1 files changed, 97 insertions, 73 deletions

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 4583e15ad03a..824c8dc4120b 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -33,6 +33,7 @@
 #include <linux/ppp_channel.h>
 #include <linux/ppp-comp.h>
 #include <linux/skbuff.h>
+#include <linux/rculist.h>
 #include <linux/rtnetlink.h>
 #include <linux/if_arp.h>
 #include <linux/ip.h>
@@ -45,6 +46,7 @@
 #include <linux/slab.h>
 #include <linux/file.h>
 #include <linux/unaligned.h>
+#include <net/netdev_lock.h>
 #include <net/slhc_vj.h>
 #include <linux/atomic.h>
 #include <linux/refcount.h>
@@ -72,6 +74,17 @@
 #define PPP_PROTO_LEN	2
 #define PPP_LCP_HDRLEN	4
 
+/* The filter instructions generated by libpcap are constructed
+ * assuming a four-byte PPP header on each packet, where the last
+ * 2 bytes are the protocol field defined in the RFC and the first
+ * byte of the first 2 bytes indicates the direction.
+ * The second byte is currently unused, but we still need to initialize
+ * it to prevent crafted BPF programs from reading them which would
+ * cause reading of uninitialized data.
+ */
+#define PPP_FILTER_OUTBOUND_TAG 0x0100
+#define PPP_FILTER_INBOUND_TAG  0x0000
+
 /*
  * An instance of /dev/ppp can be associated with either a ppp
  * interface unit or a ppp channel.  In both cases, file->private_data
@@ -95,16 +108,9 @@ struct ppp_file {
 #define PF_TO_PPP(pf)		PF_TO_X(pf, struct ppp)
 #define PF_TO_CHANNEL(pf)	PF_TO_X(pf, struct channel)
 
-/*
- * Data structure to hold primary network stats for which
- * we want to use 64 bit storage.  Other network stats
- * are stored in dev->stats of the ppp strucute.
- */
-struct ppp_link_stats {
-	u64 rx_packets;
-	u64 tx_packets;
-	u64 rx_bytes;
-	u64 tx_bytes;
+struct ppp_xmit_recursion {
+	struct task_struct *owner;
+	local_lock_t bh_lock;
 };
 
 /*
@@ -120,7 +126,7 @@ struct ppp {
 	int		n_channels;	/* how many channels are attached 54 */
 	spinlock_t	rlock;		/* lock for receive side 58 */
 	spinlock_t	wlock;		/* lock for transmit side 5c */
-	int __percpu	*xmit_recursion; /* xmit recursion detect */
+	struct ppp_xmit_recursion __percpu *xmit_recursion; /* xmit recursion detect */
 	int		mru;		/* max receive unit 60 */
 	unsigned int	flags;		/* control bits 64 */
 	unsigned int	xstate;		/* transmit state bits 68 */
@@ -150,7 +156,6 @@ struct ppp {
 	struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 #endif /* CONFIG_PPP_FILTER */
 	struct net	*ppp_net;	/* the net we belong to */
-	struct ppp_link_stats stats64;	/* 64 bit network stats */
 };
 
 /*
@@ -1119,6 +1124,8 @@ static const struct file_operations ppp_device_fops = {
 	.llseek		= noop_llseek,
 };
 
+static void ppp_nl_dellink(struct net_device *dev, struct list_head *head);
+
 static __net_init int ppp_init_net(struct net *net)
 {
 	struct ppp_net *pn = net_generic(net, ppp_net_id);
@@ -1134,28 +1141,20 @@ static __net_init int ppp_init_net(struct net *net)
 	return 0;
 }
 
-static __net_exit void ppp_exit_net(struct net *net)
+static __net_exit void ppp_exit_rtnl_net(struct net *net,
+					 struct list_head *dev_to_kill)
 {
 	struct ppp_net *pn = net_generic(net, ppp_net_id);
-	struct net_device *dev;
-	struct net_device *aux;
 	struct ppp *ppp;
-	LIST_HEAD(list);
 	int id;
 
