4.19-stable review patch. If anyone has any objections, please let me know.
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From: Aleksandr Mishin amishin@t-argos.ru
[ 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@t-argos.ru Reviewed-by: Simon Horman horms@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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 a1bda1683ebfc..d90500573f5b7 100644 --- a/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c +++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c @@ -289,13 +289,12 @@ 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));