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authorAlexey Kuznetsov <kuznet@ms2.inr.ac.ru>2006-07-25 16:45:12 -0700
committerDavid S. Miller <davem@davemloft.net>2006-07-25 16:45:12 -0700
commit722874909271a807b243a797c2958e0a12992964 (patch)
tree341d9c20eacdf8f452d8e2eea61fe2d40923179d
parentb6e77a5346d8a739227ed73c2269966a4fd652b4 (diff)
[IPV4] ipmr: ip multicast route bug fix.
IP multicast route code was reusing an skb which causes use after free and double free. From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Note, it is real skb_clone(), not alloc_skb(). Equeued skb contains the whole half-prepared netlink message plus room for the rest. It could be also skb_copy(), if we want to be puristic about mangling cloned data, but original copy is really not going to be used. Acked-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/ipmr.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 9ccacf57f08..85893eef6b1 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1578,6 +1578,7 @@ int ipmr_get_route(struct sk_buff *skb, struct rtmsg *rtm, int nowait)
cache = ipmr_cache_find(rt->rt_src, rt->rt_dst);
if (cache==NULL) {
+ struct sk_buff *skb2;
struct net_device *dev;
int vif;
@@ -1591,12 +1592,18 @@ int ipmr_get_route(struct sk_buff *skb, struct rtmsg *rtm, int nowait)
read_unlock(&mrt_lock);
return -ENODEV;
}
- skb->nh.raw = skb_push(skb, sizeof(struct iphdr));
- skb->nh.iph->ihl = sizeof(struct iphdr)>>2;
- skb->nh.iph->saddr = rt->rt_src;
- skb->nh.iph->daddr = rt->rt_dst;
- skb->nh.iph->version = 0;
- err = ipmr_cache_unresolved(vif, skb);
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (!skb2) {
+ read_unlock(&mrt_lock);
+ return -ENOMEM;
+ }
+
+ skb2->nh.raw = skb_push(skb2, sizeof(struct iphdr));
+ skb2->nh.iph->ihl = sizeof(struct iphdr)>>2;
+ skb2->nh.iph->saddr = rt->rt_src;
+ skb2->nh.iph->daddr = rt->rt_dst;
+ skb2->nh.iph->version = 0;
+ err = ipmr_cache_unresolved(vif, skb2);
read_unlock(&mrt_lock);
return err;
}