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=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 14D28C43441 for ; Mon, 19 Nov 2018 16:32:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE0FD208E4 for ; Mon, 19 Nov 2018 16:31:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="1EbF6Obe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE0FD208E4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730593AbeKTC4F (ORCPT ); Mon, 19 Nov 2018 21:56:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:54060 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730025AbeKTC4E (ORCPT ); Mon, 19 Nov 2018 21:56:04 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5D7C82089F; Mon, 19 Nov 2018 16:31:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542645116; bh=x8XAeMM+2C8aRZ7vocr99PbYCoI3iqGKRZCQ03fm2uI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1EbF6Obe/e0dVAqU+zAlLEOpgtWcA9KgEqbRLT0daXM5Su30A/ko1bw5BGoRXDCsx sRcSDltAT9krQP4Zw90XtzpH5BCd7gvGDrWcT0O5yh8WWTW63A12oltKC0M6rLAsUj czcm7NlSrxqLVsE6JK7F6vv4kc1JK7GcPPdhJGB0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dominique Martinet , syzbot+d4252148d198410b864f@syzkaller.appspotmail.com, Sasha Levin Subject: [PATCH 4.19 042/205] 9p: clear dangling pointers in p9stat_free Date: Mon, 19 Nov 2018 17:25:49 +0100 Message-Id: <20181119162624.920581527@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181119162616.586062722@linuxfoundation.org> References: <20181119162616.586062722@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dominique Martinet [ Upstream commit 62e3941776fea8678bb8120607039410b1b61a65 ] p9stat_free is more of a cleanup function than a 'free' function as it only frees the content of the struct; there are chances of use-after-free if it is improperly used (e.g. p9stat_free called twice as it used to be possible to) Clearing dangling pointers makes the function idempotent and safer to use. Link: http://lkml.kernel.org/r/1535410108-20650-2-git-send-email-asmadeus@codewreck.org Signed-off-by: Dominique Martinet Reported-by: syzbot+d4252148d198410b864f@syzkaller.appspotmail.com Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/9p/protocol.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/net/9p/protocol.c +++ b/net/9p/protocol.c @@ -46,10 +46,15 @@ p9pdu_writef(struct p9_fcall *pdu, int p void p9stat_free(struct p9_wstat *stbuf) { kfree(stbuf->name); + stbuf->name = NULL; kfree(stbuf->uid); + stbuf->uid = NULL; kfree(stbuf->gid); + stbuf->gid = NULL; kfree(stbuf->muid); + stbuf->muid = NULL; kfree(stbuf->extension); + stbuf->extension = NULL; } EXPORT_SYMBOL(p9stat_free);