ieee802154: properly unshare skbs in ieee802154 *_rcv functions

ieee802154 sockets do not properly unshare received skbs, which leads to
panics (at least) when they are used in conjunction with 6lowpan, so
run skb_share_check on received skbs.
6lowpan also contains a use-after-free, which is trivially fixed by
replacing the inlined skb_share_check with the explicit call.

Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Tested-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
index 6060394..0f5a69e 100644 (file)
--- a/net/ieee802154/6lowpan_rtnl.c
+++ b/net/ieee802154/6lowpan_rtnl.c
@@ -447,10 +447,13 @@ static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[])
 static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
        struct packet_type *pt, struct net_device *orig_dev)
 {
-       struct sk_buff *local_skb;
        struct ieee802154_hdr hdr;
        int ret;
 
+       skb = skb_share_check(skb, GFP_ATOMIC);
+       if (!skb)
+               goto drop;
+
        if (!netif_running(dev))
                goto drop_skb;
 
@@ -460,42 +463,36 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
        if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
                goto drop_skb;
 
-       local_skb = skb_clone(skb, GFP_ATOMIC);
-       if (!local_skb)
-               goto drop_skb;
-
-       kfree_skb(skb);
-
        /* check that it's our buffer */
        if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
-               local_skb->protocol = htons(ETH_P_IPV6);
-               local_skb->pkt_type = PACKET_HOST;
+               skb->protocol = htons(ETH_P_IPV6);
+               skb->pkt_type = PACKET_HOST;
 
                /* Pull off the 1-byte of 6lowpan header. */
-               skb_pull(local_skb, 1);
+               skb_pull(skb, 1);
 
-               ret = lowpan_give_skb_to_devices(local_skb, NULL);
+               ret = lowpan_give_skb_to_devices(skb, NULL);
                if (ret == NET_RX_DROP)
                        goto drop;
        } else {
                switch (skb->data[0] & 0xe0) {
                case LOWPAN_DISPATCH_IPHC:      /* ipv6 datagram */
-                       ret = process_data(local_skb, &hdr);
+                       ret = process_data(skb, &hdr);
                        if (ret == NET_RX_DROP)
                                goto drop;
                        break;
                case LOWPAN_DISPATCH_FRAG1:     /* first fragment header */
-                       ret = lowpan_frag_rcv(local_skb, LOWPAN_DISPATCH_FRAG1);
+                       ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
                        if (ret == 1) {
-                               ret = process_data(local_skb, &hdr);
+                               ret = process_data(skb, &hdr);
                                if (ret == NET_RX_DROP)
                                        goto drop;
                        }
                        break;
                case LOWPAN_DISPATCH_FRAGN:     /* next fragments headers */
-                       ret = lowpan_frag_rcv(local_skb, LOWPAN_DISPATCH_FRAGN);
+                       ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
                        if (ret == 1) {
-                               ret = process_data(local_skb, &hdr);
+                               ret = process_data(skb, &hdr);
                                if (ret == NET_RX_DROP)
                                        goto drop;
                        }

diff --git a/net/ieee802154/dgram.c b/net/ieee802154/dgram.c
index 4c47154..6d251a3 100644 (file)
--- a/net/ieee802154/dgram.c
+++ b/net/ieee802154/dgram.c
@@ -329,6 +329,10 @@ out:
 
 static int dgram_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
+       skb = skb_share_check(skb, GFP_ATOMIC);
+       if (!skb)
+               return NET_RX_DROP;
+
        if (sock_queue_rcv_skb(sk, skb) < 0) {
                kfree_skb(skb);
                return NET_RX_DROP;

diff --git a/net/ieee802154/raw.c b/net/ieee802154/raw.c
index e5258cf..74d54fa 100644 (file)
--- a/net/ieee802154/raw.c
+++ b/net/ieee802154/raw.c
@@ -213,6 +213,10 @@ out:
 
 static int raw_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
+       skb = skb_share_check(skb, GFP_ATOMIC);
+       if (!skb)
+               return NET_RX_DROP;
+
        if (sock_queue_rcv_skb(sk, skb) < 0) {
                kfree_skb(skb);
                return NET_RX_DROP;