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
Signed-off-by: Florent Revest <revest@chromium.org>
---
tools/testing/selftests/mm/mdwe_test.c | 98 ++++++++++++++++++++++++--
1 file changed, 92 insertions(+), 6 deletions(-)
diff --git a/tools/testing/selftests/mm/mdwe_test.c b/tools/testing/selftests/mm/mdwe_test.c
index 91aa9c3099e7..7bfc98bf9baa 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 +35,69 @@ 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, 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);
+ }
+}
+
FIXTURE(mdwe)
{
void *p;
@@ -45,28 +110,45 @@ 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 +158,17 @@ 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 +199,7 @@ 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 +225,7 @@ 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 +240,7 @@ 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);
--
2.41.0.255.g8b1d071c50-googOn Tue, Jul 04, 2023 at 05:36:29PM +0200, Florent Revest wrote: > 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 > > Signed-off-by: Florent Revest <revest@chromium.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
On Tue, Jul 04, 2023 at 05:36:29PM +0200, Florent Revest wrote:
> 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
I love more self tests! :)
>
> Signed-off-by: Florent Revest <revest@chromium.org>
> ---
> tools/testing/selftests/mm/mdwe_test.c | 98 ++++++++++++++++++++++++--
> 1 file changed, 92 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/mdwe_test.c b/tools/testing/selftests/mm/mdwe_test.c
> index 91aa9c3099e7..7bfc98bf9baa 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);
> +
An existing issue, but I think the errno should be checked for each
of these...
> 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 +35,69 @@ 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,
> +};
I think two more variants should be added to get all the combinations:
FIXTURE_VARIANT_ADD(consecutive_prctl_no_flags, same)
{
.first_flags = 0,
.second_flags = 0,
.should_work = true,
};
FIXTURE_VARIANT_ADD(consecutive_prctl_both_flags, same)
{
.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);
Please test the expected errno value here.
> + }
> +}
> +
> FIXTURE(mdwe)
> {
> void *p;
> @@ -45,28 +110,45 @@ 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 +158,17 @@ 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 +199,7 @@ 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 +225,7 @@ 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 +240,7 @@ 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);
> --
> 2.41.0.255.g8b1d071c50-goog
>
Otherwise looks good to me!
--
Kees Cook
On Sat, Aug 26, 2023 at 12:45 AM Kees Cook <keescook@chromium.org> wrote:
>
> On Tue, Jul 04, 2023 at 05:36:29PM +0200, Florent Revest wrote:
> > 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
>
> I love more self tests! :)
*Insert here a ridiculously long series of party and dancing emojis* ... :)
> >
> > Signed-off-by: Florent Revest <revest@chromium.org>
> > ---
> > tools/testing/selftests/mm/mdwe_test.c | 98 ++++++++++++++++++++++++--
> > 1 file changed, 92 insertions(+), 6 deletions(-)
> >
> > diff --git a/tools/testing/selftests/mm/mdwe_test.c b/tools/testing/selftests/mm/mdwe_test.c
> > index 91aa9c3099e7..7bfc98bf9baa 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);
> > +
>
> An existing issue, but I think the errno should be checked for each
> of these...
Makes sense! I'll add a bunch of
EXPECT_EQ(errno, EINVAL);
To every existing line here as part of a previous patch, and modify
this patch to cover errnos in the new test cases too.
> > 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 +35,69 @@ 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,
> > +};
>
> I think two more variants should be added to get all the combinations:
>
> FIXTURE_VARIANT_ADD(consecutive_prctl_no_flags, same)
> {
> .first_flags = 0,
> .second_flags = 0,
> .should_work = true,
> };
>
> FIXTURE_VARIANT_ADD(consecutive_prctl_both_flags, same)
> {
> .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,
> };
Agreed! :)
> > +
> > +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);
>
> Please test the expected errno value here.
Alright!
> > + }
> > +}
> > +
> > FIXTURE(mdwe)
> > {
> > void *p;
> > @@ -45,28 +110,45 @@ 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 +158,17 @@ 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 +199,7 @@ 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 +225,7 @@ 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 +240,7 @@ 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);
> > --
> > 2.41.0.255.g8b1d071c50-goog
> >
>
> Otherwise looks good to me!
*more happy emojis*
On Sat, Aug 26, 2023 at 12:45 AM Kees Cook <keescook@chromium.org> wrote:
>
> On Tue, Jul 04, 2023 at 05:36:29PM +0200, Florent Revest wrote:
> > 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
>
> I love more self tests! :)
>
> >
> > Signed-off-by: Florent Revest <revest@chromium.org>
> > ---
> > tools/testing/selftests/mm/mdwe_test.c | 98 ++++++++++++++++++++++++--
> > 1 file changed, 92 insertions(+), 6 deletions(-)
> >
> > diff --git a/tools/testing/selftests/mm/mdwe_test.c b/tools/testing/selftests/mm/mdwe_test.c
> > index 91aa9c3099e7..7bfc98bf9baa 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);
> > +
>
> An existing issue, but I think the errno should be checked for each
> of these...
>
> > 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 +35,69 @@ 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,
> > +};
>
> I think two more variants should be added to get all the combinations:
>
> FIXTURE_VARIANT_ADD(consecutive_prctl_no_flags, same)
> {
> .first_flags = 0,
> .second_flags = 0,
> .should_work = true,
> };
>
> FIXTURE_VARIANT_ADD(consecutive_prctl_both_flags, same)
> {
> .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);
>
> Please test the expected errno value here.
>
> > + }
> > +}
> > +
> > FIXTURE(mdwe)
> > {
> > void *p;
> > @@ -45,28 +110,45 @@ 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 +158,17 @@ 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 +199,7 @@ 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 +225,7 @@ 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 +240,7 @@ 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);
> > --
> > 2.41.0.255.g8b1d071c50-goog
> >
>
> Otherwise looks good to me!
>
> --
> Kees Cook
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