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@xxxxxxxxxxxxxx>
---
net/ipv6/calipso.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/calipso.c b/net/ipv6/calipso.c
index 37ac9de..8d772fe 100644
--- a/net/ipv6/calipso.c
+++ b/net/ipv6/calipso.c
@@ -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);
--
2.9.4
