net: 6lowpan: fix lowpan_header_create non-compression memcpy call

commit 965801e1eb624154fe5e9dc5d2ff0b7f1951a11c upstream.

In function lowpan_header_create(), we invoke the following code
construct:

  struct ipv6hdr *hdr;
  ...
  hdr = ipv6_hdr(skb);
  ...
  if (...)
    memcpy(hc06_ptr + 1, &hdr->flow_lbl[1], 2);
  else
    memcpy(hc06_ptr, &hdr, 4);

Where the else path of the condition, that is, non-compression
path, calls memcpy() with a pointer to struct ipv6hdr *hdr as
source, thus two levels of indirection. This cannot be correct,
and likely only one level of pointer was intended as source
buffer for memcpy() here.

Fixes: 44331fe2aa0d ("IEEE802.15.4: 6LoWPAN basic support")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Werner Almesberger <werner@almesberger.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index ca118e8cb141de63c8cac2e4813fad7bd70192b9..9d06b37acc4cb290a28a8de75ed65592e73ab1a7 100644 (file)
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -459,7 +459,7 @@ static int lowpan_header_create(struct sk_buff *skb,
                        hc06_ptr += 3;
                } else {
                        /* compress nothing */
-                       memcpy(hc06_ptr, &hdr, 4);
+                       memcpy(hc06_ptr, hdr, 4);
                        /* replace the top byte with new ECN | DSCP format */
                        *hc06_ptr = tmp;
                        hc06_ptr += 4;