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authorJulius Volz <juliusv@google.com>2008-07-08 14:02:19 +0200
committerJohn W. Linville <linville@tuxdriver.com>2008-07-08 14:16:08 -0400
commitb46372710ab536c0967f76be5dc41341583d4a54 (patch)
tree6cbf00e9246943306d9185267e783684a68dc27d
parent0e25b4ef220f6ef4eed120543182385b13005db9 (diff)
net/wireless/nl80211.c: fix endless Netlink callback loop.master-2008-07-08
Although I only tested similar code (I don't use any of this wireless code), the state maintainance between Netlink dump callback invocations seems wrong here and should lead to an endless loop. There are also other examples in the same file which might have the same problem. Perhaps someone can actually test this (or refute my logic). Take the simple example with only one element in the list (which should fit into the message): 1. invocation: Start: idx = 0, start = 0 Loop: condition (++idx < start) => (1 < 0) => false => no continue, fill one entry, exit loop, return skb->len > 0 2. invocation: Start: idx = 0, start = 1 Loop: condition (++idx < start) => (1 < 1) => false => no continue, fill the same entry again, exit loop, return skb->len > 0 3. invocation: Same as 2. invocation, endless invocation of callback. Also, iterations where the filling of an element fails should not be counted as completed, so idx should not be incremented in this case. Signed-off-by: Julius Volz <juliusv@google.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r--net/wireless/nl80211.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index fb75f265b39..b7fefffd2d0 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -199,12 +199,14 @@ static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)
mutex_lock(&cfg80211_drv_mutex);
list_for_each_entry(dev, &cfg80211_drv_list, list) {
- if (++idx < start)
+ if (++idx <= start)
continue;
if (nl80211_send_wiphy(skb, NETLINK_CB(cb->skb).pid,
cb->nlh->nlmsg_seq, NLM_F_MULTI,
- dev) < 0)
+ dev) < 0) {
+ idx--;
break;
+ }
}
mutex_unlock(&cfg80211_drv_mutex);