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: e32ea7e747 ("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>
This commit is contained in:
Craig Gallek 2016-01-19 14:27:08 -05:00 committed by David S. Miller
parent 52a82e23b9
commit b4ace4f1ae
2 changed files with 9 additions and 2 deletions

View File

@ -16,7 +16,7 @@ struct sock_reuseport {
};
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,

View File

@ -93,10 +93,17 @@ static struct sock_reuseport *reuseport_grow(struct sock_reuseport *reuse)
* @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)),