Commit ffbd6a62 authored Feb 11, 2020 by Arthur Kiyanovski Committed by Greg Kroah-Hartman Mar 05, 2020

net: ena: ena-com.c: prevent NULL pointer dereference



[ Upstream commit c207979f5ae10ed70aff1bb13f39f0736973de99 ]

comp_ctx can be NULL in a very rare case when an admin command is executed
during the execution of ena_remove().

The bug scenario is as follows:

* ena_destroy_device() sets the comp_ctx to be NULL
* An admin command is executed before executing unregister_netdev(),
  this can still happen because our device can still receive callbacks
  from the netdev infrastructure such as ethtool commands.
* When attempting to access the comp_ctx, the bug occurs since it's set
  to NULL

Fix:
Added a check that comp_ctx is not NULL

Fixes: 1738cd3e ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 2c3b6d7c

drivers/net/ethernet/amazon/ena/ena_com.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -201,6 +201,11 @@ static inline void comp_ctxt_release(struct ena_com_admin_queue *queue,
		static struct ena_comp_ctx get_comp_ctxt(struct ena_com_admin_queue queue,
		u16 command_id, bool capture)
		{
		if (unlikely(!queue->comp_ctx)) {
		pr_err("Completion context is NULL\n");
		return NULL;
		}

		if (unlikely(command_id >= queue->q_depth)) {
		pr_err("command id is larger than the queue size. cmd_id: %u queue size %d\n",
		command_id, queue->q_depth);