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authorBenjamin Poirier <bpoirier@suse.de>2013-04-29 11:42:14 +0000
committerDavid S. Miller <davem@davemloft.net>2013-04-30 00:43:54 -0400
commit79f632c71bea0d0864d84d6a4ce78da5a9430f5b (patch)
tree4a2aecd119c9c54944182ba665ad8279232e40ab /net/unix
parent39cc86130bc045d87f525ce7742da308ff757cec (diff)
unix/stream: fix peeking with an offset larger than data in queue
Currently, peeking on a unix stream socket with an offset larger than len of the data in the sk receive queue returns immediately with bogus data. This patch fixes this so that the behavior is the same as peeking with no offset on an empty queue: the caller blocks. Signed-off-by: Benjamin Poirier <bpoirier@suse.de> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/unix')
-rw-r--r--net/unix/af_unix.c25
1 files changed, 12 insertions, 13 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 2db702d82e7d..1a02af0e3049 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1859,10 +1859,10 @@ out:
}
/*
- * Sleep until data has arrive. But check for races..
+ * Sleep until more data has arrived. But check for races..
*/
-
-static long unix_stream_data_wait(struct sock *sk, long timeo)
+static long unix_stream_data_wait(struct sock *sk, long timeo,
+ struct sk_buff *last)
{
DEFINE_WAIT(wait);
@@ -1871,7 +1871,7 @@ static long unix_stream_data_wait(struct sock *sk, long timeo)
for (;;) {
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
- if (!skb_queue_empty(&sk->sk_receive_queue) ||
+ if (skb_peek_tail(&sk->sk_receive_queue) != last ||
sk->sk_err ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
signal_pending(current) ||
@@ -1890,8 +1890,6 @@ static long unix_stream_data_wait(struct sock *sk, long timeo)
return timeo;
}
-
-
static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *msg, size_t size,
int flags)
@@ -1936,14 +1934,12 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
goto out;
}
- skip = sk_peek_offset(sk, flags);
-
do {
int chunk;
- struct sk_buff *skb;
+ struct sk_buff *skb, *last;
unix_state_lock(sk);
- skb = skb_peek(&sk->sk_receive_queue);
+ last = skb = skb_peek(&sk->sk_receive_queue);
again:
if (skb == NULL) {
unix_sk(sk)->recursion_level = 0;
@@ -1966,7 +1962,7 @@ again:
break;
mutex_unlock(&u->readlock);
- timeo = unix_stream_data_wait(sk, timeo);
+ timeo = unix_stream_data_wait(sk, timeo, last);
if (signal_pending(current)
|| mutex_lock_interruptible(&u->readlock)) {
@@ -1980,10 +1976,13 @@ again:
break;
}
- if (skip >= skb->len) {
+ skip = sk_peek_offset(sk, flags);
+ while (skip >= skb->len) {
skip -= skb->len;
+ last = skb;
skb = skb_peek_next(skb, &sk->sk_receive_queue);
- goto again;
+ if (!skb)
+ goto again;
}
unix_state_unlock(sk);

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