On Tue, Oct 09, 2018 at 03:20:42PM -0700, Joel Fernandes (Google) wrote:
> Add tests to verify sealing memfds with the F_SEAL_FS_WRITE works as
> expected.
>
> Cc: dancol@xxxxxxxxxx
> Cc: minchan@xxxxxxxxxx
> Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
> ---
> tools/testing/selftests/memfd/memfd_test.c | 51 +++++++++++++++++++++-
> 1 file changed, 50 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
> index 10baa1652fc2..4bd2b6c87bb4 100644
> --- a/tools/testing/selftests/memfd/memfd_test.c
> +++ b/tools/testing/selftests/memfd/memfd_test.c
> @@ -27,7 +27,7 @@
>
> #define MFD_DEF_SIZE 8192
> #define STACK_SIZE 65536
> -
> +#define F_SEAL_FS_WRITE 0x0010
> /*
> * Default is not to test hugetlbfs
> */
> @@ -170,6 +170,24 @@ static void *mfd_assert_mmap_shared(int fd)
> return p;
> }
>
> +static void *mfd_fail_mmap_shared(int fd)
> +{
> + void *p;
> +
> + p = mmap(NULL,
> + mfd_def_size,
> + PROT_READ | PROT_WRITE,
> + MAP_SHARED,
> + fd,
> + 0);
> + if (p != MAP_FAILED) {
> + printf("mmap() didn't fail as expected\n");
> + abort();
> + }
> +
> + return p;
> +}
> +
Ah, this function is unused. I wrote it initially and used it but then
figured I didn't need it, and then forgot to remove it. It does not affect
the correctness of the patch. Anyway below is the updated patch.
thanks,
- Joel
------8<-----
From: "Joel Fernandes (Google)" <joel@xxxxxxxxxxxxxxxxx>
Subject: [PATCH v2.1] selftests/memfd: Add tests for F_SEAL_FS_WRITE seal
Add tests to verify sealing memfds with the F_SEAL_FS_WRITE works as
expected.
Cc: dancol@xxxxxxxxxx
Cc: minchan@xxxxxxxxxx
Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/memfd/memfd_test.c | 33 +++++++++++++++++++++-
1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index 10baa1652fc2..d074de568ba0 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -27,7 +27,7 @@
#define MFD_DEF_SIZE 8192
#define STACK_SIZE 65536
-
+#define F_SEAL_FS_WRITE 0x0010
/*
* Default is not to test hugetlbfs
*/
@@ -692,6 +692,36 @@ static void test_seal_write(void)
close(fd);
}
+/*
+ * Test SEAL_WRITE
+ * Test whether SEAL_WRITE actually prevents modifications.
+ */
+static void test_seal_fs_write(void)
+{
+ int fd;
+ void *p;
+
+ printf("%s SEAL-FS-WRITE\n", memfd_str);
+
+ fd = mfd_assert_new("kern_memfd_seal_fs_write",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ p = mfd_assert_mmap_shared(fd);
+
+ /* FS_WRITE seal can be added even with existing
+ * writeable mappings */
+ mfd_assert_has_seals(fd, 0);
+ mfd_assert_add_seals(fd, F_SEAL_FS_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_FS_WRITE);
+
+ mfd_assert_read(fd);
+ mfd_fail_write(fd);
+
+ munmap(p, mfd_def_size);
+ close(fd);
+}
+
/*
* Test SEAL_SHRINK
* Test whether SEAL_SHRINK actually prevents shrinking
@@ -945,6 +975,7 @@ int main(int argc, char **argv)
test_basic();
test_seal_write();
+ test_seal_fs_write();
test_seal_shrink();
test_seal_grow();
test_seal_resize();
--
2.19.0.605.g01d371f741-goog
