Commit ea0916e0 authored by Lorenzo Stoakes's avatar Lorenzo Stoakes Committed by Andrew Morton
Browse files

selftests/memfd: add test for mapping write-sealed memfd read-only 

Now we have reinstated the ability to map F_SEAL_WRITE mappings read-only,
assert that we are able to do this in a test to ensure that we do not
regress this again.

Link: https://lkml.kernel.org/r/a6377ec470b14c0539b4600cf8fa24bf2e4858ae.1732804776.git.lorenzo.stoakes@oracle.com


Signed-off-by: default avatarLorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Julian Orth <ju.orth@gmail.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 8ec396d0

tools/testing/selftests/memfd/memfd_test.c

+43 −0
Original line number Diff line number Diff line
@@ -282,6 +282,24 @@ static void *mfd_assert_mmap_shared(int fd) 
	return p;

}



static void *mfd_assert_mmap_read_shared(int fd)

{

	void *p;



	p = mmap(NULL,

		 mfd_def_size,

		 PROT_READ,

		 MAP_SHARED,

		 fd,

		 0);

	if (p == MAP_FAILED) {

		printf("mmap() failed: %m\n");

		abort();

	}



	return p;

}



static void *mfd_assert_mmap_private(int fd)

{

	void *p;
@@ -980,6 +998,30 @@ static void test_seal_future_write(void) 
	close(fd);

}



static void test_seal_write_map_read_shared(void)

{

	int fd;

	void *p;



	printf("%s SEAL-WRITE-MAP-READ\n", memfd_str);



	fd = mfd_assert_new("kern_memfd_seal_write_map_read",

			    mfd_def_size,

			    MFD_CLOEXEC | MFD_ALLOW_SEALING);



	mfd_assert_add_seals(fd, F_SEAL_WRITE);

	mfd_assert_has_seals(fd, F_SEAL_WRITE);



	p = mfd_assert_mmap_read_shared(fd);



	mfd_assert_read(fd);

	mfd_assert_read_shared(fd);

	mfd_fail_write(fd);



	munmap(p, mfd_def_size);

	close(fd);

}



/*

 * Test SEAL_SHRINK

 * Test whether SEAL_SHRINK actually prevents shrinking
@@ -1593,6 +1635,7 @@ int main(int argc, char **argv) 


	test_seal_write();

	test_seal_future_write();

	test_seal_write_map_read_shared();

	test_seal_shrink();

	test_seal_grow();

	test_seal_resize();