diff mbox series

[v2,2/2] kselftest: vm: add tests for memory-deny-write-execute

Message ID 20230119160344.54358-3-joey.gouly@arm.com (mailing list archive)
State New
Headers show
Series mm: In-kernel support for memory-deny-write-execute (MDWE) | expand

Commit Message

Joey Gouly Jan. 19, 2023, 4:03 p.m. UTC 
From: Kees Cook <keescook@chromium.org>

Add some tests to cover the new PR_SET_MDWE prctl.

Co-developed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
---
 tools/testing/selftests/vm/Makefile    |   1 +
 tools/testing/selftests/vm/mdwe_test.c | 197 +++++++++++++++++++++++++
 2 files changed, 198 insertions(+)
 create mode 100644 tools/testing/selftests/vm/mdwe_test.c

Comments

Peter Xu March 1, 2023, 4:35 p.m. UTC | #1 
On Thu, Jan 19, 2023 at 04:03:44PM +0000, Joey Gouly wrote:
> From: Kees Cook <keescook@chromium.org>
> 
> Add some tests to cover the new PR_SET_MDWE prctl.
> 
> Co-developed-by: Joey Gouly <joey.gouly@arm.com>
> Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Cc: Shuah Khan <shuah@kernel.org>

May need to sync prctl.h into tools/include/uapi?  Otherwise selftests/mm
build fails here.  There's also one compiler report.  A fixup attached
which works for me.

Thanks,
Joey Gouly March 2, 2023, 11:07 a.m. UTC | #2 
Hi Peter,

On Wed, Mar 01, 2023 at 11:35:56AM -0500, Peter Xu wrote:
> On Thu, Jan 19, 2023 at 04:03:44PM +0000, Joey Gouly wrote:
> > From: Kees Cook <keescook@chromium.org>
> > 
> > Add some tests to cover the new PR_SET_MDWE prctl.
> > 
> > Co-developed-by: Joey Gouly <joey.gouly@arm.com>
> > Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > Cc: Shuah Khan <shuah@kernel.org>
> 
> May need to sync prctl.h into tools/include/uapi?  Otherwise selftests/mm
> build fails here.  There's also one compiler report.  A fixup attached
> which works for me.
> 
> Thanks,
> 
> -- 
> Peter Xu

I've CC'd Arnaldo because they seem to update the tools version of prctl.h a lot.

Sorry about the 'p2' variable in the test, was there for some experiments but seems
I accidentally included it.

Acked-by: Joey Gouly <joey.gouly@arm.com>

Thanks,
Joey

> >From ce8e17c244fcc743c7006316dd431c5650480756 Mon Sep 17 00:00:00 2001
> From: Peter Xu <peterx@redhat.com>
> Date: Wed, 1 Mar 2023 11:33:34 -0500
> Subject: [PATCH] fixup! kselftest: vm: add tests for memory-deny-write-execute
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  tools/include/uapi/linux/prctl.h       | 6 ++++++
>  tools/testing/selftests/mm/mdwe_test.c | 3 +--
>  2 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/include/uapi/linux/prctl.h b/tools/include/uapi/linux/prctl.h
> index e4c629c1f1b0..759b3f53e53f 100644
> --- a/tools/include/uapi/linux/prctl.h
> +++ b/tools/include/uapi/linux/prctl.h
> @@ -281,6 +281,12 @@ struct prctl_mm_map {
>  # define PR_SME_VL_LEN_MASK		0xffff
>  # define PR_SME_VL_INHERIT		(1 << 17) /* inherit across exec */
>  
> +/* Memory deny write / execute */
> +#define PR_SET_MDWE			65
> +# define PR_MDWE_REFUSE_EXEC_GAIN	1
> +
> +#define PR_GET_MDWE			66
> +
>  #define PR_SET_VMA		0x53564d41
>  # define PR_SET_VMA_ANON_NAME		0
>  
> diff --git a/tools/testing/selftests/mm/mdwe_test.c b/tools/testing/selftests/mm/mdwe_test.c
> index f466a099f1bf..bc91bef5d254 100644
> --- a/tools/testing/selftests/mm/mdwe_test.c
> +++ b/tools/testing/selftests/mm/mdwe_test.c
> @@ -163,9 +163,8 @@ TEST_F(mdwe, mprotect_WRITE_EXEC)
>  
>  TEST_F(mdwe, mmap_FIXED)
>  {
> -	void *p, *p2;
> +	void *p;
>  
> -	p2 = mmap(NULL, self->size, PROT_READ | PROT_EXEC, self->flags, 0, 0);
>  	self->p = mmap(NULL, self->size, PROT_READ, self->flags, 0, 0);
>  	ASSERT_NE(self->p, MAP_FAILED);
>  
> -- 
> 2.39.1
>
diff mbox series

Patch

diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index 89c14e41bd43..4e1a7b1d4c52 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -56,6 +56,7 @@  TEST_GEN_PROGS += soft-dirty
 TEST_GEN_PROGS += split_huge_page_test
 TEST_GEN_FILES += ksm_tests
 TEST_GEN_PROGS += ksm_functional_tests
+TEST_GEN_PROGS += mdwe_test
 
