Commit 4cf1fe34 authored by Kees Cook's avatar Kees Cook Committed by Andrew Morton
Browse files

kselftest: vm: add tests for memory-deny-write-execute 

Add some tests to cover the new PR_SET_MDWE prctl.

Link: https://lkml.kernel.org/r/20230119160344.54358-3-joey.gouly@arm.com


Co-developed-by: default avatarJoey Gouly <joey.gouly@arm.com>
Signed-off-by: default avatarJoey Gouly <joey.gouly@arm.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jeremy Linton <jeremy.linton@arm.com>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Mark Brown <broonie@kernel.org>
Cc: nd <nd@arm.com>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Topi Miettinen <toiwoton@gmail.com>
Cc: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b507808e

tools/testing/selftests/mm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ 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)

tools/testing/selftests/mm/mdwe_test.c

0 → 100644
+197 −0
Original line number Diff line number Diff line 
// 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