soreuseport: fix NULL ptr dereference SO_REUSEPORT after bind
Marc Dionne discovered a NULL pointer dereference when setting
SO_REUSEPORT on a socket after it is bound.
This patch removes the assumption that at least one socket in the
reuseport group is bound with the SO_REUSEPORT option before other
bind calls occur.
Fixes: e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection")
Reported-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: Craig Gallek <kraig@google.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock_reuseport.h b/include/net/sock_reuseport.h
index 7dda3d7..aecd303 100644
--- a/include/net/sock_reuseport.h
+++ b/include/net/sock_reuseport.h
@@ -16,7 +16,7 @@
};
extern int reuseport_alloc(struct sock *sk);
-extern int reuseport_add_sock(struct sock *sk, const struct sock *sk2);
+extern int reuseport_add_sock(struct sock *sk, struct sock *sk2);
extern void reuseport_detach_sock(struct sock *sk);
extern struct sock *reuseport_select_sock(struct sock *sk,
u32 hash,
diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c
index 1df98c5..e92b759 100644
--- a/net/core/sock_reuseport.c
+++ b/net/core/sock_reuseport.c
@@ -93,10 +93,17 @@
* @sk2: Socket belonging to the existing reuseport group.
* May return ENOMEM and not add socket to group under memory pressure.
*/
-int reuseport_add_sock(struct sock *sk, const struct sock *sk2)
+int reuseport_add_sock(struct sock *sk, struct sock *sk2)
{
struct sock_reuseport *reuse;
+ if (!rcu_access_pointer(sk2->sk_reuseport_cb)) {
+ int err = reuseport_alloc(sk2);
+
+ if (err)
+ return err;
+ }
+
spin_lock_bh(&reuseport_lock);
reuse = rcu_dereference_protected(sk2->sk_reuseport_cb,
lockdep_is_held(&reuseport_lock)),