[PATCH v1 2/2] selftest/mseal: Add tests for madvise fixes

[jeffxu@chromium.org]

From: Jeff Xu <jeffxu@chromium.org>

Testcase for "Two fixes for madvise(MADV_DONTNEED) when sealed"

test_seal_madvise_prot_none
  shall not block when mapping is PROT_NONE

test_madvise_filebacked_writable
  shall not block writeable private filebacked mapping.

test_madvise_filebacked_was_writable - shall block.
  shall block read-only private filebacked mapping which
  was previously writable.

Fixes: 8be7258aad44 ("mseal: add mseal syscall")
Cc: <stable@vger.kernel.org> # 6.11.y: 67203f3f2a63: selftests/mm: add mseal test for no-discard madvise
Cc: <stable@vger.kernel.org> # 6.11.y: f28bdd1b17ec: selftests/mm: add more mseal traversal tests
Cc: <stable@vger.kernel.org> # 6.11.y
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
---
 tools/testing/selftests/mm/mseal_test.c | 118 +++++++++++++++++++++++-
 1 file changed, 116 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/mm/mseal_test.c b/tools/testing/selftests/mm/mseal_test.c
index 01675c412b2a..fa74dbe4a684 100644
--- a/tools/testing/selftests/mm/mseal_test.c
+++ b/tools/testing/selftests/mm/mseal_test.c
@@ -1728,7 +1728,7 @@ static void test_seal_discard_ro_anon_on_filebacked(bool seal)
 		FAIL_TEST_IF_FALSE(!ret);
 	}
 
-	/* sealing doesn't apply for file backed mapping. */
+	/* read-only private file-backed mapping, allow always */
 	ret = sys_madvise(ptr, size, MADV_DONTNEED);
 	FAIL_TEST_IF_FALSE(!ret);
 
@@ -1864,6 +1864,111 @@ static void test_seal_madvise_nodiscard(bool seal)
 	REPORT_TEST_PASS();
 }
 
+static void test_seal_madvise_prot_none(bool seal)
+{
+	void *ptr;
+	unsigned long page_size = getpagesize();
+	unsigned long size = 4 * page_size;
+	int ret;
+
+	setup_single_address(size, &ptr);
+	FAIL_TEST_IF_FALSE(ptr != (void *)-1);
+
+	ret = sys_mprotect(ptr + page_size, page_size, PROT_NONE);
+	FAIL_TEST_IF_FALSE(!ret);
+
+	if (seal) {
+		ret = seal_single_address(ptr + page_size, page_size);
+		FAIL_TEST_IF_FALSE(!ret);
+	}
+
+	/* madvise(DONTNEED) should pass on PROT_NONE sealed VMA */
+	ret = sys_madvise(ptr + page_size, page_size, MADV_DONTNEED);
+	FAIL_TEST_IF_FALSE(!ret);
+
+	REPORT_TEST_PASS();
+}
+
+static void test_madvise_filebacked_writable(bool seal)
+{
+	void *ptr;
+	unsigned long page_size = getpagesize();
+	unsigned long size = 4 * page_size;
+	int ret;
+	int fd;
+	unsigned long mapflags = MAP_PRIVATE;
+
+	fd = memfd_create("test", 0);
+	FAIL_TEST_IF_FALSE(fd > 0);
+
+	ret = fallocate(fd, 0, 0, size);
+	FAIL_TEST_IF_FALSE(!ret);
+
+	ptr = mmap(NULL, size, PROT_READ|PROT_WRITE, mapflags, fd, 0);
+	FAIL_TEST_IF_FALSE(ptr != MAP_FAILED);
+
+	if (seal) {
+		ret = sys_mseal(ptr, size);
+		FAIL_TEST_IF_FALSE(!ret);
+	}
+
+	/* sealing doesn't apply for writeable file-backed mapping. */
+	ret = sys_madvise(ptr, size, MADV_DONTNEED);
+	FAIL_TEST_IF_FALSE(!ret);
+
+	ret = sys_munmap(ptr, size);
+	if (seal)
+		FAIL_TEST_IF_FALSE(ret < 0);
+	else
+		FAIL_TEST_IF_FALSE(!ret);
+	close(fd);
+
+	REPORT_TEST_PASS();
+}
+
+static void test_madvise_filebacked_was_writable(bool seal)
+{
+	void *ptr;
+	unsigned long page_size = getpagesize();
+	unsigned long size = 4 * page_size;
+	int ret;
+	int fd;
+	unsigned long mapflags = MAP_PRIVATE;
+
+	fd = memfd_create("test", 0);
+	FAIL_TEST_IF_FALSE(fd > 0);
+
+	ret = fallocate(fd, 0, 0, size);
+	FAIL_TEST_IF_FALSE(!ret);
+
+	ptr = mmap(NULL, size, PROT_READ|PROT_WRITE, mapflags, fd, 0);
+	FAIL_TEST_IF_FALSE(ptr != MAP_FAILED);
+
+	ret = sys_mprotect(ptr, size, PROT_READ);
+	FAIL_TEST_IF_FALSE(!ret);
+
+	if (seal) {
+		ret = sys_mseal(ptr, size);
+		FAIL_TEST_IF_FALSE(!ret);
+	}
+
+	/* read-only file-backed mapping, was writable. */
+	ret = sys_madvise(ptr, size, MADV_DONTNEED);
+	if (seal)
+		FAIL_TEST_IF_FALSE(ret < 0);
+	else
+		FAIL_TEST_IF_FALSE(!ret);
+
+	ret = sys_munmap(ptr, size);
+	if (seal)
+		FAIL_TEST_IF_FALSE(ret < 0);
+	else
+		FAIL_TEST_IF_FALSE(!ret);
+	close(fd);
+
+	REPORT_TEST_PASS();
+}
+
 int main(int argc, char **argv)
 {
 	bool test_seal = seal_support();
@@ -1876,7 +1981,7 @@ int main(int argc, char **argv)
 	if (!pkey_supported())
 		ksft_print_msg("PKEY not supported\n");
 
-	ksft_set_plan(88);
+	ksft_set_plan(94);
 
 	test_seal_addseal();
 	test_seal_unmapped_start();
@@ -1985,5 +2090,14 @@ int main(int argc, char **argv)
 	test_seal_discard_ro_anon_on_pkey(false);
 	test_seal_discard_ro_anon_on_pkey(true);
 
+	test_seal_madvise_prot_none(false);
+	test_seal_madvise_prot_none(true);
+
+	test_madvise_filebacked_writable(false);
+	test_madvise_filebacked_writable(true);
+
+	test_madvise_filebacked_was_writable(false);
+	test_madvise_filebacked_was_writable(true);
+
 	ksft_finished();
 }
-- 
2.47.0.rc1.288.g06298d1525-goog