From patchwork Mon Mar 1 16:12:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 390284 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 ED2DDC433E9 for ; Mon, 1 Mar 2021 16:21:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E42164F46 for ; Mon, 1 Mar 2021 16:21:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235389AbhCAQVJ (ORCPT ); Mon, 1 Mar 2021 11:21:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:56642 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237783AbhCAQTG (ORCPT ); Mon, 1 Mar 2021 11:19:06 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C521C64EBE; Mon, 1 Mar 2021 16:17:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614615447; bh=HD8zoycEz+avgQXZPfOseUSnSMHTUb6/F9Ww9RKB07M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zyzi8gKrE4jdX3asYnyH6V9IuX9QSIu83vZ+ndctXwMO2aYb6B7EjAJCrPz7iYNtK lsV2Re/0OliePbxTG83OAHN0ca3j8zIT7/HPwT5nX6ir3I73oyWdz1emlVmLtWGI48 FLzFl4W5GXEwNIDWxb9rZHrKrxwDRmLBjOJaBAds= 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 4.4 33/93] jffs2: fix use after free in jffs2_sum_write_data() Date: Mon, 1 Mar 2021 17:12:45 +0100 Message-Id: <20210301161008.543271476@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161006.881950696@linuxfoundation.org> References: <20210301161006.881950696@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 bc5385471a6e3..c05d6f5f10ecd 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);