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Message-ID: <20230517150321.2890206-6-revest@chromium.org>
Date: Wed, 17 May 2023 17:03:21 +0200
From: Florent Revest <revest@...omium.org>
To: linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc: akpm@...ux-foundation.org, catalin.marinas@....com,
anshuman.khandual@....com, joey.gouly@....com, mhocko@...e.com,
keescook@...omium.org, david@...hat.com, peterx@...hat.com,
izbyshev@...ras.ru, broonie@...nel.org, szabolcs.nagy@....com,
kpsingh@...nel.org, gthelen@...gle.com, toiwoton@...il.com,
Florent Revest <revest@...omium.org>
Subject: [PATCH v2 5/5] kselftest: vm: Add tests for no-inherit memory-deny-write-execute
Add some tests to cover the new PR_MDWE_NO_INHERIT flag of the
PR_SET_MDWE prctl.
Signed-off-by: Florent Revest <revest@...omium.org>
---
tools/testing/selftests/mm/mdwe_test.c | 95 ++++++++++++++++++++++++--
1 file changed, 89 insertions(+), 6 deletions(-)
diff --git a/tools/testing/selftests/mm/mdwe_test.c b/tools/testing/selftests/mm/mdwe_test.c
index 91aa9c3099e7..9f08ed1b99ae 100644
--- a/tools/testing/selftests/mm/mdwe_test.c
+++ b/tools/testing/selftests/mm/mdwe_test.c
@@ -22,6 +22,8 @@
TEST(prctl_flags)
{
+ EXPECT_LT(prctl(PR_SET_MDWE, PR_MDWE_NO_INHERIT, 0L, 0L, 7L), 0);
+
EXPECT_LT(prctl(PR_SET_MDWE, 7L, 0L, 0L, 0L), 0);
EXPECT_LT(prctl(PR_SET_MDWE, 0L, 7L, 0L, 0L), 0);
EXPECT_LT(prctl(PR_SET_MDWE, 0L, 0L, 7L, 0L), 0);
@@ -33,6 +35,66 @@ TEST(prctl_flags)
EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 0L, 7L), 0);
}
+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, same)
+{
+ .first_flags = PR_MDWE_REFUSE_EXEC_GAIN,
+ .second_flags = PR_MDWE_REFUSE_EXEC_GAIN,
+ .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, can_lower_privileges)
+{
+ .first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
+ .second_flags = PR_MDWE_REFUSE_EXEC_GAIN,
+ .should_work = true,
+};
+
+FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_gain_privileges)
+{
+ .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);
+ } else {
+ EXPECT_NE(ret, 0);
+ }
+}
+
FIXTURE(mdwe)
{
void *p;
@@ -45,28 +107,45 @@ 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;
@@ -76,13 +155,17 @@ 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();
@@ -113,7 +196,7 @@ 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);
@@ -139,7 +222,7 @@ 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);
@@ -154,7 +237,7 @@ 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);
--
2.40.1.606.ga4b1b128d6-goog
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