From d44447229e35115675d166b51a52e512c281475c Mon Sep 17 00:00:00 2001 From: Ursula Braun Date: Thu, 7 Feb 2008 18:07:19 -0800 Subject: [AF_IUCV]: broken send_skb_q results in endless loop A race has been detected in iucv_callback_txdone(). skb_unlink has to be done inside the locked area. In addition checkings for successful allocations are inserted. Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- net/iucv/af_iucv.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'net/iucv/af_iucv.c') diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index 2255e3c082ed..b3f5f840d067 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -482,6 +482,10 @@ static int iucv_sock_connect(struct socket *sock, struct sockaddr *addr, /* Create path. */ iucv->path = iucv_path_alloc(IUCV_QUEUELEN_DEFAULT, IPRMDATA, GFP_KERNEL); + if (!iucv->path) { + err = -ENOMEM; + goto done; + } err = iucv_path_connect(iucv->path, &af_iucv_handler, sa->siucv_user_id, NULL, user_data, sk); if (err) { @@ -1094,6 +1098,8 @@ static void iucv_callback_rx(struct iucv_path *path, struct iucv_message *msg) save_message: save_msg = kzalloc(sizeof(struct sock_msg_q), GFP_ATOMIC | GFP_DMA); + if (!save_msg) + return; save_msg->path = path; save_msg->msg = *msg; @@ -1118,10 +1124,10 @@ static void iucv_callback_txdone(struct iucv_path *path, this = list_skb; list_skb = list_skb->next; } while (memcmp(&msg->tag, this->cb, 4) && list_skb); + __skb_unlink(this, list); spin_unlock_irqrestore(&list->lock, flags); - skb_unlink(this, &iucv_sk(sk)->send_skb_q); kfree_skb(this); } -- cgit v1.2.3 From f2a77991a918218be4a3ac78250e7eba2282be59 Mon Sep 17 00:00:00 2001 From: Ursula Braun Date: Thu, 7 Feb 2008 18:07:44 -0800 Subject: [AF_IUCV]: defensive programming of iucv_callback_txdone The loop in iucv_callback_txdone presumes existence of an entry with msg->tag in the send_skb_q list. In error cases this assumption might be wrong and might cause an endless loop. Loop is rewritten to guarantee loop end in case of missing msg->tag entry in send_skb_q. Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- net/iucv/af_iucv.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'net/iucv/af_iucv.c') diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index b3f5f840d067..fee22caf1bad 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -1112,24 +1112,31 @@ static void iucv_callback_txdone(struct iucv_path *path, struct iucv_message *msg) { struct sock *sk = path->private; - struct sk_buff *this; + struct sk_buff *this = NULL; struct sk_buff_head *list = &iucv_sk(sk)->send_skb_q; struct sk_buff *list_skb = list->next; unsigned long flags; - if (list_skb) { + if (!skb_queue_empty(list)) { spin_lock_irqsave(&list->lock, flags); - do { - this = list_skb; + while (list_skb != (struct sk_buff *)list) { + if (!memcmp(&msg->tag, list_skb->cb, 4)) { + this = list_skb; + break; + } list_skb = list_skb->next; - } while (memcmp(&msg->tag, this->cb, 4) && list_skb); - __skb_unlink(this, list); + } + if (this) + __skb_unlink(this, list); spin_unlock_irqrestore(&list->lock, flags); - kfree_skb(this); + if (this) + kfree_skb(this); } + if (!this) + printk(KERN_ERR "AF_IUCV msg tag %u not found\n", msg->tag); if (sk->sk_state == IUCV_CLOSING) { if (skb_queue_empty(&iucv_sk(sk)->send_skb_q)) { -- cgit v1.2.3