[PATCH net v2] liquidio: Fix potential null pointer dereference

From: Aleksandr Mishin
Date: Fri Mar 22 2024 - 16:16:07 EST


In lio_vf_rep_copy_packet() pg_info->page is compared to a NULL value,
but then it is unconditionally passed to skb_add_rx_frag() which could
lead to null pointer dereference.
Fix this bug by moving skb_add_rx_frag() into conditional scope.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 1f233f327913 ("liquidio: switchdev support for LiquidIO NIC")
Signed-off-by: Aleksandr Mishin <amishin@xxxxxxxxxx>
---
v2: Fix incorrect 'Fixes' tag format

drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c
index aa6c0dfb6f1c..e26b4ed33dc8 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c
@@ -272,13 +272,12 @@ lio_vf_rep_copy_packet(struct octeon_device *oct,
pg_info->page_offset;
memcpy(skb->data, va, MIN_SKB_SIZE);
skb_put(skb, MIN_SKB_SIZE);
+ skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
+ pg_info->page,
+ pg_info->page_offset + MIN_SKB_SIZE,
+ len - MIN_SKB_SIZE,
+ LIO_RXBUFFER_SZ);
}
-
- skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
- pg_info->page,
- pg_info->page_offset + MIN_SKB_SIZE,
- len - MIN_SKB_SIZE,
- LIO_RXBUFFER_SZ);
} else {
struct octeon_skb_page_info *pg_info =
((struct octeon_skb_page_info *)(skb->cb));
--
2.30.2