1 files changed, 60 insertions, 32 deletions

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index fe380fe196e7..def84e87e05b 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -44,7 +44,8 @@
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/file.h>
-#include <asm/unaligned.h>
+#include <linux/unaligned.h>
+#include <net/netdev_lock.h>
 #include <net/slhc_vj.h>
 #include <linux/atomic.h>
 #include <linux/refcount.h>
@@ -70,6 +71,18 @@
 #define MPHDRLEN_SSN	4	/* ditto with short sequence numbers */
 
 #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
@@ -493,6 +506,15 @@ static ssize_t ppp_read(struct file *file, char __user *buf,
 	return ret;
 }
 
+static bool ppp_check_packet(struct sk_buff *skb, size_t count)
+{
+	/* LCP packets must include LCP header which 4 bytes long:
+	 * 1-byte code, 1-byte identifier, and 2-byte length.
+	 */
+	return get_unaligned_be16(skb->data) != PPP_LCP ||
+		count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN;
+}
+
 static ssize_t ppp_write(struct file *file, const char __user *buf,
 			 size_t count, loff_t *ppos)
 {
@@ -515,6 +537,11 @@ static ssize_t ppp_write(struct file *file, const char __user *buf,
 		kfree_skb(skb);
 		goto out;
 	}
+	ret = -EINVAL;
+	if (unlikely(!ppp_check_packet(skb, count))) {
+		kfree_skb(skb);
+		goto out;
+	}
 
 	switch (pf->kind) {
 	case INTERFACE:
@@ -1104,6 +1131,8 @@ 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);
@@ -1119,28 +1148,20 @@ 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);
@@ -1150,6 +1171,7 @@ 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),
@@ -1288,10 +1310,13 @@ 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,
@@ -1328,7 +1353,7 @@ 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);
@@ -1357,7 +1382,7 @@ static struct net *ppp_nl_get_link_net(const struct net_device *dev)
 {
 	struct ppp *ppp = netdev_priv(dev);
 
-	return ppp->ppp_net;
+	return READ_ONCE(ppp->ppp_net);
 }
 
 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
@@ -1616,7 +1641,7 @@ static void ppp_setup(struct net_device *dev)
 	dev->netdev_ops = &ppp_netdev_ops;
 	SET_NETDEV_DEVTYPE(dev, &ppp_type);
 
-	dev->features |= NETIF_F_LLTX;
+	dev->lltx = true;
 
 	dev->hard_header_len = PPP_HDRLEN;
 	dev->mtu = PPP_MRU;
@@ -1747,10 +1772,10 @@ 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)
@@ -2254,7 +2279,7 @@ static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
 	if (!pchb)
 		goto out_rcu;
 
-	spin_lock(&pchb->downl);
+	spin_lock_bh(&pchb->downl);
 	if (!pchb->chan) {
 		/* channel got unregistered */
 		kfree_skb(skb);
@@ -2266,7 +2291,7 @@ static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
 		kfree_skb(skb);
 
 outl:
-	spin_unlock(&pchb->downl);
+	spin_unlock_bh(&pchb->downl);
 out_rcu:
 	rcu_read_unlock();
 
@@ -2467,14 +2492,13 @@ 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)
@@ -3475,6 +3499,10 @@ 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;