diff options
| author | Stephane Grosjean | 2019-10-08 10:35:44 +0200 |
|---|---|---|
| committer | Marc Kleine-Budde | 2019-11-04 21:47:20 +0100 |
| commit | de280f403f2996679e2607384980703710576fed (patch) | |
| tree | bae51f20f837c6e9f37ffd8ba6082aab286fd139 | |
| parent | 5e269324db5adb2f5f6ec9a93a9c7b0672932b47 (diff) | |
can: peak_usb: fix a potential out-of-sync while decoding packets
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 <s.grosjean@peak-system.com>
Fixes: 46be265d3388 ("can: usb: PEAK-System Technik PCAN-USB specific part")
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
| -rw-r--r-- | drivers/net/can/usb/peak_usb/pcan_usb.c | 17 |
1 files 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++; } } |