From patchwork Mon Mar 1 16:12:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 390044 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=-18.8 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 70722C433DB for ; Mon, 1 Mar 2021 17:14:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C68764F45 for ; Mon, 1 Mar 2021 17:14:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237603AbhCARMo (ORCPT ); Mon, 1 Mar 2021 12:12:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:35318 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237043AbhCARGm (ORCPT ); Mon, 1 Mar 2021 12:06:42 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 45C0065002; Mon, 1 Mar 2021 16:40:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614616815; bh=+nZLZ+8DU1bB546hofKiUfN1z70R/SeU+DeYtpUD6Us=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m0TYM7Opn+pnwOcylusISD2CerY750+bEPEQXn/AQqr/oBGEZIYgp9PyQoxw2w3Yj dcM5mIkcfiNMrfpTZeE+/nmjTaT0a2SjQpbLfexti+PhhWmlh01//MZ0lJ0LYQWiWO 0eaEzVWxPl0C57+utgf+xzCPGGBEirK+Q39mTWz8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tom Rix , Nathan Chancellor , Richard Weinberger , Sasha Levin Subject: [PATCH 4.19 106/247] jffs2: fix use after free in jffs2_sum_write_data() Date: Mon, 1 Mar 2021 17:12:06 +0100 Message-Id: <20210301161036.861294995@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161031.684018251@linuxfoundation.org> References: <20210301161031.684018251@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tom Rix [ Upstream commit 19646447ad3a680d2ab08c097585b7d96a66126b ] clang static analysis reports this problem fs/jffs2/summary.c:794:31: warning: Use of memory after it is freed c->summary->sum_list_head = temp->u.next; ^~~~~~~~~~~~ In jffs2_sum_write_data(), in a loop summary data is handles a node at a time. When it has written out the node it is removed the summary list, and the node is deleted. In the corner case when a JFFS2_FEATURE_RWCOMPAT_COPY is seen, a call is made to jffs2_sum_disable_collecting(). jffs2_sum_disable_collecting() deletes the whole list which conflicts with the loop's deleting the list by parts. To preserve the old behavior of stopping the write midway, bail out of the loop after disabling summary collection. Fixes: 6171586a7ae5 ("[JFFS2] Correct handling of JFFS2_FEATURE_RWCOMPAT_COPY nodes.") Signed-off-by: Tom Rix Reviewed-by: Nathan Chancellor Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- fs/jffs2/summary.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/jffs2/summary.c b/fs/jffs2/summary.c index be7c8a6a57480..4fe64519870f1 100644 --- a/fs/jffs2/summary.c +++ b/fs/jffs2/summary.c @@ -783,6 +783,8 @@ static int jffs2_sum_write_data(struct jffs2_sb_info *c, struct jffs2_eraseblock dbg_summary("Writing unknown RWCOMPAT_COPY node type %x\n", je16_to_cpu(temp->u.nodetype)); jffs2_sum_disable_collecting(c->summary); + /* The above call removes the list, nothing more to do */ + goto bail_rwcompat; } else { BUG(); /* unknown node in summary information */ } @@ -794,6 +796,7 @@ static int jffs2_sum_write_data(struct jffs2_sb_info *c, struct jffs2_eraseblock c->summary->sum_num--; } + bail_rwcompat: jffs2_sum_reset_collected(c->summary);