 ifeq ($(MACHINE),x86_64)
 CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_32bit_program.c -m32)
diff --git a/tools/testing/selftests/vm/mdwe_test.c b/tools/testing/selftests/vm/mdwe_test.c
new file mode 100644
index 000000000000..f466a099f1bf
--- /dev/null
+++ b/tools/testing/selftests/vm/mdwe_test.c
@@ -0,0 +1,197 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#ifdef __aarch64__
+#include <asm/hwcap.h>
+#endif
+
+#include <linux/mman.h>
+#include <linux/prctl.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/auxv.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "../kselftest_harness.h"
+
+#ifndef __aarch64__
+# define PROT_BTI	0
+#endif
+
+TEST(prctl_flags)
+{
+	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);
+	EXPECT_LT(prctl(PR_SET_MDWE, 0L, 0L, 0L, 7L), 0);
+
+	EXPECT_LT(prctl(PR_GET_MDWE, 7L, 0L, 0L, 0L), 0);
+	EXPECT_LT(prctl(PR_GET_MDWE, 0L, 7L, 0L, 0L), 0);
+	EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 7L, 0L), 0);
+	EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 0L, 7L), 0);
+}
+
+FIXTURE(mdwe)
+{
+	void *p;
+	int flags;
+	size_t size;
+	pid_t pid;
+};
+
+FIXTURE_VARIANT(mdwe)
+{
+	bool enabled;
+	bool forked;
+};
+
+FIXTURE_VARIANT_ADD(mdwe, stock)
+{
+        .enabled = false,
+	.forked = false,
+};
+
+FIXTURE_VARIANT_ADD(mdwe, enabled)
+{
+        .enabled = true,
+	.forked = false,
+};
+
+FIXTURE_VARIANT_ADD(mdwe, forked)
+{
+        .enabled = true,
+	.forked = true,
+};
+
+FIXTURE_SETUP(mdwe)
+{
+	int ret, status;
+
+	self->p = NULL;
+	self->flags = MAP_SHARED | MAP_ANONYMOUS;
+	self->size = getpagesize();
+
+	if (!variant->enabled)
+		return;
+
+	ret = prctl(PR_SET_MDWE, PR_MDWE_REFUSE_EXEC_GAIN, 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);
+
+	if (variant->forked) {
+		self->pid = fork();
+		ASSERT_GE(self->pid, 0) {
+			TH_LOG("fork failed\n");
+		}
+
+		if (self->pid > 0) {
+			ret = waitpid(self->pid, &status, 0);
+			ASSERT_TRUE(WIFEXITED(status));
+			exit(WEXITSTATUS(status));
+		}
+	}
+}
+
+FIXTURE_TEARDOWN(mdwe)
+{
+	if (self->p && self->p != MAP_FAILED)
+		munmap(self->p, self->size);
+}
+
+TEST_F(mdwe, mmap_READ_EXEC)
+{
+	self->p = mmap(NULL, self->size, PROT_READ | PROT_EXEC, self->flags, 0, 0);
+	EXPECT_NE(self->p, MAP_FAILED);
+}
+
+TEST_F(mdwe, mmap_WRITE_EXEC)
+{
+	self->p = mmap(NULL, self->size, PROT_WRITE | PROT_EXEC, self->flags, 0, 0);
+	if (variant->enabled) {
+		EXPECT_EQ(self->p, MAP_FAILED);
+	} else {
+		EXPECT_NE(self->p, MAP_FAILED);
+	}
+}
+
+TEST_F(mdwe, mprotect_stay_EXEC)
+{
+	int ret;
+
+	self->p = mmap(NULL, self->size, PROT_READ | PROT_EXEC, self->flags, 0, 0);
+	ASSERT_NE(self->p, MAP_FAILED);
+
+	ret = mprotect(self->p, self->size, PROT_READ | PROT_EXEC);
+	EXPECT_EQ(ret, 0);
+}
+
+TEST_F(mdwe, mprotect_add_EXEC)
+{
+	int ret;
+
+	self->p = mmap(NULL, self->size, PROT_READ, self->flags, 0, 0);
+	ASSERT_NE(self->p, MAP_FAILED);
+
+	ret = mprotect(self->p, self->size, PROT_READ | PROT_EXEC);
+	if (variant->enabled) {
+		EXPECT_LT(ret, 0);
+	} else {
+		EXPECT_EQ(ret, 0);
+	}
+}
+
+TEST_F(mdwe, mprotect_WRITE_EXEC)
+{
+	int ret;
+
+	self->p = mmap(NULL, self->size, PROT_WRITE, self->flags, 0, 0);
+	ASSERT_NE(self->p, MAP_FAILED);
+
+	ret = mprotect(self->p, self->size, PROT_WRITE | PROT_EXEC);
+	if (variant->enabled) {
+		EXPECT_LT(ret, 0);
+	} else {
+		EXPECT_EQ(ret, 0);
+	}
+}
+
+TEST_F(mdwe, mmap_FIXED)
+{
+	void *p, *p2;
+
+	p2 = mmap(NULL, self->size, PROT_READ | PROT_EXEC, self->flags, 0, 0);
+	self->p = mmap(NULL, self->size, PROT_READ, self->flags, 0, 0);
+	ASSERT_NE(self->p, MAP_FAILED);
+
+	p = mmap(self->p + self->size, self->size, PROT_READ | PROT_EXEC,
+		 self->flags | MAP_FIXED, 0, 0);
+	if (variant->enabled) {
+		EXPECT_EQ(p, MAP_FAILED);
+	} else {
+		EXPECT_EQ(p, self->p);
+	}
+}
+
+TEST_F(mdwe, arm64_BTI)
+{
+	int ret;
+
+#ifdef __aarch64__
+	if (!(getauxval(AT_HWCAP2) & HWCAP2_BTI))
+#endif
+		SKIP(return, "HWCAP2_BTI not supported");
+
+	self->p = mmap(NULL, self->size, PROT_EXEC, self->flags, 0, 0);
+	ASSERT_NE(self->p, MAP_FAILED);
+
+	ret = mprotect(self->p, self->size, PROT_EXEC | PROT_BTI);
+	EXPECT_EQ(ret, 0);
+}
+
+TEST_HARNESS_MAIN