From patchwork Fri Aug 7 10:51:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 262656 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=-13.0 required=3.0 tests=BAYES_00, 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 3E994C433E0 for ; Fri, 7 Aug 2020 11:11:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D58022C9F for ; Fri, 7 Aug 2020 11:11:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728209AbgHGLJx (ORCPT ); Fri, 7 Aug 2020 07:09:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728091AbgHGKxh (ORCPT ); Fri, 7 Aug 2020 06:53:37 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45B6DC0617A9 for ; Fri, 7 Aug 2020 03:52:24 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1k3zym-0004nB-Ib; Fri, 07 Aug 2020 12:52:04 +0200 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1k3zyk-0007IK-6V; Fri, 07 Aug 2020 12:52:02 +0200 From: Oleksij Rempel To: dev.kurt@vandijck-laurijssen.be, mkl@pengutronix.de, wg@grandegger.com Cc: Oleksij Rempel , syzbot+5322482fe520b02aea30@syzkaller.appspotmail.com, linux-stable , kernel@pengutronix.de, linux-can@vger.kernel.org, netdev@vger.kernel.org, David Jander Subject: [PATCH v1 2/5] can: j1939: transport: j1939_session_tx_dat(): fix use-after-free read in j1939_tp_txtimer() Date: Fri, 7 Aug 2020 12:51:57 +0200 Message-Id: <20200807105200.26441-3-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200807105200.26441-1-o.rempel@pengutronix.de> References: <20200807105200.26441-1-o.rempel@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The current stack implementation do not support ECTS requests of not aligned TP sized blocks. If ECTS will request a block with size and offset spanning two TP blocks, this will cause memcpy() to read beyond the queued skb (which does only contain one TP sized block). Sometimes KASAN will detect this read if the memory region beyond the skb was previously allocated and freed. In other situations it will stay undetected. The ETP transfer in any case will be corrupted. This patch adds a sanity check to avoid this kind of read and abort the session with error J1939_XTP_ABORT_ECTS_TOO_BIG. Reported-by: syzbot+5322482fe520b02aea30@syzkaller.appspotmail.com Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Cc: linux-stable # >= v5.4 Signed-off-by: Oleksij Rempel --- net/can/j1939/transport.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c index b135c5e2a86e..30957c9a8eb7 100644 --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -787,6 +787,18 @@ static int j1939_session_tx_dat(struct j1939_session *session) if (len > 7) len = 7; + if (offset + len > se_skb->len) { + netdev_err_once(priv->ndev, + "%s: 0x%p: requested data outside of queued buffer: offset %i, len %i, pkt.tx: %i\n", + __func__, session, skcb->offset, se_skb->len , session->pkt.tx); + return -EOVERFLOW; + } + + if (!len) { + ret = -ENOBUFS; + break; + } + memcpy(&dat[1], &tpdat[offset], len); ret = j1939_tp_tx_dat(session, dat, len + 1); if (ret < 0) { @@ -1120,6 +1132,9 @@ static enum hrtimer_restart j1939_tp_txtimer(struct hrtimer *hrtimer) * cleanup including propagation of the error to user space. */ break; + case -EOVERFLOW: + j1939_session_cancel(session, J1939_XTP_ABORT_ECTS_TOO_BIG); + break; case 0: session->tx_retry = 0; break;