From patchwork Tue Mar 9 21:43:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 12126653 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC86BC433E6 for ; Tue, 9 Mar 2021 21:43:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 984FF64FAD for ; Tue, 9 Mar 2021 21:43:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 984FF64FAD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 170C18D014E; Tue, 9 Mar 2021 16:43:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0832A8D0148; Tue, 9 Mar 2021 16:43:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D310F8D014E; Tue, 9 Mar 2021 16:43:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0038.hostedemail.com [216.40.44.38]) by kanga.kvack.org (Postfix) with ESMTP id B065A8D0148 for ; Tue, 9 Mar 2021 16:43:15 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 7774F824999B for ; Tue, 9 Mar 2021 21:43:15 +0000 (UTC) X-FDA: 77901661950.03.020DB33 Received: from mail-pj1-f51.google.com (mail-pj1-f51.google.com [209.85.216.51]) by imf18.hostedemail.com (Postfix) with ESMTP id A4A7420001EA for ; Tue, 9 Mar 2021 21:43:15 +0000 (UTC) Received: by mail-pj1-f51.google.com with SMTP id fu20so1619804pjb.2 for ; Tue, 09 Mar 2021 13:43:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=uk0/1LocoDticB91SF6FsgWpOKPsEr1Pb6N+E6L28KI=; b=fXCfvnU3D4wVS2gnx4R+6sEkANTA5C4Qx8s+R2Snvl4CfYrjd711MJmnMdXeC6GL/I PCoEcCoP0iSQ5ydymCVNPBPt0drSoZzLLX1BF0oLBizNtnX90NKPXVxlmNQlaA8fAIoj ryM7dBfe4KsBcn46bv7w6H7Idv2DnikOzytCY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=uk0/1LocoDticB91SF6FsgWpOKPsEr1Pb6N+E6L28KI=; b=r1Ev70Gl0VxV+Wur/K79LSRrxQiGPQoEQ0pg4spfUMYVIDB3bgSYy+rGzqbZQMPOTn Gem/P7S6AwSd2CL5+/VoH2Sq3C7jO3Sd+cjs9XekXc3Yb0mwsGnHKpicMgiX4H7ZT+Pv nlz7GhcBVZQIq8Jro/8sdBpouhl1Mcr2sutMtYQv29NspYN5CHICu5eamWeqbn4Hq1Q/ g9XMNQNO/LvIJkOhFsYFyVMiOzjiWzOWQcNiFq0PIXYinRIU8yKprT6KGkz4aAHr0u1s vU7DOB5vpyJccUbK31KKzr3/VrCgzr/Yg4krUGu6kGt1AZKQiTshGCHURpJ874GQ+aa4 YV4A== X-Gm-Message-State: AOAM533ZYFN3+7Xo3fRJXsZpGgTizU1XgUux6kG5O9XaRRN25mxkLVZS 5lGG/2ig1VAYnx6U2ulN1qOUjw== X-Google-Smtp-Source: ABdhPJwMAeJop9UPtI3jZOkzjoT12RbrdsqpFgJGTkl99HdMDta1V57qg5ZxtpfVe+IAGkz4ensuyA== X-Received: by 2002:a17:902:6ac1:b029:e3:dbc0:bc44 with SMTP id i1-20020a1709026ac1b02900e3dbc0bc44mr27861641plt.15.1615326193986; Tue, 09 Mar 2021 13:43:13 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id v3sm13672138pff.217.2021.03.09.13.43.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Mar 2021 13:43:11 -0800 (PST) From: Kees Cook To: Thomas Gleixner Cc: Kees Cook , Elena Reshetova , x86@kernel.org, Andy Lutomirski , Peter Zijlstra , Catalin Marinas , Will Deacon , Mark Rutland , Alexander Potapenko , Alexander Popov , Ard Biesheuvel , Jann Horn , kernel-hardening@lists.openwall.com, linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka , David Hildenbrand , Mike Rapoport , Andrew Morton , Jonathan Corbet , Randy Dunlap Subject: [PATCH v5 7/7] lkdtm: Add REPORT_STACK for checking stack offsets Date: Tue, 9 Mar 2021 13:43:01 -0800 Message-Id: <20210309214301.678739-8-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210309214301.678739-1-keescook@chromium.org> References: <20210309214301.678739-1-keescook@chromium.org> MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; g=fb815901a1ccc1d9c4ca5c3e3cd3729b7f382fe2; i=b69wRsxT78r/3tM1mGa7N6ME6+rlXyFg15giRWRwPAQ=; m=aFqgiEE+nAZdug79A1F+fVTg9ZceUb0WPE8cbHqssVg=; p=ZQ32/kILkW5AD3nBZHO0VMTp4prIPkm7+DdhCHX8KdA= X-Patch-Sig: