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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id u15-20020a056a00098f00b004faa58d44eesm839224pfg.145.2022.03.23.15.30.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Mar 2022 15:30:45 -0700 (PDT) Date: Wed, 23 Mar 2022 15:30:44 -0700 From: Kees Cook To: Matthew Wilcox Cc: Christoph Hellwig , kernel test robot , "Martin K. Petersen" , Bart Van Assche , John Garry , LKML , lkp@lists.01.org, lkp@intel.com, linux-mm@kvack.org, linux-hardening@vger.kernel.org Subject: Re: [scsi] 6aded12b10: kernel_BUG_at_mm/usercopy.c Message-ID: <202203231529.0CB76344@keescook> References: <20220320143453.GD6208@xsang-OptiPlex-9020> <20220323071409.GA25480@lst.de> <202203230809.D63BF9511@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=HYy8RfEc; spf=pass (imf27.hostedemail.com: domain of keescook@chromium.org designates 209.85.215.180 as permitted sender) smtp.mailfrom=keescook@chromium.org; dmarc=pass (policy=none) header.from=chromium.org X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 98AC34003A X-Stat-Signature: xxt6xy5o8b7muic64hu4iikc4wdhtimi X-HE-Tag: 1648074646-986370 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: On Wed, Mar 23, 2022 at 03:42:34PM +0000, Matthew Wilcox wrote: > On Wed, Mar 23, 2022 at 08:40:30AM -0700, Kees Cook wrote: > > On Wed, Mar 23, 2022 at 08:14:10AM +0100, Christoph Hellwig wrote: > > > The actual warning is; > > > > > > [ 34.496096][ T331] usercopy: Kernel memory overwrite attempt detected to spans multiple pages (off set 0, size 6)! > > > > > > This is for the cmnd field in struct scsi_cmnd, which is allocated by > > > the block layer as part of the request allocator. So with a specific > > > packing it can legitimately span pages. > > > > > > Kees: how can we annotate that this is ok? > > > > The main problem is that CONFIG_HARDENED_USERCOPY_PAGESPAN=y is broken > > (and nothing should be setting it). > > > > This series removes it: > > https://lore.kernel.org/linux-hardening/20220110231530.665970-1-willy@infradead.org/ > > > > Matthew, what's the status of that series? Will it make the current > > merge window? > > I thought you were going to merge it! I haven't put it in any of my > public trees. LOL. Okay, you'd mentioned another check, so I wasn't sure. I can go ahead and snag it, but I'll likely wait until the next window and let it live in -next for a while, unless you think it should get YOLOed in. :) -Kees -- Kees Cook