[pve-devel] pve-firewall: default loglevel behaviour change
Alexandre DERUMIER
aderumier at odiso.com
Thu May 16 09:04:18 CEST 2019
>>When we added this we had some discussion about the sensible default, IIRC,
>>I initially was for no ratelimit per default, but Christian argued that with
>>the bucket burst limit we have a sensible balance between spamming the logs
>>(if something is off, and a lot of packets get generated) but still seeing
>>bursts. FYI, you can also just set log_ratelimit to 0 (enabled is the default
>>key), but not sure if we want tot change this to opt-out, I mean either way
>>one only needs to change it once per cluster...
yes, no problem.
But the GUI is a little bit strange.
if log_ratelimit is undefined, the GUI show "log rate limit: enable=0" (and rate limit is a default 1/sec).
then, you need to click the checkbox to enable ratelimit, then click again to disable it to finally
have the value "log_ratelimit: enable=0"
----- Mail original -----
De: "Thomas Lamprecht" <t.lamprecht at proxmox.com>
À: "pve-devel" <pve-devel at pve.proxmox.com>, "aderumier" <aderumier at odiso.com>, "Christian Ebner" <c.ebner at proxmox.com>
Envoyé: Jeudi 16 Mai 2019 08:53:37
Objet: Re: [pve-devel] pve-firewall: default loglevel behaviour change
On 5/16/19 1:18 AM, Alexandre DERUMIER wrote:
> Thanks !
>
> Also,
> about new log ratelimit
> https://git.proxmox.com/?p=pve-firewall.git;a=blobdiff;f=src/PVE/Firewall.pm;h=48e630004bf424c2db578aad3e60eb61db42f8e6;hp=ba1cb5f5924af094fe647f98d40e2703eca96ff4;hb=cc37e0005d0617e405883fd12b80faf65cedb153;hpb=95ed90a9a8418173ab7cac2d0c1f6ddd04c376cc
>
> it's seem that the default is now
> +my $global_log_ratelimit = '--limit 1/sec';
>
>
> (If don't have the option "log_ratelimit" in cluster.fw)
>
>
>
> +my $set_global_log_ratelimit = sub {
> + my $cluster_opts = shift;
> +
> + $global_log_ratelimit = '--limit 1/sec';
> + if (defined(my $log_rlimit = $cluster_opts->{log_ratelimit})) {
> + my $ll_format = $cluster_option_properties->{log_ratelimit}->{format};
> + my $limit = PVE::JSONSchema::parse_property_string($ll_format, $log_rlimit);
> +
> + if ($limit->{enable}) {
> + if (my $rate = $limit->{rate}) {
> + $global_log_ratelimit = "--limit $rate";
> + }
> + if (my $burst = $limit->{burst}) {
> + $global_log_ratelimit .= " --limit-burst $burst";
> + }
> + } else {
> + $global_log_ratelimit = undef;
> + }
> + }
> +};
>
>
> but it's correctly disabled with
> "log_ratelimit: enable=0" in cluster.fw
>
> I think the behaviour should be also the same when option is not defined.
When we added this we had some discussion about the sensible default, IIRC,
I initially was for no ratelimit per default, but Christian argued that with
the bucket burst limit we have a sensible balance between spamming the logs
(if something is off, and a lot of packets get generated) but still seeing
bursts. FYI, you can also just set log_ratelimit to 0 (enabled is the default
key), but not sure if we want tot change this to opt-out, I mean either way
one only needs to change it once per cluster...
>
>
> ----- Mail original -----
> De: "Christian Ebner" <c.ebner at proxmox.com>
> À: "pve-devel" <pve-devel at pve.proxmox.com>, "aderumier" <aderumier at odiso.com>
> Envoyé: Mercredi 15 Mai 2019 17:03:13
> Objet: Re: [pve-devel] pve-firewall: default loglevel behaviour change
>
> Hi Alexandre,
>
> you are right, logging the packets passing the firewall bridge seems a bit overkill and redundant.
>
> Will send a patch to fix this.
