| Message ID | 20161019132539.x2ou3hfgutxe6d57@dwarf.suse.cz |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index cc7c26d..f7c7c2b 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -1247,9 +1247,6 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, struct inet6_ifaddr *i idev->cnf.temp_valid_lft + age); tmp_prefered_lft = idev->cnf.temp_prefered_lft + age - idev->desync_factor; - /* guard against underflow in case of concurrent updates to cnf */ - if (unlikely(tmp_prefered_lft < 0)) - tmp_prefered_lft = 0; tmp_prefered_lft = min_t(__u32, ifp->prefered_lft, tmp_prefered_lft); tmp_plen = ifp->prefix_len; tmp_tstamp = ifp->tstamp;
The check for an underflow of tmp_prefered_lft is always false because tmp_prefered_lft is unsigned. The intention of the check was to guard against racing with an update of the temp_prefered_lft sysctl, potentially resulting in an underflow and a very large preferred lifetime. However, the result of the check in such a situation would be not creating the temporary address at all, which might be an even worse outcome than the bogus lifetime. Drop the faulty check. Signed-off-by: Jiri Bohac <jbohac@suse.cz> Reported-by: Julia Lawall <julia.lawall@lip6.fr> Fixes: 76506a986dc3 ("IPv6: fix DESYNC_FACTOR")