-	rtnl_lock();
-	for_each_netdev_safe(net, dev, aux) {
-		if (dev->netdev_ops == &ppp_netdev_ops)
-			unregister_netdevice_queue(dev, &list);
-	}
-
 	idr_for_each_entry(&pn->units_idr, ppp, id)
-		/* Skip devices already unregistered by previous loop */
-		if (!net_eq(dev_net(ppp->dev), net))
-			unregister_netdevice_queue(ppp->dev, &list);
+		ppp_nl_dellink(ppp->dev, dev_to_kill);
+}
 
-	unregister_netdevice_many(&list);
-	rtnl_unlock();
+static __net_exit void ppp_exit_net(struct net *net)
+{
+	struct ppp_net *pn = net_generic(net, ppp_net_id);
 
 	mutex_destroy(&pn->all_ppp_mutex);
 	idr_destroy(&pn->units_idr);
@@ -1165,6 +1164,7 @@ static __net_exit void ppp_exit_net(struct net *net)
 
 static struct pernet_operations ppp_net_ops = {
 	.init = ppp_init_net,
+	.exit_rtnl = ppp_exit_rtnl_net,
 	.exit = ppp_exit_net,
 	.id   = &ppp_net_id,
 	.size = sizeof(struct ppp_net),
@@ -1255,13 +1255,18 @@ static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
 	spin_lock_init(&ppp->rlock);
 	spin_lock_init(&ppp->wlock);
 
-	ppp->xmit_recursion = alloc_percpu(int);
+	ppp->xmit_recursion = alloc_percpu(struct ppp_xmit_recursion);
 	if (!ppp->xmit_recursion) {
 		err = -ENOMEM;
 		goto err1;
 	}
-	for_each_possible_cpu(cpu)
-		(*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
+	for_each_possible_cpu(cpu) {
+		struct ppp_xmit_recursion *xmit_recursion;
+
+		xmit_recursion = per_cpu_ptr(ppp->xmit_recursion, cpu);
+		xmit_recursion->owner = NULL;
+		local_lock_init(&xmit_recursion->bh_lock);
+	}
 
 #ifdef CONFIG_PPP_MULTILINK
 	ppp->minseq = -1;
@@ -1303,10 +1308,13 @@ static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
 	return 0;
 }
 
-static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int ppp_nl_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct ppp_config conf = {
 		.unit = -1,
 		.ifname_is_set = true,
@@ -1343,7 +1351,7 @@ static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
 	if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
 		conf.ifname_is_set = false;
 
-	err = ppp_dev_configure(src_net, dev, &conf);
+	err = ppp_dev_configure(link_net, dev, &conf);
 
 out_unlock:
 	mutex_unlock(&ppp_mutex);
@@ -1529,23 +1537,12 @@ ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
 static void
 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
 {
-	struct ppp *ppp = netdev_priv(dev);
-
-	ppp_recv_lock(ppp);
-	stats64->rx_packets = ppp->stats64.rx_packets;
-	stats64->rx_bytes   = ppp->stats64.rx_bytes;
-	ppp_recv_unlock(ppp);
-
-	ppp_xmit_lock(ppp);
-	stats64->tx_packets = ppp->stats64.tx_packets;
-	stats64->tx_bytes   = ppp->stats64.tx_bytes;
-	ppp_xmit_unlock(ppp);
-
 	stats64->rx_errors        = dev->stats.rx_errors;
 	stats64->tx_errors        = dev->stats.tx_errors;
 	stats64->rx_dropped       = dev->stats.rx_dropped;
 	stats64->tx_dropped       = dev->stats.tx_dropped;
 	stats64->rx_length_errors = dev->stats.rx_length_errors;
+	dev_fetch_sw_netstats(stats64, dev->tstats);
 }
 
 static int ppp_dev_init(struct net_device *dev)
@@ -1602,11 +1599,14 @@ static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
 	if (ppp->flags & SC_MULTILINK)
 		return -EOPNOTSUPP;
 
