1 // SPDX-License-Identifier: GPL-2.0-or-later
5 #include <asm-generic/mman.h> /* Force the import of the tools version. */
11 #include <signal.h>
25  * "If the signal occurs other than as the result of calling the abort or raise
26  *  function, the behavior is undefined if the signal handler refers to any
65  * Enable our signal catcher and try to read/write the specified buffer. The
67  * signal.
73 	/* Tell signal handler to jump back here on fatal signal. */  in try_access_buf()
75 	/* If a fatal signal arose, we will jump back here and failed is set. */  in try_access_buf()
89 /* Try and read from a buffer, return true if no fatal signal. */
95 /* Try and write to a buffer, return true if no fatal signal. */
126 	self->page_size = (unsigned long)sysconf(_SC_PAGESIZE);  in FIXTURE_SETUP()
143 	const unsigned long page_size = self->page_size;  in TEST_F()
148 		   MAP_PRIVATE | MAP_ANON, -1, 0);  in TEST_F()
166 	/* Establish a guard page at the end of the mapping. */  in TEST_F()
167 	ASSERT_EQ(madvise(&ptr[(NUM_PAGES - 1) * page_size], page_size,  in TEST_F()
170 	/* Check that both guard pages result in SIGSEGV. */  in TEST_F()
172 	ASSERT_FALSE(try_read_write_buf(&ptr[(NUM_PAGES - 1) * page_size]));  in TEST_F()
174 	/* Remove the first guard page. */  in TEST_F()
180 	/* Remove the last guard page. */  in TEST_F()
181 	ASSERT_FALSE(madvise(&ptr[(NUM_PAGES - 1) * page_size], page_size,  in TEST_F()
185 	ASSERT_TRUE(try_read_write_buf(&ptr[(NUM_PAGES - 1) * page_size]));  in TEST_F()
189 	 *  these be faulted in, so this also tests that we can install guard  in TEST_F()
194 	/* Make sure they are all guard pages. */  in TEST_F()
208 	/* Remove guard pages. */  in TEST_F()
219 	 * Now remove all guard pages, make sure we don't remove existing  in TEST_F()
236 	const unsigned long page_size = self->page_size;  in TEST_F()
242 			  MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
247 		    MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
253 		    MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
259 		    MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
270 	 * [---]      [---]      [---]  in TEST_F()
274 	 * Now mark the whole range as guard pages and make sure all VMAs are as  in TEST_F()
281 	 * -ENOMEM. Also if anything runs out of memory it is set to  in TEST_F()
282 	 * -ENOMEM. You are meant to guess which is which.  in TEST_F()
284 	ASSERT_EQ(madvise(ptr_region, 100 * page_size, MADV_GUARD_INSTALL), -1);  in TEST_F()
307 	ASSERT_EQ(madvise(ptr_region, 100 * page_size, MADV_GUARD_REMOVE), -1);  in TEST_F()
331 		   MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
335 		   MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
342 	 * [---][xxxx][---][xxxx][---]  in TEST_F()
372 	const unsigned long page_size = self->page_size;  in TEST_F()
379 	ASSERT_NE(pidfd, -1);  in TEST_F()
383 			  MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
393 		    MAP_FIXED | MAP_ANON | MAP_PRIVATE | MAP_POPULATE, -1, 0);  in TEST_F()
395 	/* We want guard markers at start/end of each VMA. */  in TEST_F()
404 		    MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
414 		    MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
427 	/* Now guard in one step. */  in TEST_F()
431 	if (count == -1 && errno == EPERM)  in TEST_F()
469 /* Assert that unmapping ranges does not leave guard markers behind. */
472 	const unsigned long page_size = self->page_size;  in TEST_F()
476 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
479 	/* Guard first and last pages. */  in TEST_F()
493 			MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
496 			MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
507 /* Assert that mprotect() operations have no bearing on guard markers. */
510 	const unsigned long page_size = self->page_size;  in TEST_F()
515 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
518 	/* Guard the middle of the range. */  in TEST_F()
526 	/* Now make these pages read-only. */  in TEST_F()
533 	/* Make sure we can guard again without issue.*/  in TEST_F()
555 /* Split and merge VMAs and make sure guard pages still behave. */
558 	const unsigned long page_size = self->page_size;  in TEST_F()
563 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
566 	/* Guard the whole range. */  in TEST_F()
581 	/* Make sure the remaining ranges are guarded post-split. */  in TEST_F()
603 	/* Now map them again - the unmap will have cleared the guards. */  in TEST_F()
605 		       MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
608 		       MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
611 		       MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
614 	/* Now make sure guard pages are established. */  in TEST_F()
623 	/* Now guard everything again. */  in TEST_F()
686 /* Assert that MADV_DONTNEED does not remove guard markers. */
689 	const unsigned long page_size = self->page_size;  in TEST_F()
694 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
704 	/* Guard every other page. */  in TEST_F()
715 	/* Check to ensure guard markers are still in place. */  in TEST_F()
739 /* Assert that mlock()'ed pages work correctly with guard markers. */
742 	const unsigned long page_size = self->page_size;  in TEST_F()
747 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
760 	/* Now try to guard, should fail with EINVAL. */  in TEST_F()
761 	ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_INSTALL), -1);  in TEST_F()
767 	/* Guard first half of range, should now succeed. */  in TEST_F()
770 	/* Make sure guard works. */  in TEST_F()
784 	 * Now lock the latter part of the range. We can't lock the guard pages,  in TEST_F()
791 	 * Now remove guard pages, we permit mlock()'d ranges to have guard  in TEST_F()
792 	 * pages removed as it is a non-destructive operation.  in TEST_F()
796 	/* Now check that no guard pages remain. */  in TEST_F()
809  * guard markers where possible.
