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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id f17sm3420650pfq.141.2020.10.22.15.38.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Oct 2020 15:38:42 -0700 (PDT) Date: Thu, 22 Oct 2020 15:38:41 -0700 From: Kees Cook To: Sami Tolvanen Subject: Re: [PATCH 1/2] scs: switch to vmapped shadow stacks Message-ID: <202010221538.9FA560D5B0@keescook> References: <20201022202355.3529836-1-samitolvanen@google.com> <20201022202355.3529836-2-samitolvanen@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201022202355.3529836-2-samitolvanen@google.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201022_183948_064893_D784F699 X-CRM114-Status: GOOD ( 12.77 ) 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: , Cc: Mark Rutland , Ard Biesheuvel , Catalin Marinas , linux-kernel@vger.kernel.org, James Morse , Will Deacon , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Oct 22, 2020 at 01:23:54PM -0700, Sami Tolvanen wrote: > The kernel currently uses kmem_cache to allocate shadow call stacks, > which means an overflow may not be immediately detected and can > potentially result in another task's shadow stack to be overwritten. > > This change switches SCS to use virtually mapped shadow stacks, > which increases shadow stack size to a full page and provides more > robust overflow detection similarly to VMAP_STACK. > > Signed-off-by: Sami Tolvanen Thanks! I much prefer this to kmem. :) Reviewed-by: Kees Cook -- Kees Cook _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel