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=-9.7 required=3.0 tests=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 0010EC5DF60 for ; Tue, 5 Nov 2019 16:32:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D29E321929 for ; Tue, 5 Nov 2019 16:32:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390338AbfKEQcl (ORCPT ); Tue, 5 Nov 2019 11:32:41 -0500 Received: from metis.ext.pengutronix.de ([85.220.165.71]:50625 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390304AbfKEQck (ORCPT ); Tue, 5 Nov 2019 11:32:40 -0500 Received: from heimdall.vpn.pengutronix.de ([2001:67c:670:205:1d::14] helo=blackshift.org) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1iS1l0-0002Hp-KB; Tue, 05 Nov 2019 17:32:38 +0100 From: Marc Kleine-Budde To: netdev@vger.kernel.org Cc: davem@davemloft.net, linux-can@vger.kernel.org, kernel@pengutronix.de, Stephane Grosjean , linux-stable , Marc Kleine-Budde Subject: [PATCH 06/33] can: peak_usb: fix a potential out-of-sync while decoding packets Date: Tue, 5 Nov 2019 17:31:48 +0100 Message-Id: <20191105163215.30194-7-mkl@pengutronix.de> X-Mailer: git-send-email 2.24.0.rc1 In-Reply-To: <20191105163215.30194-1-mkl@pengutronix.de> References: <20191105163215.30194-1-mkl@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:205:1d::14 X-SA-Exim-Mail-From: mkl@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 From: Stephane Grosjean When decoding a buffer received from PCAN-USB, the first timestamp read in a packet is a 16-bit coded time base, and the next ones are an 8-bit offset to this base, regardless of the type of packet read. This patch corrects a potential loss of synchronization by using a timestamp index read from the buffer, rather than an index of received data packets, to determine on the sizeof the timestamp to be read from the packet being decoded. Signed-off-by: Stephane Grosjean Fixes: 46be265d3388 ("can: usb: PEAK-System Technik PCAN-USB specific part") Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/usb/peak_usb/pcan_usb.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/net/can/usb/peak_usb/pcan_usb.c b/drivers/net/can/usb/peak_usb/pcan_usb.c index 617da295b6c1..5a66c9f53aae 100644 --- a/drivers/net/can/usb/peak_usb/pcan_usb.c +++ b/drivers/net/can/usb/peak_usb/pcan_usb.c @@ -100,7 +100,7 @@ struct pcan_usb_msg_context { u8 *end; u8 rec_cnt; u8 rec_idx; - u8 rec_data_idx; + u8 rec_ts_idx; struct net_device *netdev; struct pcan_usb *pdev; }; @@ -547,10 +547,15 @@ static int pcan_usb_decode_status(struct pcan_usb_msg_context *mc, mc->ptr += PCAN_USB_CMD_ARGS; if (status_len & PCAN_USB_STATUSLEN_TIMESTAMP) { - int err = pcan_usb_decode_ts(mc, !mc->rec_idx); + int err = pcan_usb_decode_ts(mc, !mc->rec_ts_idx); if (err) return err; + + /* Next packet in the buffer will have a timestamp on a single + * byte + */ + mc->rec_ts_idx++; } switch (f) { @@ -632,10 +637,13 @@ static int pcan_usb_decode_data(struct pcan_usb_msg_context *mc, u8 status_len) cf->can_dlc = get_can_dlc(rec_len); - /* first data packet timestamp is a word */ - if (pcan_usb_decode_ts(mc, !mc->rec_data_idx)) + /* Only first packet timestamp is a word */ + if (pcan_usb_decode_ts(mc, !mc->rec_ts_idx)) goto decode_failed; + /* Next packet in the buffer will have a timestamp on a single byte */ + mc->rec_ts_idx++; + /* read data */ memset(cf->data, 0x0, sizeof(cf->data)); if (status_len & PCAN_USB_STATUSLEN_RTR) { @@ -688,7 +696,6 @@ static int pcan_usb_decode_msg(struct peak_usb_device *dev, u8 *ibuf, u32 lbuf) /* handle normal can frames here */ } else { err = pcan_usb_decode_data(&mc, sl); - mc.rec_data_idx++; } } -- 2.24.0.rc1