1 // SPDX-License-Identifier: GPL-2.0-or-later
5 #include <asm-generic/mman.h> /* Force the import of the tools version. */
13 #include <signal.h>
30  * "If the signal occurs other than as the result of calling the abort or raise
31  *  function, the behavior is undefined if the signal handler refers to any
76 	switch (variant->backing) {  in is_anon_backed()
93 	switch (variant->backing) {  in mmap_()
96 		fd = -1;  in mmap_()
101 		fd = self->fd;  in mmap_()
131  * Enable our signal catcher and try to read/write the specified buffer. The
133  * signal.
139 	/* Tell signal handler to jump back here on fatal signal. */  in try_access_buf()
141 	/* If a fatal signal arose, we will jump back here and failed is set. */  in try_access_buf()
155 /* Try and read from a buffer, return true if no fatal signal. */
161 /* Try and write to a buffer, return true if no fatal signal. */
265 	self->page_size = (unsigned long)sysconf(_SC_PAGESIZE);  in FIXTURE_SETUP()
268 	switch (variant->backing) {  in FIXTURE_SETUP()
272 		self->fd = open_file("", self->path);  in FIXTURE_SETUP()
275 		self->fd = memfd_create(self->path, 0);  in FIXTURE_SETUP()
280 	ASSERT_EQ(ftruncate(self->fd, 100 * self->page_size), 0);  in FIXTURE_SETUP()
287 	if (variant->backing == ANON_BACKED)  in FIXTURE_TEARDOWN_PARENT()
290 	if (self->fd >= 0)  in FIXTURE_TEARDOWN_PARENT()
291 		close(self->fd);  in FIXTURE_TEARDOWN_PARENT()
293 	if (self->path[0] != '\0')  in FIXTURE_TEARDOWN_PARENT()
294 		unlink(self->path);  in FIXTURE_TEARDOWN_PARENT()
300 	const unsigned long page_size = self->page_size;  in TEST_F()
323 	/* Establish a guard page at the end of the mapping. */  in TEST_F()
324 	ASSERT_EQ(madvise(&ptr[(NUM_PAGES - 1) * page_size], page_size,  in TEST_F()
327 	/* Check that both guard pages result in SIGSEGV. */  in TEST_F()
329 	ASSERT_FALSE(try_read_write_buf(&ptr[(NUM_PAGES - 1) * page_size]));  in TEST_F()
331 	/* Remove the first guard page. */  in TEST_F()
337 	/* Remove the last guard page. */  in TEST_F()
338 	ASSERT_FALSE(madvise(&ptr[(NUM_PAGES - 1) * page_size], page_size,  in TEST_F()
342 	ASSERT_TRUE(try_read_write_buf(&ptr[(NUM_PAGES - 1) * page_size]));  in TEST_F()
346 	 *  these be faulted in, so this also tests that we can install guard  in TEST_F()
351 	/* Make sure they are all guard pages. */  in TEST_F()
365 	/* Remove guard pages. */  in TEST_F()
376 	 * Now remove all guard pages, make sure we don't remove existing  in TEST_F()
393 	const unsigned long page_size = self->page_size;  in TEST_F()
425 	 * [---]      [---]      [---]  in TEST_F()
429 	 * Now mark the whole range as guard pages and make sure all VMAs are as  in TEST_F()
436 	 * -ENOMEM. Also if anything runs out of memory it is set to  in TEST_F()
437 	 * -ENOMEM. You are meant to guess which is which.  in TEST_F()
439 	ASSERT_EQ(madvise(ptr_region, 100 * page_size, MADV_GUARD_INSTALL), -1);  in TEST_F()
462 	ASSERT_EQ(madvise(ptr_region, 100 * page_size, MADV_GUARD_REMOVE), -1);  in TEST_F()
495 	 * [---][xxxx][---][xxxx][---]  in TEST_F()
525 	const unsigned long page_size = self->page_size;  in TEST_F()
543 	/* We want guard markers at start/end of each VMA. */  in TEST_F()
573 	/* Now guard in one step. */  in TEST_F()
577 	if (count == -1 && errno == EPERM)  in TEST_F()
614 /* Assert that unmapping ranges does not leave guard markers behind. */
617 	const unsigned long page_size = self->page_size;  in TEST_F()
624 	/* Guard first and last pages. */  in TEST_F()
652 /* Assert that mprotect() operations have no bearing on guard markers. */
655 	const unsigned long page_size = self->page_size;  in TEST_F()
