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Edgecombe" , Ard Biesheuvel , Szabolcs Nagy , Kees Cook , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Thiago Jung Bauermann , Ross Burton , David Spickett , Yury Khrustalev , Wilco Dijkstra , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v13 04/40] prctl: arch-agnostic prctl for shadow stack Message-ID: References: <20241001-arm64-gcs-v13-0-222b78d87eee@kernel.org> <20241001-arm64-gcs-v13-4-222b78d87eee@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20241001-arm64-gcs-v13-4-222b78d87eee@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241001_161320_241803_278AE016 X-CRM114-Status: GOOD ( 18.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Oct 01, 2024 at 11:58:43PM +0100, Mark Brown wrote: >Three architectures (x86, aarch64, riscv) have announced support for >shadow stacks with fairly similar functionality. While x86 is using >arch_prctl() to control the functionality neither arm64 nor riscv uses >that interface so this patch adds arch-agnostic prctl() support to >get and set status of shadow stacks and lock the current configuation to >prevent further changes, with support for turning on and off individual >subfeatures so applications can limit their exposure to features that >they do not need. The features are: > > - PR_SHADOW_STACK_ENABLE: Tracking and enforcement of shadow stacks, > including allocation of a shadow stack if one is not already > allocated. > - PR_SHADOW_STACK_WRITE: Writes to specific addresses in the shadow > stack. > - PR_SHADOW_STACK_PUSH: Push additional values onto the shadow stack. > >These features are expected to be inherited by new threads and cleared >on exec(), unknown features should be rejected for enable but accepted >for locking (in order to allow for future proofing). > >This is based on a patch originally written by Deepak Gupta but modified >fairly heavily, support for indirect landing pads is removed, additional >modes added and the locking interface reworked. The set status prctl() >is also reworked to just set flags, if setting/reading the shadow stack >pointer is required this could be a separate prctl. > >Reviewed-by: Thiago Jung Bauermann >Reviewed-by: Catalin Marinas >Acked-by: Yury Khrustalev >Signed-off-by: Mark Brown >--- > include/linux/mm.h | 4 ++++ > include/uapi/linux/prctl.h | 22 ++++++++++++++++++++++ > kernel/sys.c | 30 ++++++++++++++++++++++++++++++ > 3 files changed, 56 insertions(+) Reviewed-by: Deepak Gupta >