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authorSoheil Hassas Yeganeh <soheil@google.com>2017-03-19 00:02:59 +0300
committerDavid S. Miller <davem@davemloft.net>2017-03-22 04:44:17 +0300
commit8605330aac5a5785630aec8f64378a54891937cc (patch)
treee8f9013a8686b4027210b60d747c55d4229c4e5a /net/core/skbuff.c
parent23bb09cfbe04076ef647da3889a5a5ab6cbe6f15 (diff)
downloadlinux-8605330aac5a5785630aec8f64378a54891937cc.tar.xz
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>
Diffstat (limited to 'net/core/skbuff.c')
-rw-r--r--net/core/skbuff.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index cd4ba8c6b609..b1fbd1958eb6 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3694,6 +3694,15 @@ static void sock_rmem_free(struct sk_buff *skb)
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 @@ int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
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);