663 	/* Guard the middle of the range. */  in TEST_F()
671 	/* Now make these pages read-only. */  in TEST_F()
678 	/* Make sure we can guard again without issue.*/  in TEST_F()
700 /* Split and merge VMAs and make sure guard pages still behave. */
703 	const unsigned long page_size = self->page_size;  in TEST_F()
711 	/* Guard the whole range. */  in TEST_F()
726 	/* Make sure the remaining ranges are guarded post-split. */  in TEST_F()
748 	/* Now map them again - the unmap will have cleared the guards. */  in TEST_F()
759 	/* Now make sure guard pages are established. */  in TEST_F()
768 	/* Now guard everything again. */  in TEST_F()
831 /* Assert that MADV_DONTNEED does not remove guard markers. */
834 	const unsigned long page_size = self->page_size;  in TEST_F()
849 	/* Guard every other page. */  in TEST_F()
860 	/* Check to ensure guard markers are still in place. */  in TEST_F()
869 			switch (variant->backing) {  in TEST_F()
892 /* Assert that mlock()'ed pages work correctly with guard markers. */
895 	const unsigned long page_size = self->page_size;  in TEST_F()
913 	/* Now try to guard, should fail with EINVAL. */  in TEST_F()
914 	ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_INSTALL), -1);  in TEST_F()
920 	/* Guard first half of range, should now succeed. */  in TEST_F()
923 	/* Make sure guard works. */  in TEST_F()
937 	 * Now lock the latter part of the range. We can't lock the guard pages,  in TEST_F()
944 	 * Now remove guard pages, we permit mlock()'d ranges to have guard  in TEST_F()
945 	 * pages removed as it is a non-destructive operation.  in TEST_F()
949 	/* Now check that no guard pages remain. */  in TEST_F()
962  * guard markers where possible.
964  * - Moving a mapping alone should retain markers as they are.
968 	const unsigned long page_size = self->page_size;  in TEST_F()
976 	/* Place guard markers at both ends of the 5 page span. */  in TEST_F()
980 	/* Make sure the guard pages are in effect. */  in TEST_F()
993 	/* Make sure the guard markers are retained. */  in TEST_F()
998 	 * Clean up - we only need reference the new pointer as we overwrote the  in TEST_F()
1006  * guard markers where possible.
1008  * Expanding should retain guard pages, only now in different position. The user
1009  * will have to remove guard pages manually to fix up (they'd have to do the
1014 	const unsigned long page_size = self->page_size;  in TEST_F()
1024 	/* Place guard markers at both ends of the 5 page span. */  in TEST_F()
1037 	 * Make sure the guard markers are retained in their original positions.  in TEST_F()
1052 	 * Again, make sure the guard markers are retained in their original positions.  in TEST_F()
1058 	 * A real user would have to remove guard markers, but would reasonably  in TEST_F()
1060 	 * guard markers.  in TEST_F()
1068  * guard markers where possible.
1076 	const unsigned long page_size = self->page_size;  in TEST_F()
1085 	/* Place guard markers at both ends of the 5 page span. */  in TEST_F()
1097 	/* We expect the guard marker at the start to be retained... */  in TEST_F()
1100 	/* ...But remaining pages will not have guard markers. */  in TEST_F()
1108 	 * As with expansion, a real user would have to remove guard pages and  in TEST_F()
1120 	/* Again, we expect the guard marker at the start to be retained... */  in TEST_F()
1123 	/* ...But remaining pages will not have guard markers. */  in TEST_F()
1136  * retain guard pages.
1140 	const unsigned long page_size = self->page_size;  in TEST_F()
1150 	/* Establish guard pages in the first 5 pages. */  in TEST_F()
1154 	ASSERT_NE(pid, -1);  in TEST_F()
1191  * and then guard and unguard the range.
