diff options
| author | Willem de Bruijn <willemb@google.com> | 2017-08-10 12:41:58 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-08-26 02:14:49 +0100 |
| commit | ec26c86f4d9fe22ceb9b997aa9134f684b756282 (patch) | |
| tree | 9e5e50182c1e04b3cadb0efdd1d9fdd735e792c9 | |
| parent | b6ec053486fa50c169eb377e53c72b2a481fbd00 (diff) | |
packet: fix tp_reserve race in packet_set_ring
commit c27927e372f0785f3303e8fad94b85945e2c97b7 upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -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 5b4fb92144b0..d798c2fcd114 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3345,14 +3345,19 @@ 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: { |