811  * - Moving a mapping alone should retain markers as they are.
815 	const unsigned long page_size = self->page_size;  in TEST_F()
820 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
823 	/* Place guard markers at both ends of the 5 page span. */  in TEST_F()
827 	/* Make sure the guard pages are in effect. */  in TEST_F()
835 		       -1, 0);  in TEST_F()
841 	/* Make sure the guard markers are retained. */  in TEST_F()
846 	 * Clean up - we only need reference the new pointer as we overwrote the  in TEST_F()
854  * guard markers where possible.
856  * Expanding should retain guard pages, only now in different position. The user
857  * will have to remove guard pages manually to fix up (they'd have to do the
862 	const unsigned long page_size = self->page_size;  in TEST_F()
867 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
872 	/* Place guard markers at both ends of the 5 page span. */  in TEST_F()
885 	 * Make sure the guard markers are retained in their original positions.  in TEST_F()
892 		       MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
901 	 * Again, make sure the guard markers are retained in their original positions.  in TEST_F()
907 	 * A real user would have to remove guard markers, but would reasonably  in TEST_F()
909 	 * guard markers.  in TEST_F()
917  * guard markers where possible.
925 	const unsigned long page_size = self->page_size;  in TEST_F()
931 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
934 	/* Place guard markers at both ends of the 5 page span. */  in TEST_F()
946 	/* We expect the guard marker at the start to be retained... */  in TEST_F()
949 	/* ...But remaining pages will not have guard markers. */  in TEST_F()
957 	 * As with expansion, a real user would have to remove guard pages and  in TEST_F()
969 	/* Again, we expect the guard marker at the start to be retained... */  in TEST_F()
972 	/* ...But remaining pages will not have guard markers. */  in TEST_F()
985  * retain guard pages.
989 	const unsigned long page_size = self->page_size;  in TEST_F()
996 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
999 	/* Establish guard pages in the first 5 pages. */  in TEST_F()
1003 	ASSERT_NE(pid, -1);  in TEST_F()
1040  * and then guard and unguard the range.
1044 	const unsigned long page_size = self->page_size;  in TEST_F()
1051 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
1062 	ASSERT_NE(pid, -1);  in TEST_F()
1074 		/* Establish guard pages across the whole range. */  in TEST_F()
1080 		 * By removing the guard pages, the page tables will be  in TEST_F()
1115 	const unsigned long page_size = self->page_size;  in TEST_F()
1122 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
1128 	/* Guard the first 5 pages. */  in TEST_F()
1132 	ASSERT_NE(pid, -1);  in TEST_F()
1136 		/* Guard will have been wiped. */  in TEST_F()
1150 	/* Guard markers should be in effect.*/  in TEST_F()
1162 /* Ensure that MADV_FREE retains guard entries as expected. */
1165 	const unsigned long page_size = self->page_size;  in TEST_F()
1171 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
1174 	/* Guard range. */  in TEST_F()
1187 	/* This should leave the guard markers in place. */  in TEST_F()
1201 	const unsigned long page_size = self->page_size;  in TEST_F()
1206 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
1209 	/* Guard range. */  in TEST_F()
1213 	ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_POPULATE_READ), -1);  in TEST_F()
1217 	ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_POPULATE_WRITE), -1);  in TEST_F()
1224 /* Ensure that MADV_COLD, MADV_PAGEOUT do not remove guard markers. */
1227 	const unsigned long page_size = self->page_size;  in TEST_F()
1233 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
1236 	/* Guard range. */  in TEST_F()
1246 	/* Now mark cold. This should have no impact on guard markers. */  in TEST_F()
1270 /* Ensure that guard pages do not break userfaultd. */
1273 	const unsigned long page_size = self->page_size;  in TEST_F()
1286 	if (uffd == -1 && errno == EPERM)  in TEST_F()
1288 	ASSERT_NE(uffd, -1);  in TEST_F()
1294 		   MAP_ANON | MAP_PRIVATE, -1, 0);  in TEST_F()
1304 	/* Guard the range. This should not trigger the uffd. */  in TEST_F()