Medium - The Mystery of the Endless HTTPS Call

cclient.c

/*
# OpenSSL is compiled with debug and trace:
./config --prefix=$HOME/openssl-bin --openssldir=$HOME/openssl --debug -DDEBUG_SAFESTACK enable-ssl-trace

# Gen & exec
$ gcc cclient.c -o cclient -lssl -lcrypto -L$HOME/openssl-bin/lib -I$HOME/openssl-bin/include
$ ./main.o HOST USER TOKEN BATCH_ID
*/
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <sys/time.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/bio.h>


void print_current_time_with_ms(void) {
  long            ms; // Milliseconds
  time_t          s;  // Seconds
  struct timespec spec;

  clock_gettime(CLOCK_MONOTONIC, &spec);

  s  = spec.tv_sec;
  ms = spec.tv_nsec / 1.0e6; // Convert nanoseconds to milliseconds
  if (ms > 999) {
      s++;
      ms = 0;
  }
  printf("\ntime[%09ld.%03ld] ", s, ms);
}

long bio_dump_callback(BIO *bio, int cmd, const char *argp,
                     int argi, long argl, long ret)
{
  BIO *out;

  print_current_time_with_ms();
  BIO_debug_callback(bio, cmd, argp, argi, argl, ret);

  out = (BIO *)BIO_get_callback_arg(bio);
  if (out != NULL) {
      if (argp) {
          BIO_dump(out, argp, ret);
      }
  }
  return ret;
}

int main(int argc, char **argv) {
  if (argc != 5) {
      printf("Usage: %s HOST USER TOKEN BATCH_ID\n", argv[0]);
      return 1;
  }

  char* host = argv[1];
  char* user = argv[2];
  char* token = argv[3];
  char* batch_id = argv[4];

  // Registers the SSL/TLS ciphers and digests,
  // basically start the security layer
  SSL_library_init();

  // Creates a new SSL_CTX object as a framework to establish TLS/SSL
  SSL_CTX* ctx;
  ctx = SSL_CTX_new(SSLv23_client_method());
  if (ctx == NULL) {
      printf(" ! Ctx is null.\n");
      return 1;
  }

  // Creates a new BIO chain consisting of an SSL BIO
  BIO* bio;
  bio = BIO_new_ssl_connect(ctx);

  // Enable BIO tracing
  BIO_set_callback(bio, bio_dump_callback);
  BIO_set_callback_arg(bio, (char *)BIO_new_fp(stdout, 0));

  // Attempts to connect the supplied BIO
  BIO_set_conn_hostname(bio, host);
  if (BIO_do_connect(bio) < 1) {
      printf(" ! Connection failed.\n");
      return 1;
  }

  // The HTTP request
  char payload[128], write_buf[1024];
  sprintf(
      payload,
      "{\"params\": {\"context\": {\"currentDocument\": \"/default-domain/UserWorkspaces/%s\"}}",
      user
  );
  sprintf(
      write_buf,
      "POST /nuxeo/api/v1/upload/%s/0/execute/FileManager.Import HTTP/1.1\r\n"
      "Host: %s\r\n"
      "Content-Length: %zu\r\n"
      "Content-Type: application/json\r\n"
      "X-Batch-No-Drop: true\r\n"
      "Cache-Control: no-cache\r\n"
      "Connection: close\r\n"
      "Cookie: X-Authentication-Token=%s\r\n"
      "\r\n"
      "%s",
      batch_id, host, strlen(payload), token, payload
  );
  printf(" > HTTPS request\n%s\n", write_buf);

  // Attempts to write len bytes from buf to BIO
  if (BIO_write(bio, write_buf, strlen(write_buf)) <= 0) {
      printf(" ! POST failed.\n");
      return 1;
  }

  // Variables used to read the response from the server
  int size;
  int buf_size = 1023;
  char buf[buf_size + 1];

  // Read the response message
  printf(" < HTTPS response:\n");
  do {
      // Get chunks of the response *buf_size* bytes at the time
      size = BIO_read(bio, buf, buf_size);

      // Terminate the string with a 0, to let know C when the string ends
      buf[size] = 0;

      printf("%s", buf);
  } while (size == buf_size);
  printf("\n");

  // Clean-up
  BIO_free_all(bio);
  SSL_CTX_free(ctx);

  return 0;
}