From 38a01c9700b0dcafe97dfa9dc7531bf4a245deff Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Mon, 23 Feb 2026 17:51:17 +0100 Subject: can: ems_usb: ems_usb_read_bulk_callback(): check the proper length of a message When looking at the data in a USB urb, the actual_length is the size of the buffer passed to the driver, not the transfer_buffer_length which is set by the driver as the max size of the buffer. When parsing the messages in ems_usb_read_bulk_callback() properly check the size both at the beginning of parsing the message to make sure it is big enough for the expected structure, and at the end of the message to make sure we don't overflow past the end of the buffer for the next message. Cc: Vincent Mailhol Cc: Marc Kleine-Budde Cc: stable@kernel.org Assisted-by: gkh_clanker_2000 Signed-off-by: Greg Kroah-Hartman Link: https://patch.msgid.link/2026022316-answering-strainer-a5db@gregkh Fixes: 702171adeed3 ("ems_usb: Added support for EMS CPC-USB/ARM7 CAN/USB interface") Signed-off-by: Marc Kleine-Budde --- drivers/net/can/usb/ems_usb.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c index 4c219a5b139b..9b25dda7c183 100644 --- a/drivers/net/can/usb/ems_usb.c +++ b/drivers/net/can/usb/ems_usb.c @@ -445,6 +445,11 @@ static void ems_usb_read_bulk_callback(struct urb *urb) start = CPC_HEADER_SIZE; while (msg_count) { + if (start + CPC_MSG_HEADER_LEN > urb->actual_length) { + netdev_err(netdev, "format error\n"); + break; + } + msg = (struct ems_cpc_msg *)&ibuf[start]; switch (msg->type) { @@ -474,7 +479,7 @@ static void ems_usb_read_bulk_callback(struct urb *urb) start += CPC_MSG_HEADER_LEN + msg->length; msg_count--; - if (start > urb->transfer_buffer_length) { + if (start > urb->actual_length) { netdev_err(netdev, "format error\n"); break; } -- cgit v1.2.3