lkml.org 
[lkml]   [2018]   [Nov]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH -next 2/2] selftests/memfd: modify tests for F_SEAL_FUTURE_WRITE seal
Date
Modify the tests for F_SEAL_FUTURE_WRITE based on the changes
introduced in previous patch.

Also add a test to make sure the reopen issue pointed by Jann Horn [1]
is fixed.

[1] https://lore.kernel.org/lkml/CAG48ez1h=v-JYnDw81HaYJzOfrNhwYksxmc2r=cJvdQVgYM+NA@mail.gmail.com/

Cc: Jann Horn <jannh@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
tools/testing/selftests/memfd/memfd_test.c | 88 +++++++++++-----------
1 file changed, 44 insertions(+), 44 deletions(-)

diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index 32b207ca7372..c67d32eeb668 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -54,6 +54,22 @@ static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
return fd;
}

+static int mfd_assert_reopen_fd(int fd_in)
+{
+ int r, fd;
+ char path[100];
+
+ sprintf(path, "/proc/self/fd/%d", fd_in);
+
+ fd = open(path, O_RDWR);
+ if (fd < 0) {
+ printf("re-open of existing fd %d failed\n", fd_in);
+ abort();
+ }
+
+ return fd;
+}
+
static void mfd_fail_new(const char *name, unsigned int flags)
{
int r;
@@ -255,6 +271,25 @@ static void mfd_assert_read(int fd)
munmap(p, mfd_def_size);
}

+/* Test that PROT_READ + MAP_SHARED mappings work. */
+static void mfd_assert_read_shared(int fd)
+{
+ void *p;
+
+ /* verify PROT_READ and MAP_SHARED *is* allowed */
+ p = mmap(NULL,
+ mfd_def_size,
+ PROT_READ,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+ munmap(p, mfd_def_size);
+}
+
static void mfd_assert_write(int fd)
{
ssize_t l;
@@ -698,7 +733,7 @@ static void test_seal_write(void)
*/
static void test_seal_future_write(void)
{
- int fd;
+ int fd, fd2;
void *p;

printf("%s SEAL-FUTURE-WRITE\n", memfd_str);
@@ -710,58 +745,23 @@ static void test_seal_future_write(void)
p = mfd_assert_mmap_shared(fd);

mfd_assert_has_seals(fd, 0);
- /* Not adding grow/shrink seals makes the future write
- * seal fail to get added
- */
- mfd_fail_add_seals(fd, F_SEAL_FUTURE_WRITE);
-
- mfd_assert_add_seals(fd, F_SEAL_GROW);
- mfd_assert_has_seals(fd, F_SEAL_GROW);
-
- /* Should still fail since shrink seal has
- * not yet been added
- */
- mfd_fail_add_seals(fd, F_SEAL_FUTURE_WRITE);
-
- mfd_assert_add_seals(fd, F_SEAL_SHRINK);
- mfd_assert_has_seals(fd, F_SEAL_GROW |
- F_SEAL_SHRINK);

- /* Now should succeed, also verifies that the seal
- * could be added with an existing writable mmap
- */
mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);
- mfd_assert_has_seals(fd, F_SEAL_SHRINK |
- F_SEAL_GROW |
- F_SEAL_FUTURE_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_FUTURE_WRITE);

/* read should pass, writes should fail */
mfd_assert_read(fd);
+ mfd_assert_read_shared(fd);
mfd_fail_write(fd);

- munmap(p, mfd_def_size);
- close(fd);
-
- /* Test adding all seals (grow, shrink, future write) at once */
- fd = mfd_assert_new("kern_memfd_seal_future_write2",
- mfd_def_size,
- MFD_CLOEXEC | MFD_ALLOW_SEALING);
-
- p = mfd_assert_mmap_shared(fd);
-
- mfd_assert_has_seals(fd, 0);
- mfd_assert_add_seals(fd, F_SEAL_SHRINK |
- F_SEAL_GROW |
- F_SEAL_FUTURE_WRITE);
- mfd_assert_has_seals(fd, F_SEAL_SHRINK |
- F_SEAL_GROW |
- F_SEAL_FUTURE_WRITE);
-
- /* read should pass, writes should fail */
- mfd_assert_read(fd);
- mfd_fail_write(fd);
+ fd2 = mfd_assert_reopen_fd(fd);
+ /* read should pass, writes should still fail */
+ mfd_assert_read(fd2);
+ mfd_assert_read_shared(fd2);
+ mfd_fail_write(fd2);

munmap(p, mfd_def_size);
+ close(fd2);
close(fd);
}

--
2.19.1.1215.g8438c0b245-goog
\
 
 \ /
  Last update: 2018-11-20 06:22    [W:0.068 / U:9.644 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site