tests/fcntl.c

   1 #include <darwintest.h>
   2 #include <fcntl.h>
   3 #include <sys/mman.h>
   4 #include <darwintest_utils.h>
   5 #include <mach/vm_page_size.h>
   6
   7 /** Verify that F_ADDSIGS does not page fault off the end of the user blob
   8  * 1. Find VA space for 3 pages
   9  * 2. Unmap the last page
  10  * 3. Start fs_blob_start at PAGE_SIZE + 1 bytes away from the end of the
  11  * VA region (such that any read of more than PAGE_SIZE + 1 bytes will fault)
  12  * 4. Call fcntl with the arguments and verify the output is not EFAULT
  13  */
  14 T_DECL(fcntl_addsig, "Verify that fcntl(F_ADDSIGS) doesn't EFAULT", T_META_NAMESPACE("xnu.vfs")) {
  15         void* blob_space = mmap(NULL, vm_page_size * 3, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
  16         T_ASSERT_NE(blob_space, MAP_FAILED, "Blob Region: %p [%zd]", blob_space, vm_page_size);
  17
  18         T_ASSERT_POSIX_SUCCESS(munmap((char*)blob_space + (vm_page_size * 2), vm_page_size), NULL);
  19
  20         size_t blob_size = vm_page_size + 1;
  21         char* blob_start = ((char*)blob_space) + (vm_page_size * 2) - blob_size;
  22         fsignatures_t args = { .fs_file_start = 0, .fs_blob_start =  blob_start, .fs_blob_size = blob_size};
  23
  24         // Create test file to operate on
  25         const char * tmp_dir = dt_tmpdir();
  26         char tmp_file_name[PATH_MAX];
  27         sprintf(tmp_file_name, "%s/foo", tmp_dir);
  28         FILE* tmp_file = fopen(tmp_file_name, "wx");
  29         fprintf(tmp_file, "Just some random content");
  30         fclose(tmp_file);
  31
  32         int fd = open(tmp_file_name, O_RDONLY);
  33         T_ASSERT_POSIX_SUCCESS(fd, "tmp file: %s", tmp_file_name);
  34
  35         // This command will fail, but should not fail with EFAULT
  36         int result = fcntl(fd, F_ADDSIGS, &args);
  37         int error = errno;
  38         T_QUIET; T_EXPECT_EQ(result, -1, NULL);
  39         // EBADEXEC is expected, but not required for success of this test
  40         T_EXPECT_NE(error, EFAULT, "fcntl: %d (%d:%s)", result, error, strerror(error));
  41 }