inet: Fix get port to handle zero port number with soreuseport set

A user may call listen with binding an explicit port with the intent
that the kernel will assign an available port to the socket. In this
case inet_csk_get_port does a port scan. For such sockets, the user may
also set soreuseport with the intent a creating more sockets for the
port that is selected. The problem is that the initial socket being
opened could inadvertently choose an existing and unreleated port
number that was already created with soreuseport.

This patch adds a boolean parameter to inet_bind_conflict that indicates
rather soreuseport is allowed for the check (in addition to
sk->sk_reuseport). In calls to inet_bind_conflict from inet_csk_get_port
the argument is set to true if an explicit port is being looked up (snum
argument is nonzero), and is false if port scan is done.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert
2016-12-14 16:54:16 -08:00
committed by David S. Miller
parent 9af7e923fd
commit 0643ee4fd1
4 changed files with 19 additions and 11 deletions

View File

@@ -22,7 +22,8 @@ struct sock;
struct sockaddr;
int inet6_csk_bind_conflict(const struct sock *sk,
const struct inet_bind_bucket *tb, bool relax);
const struct inet_bind_bucket *tb, bool relax,
bool soreuseport_ok);
struct dst_entry *inet6_csk_route_req(const struct sock *sk, struct flowi6 *fl6,
const struct request_sock *req, u8 proto);