[PATCH][next] netfilter: conntrack: fix an unsigned int comparison to less than zero

From: Colin King
Date: Tue May 26 2020 - 14:07:20 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

The error check to see if protoff is less than zero is always false
because it is a unsigned int. The call to ipv6_skip_exthdr can return
negative values for an error so cast protoff to int to fix this check.

Addresses-Coverity: ("Macro compares unsigned to 0 (no effect)")
Fixes: ee04805ff54a ("netfilter: conntrack: make conntrack userspace helpers work again")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
net/netfilter/nf_conntrack_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 08e0c19f6b39..2933b96a90c6 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -2114,7 +2114,7 @@ static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct,
pnum = ipv6_hdr(skb)->nexthdr;
protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
&frag_off);
- if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
+ if ((int)protoff < 0 || (frag_off & htons(~0x7)) != 0)
return 0;
break;
}
--
2.25.1