From: Florian Westphal Date: Fri, 16 Dec 2011 17:35:15 +0000 (+0100) Subject: netfilter: xt_connbytes: handle negation correctly X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=0354b48f633ae435acbc01b470a1ce8cfeff3e9f;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git 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: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- diff --git a/net/netfilter/xt_connbytes.c b/net/netfilter/xt_connbytes.c index 5b138506690..9ddf1c3bfb3 100644 --- a/net/netfilter/xt_connbytes.c +++ b/net/netfilter/xt_connbytes.c @@ -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)