1195 	const unsigned long page_size = self->page_size;  in TEST_F()
1200 	if (variant->backing != ANON_BACKED)  in TEST_F()
1216 	ASSERT_NE(pid, -1);  in TEST_F()
1228 		/* Establish guard pages across the whole range. */  in TEST_F()
1234 		 * By removing the guard pages, the page tables will be  in TEST_F()
1269 	const unsigned long page_size = self->page_size;  in TEST_F()
1274 	if (variant->backing != ANON_BACKED)  in TEST_F()
1285 	/* Guard the first 5 pages. */  in TEST_F()
1289 	ASSERT_NE(pid, -1);  in TEST_F()
1293 		/* Guard will have been wiped. */  in TEST_F()
1307 	/* Guard markers should be in effect.*/  in TEST_F()
1319 /* Ensure that MADV_FREE retains guard entries as expected. */
1322 	const unsigned long page_size = self->page_size;  in TEST_F()
1326 	if (variant->backing != ANON_BACKED)  in TEST_F()
1334 	/* Guard range. */  in TEST_F()
1347 	/* This should leave the guard markers in place. */  in TEST_F()
1361 	const unsigned long page_size = self->page_size;  in TEST_F()
1369 	/* Guard range. */  in TEST_F()
1373 	ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_POPULATE_READ), -1);  in TEST_F()
1377 	ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_POPULATE_WRITE), -1);  in TEST_F()
1384 /* Ensure that MADV_COLD, MADV_PAGEOUT do not remove guard markers. */
1387 	const unsigned long page_size = self->page_size;  in TEST_F()
1396 	/* Guard range. */  in TEST_F()
1406 	/* Now mark cold. This should have no impact on guard markers. */  in TEST_F()
1430 /* Ensure that guard pages do not break userfaultd. */
1433 	const unsigned long page_size = self->page_size;  in TEST_F()
1449 	if (uffd == -1) {  in TEST_F()
1464 	ASSERT_NE(uffd, -1);  in TEST_F()
1480 	/* Guard the range. This should not trigger the uffd. */  in TEST_F()
1497  * Mark a region within a file-backed mapping using MADV_SEQUENTIAL so we
1498  * aggressively read-ahead, then install guard regions and assert that it
1501  * We page out using MADV_PAGEOUT before checking guard regions so we drop page
1508 	const unsigned long page_size = self->page_size;  in TEST_F()
1510 	if (variant->backing == ANON_BACKED)  in TEST_F()
1511 		SKIP(return, "MADV_SEQUENTIAL meaningful only for file-backed");  in TEST_F()
1524 	/* Mark every other page a guard page. */  in TEST_F()
1547 	/* Now remove guard pages. */  in TEST_F()
1558  * Check that file-backed mappings implement guard regions with MAP_PRIVATE
1563 	const unsigned long page_size = self->page_size;  in TEST_F()
1567 	if (variant->backing == ANON_BACKED)  in TEST_F()
1568 		SKIP(return, "MAP_PRIVATE test specific to file-backed");  in TEST_F()
1574 	ptr_private = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, self->fd, 0);  in TEST_F()
1580 	/* Install guard regions in every other page in the shared mapping. */  in TEST_F()
1594 	/* Install guard regions in every other page in the private mapping. */  in TEST_F()
1608 	/* Remove guard regions from shared mapping. */  in TEST_F()
1618 	/* Remove guard regions from private mapping. */  in TEST_F()
1661 		/* Ensure guard regions as expected. */  in TEST_F()
1667 	/* Remove the guard regions altogether. */  in TEST_F()
1677 	 * As we removed guard regions, the private pages from the first 5 will  in TEST_F()
1703 /* Test that guard regions established over a read-only mapping function correctly. */
1706 	const unsigned long page_size = self->page_size;  in TEST_F()
1710 	if (variant->backing != LOCAL_FILE_BACKED)  in TEST_F()
1711 		SKIP(return, "Read-only test specific to file-backed");  in TEST_F()
1719 	/* Close the fd so we can re-open read-only. */  in TEST_F()
1720 	ASSERT_EQ(close(self->fd), 0);  in TEST_F()
