From 8605330aac5a5785630aec8f64378a54891937cc Mon Sep 17 00:00:00 2001 From: Soheil Hassas Yeganeh <soheil@google.com> Date: Sat, 18 Mar 2017 17:02:59 -0400 Subject: 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> --- net/core/skbuff.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'net/core/skbuff.c') 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); -- cgit v1.2.3 From 4ef1b2869447411ad3ef91ad7d4891a83c1a509a Mon Sep 17 00:00:00 2001 From: Soheil Hassas Yeganeh <soheil@google.com> Date: Sat, 18 Mar 2017 17:03:00 -0400 Subject: tcp: mark skbs with SCM_TIMESTAMPING_OPT_STATS SOF_TIMESTAMPING_OPT_STATS can be enabled and disabled while packets are collected on the error queue. So, checking SOF_TIMESTAMPING_OPT_STATS in sk->sk_tsflags is not enough to safely assume that the skb contains OPT_STATS data. Add a bit in sock_exterr_skb to indicate whether the skb contains opt_stats data. 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> --- include/linux/errqueue.h | 2 ++ net/core/skbuff.c | 17 +++++++++++------ net/socket.c | 2 +- 3 files changed, 14 insertions(+), 7 deletions(-) (limited to 'net/core/skbuff.c') diff --git a/include/linux/errqueue.h b/include/linux/errqueue.h index 9ca23fcfb5d7..6fdfc884fdeb 100644 --- a/include/linux/errqueue.h +++ b/include/linux/errqueue.h @@ -20,6 +20,8 @@ struct sock_exterr_skb { struct sock_extended_err ee; u16 addr_offset; __be16 port; + u8 opt_stats:1, + unused:7; }; #endif diff --git a/net/core/skbuff.c b/net/core/skbuff.c index b1fbd1958eb6..9f781092fda9 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3793,16 +3793,20 @@ EXPORT_SYMBOL(skb_clone_sk); static void __skb_complete_tx_timestamp(struct sk_buff *skb, struct sock *sk, - int tstype) + int tstype, + bool opt_stats) { struct sock_exterr_skb *serr; int err; + BUILD_BUG_ON(sizeof(struct sock_exterr_skb) > sizeof(skb->cb)); + serr = SKB_EXT_ERR(skb); memset(serr, 0, sizeof(*serr)); serr->ee.ee_errno = ENOMSG; serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING; serr->ee.ee_info = tstype; + serr->opt_stats = opt_stats; if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) { serr->ee.ee_data = skb_shinfo(skb)->tskey; if (sk->sk_protocol == IPPROTO_TCP && @@ -3843,7 +3847,7 @@ void skb_complete_tx_timestamp(struct sk_buff *skb, */ if (likely(atomic_inc_not_zero(&sk->sk_refcnt))) { *skb_hwtstamps(skb) = *hwtstamps; - __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND); + __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false); sock_put(sk); } } @@ -3854,7 +3858,7 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb, struct sock *sk, int tstype) { struct sk_buff *skb; - bool tsonly; + bool tsonly, opt_stats = false; if (!sk) return; @@ -3867,9 +3871,10 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb, #ifdef CONFIG_INET if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) && sk->sk_protocol == IPPROTO_TCP && - sk->sk_type == SOCK_STREAM) + sk->sk_type == SOCK_STREAM) { skb = tcp_get_timestamping_opt_stats(sk); - else + opt_stats = true; + } else #endif skb = alloc_skb(0, GFP_ATOMIC); } else { @@ -3888,7 +3893,7 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb, else skb->tstamp = ktime_get_real(); - __skb_complete_tx_timestamp(skb, sk, tstype); + __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats); } EXPORT_SYMBOL_GPL(__skb_tstamp_tx); diff --git a/net/socket.c b/net/socket.c index 692d6989d2c2..985ef06792d6 100644 --- a/net/socket.c +++ b/net/socket.c @@ -706,7 +706,7 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk, SCM_TIMESTAMPING, sizeof(tss), &tss); if (skb_is_err_queue(skb) && skb->len && - (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS)) + SKB_EXT_ERR(skb)->opt_stats) put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_OPT_STATS, skb->len, skb->data); } -- cgit v1.2.3