none/tests/pselect_alarm.c

   1 /* Tries to exploit bug in pselect mask handling:
   2    https://bugs.kde.org/show_bug.cgi?id=359871
   3    where client program was able to successfully block VG_SIGVGKILL. */
   4
   5 #include <sys/select.h>
   6 #include <assert.h>
   7 #include <errno.h>
   8 #include <pthread.h>
   9 #include <signal.h>
  10 #include <stdio.h>
  11 #include <unistd.h>
  12
  13 static int ready = 0;
  14 static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
  15 static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
  16
  17 static void *
  18 mythr(void *ignore)
  19 {
  20     pthread_mutex_lock(&mutex);
  21     ready = 1;
  22     pthread_cond_signal(&cond);
  23     pthread_mutex_unlock(&mutex);
  24
  25     sigset_t ss;
  26     sigfillset(&ss);
  27     while (1) {
  28         struct timespec ts = {10000, 0};
  29         pselect(0, NULL, NULL, NULL, &ts, &ss);
  30     }
  31
  32     return NULL;
  33 }
  34
  35 int
  36 main()
  37 {
  38     pthread_t thr;
  39     int ret = pthread_create(&thr, NULL, mythr, NULL);
  40     if (ret != 0) {
  41         fprintf(stderr, "pthread_create failed\n");
  42         return 1;
  43     }
  44
  45     pthread_mutex_lock(&mutex);
  46     while (ready == 0) {
  47         pthread_cond_wait(&cond, &mutex);
  48     }
  49     pthread_mutex_unlock(&mutex);
  50
  51 #if defined(VGO_linux)
  52     assert(pselect(0, NULL, NULL, NULL, NULL, (sigset_t *)12) == -1);
  53     assert(errno == EFAULT);
  54 #endif
  55
  56     alarm(1); /* Unhandled SIGALRM should cause exit. */
  57     while (1)
  58         sleep(1);
  59
  60     return 0;
  61 }