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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2026-02-23 17:51:17 +0100
committerMarc Kleine-Budde <mkl@pengutronix.de>2026-03-02 11:03:42 +0100
commit38a01c9700b0dcafe97dfa9dc7531bf4a245deff (patch)
tree00391d662f5ec0f9e3915a0f0863a43140f351f6
parent968b098220e393a10488b6a5dddb302b2eaedf66 (diff)
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 <mailhol@kernel.org> Cc: Marc Kleine-Budde <mkl@pengutronix.de> Cc: stable@kernel.org Assisted-by: gkh_clanker_2000 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 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 <mkl@pengutronix.de>
-rw-r--r--drivers/net/can/usb/ems_usb.c7
1 files changed, 6 insertions, 1 deletions
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;
}