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authorWillem de Bruijn <willemb@google.com>2017-08-10 12:41:58 -0400
committerBen Hutchings <ben@decadent.org.uk>2017-08-26 02:14:06 +0100
commit8f716035da0ad35d5a65668eb3c10aad6c439d7b (patch)
tree94be4741a38a53a6b340f3a9194fcc36c3f71d40
parent3557f62ec91e10cb2ac8e5f312bec0977d67803f (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.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index e961773a4138..57b5add0c978 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3132,14 +3132,19 @@ 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:
{