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Diffstat (limited to 'net/dccp/ipv4.c')
-rw-r--r--net/dccp/ipv4.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index a545ad71201c..a5361fb7a415 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -255,12 +255,17 @@ static int dccp_v4_err(struct sk_buff *skb, u32 info)
int err;
struct net *net = dev_net(skb->dev);
- /* Only need dccph_dport & dccph_sport which are the first
- * 4 bytes in dccp header.
+ /* For the first __dccp_basic_hdr_len() check, we only need dh->dccph_x,
+ * which is in byte 7 of the dccp header.
* Our caller (icmp_socket_deliver()) already pulled 8 bytes for us.
+ *
+ * Later on, we want to access the sequence number fields, which are
+ * beyond 8 bytes, so we have to pskb_may_pull() ourselves.
*/
- BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
- BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
+ dh = (struct dccp_hdr *)(skb->data + offset);
+ if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh)))
+ return -EINVAL;
+ iph = (struct iphdr *)skb->data;
dh = (struct dccp_hdr *)(skb->data + offset);
sk = __inet_lookup_established(net, &dccp_hashinfo,