From mboxrd@z Thu Jan 1 00:00:00 1970 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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 407B6C4727C for ; Thu, 1 Oct 2020 09:06:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4F0220B1F for ; Thu, 1 Oct 2020 09:06:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="a34Jtsu0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731747AbgJAJGA (ORCPT ); Thu, 1 Oct 2020 05:06:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725894AbgJAJGA (ORCPT ); Thu, 1 Oct 2020 05:06:00 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DDDC2C0613D0; Thu, 1 Oct 2020 02:05:59 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id s31so3557328pga.7; Thu, 01 Oct 2020 02:05:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=o+n930xyfkrF12hPhSCQSJtiGdIh1Oqz/H5hvm0xQ2E=; b=a34Jtsu0JJNqL+ebJlBV+1sTp5jHO3arcKpfJkh+K55BWhKHBDp8S6SnJuYgbxiSlu lp0eNiBLX4pIxo0IYgTgfhm2zuhBh8O2UmvP3uyptpYO3utovwbzTMKftqNx5K2iRNzo BXLpa+WfF2X0AYr3TGL0QXZbgP3cVCn5Uo+ujromNLp9vD46zb+fhEaZUpma+evsCE0E +zNHnLIvPH2lurCRUak86+bY6jblUfw7iKQbRK/+oZzRg0pFivsxwmF4jyUaAJ8IYUI4 iVsDC3gEPjT8tjVYZkWoS0282eVasCq3uwkps5VJGd/4aa5FjUFmL8S5LzI9VJPhwxtn GzgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=o+n930xyfkrF12hPhSCQSJtiGdIh1Oqz/H5hvm0xQ2E=; b=nFwk9qjMyiHyhDq4lWpo+9gRUaqMkgKb7DcHqngKbHNg0RsmljEXrheFQxOFIMfYVT a4oUDB0tiuZ2zezmzjBp1T4czaRbmVy9VyhjwAemnWksJLsHYKvBK7R4hOnSvqhFcsHq o/SI5URROpXJOUitZPeouaQGS3d/uj9I3vL/L7DDDMgjjf3XdWDNcuvbYqAQENpVjQUO SD92nITicpz/WaoBWNNFUQfV23XZA1IZFIC6KF7WKlK7IqV4VqHkkcp8FWgVoq+KG4vi TeH7XACgIYUWI/AgBx+FHUrHOQXqQqA1h0aFoUkuiCf/ryyfh/pBFOgk7pTggKRF/lLF wYAA== X-Gm-Message-State: AOAM532t+61Ub3R74ymLO/4IEiwJg521iOtr6twrIB5weXrykXT9kjCF Ibt9CcdxSwcIuTGYbVLq7/dg5Ud71ZSV8yJH X-Google-Smtp-Source: ABdhPJxEo2cCaMAsL2FuAUfE+cu6vWbE7YNB1CKjOvfZm/YpDXdKe0OwpxnXA6BQHS+XYEojiaVgIQ== X-Received: by 2002:a62:26c1:0:b029:142:2501:35ef with SMTP id m184-20020a6226c10000b0290142250135efmr6072501pfm.79.1601543159103; Thu, 01 Oct 2020 02:05:59 -0700 (PDT) Received: from localhost.localdomain ([45.118.167.204]) by smtp.googlemail.com with ESMTPSA id q5sm4489607pgh.16.2020.10.01.02.05.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Oct 2020 02:05:57 -0700 (PDT) From: Anmol Karn To: jack@suse.cz, jeffm@suse.com Cc: linux-kernel@vger.kernel.org, reiserfs-devel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, syzkaller-bugs@googlegroups.com, anmol.karan123@gmail.com, syzbot+9b33c9b118d77ff59b6f@syzkaller.appspotmail.com Subject: [Linux-kernel-mentees] [PATCH] fs: reiserfs: xattr: Fix null pointer derefernce in open_xa_root() Date: Thu, 1 Oct 2020 14:35:47 +0530 Message-Id: <20201001090547.431840-1-anmol.karan123@gmail.com> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org d_really_is_negative() checks for the dentry->d_inode whether it's NULL or not, but in open_xa_root(), when it checks 'privroot->d_inode', it doesn't check whether privroot is NULL or not, this leads to a null pointer dereference while calling it from open_xa_dir() while initializing xaroot. - fs/reiserfs/xattr.c The bug seems to get triggered at this line: if (d_really_is_negative(privroot)) return ERR_PTR(-EOPNOTSUPP); Fix it by adding a NULL check for privroot. Reported-and-tested-by: syzbot+9b33c9b118d77ff59b6f@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=9b33c9b118d77ff59b6f Signed-off-by: Anmol Karn --- fs/reiserfs/xattr.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c index 28b241cd6987..a75480d0ee7e 100644 --- a/fs/reiserfs/xattr.c +++ b/fs/reiserfs/xattr.c @@ -121,8 +121,9 @@ static struct dentry *open_xa_root(struct super_block *sb, int flags) struct dentry *privroot = REISERFS_SB(sb)->priv_root; struct dentry *xaroot; - if (d_really_is_negative(privroot)) + if (!privroot || d_really_is_negative(privroot)) { return ERR_PTR(-EOPNOTSUPP); + } inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR); -- 2.28.0