From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:44668 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726253AbeLLXOn (ORCPT ); Wed, 12 Dec 2018 18:14:43 -0500 Date: Wed, 12 Dec 2018 18:14:41 -0500 From: Sasha Levin To: Kees Cook Cc: "# 3.4.x" , LKML Subject: Re: [PATCH AUTOSEL 4.19 104/123] pstore/ram: Correctly calculate usable PRZ bytes Message-ID: <20181212231441.GG2746@sasha-vm> References: <20181205093555.5386-1-sashal@kernel.org> <20181205093555.5386-104-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: On Wed, Dec 05, 2018 at 02:57:08PM -0800, Kees Cook wrote: >On Wed, Dec 5, 2018 at 1:41 AM Sasha Levin wrote: >> >> From: Kees Cook >> >> [ Upstream commit 89d328f637b9904b6d4c9af73c8a608b8dd4d6f8 ] >> >> The actual number of bytes stored in a PRZ is smaller than the >> bytes requested by platform data, since there is a header on each >> PRZ. Additionally, if ECC is enabled, there are trailing bytes used >> as well. Normally this mismatch doesn't matter since PRZs are circular >> buffers and the leading "overflow" bytes are just thrown away. However, in >> the case of a compressed record, this rather badly corrupts the results. >> >> This corruption was visible with "ramoops.mem_size=204800 ramoops.ecc=1". >> Any stored crashes would not be uncompressable (producing a pstorefs >> "dmesg-*.enc.z" file), and triggering errors at boot: >> >> [ 2.790759] pstore: crypto_comp_decompress failed, ret = -22! >> >> Backporting this depends on commit 70ad35db3321 ("pstore: Convert console >> write to use ->write_buf") > >Please note the above. If this gets backported, this one is needed too. Okay, I've added 70ad35db3321 for 4.9, 4.4, and 3.18. -- Thanks, Sasha