memcheck/tests/linux/memfd_create.c

   1 #define _GNU_SOURCE
   2
   3 #include <assert.h>
   4 #include <errno.h>
   5 #include <fcntl.h>
   6 #include <sys/mman.h>
   7 #include <unistd.h>
   8
   9 #include "../../memcheck.h"
  10
  11 static void
  12 assert_expected (int fd, int expected_seals)
  13 {
  14   int current_seals = fcntl (fd, F_GET_SEALS);
  15   assert (current_seals == expected_seals);
  16 }
  17
  18 static void
  19 add_seal (int fd, int *expected_seals, int new_seal)
  20 {
  21   int r = fcntl (fd, F_ADD_SEALS, new_seal);
  22   assert (r == 0);
  23
  24   *expected_seals |= new_seal;
  25
  26   // Make sure we get the result we expected.
  27   assert_expected (fd, *expected_seals);
  28 }
  29
  30 static void
  31 add_seal_expect_fail (int fd, int new_seal, int expected_errno)
  32 {
  33   int r = fcntl (fd, F_ADD_SEALS, new_seal);
  34   assert (r == -1 && errno == expected_errno);
  35 }
  36
  37 int
  38 main (void)
  39 {
  40   int expected_seals = 0;
  41   int fd;
  42
  43   // Try with an fd that doesn't support sealing.
  44   fd = memfd_create ("xyz", 0);
  45   if (fd < 0)
  46     {
  47       // Not supported, nothing to test...
  48       return 1;
  49     }
  50
  51   assert_expected (fd, F_SEAL_SEAL);
  52   add_seal_expect_fail (fd, F_SEAL_WRITE, EPERM);
  53   assert_expected (fd, F_SEAL_SEAL); // ...should still be unset after failed attempt
  54   close (fd);
  55
  56   // Now, try the successful case.
  57   fd = memfd_create ("xyz", MFD_ALLOW_SEALING);
  58   add_seal (fd, &expected_seals, F_SEAL_SHRINK);
  59   add_seal (fd, &expected_seals, F_SEAL_GROW);
  60
  61   // Now prevent more sealing.
  62   add_seal (fd, &expected_seals, F_SEAL_SEAL);
  63
  64   // And make sure that it indeed fails.
  65   add_seal_expect_fail (fd, F_SEAL_WRITE, EPERM);
  66   assert_expected (fd, expected_seals);
  67   close (fd);
  68
  69   // Test the only memory failure possible: passing an undefined argument to F_ADD_SEALS
  70   int undefined_seal = 0;
  71   VALGRIND_MAKE_MEM_UNDEFINED(&undefined_seal, sizeof undefined_seal);
  72   fcntl (-1, F_ADD_SEALS, undefined_seal);
  73
  74   return 0;
  75 }