1 files changed, 25 insertions, 10 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 9abc503b19b7..fb8b0546485b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2283,8 +2283,8 @@ EXPORT_SYMBOL(skb_checksum_help);
 
 __be16 skb_network_protocol(struct sk_buff *skb, int *depth)
 {
+        unsigned int vlan_depth = skb->mac_len;
         __be16 type = skb->protocol;
-        int vlan_depth = skb->mac_len;
 
         /* Tunnel gso handlers can set protocol to ethernet. */
         if (type == htons(ETH_P_TEB)) {
@@ -2297,15 +2297,30 @@ __be16 skb_network_protocol(struct sk_buff *skb, int *depth)
                 type = eth->h_proto;
         }
 
-        while (type == htons(ETH_P_8021Q) || type == htons(ETH_P_8021AD)) {
-                struct vlan_hdr *vh;
-
-                if (unlikely(!pskb_may_pull(skb, vlan_depth + VLAN_HLEN)))
-                        return 0;
-
-                vh = (struct vlan_hdr *)(skb->data + vlan_depth);
-                type = vh->h_vlan_encapsulated_proto;
-                vlan_depth += VLAN_HLEN;
+        /* if skb->protocol is 802.1Q/AD then the header should already be
+         * present at mac_len - VLAN_HLEN (if mac_len > 0), or at
+         * ETH_HLEN otherwise
+         */
+        if (type == htons(ETH_P_8021Q) || type == htons(ETH_P_8021AD)) {
+                if (vlan_depth) {
+                        if (unlikely(WARN_ON(vlan_depth < VLAN_HLEN)))
+                                return 0;
+                        vlan_depth -= VLAN_HLEN;
+                } else {
+                        vlan_depth = ETH_HLEN;
+                }
+                do {
+                        struct vlan_hdr *vh;
+
+                        if (unlikely(!pskb_may_pull(skb,
+                                                    vlan_depth + VLAN_HLEN)))
+                                return 0;
+
+                        vh = (struct vlan_hdr *)(skb->data + vlan_depth);
+                        type = vh->h_vlan_encapsulated_proto;
+                        vlan_depth += VLAN_HLEN;
+                } while (type == htons(ETH_P_8021Q) ||
+                         type == htons(ETH_P_8021AD));
         }
 
         *depth = vlan_depth;