Commit 0354b48f authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso

netfilter: xt_connbytes: handle negation correctly

"! --connbytes 23:42" should match if the packet/byte count is not in range.

As there is no explict "invert match" toggle in the match structure,
userspace swaps the from and to arguments
(i.e., as if "--connbytes 42:23" were given).

However, "what <= 23 && what >= 42" will always be false.

Change things so we use "||" in case "from" is larger than "to".

This change may look like it breaks backwards compatibility when "to" is 0.
However, older iptables binaries will refuse "connbytes 42:0",
and current releases treat it to mean "! --connbytes 0:42",
so we should be fine.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 3f1e6d3f
......@@ -87,10 +87,10 @@ connbytes_mt(const struct sk_buff *skb, struct xt_action_param *par)
break;
}
if (sinfo->count.to)
if (sinfo->count.to >= sinfo->count.from)
return what <= sinfo->count.to && what >= sinfo->count.from;
else
return what >= sinfo->count.from;
else /* inverted */
return what < sinfo->count.to || what > sinfo->count.from;
}
static int connbytes_mt_check(const struct xt_mtchk_param *par)
......
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