-	if (list_empty(&ppp->channels))
+	pch = list_first_or_null_rcu(&ppp->channels, struct channel, clist);
+	if (!pch)
+		return -ENODEV;
+
+	chan = READ_ONCE(pch->chan);
+	if (!chan)
 		return -ENODEV;
 
-	pch = list_first_entry(&ppp->channels, struct channel, clist);
-	chan = pch->chan;
 	if (!chan->ops->fill_forward_path)
 		return -EOPNOTSUPP;
 
@@ -1640,6 +1640,7 @@ static void ppp_setup(struct net_device *dev)
 	dev->type = ARPHRD_PPP;
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 	dev->priv_destructor = ppp_dev_priv_destructor;
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	netif_keep_dst(dev);
 }
 
@@ -1673,15 +1674,20 @@ static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
 
 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
 {
+	struct ppp_xmit_recursion *xmit_recursion;
+
 	local_bh_disable();
 
-	if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
+	xmit_recursion = this_cpu_ptr(ppp->xmit_recursion);
+	if (xmit_recursion->owner == current)
 		goto err;
+	local_lock_nested_bh(&ppp->xmit_recursion->bh_lock);
+	xmit_recursion->owner = current;
 
-	(*this_cpu_ptr(ppp->xmit_recursion))++;
 	__ppp_xmit_process(ppp, skb);
-	(*this_cpu_ptr(ppp->xmit_recursion))--;
 
+	xmit_recursion->owner = NULL;
+	local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock);
 	local_bh_enable();
 
 	return;
@@ -1762,10 +1768,10 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 
 	if (proto < 0x8000) {
 #ifdef CONFIG_PPP_FILTER
-		/* check if we should pass this packet */
-		/* the filter instructions are constructed assuming
-		   a four-byte PPP header on each packet */
-		*(u8 *)skb_push(skb, 2) = 1;
+		/* check if the packet passes the pass and active filters.
+		 * See comment for PPP_FILTER_OUTBOUND_TAG above.
+		 */
+		*(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_OUTBOUND_TAG);
 		if (ppp->pass_filter &&
 		    bpf_prog_run(ppp->pass_filter, skb) == 0) {
 			if (ppp->debug & 1)
@@ -1786,8 +1792,7 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 #endif /* CONFIG_PPP_FILTER */
 	}
 
-	++ppp->stats64.tx_packets;
-	ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
+	dev_sw_netstats_tx_add(ppp->dev, 1, skb->len - PPP_PROTO_LEN);
 
 	switch (proto) {
 	case PPP_IP:
@@ -2183,11 +2188,16 @@ static void __ppp_channel_push(struct channel *pch)
 
 static void ppp_channel_push(struct channel *pch)
 {
+	struct ppp_xmit_recursion *xmit_recursion;
+
 	read_lock_bh(&pch->upl);
 	if (pch->ppp) {
-		(*this_cpu_ptr(pch->ppp->xmit_recursion))++;
+		xmit_recursion = this_cpu_ptr(pch->ppp->xmit_recursion);
+		local_lock_nested_bh(&pch->ppp->xmit_recursion->bh_lock);
+		xmit_recursion->owner = current;
 		__ppp_channel_push(pch);
-		(*this_cpu_ptr(pch->ppp->xmit_recursion))--;
+		xmit_recursion->owner = NULL;
+		local_unlock_nested_bh(&pch->ppp->xmit_recursion->bh_lock);
 	} else {
 		__ppp_channel_push(pch);
 	}
@@ -2464,8 +2474,7 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
 		break;
 	}
 
-	++ppp->stats64.rx_packets;
-	ppp->stats64.rx_bytes += skb->len - 2;
+	dev_sw_netstats_rx_add(ppp->dev, skb->len - PPP_PROTO_LEN);
 
 	npi = proto_to_npindex(proto);
 	if (npi < 0) {
@@ -2482,14 +2491,13 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
 		/* network protocol frame - give it to the kernel */
 
