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authorsubashab@codeaurora.org <subashab@codeaurora.org>2015-01-23 22:26:02 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-02-26 17:48:48 -0800
commit688ba993d1b7e3c84b1a87f39cd14b01b4716306 (patch)
tree7947da202697d41e888ae7b86477bc9fc3916313 /net
parentbd1f50c627afe99e374da23b76f0d0ee83244223 (diff)
downloadlinux-linaro-stable-688ba993d1b7e3c84b1a87f39cd14b01b4716306.tar.gz
ping: Fix race in free in receive path
[ Upstream commit fc752f1f43c1c038a2c6ae58cc739ebb5953ccb0 ] An exception is seen in ICMP ping receive path where the skb destructor sock_rfree() tries to access a freed socket. This happens because ping_rcv() releases socket reference with sock_put() and this internally frees up the socket. Later icmp_rcv() will try to free the skb and as part of this, skb destructor is called and which leads to a kernel panic as the socket is freed already in ping_rcv(). -->|exception -007|sk_mem_uncharge -007|sock_rfree -008|skb_release_head_state -009|skb_release_all -009|__kfree_skb -010|kfree_skb -011|icmp_rcv -012|ip_local_deliver_finish Fix this incorrect free by cloning this skb and processing this cloned skb instead. This patch was suggested by Eric Dumazet Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ping.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index aa857a4a06a8..698f3a2ac5ae 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -720,8 +720,11 @@ void ping_rcv(struct sk_buff *skb)
sk = ping_v4_lookup(net, saddr, daddr, ntohs(icmph->un.echo.id),
skb->dev->ifindex);
if (sk != NULL) {
+ struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
+
pr_debug("rcv on socket %p\n", sk);
- ping_queue_rcv_skb(sk, skb_get(skb));
+ if (skb2)
+ ping_queue_rcv_skb(sk, skb2);
sock_put(sk);
return;
}