From: Kees Cook <[email protected]>
Add some tests to cover the new PR_SET_MDWE prctl.
Co-developed-by: Joey Gouly <[email protected]>
Signed-off-by: Joey Gouly <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Cc: Shuah Khan <[email protected]>
---
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
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
--
2.17.1
On Thu, Jan 19, 2023 at 04:03:44PM +0000, Joey Gouly wrote:
> From: Kees Cook <[email protected]>
>
> Add some tests to cover the new PR_SET_MDWE prctl.
>
> Co-developed-by: Joey Gouly <[email protected]>
> Signed-off-by: Joey Gouly <[email protected]>
> Signed-off-by: Kees Cook <[email protected]>
> Cc: Shuah Khan <[email protected]>
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
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 <[email protected]>
> >
> > Add some tests to cover the new PR_SET_MDWE prctl.
> >
> > Co-developed-by: Joey Gouly <[email protected]>
> > Signed-off-by: Joey Gouly <[email protected]>
> > Signed-off-by: Kees Cook <[email protected]>
> > Cc: Shuah Khan <[email protected]>
>
> 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 <[email protected]>
Thanks,
Joey
> >From ce8e17c244fcc743c7006316dd431c5650480756 Mon Sep 17 00:00:00 2001
> From: Peter Xu <[email protected]>
> 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 <[email protected]>
> ---
> 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
>