The patch titled
Subject: kselftest: vm: add tests for no-inherit memory-deny-write-execute
has been added to the -mm mm-unstable branch. Its filename is
kselftest-vm-add-tests-for-no-inherit-memory-deny-write-execute.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kselftest-vm-add-tests-for-no-inherit-memory-deny-write-execute.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Florent Revest <revest@xxxxxxxxxxxx>
Subject: kselftest: vm: add tests for no-inherit memory-deny-write-execute
Date: Mon, 28 Aug 2023 17:08:58 +0200
Add some tests to cover the new PR_MDWE_NO_INHERIT flag of the
PR_SET_MDWE prctl.
Check that:
- it can't be set without PR_SET_MDWE
- MDWE flags can't be unset
- when set, PR_SET_MDWE doesn't propagate to children
Link: https://lkml.kernel.org/r/20230828150858.393570-7-revest@xxxxxxxxxxxx
Signed-off-by: Florent Revest <revest@xxxxxxxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Alexey Izbyshev <izbyshev@xxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Ayush Jain <ayush.jain3@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Joey Gouly <joey.gouly@xxxxxxx>
Cc: KP Singh <kpsingh@xxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Szabolcs Nagy <Szabolcs.Nagy@xxxxxxx>
Cc: Topi Miettinen <toiwoton@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/mm/mdwe_test.c | 114 +++++++++++++++++++++--
1 file changed, 108 insertions(+), 6 deletions(-)
--- a/tools/testing/selftests/mm/mdwe_test.c~kselftest-vm-add-tests-for-no-inherit-memory-deny-write-execute
+++ a/tools/testing/selftests/mm/mdwe_test.c
@@ -22,6 +22,9 @@
TEST(prctl_flags)
{
+ EXPECT_LT(prctl(PR_SET_MDWE, PR_MDWE_NO_INHERIT, 0L, 0L, 7L), 0);
+ EXPECT_EQ(errno, EINVAL);
+
EXPECT_LT(prctl(PR_SET_MDWE, 7L, 0L, 0L, 0L), 0);
EXPECT_EQ(errno, EINVAL);
EXPECT_LT(prctl(PR_SET_MDWE, 0L, 7L, 0L, 0L), 0);
@@ -41,6 +44,84 @@ TEST(prctl_flags)
EXPECT_EQ(errno, EINVAL);
}
+FIXTURE(consecutive_prctl_flags) {};
+FIXTURE_SETUP(consecutive_prctl_flags) {}
+FIXTURE_TEARDOWN(consecutive_prctl_flags) {}
+
+FIXTURE_VARIANT(consecutive_prctl_flags)
+{
+ unsigned long first_flags;
+ unsigned long second_flags;
+ bool should_work;
+};
+
+FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_keep_no_flags)
+{
+ .first_flags = 0,
+ .second_flags = 0,
+ .should_work = true,
+};
+
+FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_keep_exec_gain)
+{
+ .first_flags = PR_MDWE_REFUSE_EXEC_GAIN,
+ .second_flags = PR_MDWE_REFUSE_EXEC_GAIN,
+ .should_work = true,
+};
+
+FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_keep_both_flags)
+{
+ .first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
+ .second_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
+ .should_work = true,
+};
+
+FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_mdwe)
+{
+ .first_flags = PR_MDWE_REFUSE_EXEC_GAIN,
+ .second_flags = 0,
+ .should_work = false,
+};
+
+FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_mdwe_no_inherit)
+{
+ .first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
+ .second_flags = 0,
+ .should_work = false,
+};
+
+FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_no_inherit)
+{
+ .first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
