ipv6: Check ip6_find_1stfragopt() return value properly.
Do not use unsigned variables to see if it returns a negative
error or not.
Fixes: 2423496af35d ("ipv6: Prevent overrun when parsing v6 header options")
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index eab36ab..280268f 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -63,7 +63,6 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
const struct net_offload *ops;
int proto;
struct frag_hdr *fptr;
- unsigned int unfrag_ip6hlen;
unsigned int payload_len;
u8 *prevhdr;
int offset = 0;
@@ -116,10 +115,10 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
skb->network_header = (u8 *)ipv6h - skb->head;
if (udpfrag) {
- unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
- if (unfrag_ip6hlen < 0)
- return ERR_PTR(unfrag_ip6hlen);
- fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen);
+ int err = ip6_find_1stfragopt(skb, &prevhdr);
+ if (err < 0)
+ return ERR_PTR(err);
+ fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
fptr->frag_off = htons(offset);
if (skb->next)
fptr->frag_off |= htons(IP6_MF);