From patchwork Mon May 10 10:20:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 12247643 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 8C4EDC43460 for ; Mon, 10 May 2021 10:52:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5735761C65 for ; Mon, 10 May 2021 10:52:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232851AbhEJKyA (ORCPT ); Mon, 10 May 2021 06:54:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:41454 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233253AbhEJKwN (ORCPT ); Mon, 10 May 2021 06:52:13 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 71FDD61876; Mon, 10 May 2021 10:40:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620643254; bh=SqM/N6JzNeVkkCEtOVfKCgRU/lkUPfSXPQSHx4t8blo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tl1wi8pcg2zcxMzIkIUxD7b5ml4BmEEJvZjQKXhkuPtJ1N0M6Aaw0wvyi2SUtM3t1 zsB+BDKWFoUf9RUab1eROh3/KXwGoRlw/PcFBwuK9OIQO/YZALKpTUjxr+qzaO4mrv KvZPTBaN2jarxa0lANnHl8inAKJfqSDqOQeB9Me0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+ba2e91df8f74809417fa@syzkaller.appspotmail.com, syzbot+f3a0fa110fd630ab56c8@syzkaller.appspotmail.com, Randy Dunlap , Trond Myklebust , Anna Schumaker , linux-nfs@vger.kernel.org, David Howells , Al Viro Subject: [PATCH 5.10 233/299] NFS: fs_context: validate UDP retrans to prevent shift out-of-bounds Date: Mon, 10 May 2021 12:20:30 +0200 Message-Id: <20210510102012.656313062@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102004.821838356@linuxfoundation.org> References: <20210510102004.821838356@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Randy Dunlap commit c09f11ef35955785f92369e25819bf0629df2e59 upstream. Fix shift out-of-bounds in xprt_calc_majortimeo(). This is caused by a garbage timeout (retrans) mount option being passed to nfs mount, in this case from syzkaller. If the protocol is XPRT_TRANSPORT_UDP, then 'retrans' is a shift value for a 64-bit long integer, so 'retrans' cannot be >= 64. If it is >= 64, fail the mount and return an error. Fixes: 9954bf92c0cd ("NFS: Move mount parameterisation bits into their own file") Reported-by: syzbot+ba2e91df8f74809417fa@syzkaller.appspotmail.com Reported-by: syzbot+f3a0fa110fd630ab56c8@syzkaller.appspotmail.com Signed-off-by: Randy Dunlap Cc: Trond Myklebust Cc: Anna Schumaker Cc: linux-nfs@vger.kernel.org Cc: David Howells Cc: Al Viro Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- fs/nfs/fs_context.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/fs/nfs/fs_context.c +++ b/fs/nfs/fs_context.c @@ -938,6 +938,15 @@ static int nfs23_parse_monolithic(struct sizeof(mntfh->data) - mntfh->size); /* + * for proto == XPRT_TRANSPORT_UDP, which is what uses + * to_exponential, implying shift: limit the shift value + * to BITS_PER_LONG (majortimeo is unsigned long) + */ + if (!(data->flags & NFS_MOUNT_TCP)) /* this will be UDP */ + if (data->retrans >= 64) /* shift value is too large */ + goto out_invalid_data; + + /* * Translate to nfs_fs_context, which nfs_fill_super * can deal with. */ @@ -1037,6 +1046,9 @@ out_no_address: out_invalid_fh: return nfs_invalf(fc, "NFS: invalid root filehandle"); + +out_invalid_data: + return nfs_invalf(fc, "NFS: invalid binary mount data"); } #if IS_ENABLED(CONFIG_NFS_V4)