net/ipv6: Fix CALIPSO causing GPF with datagram support

When using CALIPSO with IPPROTO_UDP it is possible to trigger a GPF as the
IP header may have moved.

Also update the payload length after adding the CALIPSO option.

Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Richard Haines 2017-06-05 16:44:40 +01:00 committed by David S. Miller
parent 594238158b
commit e3ebdb20fd

View File

@ -1319,7 +1319,7 @@ static int calipso_skbuff_setattr(struct sk_buff *skb,
struct ipv6hdr *ip6_hdr;
struct ipv6_opt_hdr *hop;
unsigned char buf[CALIPSO_MAX_BUFFER];
int len_delta, new_end, pad;
int len_delta, new_end, pad, payload;
unsigned int start, end;
ip6_hdr = ipv6_hdr(skb);
@ -1346,6 +1346,8 @@ static int calipso_skbuff_setattr(struct sk_buff *skb,
if (ret_val < 0)
return ret_val;
ip6_hdr = ipv6_hdr(skb); /* Reset as skb_cow() may have moved it */
if (len_delta) {
if (len_delta > 0)
skb_push(skb, len_delta);
@ -1355,6 +1357,8 @@ static int calipso_skbuff_setattr(struct sk_buff *skb,
sizeof(*ip6_hdr) + start);
skb_reset_network_header(skb);
ip6_hdr = ipv6_hdr(skb);
payload = ntohs(ip6_hdr->payload_len);
ip6_hdr->payload_len = htons(payload + len_delta);
}
hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);