diff options
| author | Willem de Bruijn <willemb@google.com> | 2017-08-10 12:41:58 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-10 09:52:12 -0700 |
| commit | c27927e372f0785f3303e8fad94b85945e2c97b7 (patch) | |
| tree | 3602b8aeb2cc349ba954d4ff17028d364e395c56 | |
| parent | 85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa (diff) | |
packet: fix tp_reserve race in packet_set_ring
Updates to tp_reserve can race with reads of the field in
packet_set_ring. Avoid this by holding the socket lock during
updates in setsockopt PACKET_RESERVE.
This bug was discovered by syzkaller.
Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/packet/af_packet.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 0615c2a950fa..008a45ca3112 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3700,14 +3700,19 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv if (optlen != sizeof(val)) return -EINVAL; - if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) - return -EBUSY; if (copy_from_user(&val, optval, sizeof(val))) return -EFAULT; if (val > INT_MAX) return -EINVAL; - po->tp_reserve = val; - return 0; + lock_sock(sk); + if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) { + ret = -EBUSY; + } else { + po->tp_reserve = val; + ret = 0; + } + release_sock(sk); + return ret; } case PACKET_LOSS: { |