bpf: in __bpf_redirect_no_mac pull mac only if present

[tomoyo/tomoyo-test1.git] / net / core / filter.c

diff --git a/net/core/filter.c b/net/core/filter.c
index dab10d2..7559d68 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2020,18 +2020,19 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb)
 static int __bpf_redirect_no_mac(struct sk_buff *skb, struct net_device *dev,
                                 u32 flags)
 {
-       /* skb->mac_len is not set on normal egress */
-       unsigned int mlen = skb->network_header - skb->mac_header;
+       unsigned int mlen = skb_network_offset(skb);
 
-       __skb_pull(skb, mlen);
+       if (mlen) {
+               __skb_pull(skb, mlen);
 
-       /* At ingress, the mac header has already been pulled once.
-        * At egress, skb_pospull_rcsum has to be done in case that
-        * the skb is originated from ingress (i.e. a forwarded skb)
-        * to ensure that rcsum starts at net header.
-        */
-       if (!skb_at_tc_ingress(skb))
-               skb_postpull_rcsum(skb, skb_mac_header(skb), mlen);
+               /* At ingress, the mac header has already been pulled once.
+                * At egress, skb_pospull_rcsum has to be done in case that
+                * the skb is originated from ingress (i.e. a forwarded skb)
+                * to ensure that rcsum starts at net header.
+                */
+               if (!skb_at_tc_ingress(skb))
+                       skb_postpull_rcsum(skb, skb_mac_header(skb), mlen);
+       }
        skb_pop_mac_header(skb);
        skb_reset_mac_len(skb);
        return flags & BPF_F_INGRESS ?