Commit 9ce12630 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Will Deacon
Browse files

selftests, arm64: add a selftest for passing tagged pointers to kernel 



This patch is a part of a series that extends kernel ABI to allow to pass
tagged user pointers (with the top byte set to something else other than
0x00) as syscall arguments.

This patch adds a simple test, that calls the uname syscall with a
tagged user pointer as an argument. Without the kernel accepting tagged
user pointers the test fails with EFAULT.

Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 63f0c603

tools/testing/selftests/arm64/.gitignore

0 → 100644
+1 −0
Original line number Diff line number Diff line 
tags_test

tools/testing/selftests/arm64/Makefile

0 → 100644
+11 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0



# ARCH can be overridden by the user for cross compiling

ARCH ?= $(shell uname -m 2>/dev/null || echo not)



ifneq (,$(filter $(ARCH),aarch64 arm64))

TEST_GEN_PROGS := tags_test

TEST_PROGS := run_tags_test.sh

endif



include ../lib.mk

tools/testing/selftests/arm64/run_tags_test.sh

0 → 100755
+12 −0
Original line number Diff line number Diff line 
#!/bin/sh

# SPDX-License-Identifier: GPL-2.0



echo "--------------------"

echo "running tags test"

echo "--------------------"

./tags_test

if [ $? -ne 0 ]; then

	echo "[FAIL]"

else

	echo "[PASS]"

fi

tools/testing/selftests/arm64/tags_test.c

0 → 100644
+29 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <stdint.h>

#include <sys/prctl.h>

#include <sys/utsname.h>



#define SHIFT_TAG(tag)		((uint64_t)(tag) << 56)

#define SET_TAG(ptr, tag)	(((uint64_t)(ptr) & ~SHIFT_TAG(0xff)) | \

					SHIFT_TAG(tag))



int main(void)

{

	static int tbi_enabled = 0;

	struct utsname *ptr, *tagged_ptr;

	int err;



	if (prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) == 0)

		tbi_enabled = 1;

	ptr = (struct utsname *)malloc(sizeof(*ptr));

	if (tbi_enabled)

		tagged_ptr = (struct utsname *)SET_TAG(ptr, 0x42);

	err = uname(tagged_ptr);

	free(ptr);



	return err;

}