Re: [PATCH 4/4] selftests/memfd: add tests for MFD_NOEXEC

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 4/1/22 4:08 PM, Daniel Verkamp wrote:
Tests that ensure MFD_NOEXEC memfds have the appropriate mode bits and
cannot be chmod-ed into being executable.

Signed-off-by: Daniel Verkamp <dverkamp@xxxxxxxxxxxx>
---
  tools/testing/selftests/memfd/memfd_test.c | 34 ++++++++++++++++++++++
  1 file changed, 34 insertions(+)

diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index fdb0e46e9df9..a79567161cdf 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -32,6 +32,10 @@
  #define F_SEAL_EXEC	0x0020
  #endif
+#ifndef MFD_NOEXEC
+#define MFD_NOEXEC	0x0008U
+#endif
+
  /*
   * Default is not to test hugetlbfs
   */
@@ -959,6 +963,35 @@ static void test_seal_exec(void)
  	close(fd);
  }
+/*
+ * Test memfd_create with MFD_NOEXEC flag
+ * Test that MFD_NOEXEC applies F_SEAL_EXEC and prevents change of exec bits
+ */
+static void test_noexec(void)
+{
+	int fd;
+
+	printf("%s NOEXEC\n", memfd_str);
+
+	/* Create with NOEXEC and ALLOW_SEALING */
+	fd = mfd_assert_new("kern_memfd_noexec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC);

Don't we need to check fd here?

+	mfd_assert_mode(fd, 0666);
+	mfd_assert_has_seals(fd, F_SEAL_EXEC);
+	mfd_fail_chmod(fd, 0777);
+	close(fd);
+
+	/* Create with NOEXEC but without ALLOW_SEALING */
+	fd = mfd_assert_new("kern_memfd_noexec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_NOEXEC);

What happens when mfd_assert_new() fails - don't we need to check fd?

+	mfd_assert_mode(fd, 0666);
+	mfd_assert_has_seals(fd, F_SEAL_EXEC | F_SEAL_SEAL);
+	mfd_fail_chmod(fd, 0777);
+	close(fd);
+}
+
  /*
   * Test sharing via dup()
   * Test that seals are shared between dupped FDs and they're all equal.
@@ -1132,6 +1165,7 @@ int main(int argc, char **argv)
test_create();
  	test_basic();
+	test_noexec();
test_seal_write();
  	test_seal_future_write();


fd isn't checked in the other test F_SEAL_EXEC in the 3/4 patch.

thanks,
-- Shuah




[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux