Messages in this thread Patch in this message | | | Subject | Re: [PATCH 1/4] kselftests/arm64: add a basic Pointer Authentication test | From | Amit Kachhap <> | Date | Mon, 31 Aug 2020 13:35:39 +0530 |
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Hi Boyan,
On 8/28/20 6:46 PM, Boyan Karatotev wrote: > PAuth signs and verifies return addresses on the stack. It does so by > inserting a Pointer Authentication code (PAC) into some of the unused top > bits of an address. This is achieved by adding paciasp/autiasp instructions > at the beginning and end of a function. > > This feature is partially backwards compatible with earlier versions of the > ARM architecture. To coerce the compiler into emitting fully backwards > compatible code the main file is compiled to target an earlier ARM version. > This allows the tests to check for the feature and print meaningful error > messages instead of crashing. > > Add a test to verify that corrupting the return address results in a > SIGSEGV on return. > > Cc: Shuah Khan <shuah@kernel.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com> > --- > tools/testing/selftests/arm64/Makefile | 2 +- > .../testing/selftests/arm64/pauth/.gitignore | 1 + > tools/testing/selftests/arm64/pauth/Makefile | 22 ++++++++++++ > tools/testing/selftests/arm64/pauth/helper.h | 10 ++++++ > tools/testing/selftests/arm64/pauth/pac.c | 32 +++++++++++++++++ > .../selftests/arm64/pauth/pac_corruptor.S | 36 +++++++++++++++++++ > 6 files changed, 102 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/arm64/pauth/.gitignore > create mode 100644 tools/testing/selftests/arm64/pauth/Makefile > create mode 100644 tools/testing/selftests/arm64/pauth/helper.h > create mode 100644 tools/testing/selftests/arm64/pauth/pac.c > create mode 100644 tools/testing/selftests/arm64/pauth/pac_corruptor.S > > diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile > index 93b567d23c8b..525506fd97b9 100644 > --- a/tools/testing/selftests/arm64/Makefile > +++ b/tools/testing/selftests/arm64/Makefile > @@ -4,7 +4,7 @@ > ARCH ?= $(shell uname -m 2>/dev/null || echo not) > > ifneq (,$(filter $(ARCH),aarch64 arm64)) > -ARM64_SUBTARGETS ?= tags signal > +ARM64_SUBTARGETS ?= tags signal pauth > else > ARM64_SUBTARGETS := > endif > diff --git a/tools/testing/selftests/arm64/pauth/.gitignore b/tools/testing/selftests/arm64/pauth/.gitignore > new file mode 100644 > index 000000000000..b557c916720a > --- /dev/null > +++ b/tools/testing/selftests/arm64/pauth/.gitignore > @@ -0,0 +1 @@ > +pac > diff --git a/tools/testing/selftests/arm64/pauth/Makefile b/tools/testing/selftests/arm64/pauth/Makefile > new file mode 100644 > index 000000000000..785c775e5e41 > --- /dev/null > +++ b/tools/testing/selftests/arm64/pauth/Makefile > @@ -0,0 +1,22 @@ > +# SPDX-License-Identifier: GPL-2.0 > +# Copyright (C) 2020 ARM Limited > + > +CFLAGS += -mbranch-protection=pac-ret
There is no CFLAGS validation present which may give error with non supported compiler.
Can you add a check something like,
+#check if the compiler works well +pauth_cc_support := $(shell if ($(CC) $(CFLAGS) -march=armv8.3-a -E -x c /dev/null -o /dev/null 2>&1) then echo "1"; fi) + +ifeq ($(pauth_cc_support),1) TEST_GEN_PROGS := pac TEST_GEN_FILES := pac_corruptor.o +endif
include ../../lib.mk
+ifeq ($(pauth_cc_support),1) # pac* and aut* instructions are not available on architectures berfore # ARMv8.3. Therefore target ARMv8.3 wherever they are used directly $(OUTPUT)/pac_corruptor.o: pac_corruptor.S @@ -19,4 +25,4 @@ $(OUTPUT)/pac_corruptor.o: pac_corruptor.S # run on earlier targets and print a meaningful error messages $(OUTPUT)/pac: pac.c $(OUTPUT)/pac_corruptor.o $(CC) $^ -o $@ $(CFLAGS) -march=armv8.2-a - +endif > + > +TEST_GEN_PROGS := pac > +TEST_GEN_FILES := pac_corruptor.o > + > +include ../../lib.mk > + > +# pac* and aut* instructions are not available on architectures berfore > +# ARMv8.3. Therefore target ARMv8.3 wherever they are used directly > +$(OUTPUT)/pac_corruptor.o: pac_corruptor.S > + $(CC) -c $^ -o $@ $(CFLAGS) -march=armv8.3-a > + > +# when -mbranch-protection is enabled and the target architecture is ARMv8.3 or > +# greater, gcc emits pac* instructions which are not in HINT NOP space, > +# preventing the tests from occurring at all. Compile for ARMv8.2 so tests can > +# run on earlier targets and print a meaningful error messages > +$(OUTPUT)/pac: pac.c $(OUTPUT)/pac_corruptor.o > + $(CC) $^ -o $@ $(CFLAGS) -march=armv8.2-a > + > diff --git a/tools/testing/selftests/arm64/pauth/helper.h b/tools/testing/selftests/arm64/pauth/helper.h > new file mode 100644 > index 000000000000..f777f88acf0a > --- /dev/null > +++ b/tools/testing/selftests/arm64/pauth/helper.h > @@ -0,0 +1,10 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* Copyright (C) 2020 ARM Limited */ > + > +#ifndef _HELPER_H_ > +#define _HELPER_H_ > + > +void pac_corruptor(void); > + > +#endif > +
Please delete extra line at end of file here and other places too.
Other changes look fine for me. After the suggested changes please free to add, Reviewed-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Thanks, Amit Daniel
> diff --git a/tools/testing/selftests/arm64/pauth/pac.c b/tools/testing/selftests/arm64/pauth/pac.c > new file mode 100644 > index 000000000000..ed445050f621 > --- /dev/null > +++ b/tools/testing/selftests/arm64/pauth/pac.c > @@ -0,0 +1,32 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright (C) 2020 ARM Limited > + > +#include <sys/auxv.h> > +#include <signal.h> > + >
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