From mboxrd@z Thu Jan 1 00:00:00 1970 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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 351FFC76195 for ; Mon, 22 Jul 2019 03:17:11 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8660521926 for ; Mon, 22 Jul 2019 03:17:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8660521926 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45sRc31QvPzDqQ6 for ; Mon, 22 Jul 2019 13:17:07 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45sRYT5b17zDqPl for ; Mon, 22 Jul 2019 13:14:53 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix, from userid 1034) id 45sRYT4F13z9sML; Mon, 22 Jul 2019 13:14:53 +1000 (AEST) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: f16d80b75a096c52354c6e0a574993f3b0dfbdfe In-Reply-To: <20190719050502.405-1-mikey@neuling.org> To: Michael Neuling From: Michael Ellerman Subject: Re: [PATCH] powerpc/tm: Fix oops on sigreturn on systems without TM Message-Id: <45sRYT4F13z9sML@ozlabs.org> Date: Mon, 22 Jul 2019 13:14:53 +1000 (AEST) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mikey@neuling.org, Praveen Pandey , gromero@br.ibm.com, linuxppc-dev@lists.ozlabs.org, Breno Leitao , Haren Myneni Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, 2019-07-19 at 05:05:02 UTC, Michael Neuling wrote: > On systems like P9 powernv where we have no TM (or P8 booted with > ppc_tm=off), userspace can construct a signal context which still has > the MSR TS bits set. The kernel tries to restore this context which > results in the following crash: > > [ 74.980557] Unexpected TM Bad Thing exception at c0000000000022fc (msr 0x8000000102a03031) tm_scratch=800000020280f033 > [ 74.980741] Oops: Unrecoverable exception, sig: 6 [#1] > [ 74.980820] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries > [ 74.980917] Modules linked in: > [ 74.980980] CPU: 0 PID: 1636 Comm: sigfuz Not tainted 5.2.0-11043-g0a8ad0ffa4 #69 > [ 74.981096] NIP: c0000000000022fc LR: 00007fffb2d67e48 CTR: 0000000000000000 > [ 74.981212] REGS: c00000003fffbd70 TRAP: 0700 Not tainted (5.2.0-11045-g7142b497d8) > [ 74.981325] MSR: 8000000102a03031 CR: 42004242 XER: 00000000 > [ 74.981463] CFAR: c0000000000022e0 IRQMASK: 0 > [ 74.981463] GPR00: 0000000000000072 00007fffb2b6e560 00007fffb2d87f00 0000000000000669 > [ 74.981463] GPR04: 00007fffb2b6e728 0000000000000000 0000000000000000 00007fffb2b6f2a8 > [ 74.981463] GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 > [ 74.981463] GPR12: 0000000000000000 00007fffb2b76900 0000000000000000 0000000000000000 > [ 74.981463] GPR16: 00007fffb2370000 00007fffb2d84390 00007fffea3a15ac 000001000a250420 > [ 74.981463] GPR20: 00007fffb2b6f260 0000000010001770 0000000000000000 0000000000000000 > [ 74.981463] GPR24: 00007fffb2d843a0 00007fffea3a14a0 0000000000010000 0000000000800000 > [ 74.981463] GPR28: 00007fffea3a14d8 00000000003d0f00 0000000000000000 00007fffb2b6e728 > [ 74.982420] NIP [c0000000000022fc] rfi_flush_fallback+0x7c/0x80 > [ 74.982517] LR [00007fffb2d67e48] 0x7fffb2d67e48 > [ 74.982593] Call Trace: > [ 74.982632] Instruction dump: > [ 74.982691] e96a0220 e96a02a8 e96a0330 e96a03b8 394a0400 4200ffdc 7d2903a6 e92d0c00 > [ 74.982809] e94d0c08 e96d0c10 e82d0c18 7db242a6 <4c000024> 7db243a6 7db142a6 f82d0c18 > > The problem is the signal code assumes TM is enabled when > CONFIG_PPC_TRANSACTIONAL_MEM is on. This may not be the case as with > P9 powernv or if `ppc_tm=off` is used on P8. > > This means any local user can crash the system. > > Fix the problem by returning a bad stack frame to the user if they try > to set the MSR TS bits with sigreturn() on systems where TM is not > supported. > > Found with sigfuz kernel selftest on P9. > > This fixes CVE-2019-13648. > > Fixes: 2b0a576d15 ("powerpc: Add new transactional memory state to the signal context") > Cc: stable@vger.kernel.org # v3.9 > Reported-by: Praveen Pandey > Signed-off-by: Michael Neuling Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/f16d80b75a096c52354c6e0a574993f3b0dfbdfe cheers