On 12/5/25 2:02 PM, Robert Obkircher wrote: > > On 12/5/25 12:58, Stefan Hanreich wrote: >> Tested this in a similar vein as the nftables one: >> * "normal" comments >> * comments that are too long >> * comments that are too long and do not truncate nicely at the 255 >> boundary >> * comments in security groups >> * emojis in comments >> >> afaict the PVECOMMENT: prefix is merely visual? it doesn't serve any >> functional purpose? At least a quick monkey-patch removing it didn't >> break anything and judging from the source code it seems fine as well. >> Imo it would be fine then to completely omit it then (even in the case >> where rule comments start with PVESIG). > > I think the parser in iptables_get_chains would at least temporarily set > an invalid signature on the chain and only override it later because the > real PVESIG: rule is always present and printed last. Relying on that > seemed a bit sketchy.
Do you mean the 'unknown' signature? Seems like this happens due to this line here in the parser callback [1]. The other regex matches only `PVESIG:` comments anyway. If we remove the prefix, adding a comment with a `PVESIG:` prefix would do that, I guess? [1] https://git.proxmox.com/?p=pve-firewall.git;a=blob;f=src/PVE/Firewall.pm;h=93f8c34466fd61bc646439275597aa24b8718053;hb=HEAD#l2093 >> >> mb someone with more experience with perl and utf-8 can chime in on the >> truncation logic? >> >> Tested-by: Stefan Hanreich <[email protected]> >> >> On 12/1/25 1:33 PM, Robert Obkircher wrote: >>> Use the iptables comment extension to include comments from the UI. >>> Prefix them with "PVECOMMENT:" to avoid interfering with the existing >>> "PVESIG:$sig" comments, which are used to store signatures for change >>> detection. >>> >>> The total length of the (unescaped) comments is limited to 255 utf8 >>> bytes. According to the man page it could be up to 256 characters, but >>> the actual implementation seems to zero terminate the buffer before >>> saving. For example, the following command produces a 255 char comment >>> ending in 'a': >>> iptables -A PVEFW-HOST-IN -m comment --comment $(python3 -c >>> "print('ab'*256)") >>> >>> Unlike the iptables command, this version truncates to valid utf8. >>> >>> Signed-off-by: Robert Obkircher <[email protected]> >>> --- >>> src/PVE/Firewall.pm | 17 ++++++++++++++++- >>> 1 file changed, 16 insertions(+), 1 deletion(-) >>> >>> diff --git a/src/PVE/Firewall.pm b/src/PVE/Firewall.pm >>> index 93f8c34..688829a 100644 >>> --- a/src/PVE/Firewall.pm >>> +++ b/src/PVE/Firewall.pm >>> @@ -2271,6 +2271,20 @@ sub ipt_gen_src_or_dst_match { >>> return $match; >>> } >>> +sub print_ipt_comment { >>> + my ($comment) = @_; >>> + return "" if !defined($comment) || $comment eq ""; >>> + $comment = encode("utf8", $comment, Encode::LEAVE_SRC); >>> + $comment = "PVECOMMENT:$comment"; # avoid any confusion with >>> PVESIG comments >>> + >>> + # man iptables-extensions says 256 chars, but the code only >>> saves 255 >>> + $comment = substr($comment, 0, 255); >>> + $comment = encode('utf8', decode('utf8', $comment, >>> Encode::FB_QUIET | Encode::LEAVE_SRC)); >>> + >>> + $comment =~ s/[\\"']/\\$1/g; # escape logic from >>> xtables_save_string seems like there is still an issue here - setting the comment `###"` I get several: Use of uninitialized value $1 in concatenation (.) or string at /usr/share/perl5/PVE/Firewall.pm line 2284. Can be easily checked via `pve-firewall compile`. >>> + return " -m comment --comment \"$comment\""; # never omit quotes >>> because of the colon >>> +} >>> + >>> # convert a %rule to an array of iptables commands >>> sub ipt_rule_to_cmds { >>> my ($rule, $chain, $ipversion, $cluster_conf, $fw_conf, $vmid) >>> = @_; >>> @@ -2375,7 +2389,8 @@ sub ipt_rule_to_cmds { >>> my $logaction = get_log_rule_base($chain, $vmid, $rule- >>> >{logmsg}, $loglevel); >>> push @iptcmds, "-A $chain $matchstr $logaction"; >>> } >>> - push @iptcmds, "-A $chain $matchstr $targetstr"; >>> + my $comment = print_ipt_comment($rule->{comment}); >>> + push @iptcmds, "-A $chain $matchstr $targetstr$comment"; >>> return @iptcmds; >>> } >>> >> _______________________________________________ pve-devel mailing list [email protected] https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
