[PATCH 5.3 076/193] can: rx-offload: can_rx_offload_queue_sorted(): fix error handling, avoid skb mem leak

From: Greg Kroah-Hartman
Date: Mon Nov 11 2019 - 13:51:30 EST


From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>

commit ca913f1ac024559ebc17f0b599af262f0ad997c9 upstream.

If the rx-offload skb_queue is full can_rx_offload_queue_sorted() will
not queue the skb and return with an error.

None of the callers of this function, issue a kfree_skb() to free the
not queued skb. This results in a memory leak.

This patch fixes the problem by freeing the skb in case of a full queue.
The return value is adjusted to -ENOBUFS to better reflect the actual
problem.

The device stats handling is left to the callers, as this function might
be used in both the rx and tx path.

Fixes: 55059f2b7f86 ("can: rx-offload: introduce can_rx_offload_get_echo_skb() and can_rx_offload_queue_sorted() functions")
Cc: linux-stable <stable@xxxxxxxxxxxxxxx>
Cc: Martin HundebÃll <martin@xxxxxxxxxx>
Reported-by: Martin HundebÃll <martin@xxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/net/can/rx-offload.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/can/rx-offload.c
+++ b/drivers/net/can/rx-offload.c
@@ -207,8 +207,10 @@ int can_rx_offload_queue_sorted(struct c
unsigned long flags;

if (skb_queue_len(&offload->skb_queue) >
- offload->skb_queue_len_max)
- return -ENOMEM;
+ offload->skb_queue_len_max) {
+ kfree_skb(skb);
+ return -ENOBUFS;
+ }

cb = can_rx_offload_get_cb(skb);
cb->timestamp = timestamp;