diff options
| -rw-r--r-- | include/net/sock.h | 15 | ||||
| -rw-r--r-- | net/core/sock.c | 16 |
2 files changed, 28 insertions, 3 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 3f1a4804bb3f..cd0b34a4f2b9 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -253,6 +253,8 @@ struct sock { struct { struct sk_buff *head; struct sk_buff *tail; + int len; + int limit; } sk_backlog; wait_queue_head_t *sk_sleep; struct dst_entry *sk_dst_cache; @@ -574,7 +576,7 @@ static inline int sk_stream_memory_free(struct sock *sk) return sk->sk_wmem_queued < sk->sk_sndbuf; } -/* The per-socket spinlock must be held here. */ +/* OOB backlog add */ static inline void sk_add_backlog(struct sock *sk, struct sk_buff *skb) { if (!sk->sk_backlog.tail) { @@ -586,6 +588,17 @@ static inline void sk_add_backlog(struct sock *sk, struct sk_buff *skb) skb->next = NULL; } +/* The per-socket spinlock must be held here. */ +static inline int sk_add_backlog_limited(struct sock *sk, struct sk_buff *skb) +{ + if (sk->sk_backlog.len >= max(sk->sk_backlog.limit, sk->sk_rcvbuf << 1)) + return -ENOBUFS; + + sk_add_backlog(sk, skb); + sk->sk_backlog.len += skb->truesize; + return 0; +} + static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb) { return sk->sk_backlog_rcv(sk, skb); diff --git a/net/core/sock.c b/net/core/sock.c index e1f6f225f012..385d26210818 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -340,8 +340,12 @@ int sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested) rc = sk_backlog_rcv(sk, skb); mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_); - } else - sk_add_backlog(sk, skb); + } else if (sk_add_backlog_limited(sk, skb)) { + bh_unlock_sock(sk); + atomic_inc(&sk->sk_drops); + goto discard_and_relse; + } + bh_unlock_sock(sk); out: sock_put(sk); @@ -1138,6 +1142,7 @@ struct sock *sk_clone(const struct sock *sk, const gfp_t priority) sock_lock_init(newsk); bh_lock_sock(newsk); newsk->sk_backlog.head = newsk->sk_backlog.tail = NULL; + newsk->sk_backlog.len = 0; atomic_set(&newsk->sk_rmem_alloc, 0); /* @@ -1541,6 +1546,12 @@ static void __release_sock(struct sock *sk) bh_lock_sock(sk); } while ((skb = sk->sk_backlog.head) != NULL); + + /* + * Doing the zeroing here guarantee we can not loop forever + * while a wild producer attempts to flood us. + */ + sk->sk_backlog.len = 0; } /** @@ -1873,6 +1884,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) sk->sk_allocation = GFP_KERNEL; sk->sk_rcvbuf = sysctl_rmem_default; sk->sk_sndbuf = sysctl_wmem_default; + sk->sk_backlog.limit = sk->sk_rcvbuf << 1; sk->sk_state = TCP_CLOSE; sk_set_socket(sk, sock); |