@@ -556,7 +556,7 @@ struct node {
* looked at the shadow stack gaps.
* 5. See if it landed in the gap.
*/
-int test_guard_gap(void)
+int test_guard_gap_other_gaps(void)
{
void *free_area, *shstk, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
struct node *head = NULL, *cur;
@@ -593,11 +593,64 @@ int test_guard_gap(void)
if (shstk - test_map - PAGE_SIZE != PAGE_SIZE)
return 1;
- printf("[OK]\tGuard gap test\n");
+ printf("[OK]\tGuard gap test, other mapping's gaps\n");
return 0;
}
+/* Tests respecting the guard gap of the mapping getting placed */
+int test_guard_gap_new_mappings_gaps(void)
+{
+ void *free_area, *shstk_start, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
+ struct node *head = NULL, *cur;
+ int ret = 0;
+
+ free_area = mmap(0, PAGE_SIZE * 4, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ munmap(free_area, PAGE_SIZE * 4);
+
+ /* Test letting map_shadow_stack find a free space */
+ shstk_start = mmap(free_area, PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (shstk_start == MAP_FAILED || shstk_start != free_area)
+ return 1;
+
+ while (test_map > shstk_start) {
+ test_map = (void *)syscall(__NR_map_shadow_stack, 0, PAGE_SIZE, 0);
+ if (test_map == MAP_FAILED) {
+ printf("[INFO]\tmap_shadow_stack MAP_FAILED\n");
+ ret = 1;
+ break;
+ }
+
+ cur = malloc(sizeof(*cur));
+ cur->mapping = test_map;
+
+ cur->next = head;
+ head = cur;
+
+ if (test_map == free_area + PAGE_SIZE) {
+ printf("[INFO]\tNew mapping has other mapping in guard gap!\n");
+ ret = 1;
+ break;
+ }
+ }
+
+ while (head) {
+ cur = head;
+ head = cur->next;
+ munmap(cur->mapping, PAGE_SIZE);
+ free(cur);
+ }
+
+ munmap(shstk_start, PAGE_SIZE);
+
+ if (!ret)
+ printf("[OK]\tGuard gap test, placement mapping's gaps\n");
+
+ return ret;
+}
+
/*
* Too complicated to pull it out of the 32 bit header, but also get the
* 64 bit one needed above. Just define a copy here.
@@ -850,9 +903,15 @@ int main(int argc, char *argv[])
goto out;
}
- if (test_guard_gap()) {
+ if (test_guard_gap_other_gaps()) {
ret = 1;
- printf("[FAIL]\tGuard gap test\n");
+ printf("[FAIL]\tGuard gap test, other mappings' gaps\n");
+ goto out;
+ }
+
+ if (test_guard_gap_new_mappings_gaps()) {
+ ret = 1;
+ printf("[FAIL]\tGuard gap test, placement mapping's gaps\n");
goto out;
}
The existing shadow stack test for guard gaps just checks that new mappings are not placed in an existing mapping's guard gap. Add one that checks that new mappings are not placed such that preexisting mappings are in the new mappings guard gap. Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> --- .../testing/selftests/x86/test_shadow_stack.c | 67 +++++++++++++++++-- 1 file changed, 63 insertions(+), 4 deletions(-)