ipsec: be careful of non existing mac headers
Niccolo Belli reported ipsec crashes in case we handle a frame without
mac header (atm in his case)
Before copying mac header, better make sure it is present.
Bugzilla reference: https://bugzilla.kernel.org/show_bug.cgi?id=42809
Reported-by: Niccolò Belli <darkbasic@linuxsystems.it>
Tested-by: Niccolò Belli <darkbasic@linuxsystems.it>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 50db9b0..ae86adee 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1465,6 +1465,16 @@
}
#endif /* NET_SKBUFF_DATA_USES_OFFSET */
+static inline void skb_mac_header_rebuild(struct sk_buff *skb)
+{
+ if (skb_mac_header_was_set(skb)) {
+ const unsigned char *old_mac = skb_mac_header(skb);
+
+ skb_set_mac_header(skb, -skb->mac_len);
+ memmove(skb_mac_header(skb), old_mac, skb->mac_len);
+ }
+}
+
static inline int skb_checksum_start_offset(const struct sk_buff *skb)
{
return skb->csum_start - skb_headroom(skb);