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net/packet: rx_owner_map depends on pg_vec

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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: 61fad6816f ("net/packet: tpacket_rcv: avoid a producer race condition")
Reported-by: Syzbot <syzbot+1ac0994a0a0c55151121@syzkaller.appspotmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20211215143937.106178-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Willem de Bruijn 2021-12-15 09:39:37 -05:00 committed by Jakub Kicinski
parent 481221775d
commit ec6af094ea
1 changed files with 3 additions and 2 deletions
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5
net/packet/af_packet.c
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@ -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;
}