From patchwork Thu Apr 14 13:10:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 562327 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B049C433EF for ; Thu, 14 Apr 2022 13:57:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345557AbiDNNxl (ORCPT ); Thu, 14 Apr 2022 09:53:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345108AbiDNNpI (ORCPT ); Thu, 14 Apr 2022 09:45:08 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F10E035A8B; Thu, 14 Apr 2022 06:42:16 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AD515B82983; Thu, 14 Apr 2022 13:42:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F31C7C385A5; Thu, 14 Apr 2022 13:42:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649943734; bh=IrcQOEkRHvkartR3DewjUWYHIioWHfFulXXJpBlKWyI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D7RhEGNyeLEO7+wqqKI1X3NtguDJ0Wkkc9LEknkAA5u4n5CT81tM6honVp5Cp3Wf3 Pu9LMFAZy3TKi9BlTHsgsZs132EWsIxhF7a20BCunStYuU156t+5F4QwAnUHH0P2nY YLF4ZhbDe2WCEJ5z/6ZNUs4EqlKpd8JH5k1kz+rc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pavel Skripkin , Dave Kleikamp , Sasha Levin , syzbot+46f5c25af73eb8330eb6@syzkaller.appspotmail.com Subject: [PATCH 5.4 260/475] jfs: fix divide error in dbNextAG Date: Thu, 14 Apr 2022 15:10:45 +0200 Message-Id: <20220414110902.386588338@linuxfoundation.org> X-Mailer: git-send-email 2.35.2 In-Reply-To: <20220414110855.141582785@linuxfoundation.org> References: <20220414110855.141582785@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Pavel Skripkin [ Upstream commit 2cc7cc01c15f57d056318c33705647f87dcd4aab ] Syzbot reported divide error in dbNextAG(). The problem was in missing validation check for malicious image. Syzbot crafted an image with bmp->db_numag equal to 0. There wasn't any validation checks, but dbNextAG() blindly use bmp->db_numag in divide expression Fix it by validating bmp->db_numag in dbMount() and return an error if image is malicious Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-and-tested-by: syzbot+46f5c25af73eb8330eb6@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Signed-off-by: Dave Kleikamp Signed-off-by: Sasha Levin --- fs/jfs/jfs_dmap.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index 6fe82ce8663e..79f3440e204b 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -148,6 +148,7 @@ static const s8 budtab[256] = { * 0 - success * -ENOMEM - insufficient memory * -EIO - i/o error + * -EINVAL - wrong bmap data */ int dbMount(struct inode *ipbmap) { @@ -179,6 +180,12 @@ int dbMount(struct inode *ipbmap) bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree); bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage); bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag); + if (!bmp->db_numag) { + release_metapage(mp); + kfree(bmp); + return -EINVAL; + } + bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel); bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag); bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);