From 1e1ad0d312f8fc04773dafb3a7f264bcba85a2d6 Mon Sep 17 00:00:00 2001 From: Arthur Kiyanovski Date: Tue, 11 Feb 2020 15:17:51 +0000 Subject: [PATCH] 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: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)") Signed-off-by: Sameeh Jubran Signed-off-by: Arthur Kiyanovski Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/amazon/ena/ena_com.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c index e1f6943..9bd2a7a 100644 --- a/drivers/net/ethernet/amazon/ena/ena_com.c +++ b/drivers/net/ethernet/amazon/ena/ena_com.c @@ -199,6 +199,11 @@ 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); -- 2.7.4