Hi Pedro
On Fri, Aug 30, 2024 at 5:57 AM Pedro Falcato pedro.falcato@gmail.com wrote:
On Thu, Aug 29, 2024 at 09:43:51PM GMT, jeffxu@chromium.org wrote:
From: Jeff Xu jeffxu@chromium.org
Add sealing test to cover mmap for Expand/shrink across vmas. Reuse the same address in !MAP_FIXED case.
Signed-off-by: Jeff Xu jeffxu@chromium.org
tools/testing/selftests/mm/mseal_test.c | 125 +++++++++++++++++++++++- 1 file changed, 124 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/mm/mseal_test.c b/tools/testing/selftests/mm/mseal_test.c index ae06c354220d..d83538039e76 100644 --- a/tools/testing/selftests/mm/mseal_test.c +++ b/tools/testing/selftests/mm/mseal_test.c @@ -2222,6 +2222,122 @@ static void test_munmap_free_multiple_ranges(bool seal) REPORT_TEST_PASS(); }
+static void test_seal_mmap_expand_seal_middle(bool seal) +{
void *ptr;unsigned long page_size = getpagesize();unsigned long size = 12 * page_size;int ret;void *ret2;int prot;setup_single_address(size, &ptr);FAIL_TEST_IF_FALSE(ptr != (void *)-1);/* ummap last 4 pages. */ret = sys_munmap(ptr + 8 * page_size, 4 * page_size);FAIL_TEST_IF_FALSE(!ret);size = get_vma_size(ptr, &prot);FAIL_TEST_IF_FALSE(size == 8 * page_size);FAIL_TEST_IF_FALSE(prot == 0x4);if (seal) {ret = sys_mseal(ptr + 4 * page_size, 4 * page_size);FAIL_TEST_IF_FALSE(!ret);}/* use mmap to expand. */ret2 = mmap(ptr, 12 * page_size, PROT_READ,MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);This is not expansion, but overwriting. Expansion is allowed through an adjacent mmap + mseal (which will merge the two VMAs).
The mmap is trying to expand the address range beginning from ptr (size 8 * page_size) to 12 * page_size. This is overwrite + expansion.
if (seal) {FAIL_TEST_IF_FALSE(ret2 == MAP_FAILED);FAIL_TEST_IF_FALSE(errno == EPERM);size = get_vma_size(ptr, &prot);FAIL_TEST_IF_FALSE(size == 4 * page_size);FAIL_TEST_IF_FALSE(prot == 0x4);size = get_vma_size(ptr + 4 * page_size, &prot);FAIL_TEST_IF_FALSE(size == 4 * page_size);FAIL_TEST_IF_FALSE(prot == 0x4);} elseFAIL_TEST_IF_FALSE(ret2 == ptr);REPORT_TEST_PASS();+}
+static void test_seal_mmap_shrink_seal_middle(bool seal) +{
void *ptr;unsigned long page_size = getpagesize();unsigned long size = 12 * page_size;int ret;void *ret2;int prot;setup_single_address(size, &ptr);FAIL_TEST_IF_FALSE(ptr != (void *)-1);if (seal) {ret = sys_mseal(ptr + 4 * page_size, 4 * page_size);FAIL_TEST_IF_FALSE(!ret);}/* use mmap to shrink. */ret2 = mmap(ptr, 7 * page_size, PROT_READ,MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);This is also a partial overwrite.
The mmap is trying to shrink the address range beginning from ptr (size 12 * page_size) to 8 * page_size. This is overwrite + shrink.
if (seal) {FAIL_TEST_IF_FALSE(ret2 == MAP_FAILED);FAIL_TEST_IF_FALSE(errno == EPERM);size = get_vma_size(ptr, &prot);FAIL_TEST_IF_FALSE(size == 4 * page_size);FAIL_TEST_IF_FALSE(prot == 0x4);size = get_vma_size(ptr + 4 * page_size, &prot);FAIL_TEST_IF_FALSE(size == 4 * page_size);FAIL_TEST_IF_FALSE(prot == 0x4);size = get_vma_size(ptr + 4 * page_size, &prot);FAIL_TEST_IF_FALSE(size == 4 * page_size);FAIL_TEST_IF_FALSE(prot == 0x4);} elseFAIL_TEST_IF_FALSE(ret2 == ptr);REPORT_TEST_PASS();+}
+static void test_seal_mmap_reuse_addr(bool seal) +{
void *ptr;unsigned long page_size = getpagesize();unsigned long size = page_size;int ret;void *ret2;int prot;setup_single_address(size, &ptr);FAIL_TEST_IF_FALSE(ptr != (void *)-1);if (seal) {ret = sys_mseal(ptr, size);FAIL_TEST_IF_FALSE(!ret);}/* use mmap to change protection. */ret2 = mmap(ptr, size, PROT_NONE,MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);This is also an overwrite. You're semantically testing the same thing, and testing the same regions of code.
This is not overwriting. MAP_FIXED is not used.
-Jeff
These 3 tests are all kind of the same thing.
-- Pedro