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Wed, 10 Jun 2020 08:19:00 -0700 (PDT) Received: from [192.168.42.234] ([213.87.161.124]) by smtp.gmail.com with ESMTPSA id q17sm5900670lfa.28.2020.06.10.08.18.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 10 Jun 2020 08:18:57 -0700 (PDT) Subject: Re: [PATCH 5/5] gcc-plugins/stackleak: Don't instrument vgettimeofday.c in arm64 VDSO To: Will Deacon , Kees Cook References: <20200604134957.505389-1-alex.popov@linux.com> <20200604134957.505389-6-alex.popov@linux.com> <20200604135806.GA3170@willie-the-truck> <202006091149.6C78419@keescook> <20200610073046.GA15939@willie-the-truck> From: Alexander Popov Autocrypt: addr=alex.popov@linux.com; prefer-encrypt=mutual; keydata= mQINBFX15q4BEADZartsIW3sQ9R+9TOuCFRIW+RDCoBWNHhqDLu+Tzf2mZevVSF0D5AMJW4f UB1QigxOuGIeSngfmgLspdYe2Kl8+P8qyfrnBcS4hLFyLGjaP7UVGtpUl7CUxz2Hct3yhsPz ID/rnCSd0Q+3thrJTq44b2kIKqM1swt/F2Er5Bl0B4o5WKx4J9k6Dz7bAMjKD8pHZJnScoP4 dzKPhrytN/iWM01eRZRc1TcIdVsRZC3hcVE6OtFoamaYmePDwWTRhmDtWYngbRDVGe3Tl8bT 7BYN7gv7Ikt7Nq2T2TOfXEQqr9CtidxBNsqFEaajbFvpLDpUPw692+4lUbQ7FL0B1WYLvWkG cVysClEyX3VBSMzIG5eTF0Dng9RqItUxpbD317ihKqYL95jk6eK6XyI8wVOCEa1V3MhtvzUo WGZVkwm9eMVZ05GbhzmT7KHBEBbCkihS+TpVxOgzvuV+heCEaaxIDWY/k8u4tgbrVVk+tIVG 99v1//kNLqd5KuwY1Y2/h2MhRrfxqGz+l/f/qghKh+1iptm6McN//1nNaIbzXQ2Ej34jeWDa xAN1C1OANOyV7mYuYPNDl5c9QrbcNGg3D6gOeGeGiMn11NjbjHae3ipH8MkX7/k8pH5q4Lhh Ra0vtJspeg77CS4b7+WC5jlK3UAKoUja3kGgkCrnfNkvKjrkEwARAQABtCZBbGV4YW5kZXIg UG9wb3YgPGFsZXgucG9wb3ZAbGludXguY29tPokCVwQTAQgAQQIbIwIeAQIXgAULCQgHAwUV CgkICwUWAgMBAAIZARYhBLl2JLAkAVM0bVvWTo4Oneu8fo+qBQJdehKcBQkLRpLuAAoJEI4O neu8fo+qrkgP/jS0EhDnWhIFBnWaUKYWeiwR69DPwCs/lNezOu63vg30O9BViEkWsWwXQA+c SVVTz5f9eB9K2me7G06A3U5AblOJKdoZeNX5GWMdrrGNLVISsa0geXNT95TRnFqE1HOZJiHT NFyw2nv+qQBUHBAKPlk3eL4/Yev/P8w990Aiiv6/RN3IoxqTfSu2tBKdQqdxTjEJ7KLBlQBm 5oMpm/P2Y/gtBiXRvBd7xgv7Y3nShPUDymjBnc+efHFqARw84VQPIG4nqVhIei8gSWps49DX kp6v4wUzUAqFo+eh/ErWmyBNETuufpxZnAljtnKpwmpFCcq9yfcMlyOO9/viKn14grabE7qE 4j3/E60wraHu8uiXJlfXmt0vG16vXb8g5a25Ck09UKkXRGkNTylXsAmRbrBrA3Moqf8QzIk9 p+aVu/vFUs4ywQrFNvn7Qwt2hWctastQJcH3jrrLk7oGLvue5KOThip0SNicnOxVhCqstjYx KEnzZxtna5+rYRg22Zbfg0sCAAEGOWFXjqg3hw400oRxTW7IhiE34Kz1wHQqNif0i5Eor+TS 22r9iF4jUSnk1jaVeRKOXY89KxzxWhnA06m8IvW1VySHoY1ZG6xEZLmbp3OuuFCbleaW07OU 9L8L1Gh1rkAz0Fc9eOR8a2HLVFnemmgAYTJqBks/sB/DD0SuuQINBFX15q4BEACtxRV/pF1P XiGSbTNPlM9z/cElzo/ICCFX+IKg+byRvOMoEgrzQ28ah0N5RXQydBtfjSOMV1IjSb3oc23z oW2J9DefC5b8G1Lx2Tz6VqRFXC5OAxuElaZeoowV1VEJuN3Ittlal0+KnRYY0PqnmLzTXGA9 