[PATCH][next] sfc: fix dereference of table before it is null checked

From: Colin King
Date: Tue May 12 2020 - 13:14:01 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

Currently pointer table is being dereferenced on a null check of
table->must_restore_filters before it is being null checked, leading
to a potential null pointer dereference issue. Fix this by null
checking table before dereferencing it when checking for a null
table->must_restore_filters.

Addresses-Coverity: ("Dereference before null check")
Fixes: e4fe938cff04 ("sfc: move 'must restore' flags out of ef10-specific nic_data")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/net/ethernet/sfc/mcdi_filters.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/sfc/mcdi_filters.c b/drivers/net/ethernet/sfc/mcdi_filters.c
index 88de95a8c08c..455a62814fb9 100644
--- a/drivers/net/ethernet/sfc/mcdi_filters.c
+++ b/drivers/net/ethernet/sfc/mcdi_filters.c
@@ -1369,10 +1369,7 @@ void efx_mcdi_filter_table_restore(struct efx_nic *efx)

WARN_ON(!rwsem_is_locked(&efx->filter_sem));

- if (!table->must_restore_filters)
- return;
-
- if (!table)
+ if (!table || !table->must_restore_filters)
return;

down_write(&table->lock);
--
2.25.1