From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f180.google.com (mail-pl1-f180.google.com [209.85.214.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 780439443 for ; Mon, 16 Sep 2024 21:55:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726523734; cv=none; b=eUEJnwtn62fYrc/toGPynknF53IupuiTDIp1Sk5oGl4pUBVFud1vo8LqILudJ00hwa+4vHinh1jgJECy01oepHiCQUltkfqQn2DUYoZDEoBNMi7Suh3uIxHwcUwCYr/wh6ix52Q2C+SPP+H1ckRRqPTwF5RY9AP0reJvNx7HBaA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726523734; c=relaxed/simple; bh=dvdb/hPpUaIakFW38vCDL3nT+2nz/7o6ghkRKdQ6CU0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VlbdLyteuEYmgTNbJB3bSpDho8dshwcCJA75NXGQC8ie++RoFiVgGS4/OQPgBo5EB2amaXINPoKaBKKkvuKd9vHjJtLBebfj7RvC1UOzdLKiIUnpSo6YmdBlZmYbN1feFRDWUIrirfdz/ON620psrnGgVh7Bexk+rnNTENdgMv0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=fromorbit.com; spf=pass smtp.mailfrom=fromorbit.com; dkim=pass (2048-bit key) header.d=fromorbit-com.20230601.gappssmtp.com header.i=@fromorbit-com.20230601.gappssmtp.com header.b=Fxa64976; arc=none smtp.client-ip=209.85.214.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=fromorbit.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fromorbit.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fromorbit-com.20230601.gappssmtp.com header.i=@fromorbit-com.20230601.gappssmtp.com header.b="Fxa64976" Received: by mail-pl1-f180.google.com with SMTP id d9443c01a7336-20792913262so30169055ad.3 for ; Mon, 16 Sep 2024 14:55:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fromorbit-com.20230601.gappssmtp.com; s=20230601; t=1726523733; x=1727128533; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=7+QcDyNxCWCtWt9+G6UHYM5MMFaIylSmdocAH+GqoOc=; b=Fxa64976TA7DtMxglyvo+6ObR75CazhewmJo1VoSdVwZHOHeYjrN3k7/+X9WF8RQ7W u4QByY1vEBGgj2m640CWQ1Uh68js277k6m+YwIjt8SO21P75SOhllw/N/GgMEX0m8+oA JvCv68RUC/aZ5VCR9wnk5jiZwGtcDkat9Fg2jp4nZQunVtAHobSjUP1dneE4CN4NTFVa gHk8PA/eDCqpNcZeS1XGd7oqBsBUHeiE6sfWHH1FdBLCc2znYkNvkNPH09hjGTkeUYYo genM5QQQIHsrTr+zmGWg7V5+exYEN76ZGSbWj4A7daN+QWGrj+5a3PbaAbS08AvJ50kL JbIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726523733; x=1727128533; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=7+QcDyNxCWCtWt9+G6UHYM5MMFaIylSmdocAH+GqoOc=; b=flRTW7EJaHwXyGUVZd3gX37Kj817xXXvBUNiFa5sAwjcVIBb/hQ+N6hZhzT7Ze/vfM l8mpw2dB8nfM3KJmSN/2SIUYVYfl/WFVu2Pz4PPPTBxAIXLOL0KF2UySvJa/QX/CQmfe ss0qYN5RRFA28j10JK4ufBcfUvnOBDFecAIn3KoOrzykbYMXkvHgLaDGsgCcWq+mGGRT QFfBK+SAKiX4eNdkPjZdwpOXIBzLLtCA8YDj2zZ0AmPJzyGY/mjVgz2dco0IaNtLWTFA 2k7GpCF0+XMlGWzUzt/ttYaI/v2OcdgxFyy+cHaGoE7ryPI7b0qnGOC/vhx6szyaMV7r eKfg== X-Forwarded-Encrypted: i=1; AJvYcCX6G/Xw+Q2vE9DXdshurR6/IcC6lLQUgu3EZK19cO50gswYKH0ucPP8TyrRICxGpoh0vQekA0L6TKw=@vger.kernel.org X-Gm-Message-State: AOJu0YxMtm7ovCM+sRxngva8GEKK4nnbcB/wlvaTbRMX2eqV5tTiqLeB w2jQeaClepl3iMstO0kA7MkbNB9O1G2Iv5ihnmIBLQY3+SdRjQE+XBqKpTRzOII= X-Google-Smtp-Source: AGHT+IF0iFN6cnO2/4mZbjdywZwBn/2zzJXSThiMoB3CX3BD1WHtQH9VedLiduQdloMWcI2cvwTppQ== X-Received: by 2002:a17:902:c946:b0:207:5ca3:8d23 with SMTP id d9443c01a7336-20782b9e330mr183198465ad.59.1726523732632; Mon, 16 Sep 2024 14:55:32 -0700 (PDT) Received: from dread.disaster.area (pa49-179-78-197.pa.nsw.optusnet.com.au. [49.179.78.197]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2079460111asm40742535ad.90.2024.09.16.14.55.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Sep 2024 14:55:32 -0700 (PDT) Received: from dave by dread.disaster.area with local (Exim 4.96) (envelope-from ) id 1sqJgv-0066Fa-1C; Tue, 17 Sep 2024 07:55:29 +1000 Date: Tue, 17 Sep 2024 07:55:29 +1000 From: Dave Chinner To: Matthew Wilcox Cc: trondmy@kernel.org, Mike Snitzer , linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH] filemap: Fix bounds checking in filemap_read() Message-ID: References: Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Sep 13, 2024 at 07:21:54PM +0100, Matthew Wilcox wrote: > On Fri, Sep 13, 2024 at 01:57:04PM -0400, trondmy@kernel.org wrote: > > If the caller supplies an iocb->ki_pos value that is close to the > > filesystem upper limit, and an iterator with a count that causes us to > > overflow that limit, then filemap_read() enters an infinite loop. > > Are we guaranteed that ki_pos lies in the range [0..s_maxbytes)? > I'm not too familiar with the upper paths of the VFS and what guarantees > we can depend on. If we are guaranteed that, could somebody document > it (and indeed create kernel-doc for struct kiocb)? filemap_read() checks this itself before doing anything else: if (unlikely(iocb->ki_pos >= inode->i_sb->s_maxbytes)) return 0; i.e. there is no guarantee provided by the upper layers, it's first checked right here in any buffered read path... -Dave. -- Dave Chinner david@fromorbit.com