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authorUrsula Braun <braunu@de.ibm.com>2008-02-08 03:07:44 +0100
committerDavid S. Miller <davem@davemloft.net>2008-02-08 03:07:44 +0100
commitf2a77991a918218be4a3ac78250e7eba2282be59 (patch)
tree40bdf696b7d2e83a0335ce1357808b45b41184dc /net
parent[AF_IUCV]: broken send_skb_q results in endless loop (diff)
downloadlinux-f2a77991a918218be4a3ac78250e7eba2282be59.tar.xz
linux-f2a77991a918218be4a3ac78250e7eba2282be59.zip
[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 <braunu@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/iucv/af_iucv.c21
1 files changed, 14 insertions, 7 deletions
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)) {