diff options
| -rw-r--r-- | doc/plugins/po.mdwn | 109 |
1 files changed, 24 insertions, 85 deletions
diff --git a/doc/plugins/po.mdwn b/doc/plugins/po.mdwn index 9298b3d37..4350e1a73 100644 --- a/doc/plugins/po.mdwn +++ b/doc/plugins/po.mdwn @@ -301,8 +301,6 @@ an initial goal, and analysing in detail the possible issues. read any file. NB: this hack depends on po4a internals to stay the same. -#### To be checked - ##### Locale::Po4a modules The modules we want to use have to be checked, as not all are safe @@ -321,52 +319,19 @@ means the `Text` module only. > Freaky code, but seems ok due to use of `quotementa`. +#### To be checked + ##### Text::WrapI18N `Text::WrapI18N` can cause DoS (see the [Debian bug #470250](http://bugs.debian.org/470250)), but it is optional and we do not need the features it provides. -It is loaded if available by `Locale::Po4a::Common`; looking at the -code, I'm not sure we can prevent this at all, but maybe some symbol -table manipulation tricks could work; overriding -`Locale::Po4a::Common::wrapi18n` may be easier. I'm no expert at all -in this field. Joey? [[--intrigeri]] - -> Update: Nicolas François suggests we add an option to po4a to -> disable it. It would do the trick, but only for people running -> a brand new po4a (probably too late for Lenny). Anyway, this option -> would have to take effect in a `BEGIN` / `eval` that I'm not -> familiar with. I can learn and do it, in case no Perl wizard -> volunteers to provide the po4a patch. [[--intrigeri]] - ->> That doesn't really need to be in a BEGIN. This patch moves it to ->> `import`, and makes this disable wrap18n: ->> `use Locale::Po4a::Common q{nowrapi18n}` --[[Joey]] - -<pre> ---- /usr/share/perl5/Locale/Po4a/Common.pm 2008-07-21 14:54:52.000000000 -0400 -+++ Common.pm 2008-11-11 18:27:34.000000000 -0500 -@@ -30,8 +30,16 @@ - use strict; - use warnings; - --BEGIN { -- if (eval { require Text::WrapI18N }) { -+sub import { -+ my $class=shift; -+ my $wrapi18n=1; -+ if ($_[0] eq 'nowrapi18n') { -+ shift; -+ $wrapi18n=0; -+ } -+ $class->export_to_level(1, $class, @_); -+ -+ if ($wrapi18n && eval { require Text::WrapI18N }) { - - # Don't bother determining the wrap column if we cannot wrap. - my $col=$ENV{COLUMNS}; -</pre> +> I proposed a patch based on Joey's to po4a-devel, allowing to fully +> disable this module's use. When it is merged upstream, we'll need to add +> `use Locale::Po4a::Common qw(nowrapi18n)` to `po.pm`, before loading +> any other `Locale::Po4a` module. A versioned dependency may be needed. +> --[[intrigeri]] ##### Term::ReadKey @@ -375,46 +340,29 @@ works nicely without it. But the po4a Debian package recommends `libterm-readkey-perl`, so it will probably be installed on most systems using the po plugin. -If `$ENV{COLUMNS}` is not set, `Locale::Po4a::Common` uses -`Term::ReadKey::GetTerminalSize()` to get the terminal size. How safe -is this? +`Term::ReadKey` has too far reaching implications for us to +be able to guarantee anything wrt. security. -Part of `Term::ReadKey` is written in C. Depending on the runtime -platform, this function use ioctl, environment, or C library function -calls, and may end up running the `resize` command (without -arguments). - -IMHO, using Term::ReadKey has too far reaching implications for us to -be able to guarantee anything wrt. security. Since it is anyway of no -use in our case, I suggest we define `ENV{COLUMNS}` before loading -`Locale::Po4a::Common`, just to be on the safe side. Joey? -[[--intrigeri]] - -> Update: adding an option to disable `Text::WrapI18N`, as Nicolas -> François suggested, would as a bonus disable `Term::ReadKey` -> as well. [[--intrigeri]] +> The option that disables `Text::WrapI18N` also disables +> `Term::ReadKey` as a consequence. [[--intrigeri]] ### msgmerge -`refreshpofiles()` runs this external program. A po4a developer -answered he does "not expect any security issues from it". +`refreshpofiles()` runs this external program. -### msgfmt +A po4a developer answered he does "not expect any security issues from +it". I did not manage to crash it with `zzuf`, nor was able to find +any past security holes. -`isvalidpo()` runs this external program. Its security should be checked. +### msgfmt -### Fuzzing input +`isvalidpo()` runs this external program. -I was not able to find any public information about gettext or po4a -having been tested with a fuzzing program, such as `zzuf` or `fusil`. -Moreover, some gettext parsers seem to be quite -[easy to crash](http://fusil.hachoir.org/trac/browser/trunk/fuzzers/fusil-gettext), -so it might be useful to bang msgmerge/po4a's heads against such -a program in order to easily detect some of the most obvious DoS. -[[--intrigeri]] +* I could not manage to make it behave badly using zzuf, it exits + cleanly when too many errors are detected. +* I could not find any past security holes. -> po4a was not fuzzy-tested, but according to one of its developers, -> "it would be really appreciated". [[--intrigeri]] +### Fuzzing input Test conditions: @@ -489,18 +437,9 @@ While: ... seems to lose the fight, at the `readpo(LICENSES.fr.po)` step, against some kind of infinite loop, deadlock, or any similar beast. -It does not seem to eat memory, though. - -Whatever format module is used does not change anything. This is thus -probably a bug in po4a's core or in a lib it depends on. - -The sub `read`, in `TransTractor.pm`, seems to be a good debugging -starting point. - -#### msgmerge -`msgmerge` is run in our `refreshpofiles` function. I did not manage -to crash it with `zzuf`. +The root of this bug lies in `Text::WrapI18N`, see above for +possible solutions. gettext/po4a rough corners -------------------------- @@ -529,7 +468,7 @@ Using the fix to [[bugs/pagetitle_function_does_not_respect_meta_titles]] from [[intrigeri]]'s `meta` branch, the generated links' text is based on the page titles set with the [[meta|plugins/meta]] plugin. This has to -be merged upstream, though. +be merged into ikiwiki upstream, though. Robustness tests ---------------- |