From: Arthur Kiyanovski <akiyano@amazon.com>
Date: Tue, 11 Feb 2020 15:17:40 +0000
Subject: net: ena: fix potential crash when rxfh key is NULL
Patch-mainline: v5.6-rc2
Git-commit: 91a65b7d3ed8450f31ab717a65dcb5f9ceb5ab02
References: git-fixes

When ethtool -X is called without an hkey, ena_com_fill_hash_function()
is called with key=NULL, which is passed to memcpy causing a crash.

This commit fixes this issue by checking key is not NULL.

Fixes: 1738cd3ed342 ("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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/amazon/ena/ena_com.c |   17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -2301,15 +2301,16 @@ int ena_com_fill_hash_function(struct en
 
 	switch (func) {
 	case ENA_ADMIN_TOEPLITZ:
-		if (key_len > sizeof(hash_key->key)) {
-			pr_err("key len (%hu) is bigger than the max supported (%zu)\n",
-			       key_len, sizeof(hash_key->key));
-			return -EINVAL;
+		if (key) {
+			if (key_len != sizeof(hash_key->key)) {
+				pr_err("key len (%hu) doesn't equal the supported size (%zu)\n",
+				       key_len, sizeof(hash_key->key));
+				return -EINVAL;
+			}
+			memcpy(hash_key->key, key, key_len);
+			rss->hash_init_val = init_val;
+			hash_key->keys_num = key_len >> 2;
 		}
-
-		memcpy(hash_key->key, key, key_len);
-		rss->hash_init_val = init_val;
-		hash_key->keys_num = key_len >> 2;
 		break;
 	case ENA_ADMIN_CRC32:
 		rss->hash_init_val = init_val;