From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id xgiLDc7yG1uAYAAAmS7hNA ; Sat, 09 Jun 2018 15:34:47 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 47132608CA; Sat, 9 Jun 2018 15:34:47 +0000 (UTC) Authentication-Results: smtp.codeaurora.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ym7o3Spf" X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,T_DKIMWL_WL_HIGH autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id A74B3606FA; Sat, 9 Jun 2018 15:34:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org A74B3606FA Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932903AbeFIPep (ORCPT + 25 others); Sat, 9 Jun 2018 11:34:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:36908 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932614AbeFIPeh (ORCPT ); Sat, 9 Jun 2018 11:34:37 -0400 Received: from localhost (D57E6652.static.ziggozakelijk.nl [213.126.102.82]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B81A4208A3; Sat, 9 Jun 2018 15:34:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1528558477; bh=gK5KAmoWpsTGS4l+qphcgJv/UD7Cw+u4TkctYxkSoVg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ym7o3SpfhywFRujaU253SaT8pbsdfAsCkA46ZnUqEVqGF1WgssxY2R70jby+X3F/p i6WOrtelxqxftvfL8mbr/ltnfEEccoeDdCcM3M9D6YG8vdiDR6ZMXA6gE9iV4U3lA0 UeFqgDYyZRHWaA3fesmYru79xBLdL+HAIWw4wUYY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vasily Gorbik , Al Viro , Linus Torvalds Subject: [PATCH 4.14 04/41] mmap: relax file size limit for regular files Date: Sat, 9 Jun 2018 17:29:36 +0200 Message-Id: <20180609152926.662160563@linuxfoundation.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180609152926.389750182@linuxfoundation.org> References: <20180609152926.389750182@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds commit 423913ad4ae5b3e8fb8983f70969fb522261ba26 upstream. Commit be83bbf80682 ("mmap: introduce sane default mmap limits") was introduced to catch problems in various ad-hoc character device drivers doing mmap and getting the size limits wrong. In the process, it used "known good" limits for the normal cases of mapping regular files and block device drivers. It turns out that the "s_maxbytes" limit was less "known good" than I thought. In particular, /proc doesn't set it, but exposes one regular file to mmap: /proc/vmcore. As a result, that file got limited to the default MAX_INT s_maxbytes value. This went unnoticed for a while, because apparently the only thing that needs it is the s390 kernel zfcpdump, but there might be other tools that use this too. Vasily suggested just changing s_maxbytes for all of /proc, which isn't wrong, but makes me nervous at this stage. So instead, just make the new mmap limit always be MAX_LFS_FILESIZE for regular files, which won't affect anything else. It wasn't the regular file case I was worried about. I'd really prefer for maxsize to have been per-inode, but that is not how things are today. Fixes: be83bbf80682 ("mmap: introduce sane default mmap limits") Reported-by: Vasily Gorbik Cc: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1318,7 +1318,7 @@ static inline int mlock_future_check(str static inline u64 file_mmap_size_max(struct file *file, struct inode *inode) { if (S_ISREG(inode->i_mode)) - return inode->i_sb->s_maxbytes; + return MAX_LFS_FILESIZE; if (S_ISBLK(inode->i_mode)) return MAX_LFS_FILESIZE;