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=-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=unavailable 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 BE91AC433DB for ; Mon, 1 Mar 2021 19:03:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 86BB264E31 for ; Mon, 1 Mar 2021 19:03:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241015AbhCATDS (ORCPT ); Mon, 1 Mar 2021 14:03:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:50204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235095AbhCAQqp (ORCPT ); Mon, 1 Mar 2021 11:46:45 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A71EB64F93; Mon, 1 Mar 2021 16:31:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614616278; bh=+nZLZ+8DU1bB546hofKiUfN1z70R/SeU+DeYtpUD6Us=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k9ZQj7nkWqTcTN8P+fUW8NUpOviQwLI+Gw+EVG7w20ELTbFK1fB5Qk2ccRBMIFQIc e+i41+rOFaoZ4uIPKEjceQBwjKbzSR/18weteFbQSZq3LZmR0oiPFA6m6TouDcs5jq 2m8kh8VnQz25cUPTBGEYY5wW+PDKuxt/ZCSQfLl0= 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 4.14 066/176] jffs2: fix use after free in jffs2_sum_write_data() Date: Mon, 1 Mar 2021 17:12:19 +0100 Message-Id: <20210301161024.237346298@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161020.931630716@linuxfoundation.org> References: <20210301161020.931630716@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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); -- 2.27.0