tcp: fix SCM_TIMESTAMPING_OPT_STATS for normal skbs
__sock_recv_timestamp can be called for both normal skbs (for
receive timestamps) and for skbs on the error queue (for transmit
timestamps).
Commit 1c885808e456
(tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING)
assumes any skb passed to __sock_recv_timestamp are from
the error queue, containing OPT_STATS in the content of the skb.
This results in accessing invalid memory or generating junk
data.
To fix this, set skb->pkt_type to PACKET_OUTGOING for packets
on the error queue. This is safe because on the receive path
on local sockets skb->pkt_type is never set to PACKET_OUTGOING.
With that, copy OPT_STATS from a packet, only if its pkt_type
is PACKET_OUTGOING.
Fixes: 1c885808e456 ("tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING")
Reported-by: JongHwan Kim <zzoru007@gmail.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index cd4ba8c..b1fbd19 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3694,6 +3694,15 @@
atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
}
+static void skb_set_err_queue(struct sk_buff *skb)
+{
+ /* pkt_type of skbs received on local sockets is never PACKET_OUTGOING.
+ * So, it is safe to (mis)use it to mark skbs on the error queue.
+ */
+ skb->pkt_type = PACKET_OUTGOING;
+ BUILD_BUG_ON(PACKET_OUTGOING == 0);
+}
+
/*
* Note: We dont mem charge error packets (no sk_forward_alloc changes)
*/
@@ -3707,6 +3716,7 @@
skb->sk = sk;
skb->destructor = sock_rmem_free;
atomic_add(skb->truesize, &sk->sk_rmem_alloc);
+ skb_set_err_queue(skb);
/* before exiting rcu section, make sure dst is refcounted */
skb_dst_force(skb);