x00\x00\x04\x80\x08\x00\x0b" \

    "\xc0\xc2\x0f\xc1\x80\x82\x40\x00\x80\x02\x00\x24\x40\x39\xcf\x32" \

    "\xd6\x60\xcf\xfa\x3f\x2f\xa9\x52\xed\x2b\xf2\xe6\x2f\xb7\x81\x96" \

    "\xf8\xda\xe9\xa0\x62\x01\x79\xe1\x0d\x5f\x38\xaa\x80\x04\x00\x08" \

    "\x00\x03\x00\x01\x80\x03\x00\x06\x80\xc1\x00\x00\x81\xe1\x1e\x81" \

    "\xea\x41\xeb\xf0\x12\xd9\x74\xbe\x13\xfd\x4b\x6c\x5c\xa2\x8f\x00";

  char fuzz_init_ack_nrsack_support[] = "\x13\x89\x13\x88\x49\xa4\xac\xb2\x00\x00\x00\x00\x02\x00\x01\xb4" \

    "\x2b\xe8\x47\x40\x00\x1c\x71\xc7\xff\xff\xff\xff\xed\x69\x58\xec" \

    "\xc0\x06\x00\x08\x00\x00\x07\xc4\x80\x00\x00\x04\xc0\x00\x00\x04" \

    "\x80\x08\x00\x0b\xc0\x10\x0f\xc1\x80\x82\x40\x00\x80\x02\x00\x24" \

    "\x40\x39\xcf\x32\xd6\x60\xcf\xfa\x3f\x2f\xa9\x52\xed\x2b\xf2\xe6" \

    "\x2f\xb7\x81\x96\xf8\xda\xe9\xa0\x62\x01\x79\xe1\x0d\x5f\x38\xaa" \

    "\x80\x04\x00\x08\x00\x03\x00\x01\x80\x03\x00\x06\x80\xc1\x00\x00" \

    "\x00\x07\x01\x50\x4b\x41\x4d\x45\x2d\x42\x53\x44\x20\x31\x2e\x31" \

    "\x00\x00\x00\x00\x64\xdb\x63\x00\x00\x00\x00\x00\xc9\x76\x03\x00" \

    "\x00\x00\x00\x00\x60\xea\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" \

    "\xb2\xac\xa4\x49\x2b\xe8\x47\x40\xd4\xc9\x79\x52\x00\x00\x00\x00" \

    "\x00\x00\x00\x00\x00\x00\x00\x00\x05\x00\x00\x00\xd4\xc9\x79\x53" \

    "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x05\x00\x00\x00" \

    "\x00\x00\x00\x00\x5a\x76\x13\x89\x01\x00\x00\x00\x00\x00\x00\x00" \

    "\x00\x00\x00\x00\x01\x00\x00\x62\x49\xa4\xac\xb2\x00\x1c\x71\xc7" \

    "\x00\x01\xff\xff\x82\xe6\xc8\x44\x80\x00\x00\x04\xc0\x00\x00\x04" \

    "\x80\x08\x00\x0b\xc0\x10\x0f\xc1\x80\x82\x40\x00\x80\x02\x00\x24" \

    "\xb6\xbb\xb5\x7f\xbb\x4b\x0e\xb5\x42\xf6\x75\x18\x4f\x79\x0f\x24" \

    "\x1c\x44\x0b\xd6\x62\xa9\x84\xe7\x2c\x3c\x7f\xad\x1b\x67\x81\x57" \

    "\x80\x04\x00\x08\x00\x03\x00\x01\x80\x03\x00\x06\x80\xc1\x00\x00" \

    "\x00\x0c\x00\x06\x00\x05\x00\x00\x02\x00\x01\xb4\x2b\xe8\x47\x40" \

    "\x00\x1c\x71\xc7\x00\x01\xff\xff\xed\x69\x58\xec\xc0\x06\x00\x08" \

    "\x00\x00\x07\xc4\x80\x00\x00\x04\xc0\x00\x00\x04\x80\x08\x00\x0b" \

    "\xc0\x10\x0f\xc1\x80\x82\x40\x00\x80\x02\x00\x24\x40\x39\xcf\x32" \

    "\xd6\x60\xcf\xfa\x3f\x2f\xa9\x52\xed\x2b\xf2\xe6\x2f\xb7\x81\x96" \

    "\xf8\xda\xe9\xa0\x62\x01\x79\xe1\x0d\x5f\x38\xaa\x80\x04\x00\x08" \

    "\x00\x03\x00\x01\x80\x03\x00\x06\x80\xc1\x00\x00\x81\xe1\x1e\x81" \

    "\xea\x41\xeb\xf0\x12\xd9\x74\xbe\x13\xfd\x4b\x6c\x5c\xa2\x8f\x00";

  char fuzz_cookie_ack[] = "\x13\x89\x13\x88\xb7\x0d\x32\x66\x00\x00\x00\x00\x0b\x00\x00\x04";

  char data_common_headr[] = "\x13\x89\x13\x88\xb7\x0d\x32\x66\x00\x00\x00\x00";

  if (!initialized) {

    initialized = initialize_fuzzer();

  }

  if (data_size < 10) {

    // Skip too small packets

    fuzzer_printf("data_size %zu makes no sense, skipping\n", data_size);

    return (0);

  }

  socket_client = usrsctp_socket(AF_CONN, SOCK_STREAM, IPPROTO_SCTP, NULL, NULL, 0, 0);

  FUZZER_ASSERT(socket_client != NULL);

  usrsctp_set_non_blocking(socket_client, 1);

  memset(&initmsg, 1, sizeof(struct sctp_initmsg));

  result = usrsctp_setsockopt(socket_client, IPPROTO_SCTP, SCTP_INITMSG, &initmsg, sizeof(struct sctp_initmsg));

