inet: Don't go into port scan when looking for specific bind port

inet_csk_get_port is called with port number (snum argument) that may be
zero or nonzero. If it is zero, then the intent is to find an available
ephemeral port number to bind to. If snum is non-zero then the caller
is asking to allocate a specific port number. In the latter case we
never want to perform the scan in ephemeral port range. It is
conceivable that this can happen if the "goto again" in "tb_found:"
is done. This patch adds a check that snum is zero before doing
the "goto again".

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index d5d3ead0a6c31e42e8843d30f8c643324a91b8e9..f59838a60ea593849d76758e60033d1339732f4d 100644 (file)
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -212,7 +212,7 @@ tb_found:
                              sk->sk_reuseport &&
                              !rcu_access_pointer(sk->sk_reuseport_cb) &&
                              uid_eq(tb->fastuid, uid))) &&
-                           smallest_size != -1 && --attempts >= 0) {
+                           !snum && smallest_size != -1 && --attempts >= 0) {
                                spin_unlock_bh(&head->lock);
                                goto again;
                        }