GYjw/p7l7iME7gLHVOggXIk7MP+O+1tSEf23n+dopQZrkEP2BKSC6ihdU4W8928pApxrX1Lt tv2HOPJKHrcfiqVuFSsb/skaFf4uveAPC4AausUhXQVpXIg8ZnxTZ+MsqlwELv+Vkm/SNEWl n0KMd58gvG3s0bE8H2GTaIO3a0TqNKUY16WgNglRUi0WYb7+CLNrYqteYMQUqX7+bB+NEj/4 8dHw+xxaIHtLXOGxW6zcPGFszaYArjGaYfiTTA1+AKWHRKvD3MJTYIonphy5EuL9EACLKjEF v3CdK5BLkqTGhPfYtE3B/Ix3CUS1Aala0L+8EjXdclVpvHQ5qXHs229EJxfUVf2ucpWNIUdf lgnjyF4B3R3BFWbM4Yv8QbLBvVv1Dc4hZ70QUXy2ZZX8keza2EzPj3apMcDmmbklSwdC5kYG EFT4ap06R2QW+6Nw27jDtbK4QhMEUCHmoOIaS9j0VTU4fR9ZCpVT/ksc2LPMhg3YqNTrnb1v RVNUZvh78zQeCXC2VamSl9DMcwARAQABiQI8BBgBCAAmAhsMFiEEuXYksCQBUzRtW9ZOjg6d 67x+j6oFAl16ErcFCQtGkwkACgkQjg6d67x+j6q7zA/+IsjSKSJypgOImN9LYjeb++7wDjXp qvEpq56oAn21CvtbGus3OcC0hrRtyZ/rC5Qc+S5SPaMRFUaK8S3j1vYC0wZJ99rrmQbcbYMh C2o0k4pSejaINmgyCajVOhUhln4IuwvZke1CLfXe1i3ZtlaIUrxfXqfYpeijfM/JSmliPxwW BRnQRcgS85xpC1pBUMrraxajaVPwu7hCTke03v6bu8zSZlgA1rd9E6KHu2VNS46VzUPjbR77 kO7u6H5PgQPKcuJwQQ+d3qa+5ZeKmoVkc2SuHVrCd1yKtAMmKBoJtSku1evXPwyBzqHFOInk mLMtrWuUhj+wtcnOWxaP+n4ODgUwc/uvyuamo0L2Gp3V5ItdIUDO/7ZpZ/3JxvERF3Yc1md8 5kfflpLzpxyl2fKaRdvxr48ZLv9XLUQ4qNuADDmJArq/+foORAX4BBFWvqZQKe8a9ZMAvGSh uoGUVg4Ks0uC4IeG7iNtd+csmBj5dNf91C7zV4bsKt0JjiJ9a4D85dtCOPmOeNuusK7xaDZc gzBW8J8RW+nUJcTpudX4TC2SGeAOyxnM5O4XJ8yZyDUY334seDRJWtS4wRHxpfYcHKTewR96 IsP1USE+9ndu6lrMXQ3aFsd1n1m1pfa/y8hiqsSYHy7JQ9Iuo9DxysOj22UNOmOE+OYPK48D j3lCqPk= Message-ID: Date: Wed, 10 Jun 2020 18:18:09 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200610073046.GA15939@willie-the-truck> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200610_081910_501140_6144123E X-CRM114-Status: GOOD ( 20.22 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: alex.popov@linux.com Cc: kernel-hardening@lists.openwall.com, Catalin Marinas , Masahiro Yamada , Vincenzo Frascino , Sven Schnelle , Naohiro Aota , Masahiro Yamada , x86@kernel.org, Emese Revfy , Iurii Zaikin , PaX Team , Laura Abbott , Mathias Krause , linux-kbuild@vger.kernel.org, Alexander Monakov , Michal Marek , Thomas Gleixner , Peter Collingbourne , linux-arm-kernel@lists.infradead.org, notify@kernel.org, Florian Weimer , gcc@gcc.gnu.org, Brad Spengler , linux-kernel@vger.kernel.org, Miguel Ojeda , Luis Chamberlain , Jessica Yu , Andrew Morton , Thiago Jung Bauermann Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 10.06.2020 10:30, Will Deacon wrote: > On Tue, Jun 09, 2020 at 12:09:27PM -0700, Kees Cook wrote: >> On Thu, Jun 04, 2020 at 02:58:06PM +0100, Will Deacon wrote: >>> On Thu, Jun 04, 2020 at 04:49:57PM +0300, Alexander