  FUZZER_ASSERT(result == 0);

  so_linger.l_onoff = 1;

  so_linger.l_linger = 0;

  result = usrsctp_setsockopt(socket_client, SOL_SOCKET, SO_LINGER, &so_linger, sizeof(struct linger));

  FUZZER_ASSERT(result == 0);

  memset(&event, 0, sizeof(event));

  event.se_on = 1;

  for (i = 0; i < (sizeof(event_types) / sizeof(uint16_t)); i++) {

    event.se_type = event_types[i];

    result = usrsctp_setsockopt(socket_client, IPPROTO_SCTP, SCTP_EVENT, &event, sizeof(event));

  }

  optval = 1;

  result = usrsctp_setsockopt(socket_client, IPPROTO_SCTP, SCTP_RECVRCVINFO, &optval, sizeof(optval));

  FUZZER_ASSERT(result == 0);

  optval = 1;

  result = usrsctp_setsockopt(socket_client, IPPROTO_SCTP, SCTP_RECVNXTINFO, &optval, sizeof(optval));

  FUZZER_ASSERT(result == 0);

  if (data[0] & I_DATA_FLAG) {

    // set the program supporting I-DATA

    optval = 2;

    result = usrsctp_setsockopt(socket_client, IPPROTO_SCTP, SCTP_FRAGMENT_INTERLEAVE, &optval, sizeof(optval));

    FUZZER_ASSERT(result == 0);

    memset(&assoc_val, 0, sizeof(assoc_val));

    assoc_val.assoc_value = 1;

    result = usrsctp_setsockopt(socket_client, IPPROTO_SCTP, SCTP_INTERLEAVING_SUPPORTED, &assoc_val, sizeof(assoc_val));

    FUZZER_ASSERT(result == 0);

  }

  optval = 1;

  result = usrsctp_setsockopt(socket_client, IPPROTO_SCTP, SCTP_REUSE_PORT, &optval, sizeof(optval));

  FUZZER_ASSERT(result == 0);

  memset(&sconn, 0, sizeof(struct sockaddr_conn));

  sconn.sconn_family = AF_CONN;

#ifdef HAVE_SCONN_LEN

  sconn.sconn_len = sizeof(struct sockaddr_conn);

#endif // HAVE_SCONN_LEN

  sconn.sconn_port = htons(5000);

  sconn.sconn_addr = (void *)1;

  result = usrsctp_bind(socket_client, (struct sockaddr *)&sconn, sizeof(struct sockaddr_conn));

  FUZZER_ASSERT(result == 0);

  optval = 1;

  result = usrsctp_setsockopt(socket_client, IPPROTO_SCTP, SCTP_NODELAY, &optval, sizeof(optval));

  FUZZER_ASSERT(result == 0);

  usrsctp_set_upcall(socket_client, handle_upcall, NULL);

  memset(&sconn, 0, sizeof(struct sockaddr_conn));

  sconn.sconn_family = AF_CONN;

#ifdef HAVE_SCONN_LEN

  sconn.sconn_len = sizeof(struct sockaddr_conn);

#endif // HAVE_SCONN_LEN

  sconn.sconn_port = htons(5001);

  sconn.sconn_addr = (void *)1;

  result = usrsctp_connect(socket_client, (struct sockaddr *)&sconn, sizeof(struct sockaddr_conn));

  FUZZER_ASSERT(result == 0 || errno == EINPROGRESS);

  if (data[0] & NR_SACK_FLAG) {

    common_header = (struct sctp_common_header*) fuzz_init_ack_nrsack_support;

    common_header->verification_tag = assoc_vtag;

    usrsctp_conninput((void *)1, fuzz_init_ack_nrsack_support, 448, 0);

  } else {

    common_header = (struct sctp_common_header*) fuzz_init_ack;

    common_header->verification_tag = assoc_vtag;

    usrsctp_conninput((void *)1, fuzz_init_ack, 448, 0);

  }

  common_header = (struct sctp_common_header*) fuzz_cookie_ack;

  common_header->verification_tag = assoc_vtag;

  usrsctp_conninput((void *)1, fuzz_cookie_ack, 16, 0);

  fuzz_data_count = 0;

  while (fuzz_data_count+4 < data_size) {

    size_t data_chunk_size = (data[fuzz_data_count+2]<<8) + data[fuzz_data_count+3];

    if (data_chunk_size == 0) {

      break;

    }

    if (fuzz_data_count + data_chunk_size > data_size) {

      data_chunk_size = data_size - fuzz_data_count;

    }

    if (data[fuzz_data_count] & NR_SACK_FLAG ||

        data[fuzz_data_count] & SACK_FLAG) {

      send_data_buffer = malloc(SEND_DATA_SIZE);

      FUZZER_ASSERT(send_data_buffer != NULL );

      memset(send_data_buffer, 1, SEND_DATA_SIZE);

      fuzzer_printf("Calling usrsctp_sendv()\n");

      usrsctp_sendv(socket_client, send_data_buffer, SEND_DATA_SIZE, NULL, 0, NULL, 0, SCTP_SENDV_NOINFO, 0);

      free(send_data_buffer);

    }

    fuzz_packet_buffer = malloc(data_chunk_size + COMMON_HEADER_SIZE);

    memcpy(fuzz_packet_buffer, data_common_headr, COMMON_HEADER_SIZE); // common header

    memcpy(fuzz_packet_buffer + COMMON_HEADER_SIZE, data+fuzz_data_count, data_chunk_size);

    usrsctp_conninput((void *)1, fuzz_packet_buffer, data_chunk_size + COMMON_HEADER_SIZE, 0);

    free(fuzz_packet_buffer);

    fuzz_data_count += data_chunk_size;

  }

  usrsctp_close(socket_client);

  return (0);

}