 #ifdef CONFIG_PPP_FILTER
-		/* check if the packet passes the pass and active filters */
-		/* the filter instructions are constructed assuming
-		   a four-byte PPP header on each packet */
 		if (ppp->pass_filter || ppp->active_filter) {
 			if (skb_unclone(skb, GFP_ATOMIC))
 				goto err;
-
-			*(u8 *)skb_push(skb, 2) = 0;
+			/* Check if the packet passes the pass and active filters.
+			 * See comment for PPP_FILTER_INBOUND_TAG above.
+			 */
+			*(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_INBOUND_TAG);
 			if (ppp->pass_filter &&
 			    bpf_prog_run(ppp->pass_filter, skb) == 0) {
 				if (ppp->debug & 1)
@@ -2990,7 +2998,7 @@ ppp_unregister_channel(struct ppp_channel *chan)
 	 */
 	down_write(&pch->chan_sem);
 	spin_lock_bh(&pch->downl);
-	pch->chan = NULL;
+	WRITE_ONCE(pch->chan, NULL);
 	spin_unlock_bh(&pch->downl);
 	up_write(&pch->chan_sem);
 	ppp_disconnect_channel(pch);
@@ -3294,14 +3302,25 @@ static void
 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
 {
 	struct slcompress *vj = ppp->vj;
+	int cpu;
 
 	memset(st, 0, sizeof(*st));
-	st->p.ppp_ipackets = ppp->stats64.rx_packets;
+	for_each_possible_cpu(cpu) {
+		struct pcpu_sw_netstats *p = per_cpu_ptr(ppp->dev->tstats, cpu);
+		u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
+
+		rx_packets = u64_stats_read(&p->rx_packets);
+		rx_bytes = u64_stats_read(&p->rx_bytes);
+		tx_packets = u64_stats_read(&p->tx_packets);
+		tx_bytes = u64_stats_read(&p->tx_bytes);
+
+		st->p.ppp_ipackets += rx_packets;
+		st->p.ppp_ibytes += rx_bytes;
+		st->p.ppp_opackets += tx_packets;
+		st->p.ppp_obytes += tx_bytes;
+	}
 	st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
-	st->p.ppp_ibytes = ppp->stats64.rx_bytes;
-	st->p.ppp_opackets = ppp->stats64.tx_packets;
 	st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
-	st->p.ppp_obytes = ppp->stats64.tx_bytes;
 	if (!vj)
 		return;
 	st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
@@ -3490,13 +3509,17 @@ ppp_connect_channel(struct channel *pch, int unit)
 		ret = -ENOTCONN;
 		goto outl;
 	}
+	if (pch->chan->direct_xmit)
+		ppp->dev->priv_flags |= IFF_NO_QUEUE;
+	else
+		ppp->dev->priv_flags &= ~IFF_NO_QUEUE;
 	spin_unlock_bh(&pch->downl);
 	if (pch->file.hdrlen > ppp->file.hdrlen)
 		ppp->file.hdrlen = pch->file.hdrlen;
 	hdrlen = pch->file.hdrlen + 2;	/* for protocol bytes */
 	if (hdrlen > ppp->dev->hard_header_len)
 		ppp->dev->hard_header_len = hdrlen;
-	list_add_tail(&pch->clist, &ppp->channels);
+	list_add_tail_rcu(&pch->clist, &ppp->channels);
 	++ppp->n_channels;
 	pch->ppp = ppp;
 	refcount_inc(&ppp->file.refcnt);
@@ -3526,10 +3549,11 @@ ppp_disconnect_channel(struct channel *pch)
 	if (ppp) {
 		/* remove it from the ppp unit's list */
 		ppp_lock(ppp);
-		list_del(&pch->clist);
+		list_del_rcu(&pch->clist);
 		if (--ppp->n_channels == 0)
 			wake_up_interruptible(&ppp->file.rwait);
 		ppp_unlock(ppp);
+		synchronize_net();
 		if (refcount_dec_and_test(&ppp->file.refcnt))
 			ppp_destroy_interface(ppp);
 		err = 0;