| Message ID | 45fab13fce077924f957cba84ba20ba4.squirrel@www.codeaurora.org |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, 2015-01-23 at 22:26 +0000, subashab@codeaurora.org wrote: > 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(). ... > Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> > Cc: Eric Dumazet <edumazet@google.com> > --- Thanks ! Signed-off-by: Eric Dumazet <edumazet@google.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: subashab@codeaurora.org Date: Fri, 23 Jan 2015 22:26:02 -0000 > 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> Applied and queued up for -stable, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index c0d82f7..2a3720f 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -966,8 +966,11 @@ bool ping_rcv(struct sk_buff *skb) sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id)); 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 true; }
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> --- net/ipv4/ping.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)