Static code analysis reveals the following bug:

        net/openvswitch/conntrack.c:281 ovs_ct_helper()
        warn: unsigned 'protoff' is never less than zero.

This signedness bug breaks error handling for IPv6 extension headers when
using conntrack helpers. Fix the error by using a local signed variable.

Fixes:  cae3a2627520: "openvswitch: Allow attaching helpers to ct
action"
Reported-by: Dan Carpenter <dan.carpen...@oracle.com>
Signed-off-by: Joe Stringer <joestrin...@nicira.com>
---
 net/openvswitch/conntrack.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index e8e524a..002a755 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -275,13 +275,15 @@ static int ovs_ct_helper(struct sk_buff *skb, u16 proto)
        case NFPROTO_IPV6: {
                u8 nexthdr = ipv6_hdr(skb)->nexthdr;
                __be16 frag_off;
+               int ofs;
 
-               protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
-                                          &nexthdr, &frag_off);
-               if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
+               ofs = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
+                                      &frag_off);
+               if (ofs < 0 || (frag_off & htons(~0x7)) != 0) {
                        pr_debug("proto header not found\n");
                        return NF_ACCEPT;
                }
+               protoff = ofs;
                break;
        }
        default:
-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to