From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
To: linux-kernel@vger.kernel.org
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>,
dancol@google.com, minchan@kernel.org,
"John Stultz" <john.stultz@linaro.org>,
"Al Viro" <viro@zeniv.linux.org.uk>,
"Andrew Morton" <akpm@linux-foundation.org>,
gregkh@linuxfoundation.org, hch@infradead.org,
"J. Bruce Fields" <bfields@fieldses.org>,
"Jeff Layton" <jlayton@kernel.org>,
jreck@google.com, "Khalid Aziz" <khalid.aziz@oracle.com>,
"Lei Yang" <Lei.Yang@windriver.com>,
linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-mm@kvack.org,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Mike Kravetz" <mike.kravetz@oracle.com>,
"Shuah Khan" <shuah@kernel.org>,
tkjos@google.com, valdis.kletnieks@vt.edu
Subject: [PATCH v3 resend 2/2] selftests/memfd: Add tests for F_SEAL_FUTURE_WRITE seal
Date: Wed, 7 Nov 2018 20:15:37 -0800 [thread overview]
Message-ID: <20181108041537.39694-2-joel@joelfernandes.org> (raw)
In-Reply-To: <20181108041537.39694-1-joel@joelfernandes.org>
Add tests to verify sealing memfds with the F_SEAL_FUTURE_WRITE works as
expected.
Cc: dancol@google.com
Cc: minchan@kernel.org
Reviewed-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
tools/testing/selftests/memfd/memfd_test.c | 74 ++++++++++++++++++++++
1 file changed, 74 insertions(+)
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index 10baa1652fc2..32b207ca7372 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -692,6 +692,79 @@ static void test_seal_write(void)
close(fd);
}
+/*
+ * Test SEAL_FUTURE_WRITE
+ * Test whether SEAL_FUTURE_WRITE actually prevents modifications.
+ */
+static void test_seal_future_write(void)
+{
+ int fd;
+ void *p;
+
+ printf("%s SEAL-FUTURE-WRITE\n", memfd_str);
+
+ fd = mfd_assert_new("kern_memfd_seal_future_write",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ 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);
+
+ /* read should pass, writes should fail */
+ mfd_assert_read(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);
+
+ munmap(p, mfd_def_size);
+ close(fd);
+}
+
/*
* Test SEAL_SHRINK
* Test whether SEAL_SHRINK actually prevents shrinking
@@ -945,6 +1018,7 @@ int main(int argc, char **argv)
test_basic();
test_seal_write();
+ test_seal_future_write();
test_seal_shrink();
test_seal_grow();
test_seal_resize();
--
2.19.1.930.g4563a0d9d0-goog
next prev parent reply other threads:[~2018-11-08 4:16 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-08 4:15 [PATCH v3 resend 1/2] mm: Add an F_SEAL_FUTURE_WRITE seal to memfd Joel Fernandes (Google)
2018-11-08 4:15 ` Joel Fernandes (Google) [this message]
2018-11-09 8:49 ` Joel Fernandes
2018-11-09 20:36 ` Andrew Morton
2018-11-10 3:54 ` Joel Fernandes
2018-11-09 21:06 ` Jann Horn
2018-11-09 21:19 ` Jann Horn
2018-11-10 3:20 ` Joel Fernandes
2018-11-10 6:05 ` Andy Lutomirski
2018-11-10 18:24 ` Joel Fernandes
2018-11-10 18:45 ` Daniel Colascione
2018-11-10 19:11 ` Daniel Colascione
2018-11-10 19:55 ` Andy Lutomirski
2018-11-10 22:09 ` Joel Fernandes
2018-11-10 22:18 ` Andy Lutomirski
2018-11-11 2:38 ` Joel Fernandes
2018-11-11 3:40 ` Andy Lutomirski
2018-11-11 4:01 ` Joel Fernandes
2018-11-11 8:09 ` Joel Fernandes
2018-11-11 8:30 ` Daniel Colascione
2018-11-11 15:14 ` Andy Lutomirski
2018-11-11 17:36 ` Joel Fernandes
[not found] ` <CAKOZuethC7+YrRyyGciUCfhSSa9cCcAFJ8g_qEw9uh3TBbyOcg@mail.gmail.com>
2018-11-10 17:10 ` Joel Fernandes
2018-11-09 21:40 ` Andy Lutomirski
2018-11-09 20:02 ` Michael Tirado
2018-11-10 1:49 ` Joel Fernandes
2018-11-09 22:20 ` Daniel Colascione
2018-11-09 22:37 ` Andy Lutomirski
2018-11-09 22:42 ` Daniel Colascione
2018-11-09 23:14 ` Andy Lutomirski
2018-11-10 1:36 ` Joel Fernandes
2018-11-09 23:46 ` Joel Fernandes
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