m=pgp; i=keescook@chromium.org; s=0x0x8972F4DFDC6DC026; b=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmBH6+QACgkQiXL039xtwCY9qhAAhOW Jji3ZCJ3RnoaGRrD0g0EhW5yFisz4YxnlNFMM7jo9oEkkaEIg5Cms4k2RvZrJ99lKsWQwbBhzNuM+ rCDNkeT8iaL2KUsW7Wo7+6szheXR5qMdUTHKKX/nOd1uPS8zHdnMNBkOts94EJQ/Zi4WoE4M380XF 47N+kZ8mPuzp9vyHEVUuPre4Dc7Tqmg2bzpBi8tjTrZBVBXul/7Plp2Wbry/KX3lrUl/vq3VaNypY MhHZhQnufm5Nkx93kwAL/aB7zoIZppUx8G4GrqzgT8InUwgfWD/KaX6atmi0FiMIzyFRKfANnk/rG gm0DClhml0R0e5xMPFHy/aDTZxyjkarc66p/PSUfKCRWOfQ9mOA6HxIcpO8phsZ176kf1Ge+nrt0D vT+mGYXOznFNK8yNioU8/h3F6A/IUtFoK0BN1KTG5azbjperev/mix3MNVLHWQn64+OmoknnIZKKf boW/jcOs+FV/7/e11Atvz5H2BQyEer7KZmWnyoc+WZi//J69k8JN11FgMyMttnfU8h5qT3YzzT4F0 sEpmlrNFTfMHnL42Lq2rKO2uVjXqqzti1VNVAPVtpBgNCWdzhlBvF4VC+Y28uivtgwCovRhH4lKaO EcmyX88q25Tn95RBx7Y7EcFqRvubjTsJTcq3Dw9W08iqQrjt+/8Lnfz7XVUtGeJQ= X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: A4A7420001EA X-Stat-Signature: hej7w81eamqwgbi6bt91rnwebbm5i4p1 Received-SPF: none (chromium.org>: No applicable sender policy available) receiver=imf18; identity=mailfrom; envelope-from=""; helo=mail-pj1-f51.google.com; client-ip=209.85.216.51 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615326195-845787 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: For validating the stack offset behavior, report the offset from a given process's first seen stack address. A quick way to measure the entropy: for i in $(seq 1 1000); do echo "REPORT_STACK" >/sys/kernel/debug/provoke-crash/DIRECT done offsets=$(dmesg | grep 'Stack offset' | cut -d: -f3 | sort | uniq -c | sort -n | wc -l) echo "$(uname -m) bits of stack entropy: $(echo "obase=2; $offsets" | bc | wc -L)" Signed-off-by: Kees Cook --- drivers/misc/lkdtm/bugs.c | 17 +++++++++++++++++ drivers/misc/lkdtm/core.c | 1 + drivers/misc/lkdtm/lkdtm.h | 1 + 3 files changed, 19 insertions(+) diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index 110f5a8538e9..0e8254d0cf0b 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -134,6 +134,23 @@ noinline void lkdtm_CORRUPT_STACK_STRONG(void) __lkdtm_CORRUPT_STACK((void *)&data); } +static pid_t stack_pid; +static unsigned long stack_addr; + +void lkdtm_REPORT_STACK(void) +{ + volatile uintptr_t magic; + pid_t pid = task_pid_nr(current); + + if (pid != stack_pid) { + pr_info("Starting stack offset tracking for pid %d\n", pid); + stack_pid = pid; + stack_addr = (uintptr_t)&magic; + } + + pr_info("Stack offset: %d\n", (int)(stack_addr - (uintptr_t)&magic)); +} + void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void) { static u8 data[5] __attribute__((aligned(4))) = {1, 2, 3, 4, 5}; diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c index b2aff4d87c01..8024b6a5cc7f 100644 --- a/drivers/misc/lkdtm/core.c +++ b/drivers/misc/lkdtm/core.c @@ -110,6 +110,7 @@ static const struct crashtype crashtypes[] = { CRASHTYPE(EXHAUST_STACK), CRASHTYPE(CORRUPT_STACK), CRASHTYPE(CORRUPT_STACK_STRONG), + CRASHTYPE(REPORT_STACK), CRASHTYPE(CORRUPT_LIST_ADD), CRASHTYPE(CORRUPT_LIST_DEL), CRASHTYPE(STACK_GUARD_PAGE_LEADING), diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 5ae48c64df24..99f90d3e5e9c 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -17,6 +17,7 @@ void lkdtm_LOOP(void); void lkdtm_EXHAUST_STACK(void); void lkdtm_CORRUPT_STACK(void); void lkdtm_CORRUPT_STACK_STRONG(void); +void lkdtm_REPORT_STACK(void); void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void); void lkdtm_SOFTLOCKUP(void); void lkdtm_HARDLOCKUP(void);