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Subject: Re: [PATCH v3 7/7] selftests/exec: Add READ_IMPLIES_EXEC tests
To:     Kees Cook <keescook@chromium.org>
Cc:     Ingo Molnar <mingo@kernel.org>,
        Hector Marco-Gisbert <hecmargi@upv.es>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Jason Gunthorpe <jgg@mellanox.com>,
        Jann Horn <jannh@google.com>,
        Russell King <linux@armlinux.org.uk>, x86@kernel.org,
        kernel-hardening@lists.openwall.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, shuah <shuah@kernel.org>
References: <20200210193049.64362-1-keescook@chromium.org>
 <20200210193049.64362-8-keescook@chromium.org>
 <4f8a5036-dc2a-90ad-5fc8-69560a5dd78e@kernel.org>
 <202002111124.0A334167@keescook>
From:   shuah <shuah@kernel.org>
Message-ID: <c09c345a-786f-25d2-1ee5-65f9cb23db6d@kernel.org>
Date:   Tue, 11 Feb 2020 14:06:53 -0700
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On 2/11/20 12:25 PM, Kees Cook wrote:
> On Tue, Feb 11, 2020 at 11:11:21AM -0700, shuah wrote:
>> On 2/10/20 12:30 PM, Kees Cook wrote:
>>> In order to check the matrix of possible states for handling
>>> READ_IMPLIES_EXEC across native, compat, and the state of PT_GNU_STACK,
>>> add tests for these execution conditions.
>>>
>>> Signed-off-by: Kees Cook <keescook@chromium.org>
>>
>> No issues for this to go through tip.
>>
>> A few problems to fix first. This fails to compile when 32-bit libraries
>> aren't installed. It should fail the 32-bit part and run other checks.
> 
> Do you mean the Makefile should detect the missing compat build deps and
> avoid building them? Testing compat is pretty important to this test, so
> it seems like missing the build deps causing the build to fail is the
> correct action here. This is likely true for the x86/ selftests too.
> 
> What would you like this to do?
> 

selftests/x86 does this already and runs the dependency check in 
x86/Makefile.


check_cc.sh:# check_cc.sh - Helper to test userspace compilation support
Makefile:CAN_BUILD_I386 := $(shell ./check_cc.sh $(CC) 
trivial_32bit_program.c -m32)
Makefile:CAN_BUILD_X86_64 := $(shell ./check_cc.sh $(CC) 
trivial_64bit_program.c)
Makefile:CAN_BUILD_WITH_NOPIE := $(shell ./check_cc.sh $(CC) 
trivial_program.c -no-pie)

Take a look and see if you can leverage this.

thanks,
-- Shuah