1 files changed, 18 insertions, 26 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index ada47e59647a..73e9c0a9c187 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -20,8 +20,10 @@
 
 #include <linux/module.h>
 
+#include <linux/bpf.h>
 #include <linux/capability.h>
 #include <linux/kernel.h>
+#include <linux/filter.h>
 #include <linux/init.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
@@ -157,6 +159,8 @@ EXPORT_SYMBOL(do_trace_netlink_extack);
 
 static inline u32 netlink_group_mask(u32 group)
 {
+	if (group > 32)
+		return 0;
 	return group ? 1 << (group - 1) : 0;
 }
 
@@ -707,9 +711,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
 	if (err < 0)
 		goto out_module;
 
-	local_bh_disable();
 	sock_prot_inuse_add(net, &netlink_proto, 1);
-	local_bh_enable();
 
 	nlk = nlk_sk(sock->sk);
 	nlk->module = module;
@@ -809,9 +811,7 @@ static int netlink_release(struct socket *sock)
 		netlink_table_ungrab();
 	}
 
-	local_bh_disable();
 	sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
-	local_bh_enable();
 	call_rcu(&nlk->rcu, deferred_put_nlk_sk);
 	return 0;
 }
@@ -1412,8 +1412,6 @@ struct netlink_broadcast_data {
 	int delivered;
 	gfp_t allocation;
 	struct sk_buff *skb, *skb2;
-	int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
-	void *tx_data;
 };
 
 static void do_one_broadcast(struct sock *sk,
@@ -1467,11 +1465,6 @@ static void do_one_broadcast(struct sock *sk,
 			p->delivery_failure = 1;
 		goto out;
 	}
-	if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
-		kfree_skb(p->skb2);
-		p->skb2 = NULL;
-		goto out;
-	}
 	if (sk_filter(sk, p->skb2)) {
 		kfree_skb(p->skb2);
 		p->skb2 = NULL;
@@ -1494,10 +1487,8 @@ out:
 	sock_put(sk);
 }
 
-int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
-	u32 group, gfp_t allocation,
-	int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
-	void *filter_data)
+int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
+		      u32 group, gfp_t allocation)
 {
 	struct net *net = sock_net(ssk);
 	struct netlink_broadcast_data info;
@@ -1516,8 +1507,6 @@ int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid
 	info.allocation = allocation;
 	info.skb = skb;
 	info.skb2 = NULL;
-	info.tx_filter = filter;
-	info.tx_data = filter_data;
 
 	/* While we sleep in clone, do not allow to change socket list */
 
@@ -1543,14 +1532,6 @@ int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid
 	}
 	return -ESRCH;
 }
-EXPORT_SYMBOL(netlink_broadcast_filtered);
-
-int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
-		      u32 group, gfp_t allocation)
-{
-	return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
-		NULL, NULL);
-}
 EXPORT_SYMBOL(netlink_broadcast);
 
 struct netlink_set_err_data {
@@ -1871,6 +1852,11 @@ static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
 	if (msg->msg_flags & MSG_OOB)
 		return -EOPNOTSUPP;
 
+	if (len == 0) {
+		pr_warn_once("Zero length message leads to an empty skb\n");
+		return -ENODATA;
+	}
+
 	err = scm_send(sock, msg, &scm, true);
 	if (err < 0)
 		return err;
@@ -1989,7 +1975,6 @@ static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 		copied = len;
 	}
 
-	skb_reset_transport_header(data_skb);
 	err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
 
 	if (msg->msg_name) {
@@ -2277,6 +2262,13 @@ static int netlink_dump(struct sock *sk)
 	 * single netdev. The outcome is MSG_TRUNC error.
 	 */
 	skb_reserve(skb, skb_tailroom(skb) - alloc_size);
+
+	/* Make sure malicious BPF programs can not read unitialized memory
+	 * from skb->head -> skb->data
+	 */
+	skb_reset_network_header(skb);
+	skb_reset_mac_header(skb);
+
 	netlink_skb_set_owner_r(skb, sk);
 
 	if (nlk->dump_done_errno > 0) {