From 1db62c04b83338ba2cf2fc010bedf3087d816f9b Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Wed, 15 Dec 2021 09:39:37 -0500 Subject: [PATCH] net/packet: rx_owner_map depends on pg_vec Packet sockets may switch ring versions. Avoid misinterpreting state between versions, whose fields share a union. rx_owner_map is only allocated with a packet ring (pg_vec) and both are swapped together. If pg_vec is NULL, meaning no packet ring was allocated, then neither was rx_owner_map. And the field may be old state from a tpacket_v3. Fixes: 6b1d969bc861 ("net/packet: tpacket_rcv: avoid a producer race condition") Reported-by: Syzbot Signed-off-by: Willem de Bruijn Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20211215143937.106178-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski --- net/packet/af_packet.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 46943a18a10d5..76c2dca7f0a59 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -4492,9 +4492,10 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u, } out_free_pg_vec: - bitmap_free(rx_owner_map); - if (pg_vec) + if (pg_vec) { + bitmap_free(rx_owner_map); free_pg_vec(pg_vec, order, req->tp_block_nr); + } out: return err; } -- 2.39.5