diff options
| author | Soheil Hassas Yeganeh <soheil@google.com> | 2017-03-18 17:02:59 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-03 08:37:41 -0700 |
| commit | cdaf15b43bd31003220cb080bcbbd57787a2fca9 (patch) | |
| tree | c467a2437363f39f097fee15126dc4daa4a7858a | |
| parent | df4c4820a0b0a688b20ffca574eae6fb68f3c477 (diff) | |
tcp: fix SCM_TIMESTAMPING_OPT_STATS for normal skbs
[ Upstream commit 8605330aac5a5785630aec8f64378a54891937cc ]
__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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/core/skbuff.c | 10 | ||||
| -rw-r--r-- | net/socket.c | 13 |
2 files changed, 22 insertions, 1 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index c3cb99ce1611..e4b6d540fa08 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3700,6 +3700,15 @@ 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) */ @@ -3713,6 +3722,7 @@ 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); diff --git a/net/socket.c b/net/socket.c index 02bd9249e295..bfdb35898e4c 100644 --- a/net/socket.c +++ b/net/socket.c @@ -654,6 +654,16 @@ 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) */ @@ -697,7 +707,8 @@ 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); } |