+ .second_flags = PR_MDWE_REFUSE_EXEC_GAIN,
+ .should_work = false,
+};
+
+FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_enable_no_inherit)
+{
+ .first_flags = PR_MDWE_REFUSE_EXEC_GAIN,
+ .second_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
+ .should_work = false,
+};
+
+TEST_F(consecutive_prctl_flags, two_prctls)
+{
+ int ret;
+
+ EXPECT_EQ(prctl(PR_SET_MDWE, variant->first_flags, 0L, 0L, 0L), 0);
+
+ ret = prctl(PR_SET_MDWE, variant->second_flags, 0L, 0L, 0L);
+ if (variant->should_work) {
+ EXPECT_EQ(ret, 0);
+
+ ret = prctl(PR_GET_MDWE, 0L, 0L, 0L, 0L);
+ ASSERT_EQ(ret, variant->second_flags);
+ } else {
+ EXPECT_NE(ret, 0);
+ ASSERT_EQ(errno, EPERM);
+ }
+}
+
FIXTURE(mdwe)
{
void *p;
@@ -53,28 +134,45 @@ FIXTURE_VARIANT(mdwe)
{
bool enabled;
bool forked;
+ bool inherit;
};
FIXTURE_VARIANT_ADD(mdwe, stock)
{
.enabled = false,
.forked = false,
+ .inherit = false,
};
FIXTURE_VARIANT_ADD(mdwe, enabled)
{
.enabled = true,
.forked = false,
+ .inherit = true,
};
-FIXTURE_VARIANT_ADD(mdwe, forked)
+FIXTURE_VARIANT_ADD(mdwe, inherited)
{
.enabled = true,
.forked = true,
+ .inherit = true,
};
+FIXTURE_VARIANT_ADD(mdwe, not_inherited)
+{
+ .enabled = true,
+ .forked = true,
+ .inherit = false,
+};
+
+static bool executable_map_should_fail(const FIXTURE_VARIANT(mdwe) *variant)
+{
+ return variant->enabled && (!variant->forked || variant->inherit);
+}
+
FIXTURE_SETUP(mdwe)
{
+ unsigned long mdwe_flags;
int ret, status;
self->p = NULL;
@@ -84,13 +182,17 @@ FIXTURE_SETUP(mdwe)
if (!variant->enabled)
return;
- ret = prctl(PR_SET_MDWE, PR_MDWE_REFUSE_EXEC_GAIN, 0L, 0L, 0L);
+ mdwe_flags = PR_MDWE_REFUSE_EXEC_GAIN;
+ if (!variant->inherit)
+ mdwe_flags |= PR_MDWE_NO_INHERIT;
+
+ ret = prctl(PR_SET_MDWE, mdwe_flags, 0L, 0L, 0L);
ASSERT_EQ(ret, 0) {
TH_LOG("PR_SET_MDWE failed or unsupported");
}
ret = prctl(PR_GET_MDWE, 0L, 0L, 0L, 0L);
- ASSERT_EQ(ret, 1);
+ ASSERT_EQ(ret, mdwe_flags);
if (variant->forked) {
self->pid = fork();
@@ -121,7 +223,7 @@ TEST_F(mdwe, mmap_READ_EXEC)
TEST_F(mdwe, mmap_WRITE_EXEC)
{
self->p = mmap(NULL, self->size, PROT_WRITE | PROT_EXEC, self->flags, 0, 0);
- if (variant->enabled) {
+ if (executable_map_should_fail(variant)) {
EXPECT_EQ(self->p, MAP_FAILED);
} else {
EXPECT_NE(self->p, MAP_FAILED);
@@ -147,7 +249,7 @@ TEST_F(mdwe, mprotect_add_EXEC)
ASSERT_NE(self->p, MAP_FAILED);
ret = mprotect(self->p, self->size, PROT_READ | PROT_EXEC);
- if (variant->enabled) {
+ if (executable_map_should_fail(variant)) {
EXPECT_LT(ret, 0);
} else {
EXPECT_EQ(ret, 0);
@@ -162,7 +264,7 @@ TEST_F(mdwe, mprotect_WRITE_EXEC)
ASSERT_NE(self->p, MAP_FAILED);
ret = mprotect(self->p, self->size, PROT_WRITE | PROT_EXEC);
- if (variant->enabled) {
+ if (executable_map_should_fail(variant)) {
EXPECT_LT(ret, 0);
} else {
EXPECT_EQ(ret, 0);
_
Patches currently in -mm which might be from revest@xxxxxxxxxxxx are
kselftest-vm-fix-tabs-spaces-inconsistency-in-the-mdwe-test.patch
kselftest-vm-fix-mdwes-mmap_fixed-test-case.patch
kselftest-vm-check-errnos-in-mdwe_test.patch
mm-make-pr_mdwe_refuse_exec_gain-an-unsigned-long.patch
mm-add-a-no_inherit-flag-to-the-pr_set_mdwe-prctl.patch
kselftest-vm-add-tests-for-no-inherit-memory-deny-write-execute.patch
