[PATCH 4.19 114/168] s390/qeth: dont process empty bridge port events

Greg Kroah-Hartman
2020-08-17T17:43:37Z

From: Julian Wiedmann <jwi@linux.ibm.com>

[ Upstream commit 02472e28b9a45471c6d8729ff2c7422baa9be46a ]

Discard events that don't contain any entries. This shouldn't happen,
but subsequent code relies on being able to use entry 0. So better
be safe than accessing garbage.

Fixes: b4d72c08b358 ("qeth: bridgeport support - basic control")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/net/qeth_l2_main.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index eb917e93fa72f..8d30f9ac3e9d5 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -1463,6 +1463,10 @@ static void qeth_bridge_state_change(struct qeth_card *card,
int extrasize;

QETH_CARD_TEXT(card, 2, "brstchng");
+ if (qports->num_entries == 0) {
+ QETH_CARD_TEXT(card, 2, "BPempty");
+ return;
+ }
if (qports->entry_length != sizeof(struct qeth_sbp_port_entry)) {
QETH_CARD_TEXT_(card, 2, "BPsz%04x", qports->entry_length);
return;
--
2.25.1