diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2009-10-09 04:43:40 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-10-13 03:16:54 -0700 |
| commit | 85584672012ee0c3b7b8e033a1ecf7c11878e45f (patch) | |
| tree | f35b38f084453e2d7260d4a7a8d13f2a01641664 /net | |
| parent | 9652041da18a1a1d9a0b7ebd9eef16bd712be38a (diff) | |
udp: Fix udp_poll() and ioctl()
udp_poll() can in some circumstances drop frames with incorrect checksums.
Problem is we now have to lock the socket while dropping frames, or risk
sk_forward corruption.
This bug is present since commit 95766fff6b9a78d1
([UDP]: Add memory accounting.)
While we are at it, we can correct ioctl(SIOCINQ) to also drop bad frames.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/udp.c | 73 |
1 files changed, 43 insertions, 30 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 6ec6a8a4a224..d0d436d6216c 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -841,6 +841,42 @@ out: return ret; } + +/** + * first_packet_length - return length of first packet in receive queue + * @sk: socket + * + * Drops all bad checksum frames, until a valid one is found. + * Returns the length of found skb, or 0 if none is found. + */ +static unsigned int first_packet_length(struct sock *sk) +{ + struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue; + struct sk_buff *skb; + unsigned int res; + + __skb_queue_head_init(&list_kill); + + spin_lock_bh(&rcvq->lock); + while ((skb = skb_peek(rcvq)) != NULL && + udp_lib_checksum_complete(skb)) { + UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, + IS_UDPLITE(sk)); + __skb_unlink(skb, rcvq); + __skb_queue_tail(&list_kill, skb); + } + res = skb ? skb->len : 0; + spin_unlock_bh(&rcvq->lock); + + if (!skb_queue_empty(&list_kill)) { + lock_sock(sk); + __skb_queue_purge(&list_kill); + sk_mem_reclaim_partial(sk); + release_sock(sk); + } + return res; +} + /* * IOCTL requests applicable to the UDP protocol */ @@ -857,21 +893,16 @@ int udp_ioctl(struct sock *sk, int cmd, unsigned long arg) case SIOCINQ: { - struct sk_buff *skb; - unsigned long amount; + unsigned int amount = first_packet_length(sk); - amount = 0; - spin_lock_bh(&sk->sk_receive_queue.lock); - skb = skb_peek(&sk->sk_receive_queue); - if (skb != NULL) { + if (amount) /* * We will only return the amount * of this packet since that is all * that will be read. */ - amount = skb->len - sizeof(struct udphdr); - } - spin_unlock_bh(&sk->sk_receive_queue.lock); + amount -= sizeof(struct udphdr); + return put_user(amount, (int __user *)arg); } @@ -1540,29 +1571,11 @@ unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait) { unsigned int mask = datagram_poll(file, sock, wait); struct sock *sk = sock->sk; - int is_lite = IS_UDPLITE(sk); /* Check for false positives due to checksum errors */ - if ((mask & POLLRDNORM) && - !(file->f_flags & O_NONBLOCK) && - !(sk->sk_shutdown & RCV_SHUTDOWN)) { - struct sk_buff_head *rcvq = &sk->sk_receive_queue; - struct sk_buff *skb; - - spin_lock_bh(&rcvq->lock); - while ((skb = skb_peek(rcvq)) != NULL && - udp_lib_checksum_complete(skb)) { - UDP_INC_STATS_BH(sock_net(sk), - UDP_MIB_INERRORS, is_lite); - __skb_unlink(skb, rcvq); - kfree_skb(skb); - } - spin_unlock_bh(&rcvq->lock); - - /* nothing to see, move along */ - if (skb == NULL) - mask &= ~(POLLIN | POLLRDNORM); - } + if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) && + !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk)) + mask &= ~(POLLIN | POLLRDNORM); return mask; |