6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Aleksandr Mishin <amishin@xxxxxxxxxx>
[ Upstream commit c44711b78608c98a3e6b49ce91678cd0917d5349 ]
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 looks
strange and could lead to null pointer dereference.
lio_vf_rep_copy_packet() call trace looks like:
octeon_droq_process_packets
octeon_droq_fast_process_packets
octeon_droq_dispatch_pkt
octeon_create_recv_info
...search in the dispatch_list...
->disp_fn(rdisp->rinfo, ...)
lio_vf_rep_pkt_recv(struct octeon_recv_info *recv_info, ...)
In this path there is no code which sets pg_info->page to NULL.
So this check looks unneeded and doesn't solve potential problem.
But I guess the author had reason to add a check and I have no such card
and can't do real test.
In addition, the code in the function liquidio_push_packet() in
liquidio/lio_core.c does exactly the same.
Based on this, I consider the most acceptable compromise solution to
adjust this issue 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>
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 600de587d7a98..e70b9ccca380e 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));
--
2.43.0
