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| author | Soheil Hassas Yeganeh <soheil@google.com> | 2017-03-18 17:02:59 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-03-21 18:44:17 -0700 |
| commit | 8605330aac5a5785630aec8f64378a54891937cc (patch) | |
| tree | e8f9013a8686b4027210b60d747c55d4229c4e5a /net/socket.c | |
| parent | 23bb09cfbe04076ef647da3889a5a5ab6cbe6f15 (diff) | |
| download | lwn-8605330aac5a5785630aec8f64378a54891937cc.tar.gz lwn-8605330aac5a5785630aec8f64378a54891937cc.zip | |
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/socket.c')
| -rw-r--r-- | net/socket.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/net/socket.c b/net/socket.c index e034fe4164be..692d6989d2c2 100644 --- a/net/socket.c +++ b/net/socket.c @@ -652,6 +652,16 @@ int kernel_sendmsg(struct socket *sock, struct msghdr *msg, } EXPORT_SYMBOL(kernel_sendmsg); +static bool skb_is_err_queue(const struct sk_buff *skb) +{ + /* pkt_type of skbs enqueued on the error queue are set to + * PACKET_OUTGOING in skb_set_err_queue(). This is only safe to do + * in recvmsg, since skbs received on a local socket will never + * have a pkt_type of PACKET_OUTGOING. + */ + return skb->pkt_type == PACKET_OUTGOING; +} + /* * called from sock_recv_timestamp() if sock_flag(sk, SOCK_RCVTSTAMP) */ @@ -695,7 +705,8 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk, put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING, sizeof(tss), &tss); - if (skb->len && (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS)) + if (skb_is_err_queue(skb) && skb->len && + (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS)) put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_OPT_STATS, skb->len, skb->data); } |