1722 	/* Re-open read-only. */  in TEST_F()
1723 	self->fd = open(self->path, O_RDONLY);  in TEST_F()
1724 	ASSERT_NE(self->fd, -1);  in TEST_F()
1725 	/* Re-map read-only. */  in TEST_F()
1736 	/* Assert that the guard regions are in place.*/  in TEST_F()
1743 	/* Remove guard regions. */  in TEST_F()
1754 	const unsigned long page_size = self->page_size;  in TEST_F()
1758 	if (variant->backing == ANON_BACKED)  in TEST_F()
1759 		SKIP(return, "Fault-around test specific to file-backed");  in TEST_F()
1787 	/* Now fault in every odd page. This should trigger fault-around. */  in TEST_F()
1794 	/* Finally, ensure that guard regions are intact as expected. */  in TEST_F()
1806 	const unsigned long page_size = self->page_size;  in TEST_F()
1810 	if (variant->backing == ANON_BACKED)  in TEST_F()
1811 		SKIP(return, "Truncation test specific to file-backed");  in TEST_F()
1838 	ASSERT_EQ(ftruncate(self->fd, 10 * page_size), 0);  in TEST_F()
1840 	/* Here the guard regions will remain intact. */  in TEST_F()
1848 	ASSERT_EQ(ftruncate(self->fd, 5 * page_size), 0);  in TEST_F()
1849 	ASSERT_EQ(ftruncate(self->fd, 10 * page_size), 0);  in TEST_F()
1851 	/* Again, guard pages will remain intact. */  in TEST_F()
1863 	const unsigned long page_size = self->page_size;  in TEST_F()
1867 	if (variant->backing == ANON_BACKED)  in TEST_F()
1868 		SKIP(return, "Truncation test specific to file-backed");  in TEST_F()
1876 	/* Install a guard region in the middle of the mapping. */  in TEST_F()
1886 	 * Where * is data and x is the guard region.  in TEST_F()
1900 	/* Ensure guard regions remain. */  in TEST_F()
1907 	/* Now remove guard region throughout. */  in TEST_F()
1910 	/* Check that the pattern exists in non-hole punched region. */  in TEST_F()
1921  * Ensure that a memfd works correctly with guard regions, that we can write
1922  * seal it then open the mapping read-only and still establish guard regions
1923  * within, remove those guard regions and have everything work correctly.
1927 	const unsigned long page_size = self->page_size;  in TEST_F()
1931 	if (variant->backing != SHMEM_BACKED)  in TEST_F()
1935 	ASSERT_EQ(close(self->fd), 0);  in TEST_F()
1938 	self->fd = memfd_create("guard_regions_memfd_seals_test",  in TEST_F()
1940 	ASSERT_NE(self->fd, -1);  in TEST_F()
1941 	ASSERT_EQ(ftruncate(self->fd, 10 * page_size), 0);  in TEST_F()
1949 	/* Write-seal the memfd. */  in TEST_F()
1950 	ASSERT_EQ(fcntl(self->fd, F_ADD_SEALS, F_SEAL_WRITE), 0);  in TEST_F()
1973 	/* Now remove guard regions. */  in TEST_F()
1991  * Since we are now permitted to establish guard regions in read-only anonymous
1993  * use, test that guard regions function with a mapping to the anonymous zero
1998 	const unsigned long page_size = self->page_size;  in TEST_F()
2005 	/* Obtain a read-only i.e. anon zero page mapping. */  in TEST_F()
2023 	/* Now remove all guard regions. */  in TEST_F()
2040  * Assert that /proc/$pid/pagemap correctly identifies guard region ranges.
2044 	const unsigned long page_size = self->page_size;  in TEST_F()
2050 	ASSERT_NE(proc_fd, -1);  in TEST_F()
2056 	/* Read from pagemap, and assert no guard regions are detected. */  in TEST_F()
2065 	/* Install a guard region in every other page. */  in TEST_F()
2072 	/* Re-read from pagemap, and assert guard regions are detected. */  in TEST_F()
2086  * Assert that PAGEMAP_SCAN correctly reports guard region ranges.
2090 	const unsigned long page_size = self->page_size;  in TEST_F()
2103 	ASSERT_NE(proc_fd, -1);  in TEST_F()
2114 	/* Install a guard region in every other page. */  in TEST_F()
2128 	/* Re-read from pagemap, and assert guard regions are detected. */  in TEST_F()