This is a note to let you know that I've just added the patch titled

can: peak: fix potential bug in packet fragmentation

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: can-peak-fix-potential-bug-in-packet-fragmentation.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From d8a243af1a68395e07ac85384a2740d4134c67f4 Mon Sep 17 00:00:00 2001

From: Stephane Grosjean s.grosjean@peak-system.com Date: Mon, 15 Jan 2018 16:31:19 +0100 Subject: can: peak: fix potential bug in packet fragmentation

From: Stephane Grosjean s.grosjean@peak-system.com

commit d8a243af1a68395e07ac85384a2740d4134c67f4 upstream.

In some rare conditions when running one PEAK USB-FD interface over a non high-speed USB controller, one useless USB fragment might be sent. This patch fixes the way a USB command is fragmented when its length is greater than 64 bytes and when the underlying USB controller is not a high-speed one.

Signed-off-by: Stephane Grosjean s.grosjean@peak-system.com Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/net/can/usb/peak_usb/pcan_usb_fd.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-)

--- a/drivers/net/can/usb/peak_usb/pcan_usb_fd.c +++ b/drivers/net/can/usb/peak_usb/pcan_usb_fd.c @@ -184,7 +184,7 @@ static int pcan_usb_fd_send_cmd(struct p void *cmd_head = pcan_usb_fd_cmd_buffer(dev); int err = 0; u8 *packet_ptr; - int i, n = 1, packet_len; + int packet_len; ptrdiff_t cmd_len;

/* usb device unregistered? */ @@ -201,17 +201,13 @@ static int pcan_usb_fd_send_cmd(struct p }

packet_ptr = cmd_head; + packet_len = cmd_len;

/* firmware is not able to re-assemble 512 bytes buffer in full-speed */ - if ((dev->udev->speed != USB_SPEED_HIGH) && - (cmd_len > PCAN_UFD_LOSPD_PKT_SIZE)) { - packet_len = PCAN_UFD_LOSPD_PKT_SIZE; - n += cmd_len / packet_len; - } else { - packet_len = cmd_len; - } + if (unlikely(dev->udev->speed != USB_SPEED_HIGH)) + packet_len = min(packet_len, PCAN_UFD_LOSPD_PKT_SIZE);

- for (i = 0; i < n; i++) { + do { err = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, PCAN_USBPRO_EP_CMDOUT), @@ -224,7 +220,12 @@ static int pcan_usb_fd_send_cmd(struct p }

packet_ptr += packet_len; - } + cmd_len -= packet_len; + + if (cmd_len < PCAN_UFD_LOSPD_PKT_SIZE) + packet_len = cmd_len; + + } while (packet_len > 0);

return err; }

Patches currently in stable-queue which might be from s.grosjean@peak-system.com are

queue-4.4/can-peak-fix-potential-bug-in-packet-fragmentation.patch