>
>> On May 15, 2019 at 4:08 PM Alexandre DERUMIER <aderumier at odiso.com> wrote:
>>
>>
>> Hi,
>>
>> since this commit
>>
>>
>> https://git.proxmox.com/?p=pve-firewall.git;a=blobdiff;f=src/PVE/Firewall.pm;h=ccc5d7ffb62f1ef4c4d59e363192f512c88742c9;hp=6ac303831a62f630d437ef0e0508decd2b72f5ac;hb=3489f8a2b9597201fe8e42fa5832507f96169619;hpb=33efd363ab32d3f8f6a9c49e481cb62a8da40b5d
>>
>> @@ -2341,10 +2348,10 @@ sub generate_tap_rules_direction {
>> # plug the tap chain to bridge chain
>> if ($direction eq 'IN') {
>> ruleset_addrule($ruleset, "PVEFW-FWBR-IN",
>> - "-m physdev --physdev-is-bridged --physdev-out $iface", "-j $tapchain");
>> + "-m physdev --physdev-is-bridged --physdev-out $iface", "-j $tapchain", $loglevel, 'FWBR-IN: ', $vmid);
>> } else {
>> ruleset_addrule($ruleset, "PVEFW-FWBR-OUT",
>> - "-m physdev --physdev-is-bridged --physdev-in $iface", "-j $tapchain");
>> + "-m physdev --physdev-is-bridged --physdev-in $iface", "-j $tapchain", $loglevel, 'FWBR-OUT: ', $vmid);
>> }
>> }
>>
>>
>>
>> The default loglevel of a vm is logging all packets comming to the tap chain
>> ex:
>> -A PVEFW-FWBR-IN -m physdev --physdev-out tap135i0 --physdev-is-bridged -m limit --limit 1/sec -j NFLOG --nflog-prefix ":135:6:PVEFW-FWBR-IN: FWBR-IN: "
>>
>> Previously, it was only for the final DROP/REJECT/ACCEPT action
>>
>>
>> Here a example with a connection to port 53, with default action input/output policy = reject, loglevelin:info, and no rule to allow port
>> [OPTIONS]
>>
>> log_level_out: info
>> macfilter: 1
>> policy_out: REJECT
>> enable: 1
>> policy_in: REJECT
>> dhcp: 0
>> log_level_in: info
>>
>> [RULES]
>>
>>
>>
>>
>>
>> 135 6 PVEFW-FWBR-IN 15/May/2019:15:53:23 +0200 FWBR-IN: IN=fwbr135i0 OUT=fwbr135i0 PHYSIN=fwln135i0 PHYSOUT=tap135i0 MAC=56:af:a2:0d:53:9b:58:49:3b:80:fb:24:08:00 SRC=10.11.53.33 DST=10.3.95.29 LEN=283 TOS=0x00 PREC=0x00 TTL=127 ID=20498 PROTO=UDP SPT=54689 DPT=389 LEN=263
>> 135 6 tap135i0-IN 15/May/2019:15:53:23 +0200 policy REJECT: IN=fwbr135i0 OUT=fwbr135i0 PHYSIN=fwln135i0 PHYSOUT=tap135i0 MAC=56:af:a2:0d:53:9b:58:49:3b:80:fb:24:08:00 SRC=10.11.53.33 DST=10.3.95.29 LEN=283 TOS=0x00 PREC=0x00 TTL=127 ID=20498 PROTO=UDP SPT=54689 DPT=389 LEN=263
>>
>>
>> As you see, it's logged twice. (once when coming to tap chain, one when final action is reject)
>>
>> Same if you make a rule in the vm, activating log on the rule, it's loggued twice.
>>
>> I would like to be able to remove this logging in FWBR-IN, and only log on rules or default input/output policy action.
>> But currently, if I disable the loglevel=nolog, it's disabling too the log for default action.
>>
>>
>> I'm not sure, but do we really need this log on FWBR-IN ? (I mean, we don't have any info if it's drop/accept/reject, so it's pretty useless, we only now that a packet is coming).
>> Or maybe could we have a different loglevel option for default input/output policy ?
>>
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>
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