Popov wrote: >>>> Don't try instrumenting functions in arch/arm64/kernel/vdso/vgettimeofday.c. >>>> Otherwise that can cause issues if the cleanup pass of stackleak gcc plugin >>>> is disabled. >>>> >>>> Signed-off-by: Alexander Popov >>>> --- >>>> arch/arm64/kernel/vdso/Makefile | 3 ++- >>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile >>>> index 3862cad2410c..9b84cafbd2da 100644 >>>> --- a/arch/arm64/kernel/vdso/Makefile >>>> +++ b/arch/arm64/kernel/vdso/Makefile >>>> @@ -32,7 +32,8 @@ UBSAN_SANITIZE := n >>>> OBJECT_FILES_NON_STANDARD := y >>>> KCOV_INSTRUMENT := n >>>> >>>> -CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables >>>> +CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables \ >>>> + $(DISABLE_STACKLEAK_PLUGIN) >>> >>> I can pick this one up via arm64, thanks. Are there any other plugins we >>> should be wary of? It looks like x86 filters out $(GCC_PLUGINS_CFLAGS) >>> when building the vDSO. >> >> I didn't realize/remember that arm64 retained the kernel build flags for >> vDSO builds. (I'm used to x86 throwing all its flags away for its vDSO.) >> >> How does 32-bit ARM do its vDSO? >> >> My quick run-through on plugins: >> >> arm_ssp_per_task_plugin.c >> 32-bit ARM only (but likely needs disabling for 32-bit ARM vDSO?) > > On arm64, the 32-bit toolchain is picked up via CC_COMPAT -- does that still > get the plugins? > >> cyc_complexity_plugin.c >> compile-time reporting only >> >> latent_entropy_plugin.c >> this shouldn't get triggered for the vDSO (no __latent_entropy >> nor __init attributes in vDSO), but perhaps explicitly disabling >> it would be a sensible thing to do, just for robustness? >> >> randomize_layout_plugin.c >> this shouldn't get triggered (again, lacking attributes), but >> should likely be disabled too. >> >> sancov_plugin.c >> This should be tracking the KCOV directly (see >> scripts/Makefile.kcov), which is already disabled here. >> >> structleak_plugin.c >> This should be fine in the vDSO, but there's not security >> boundary here, so it wouldn't be important to KEEP it enabled. > > Thanks for going through these. In general though, it seems like an > opt-in strategy would make more sense, as it doesn't make an awful lot > of sense to me for the plugins to be used to build the vDSO. > > So I would prefer that this patch filters out $(GCC_PLUGINS_CFLAGS). Ok, I will do that in the v2 of the patch series. Best regards, Alexander _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel