X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/e6992480e2e0cf965650f84aa97e01fe0fa71544..1c5a9c0cc8265a6a552b1500eb3a3d2aa17b9720:/doc/plugins/po.mdwn diff --git a/doc/plugins/po.mdwn b/doc/plugins/po.mdwn index 4350e1a73..f3b70b5f7 100644 --- a/doc/plugins/po.mdwn +++ b/doc/plugins/po.mdwn @@ -5,6 +5,8 @@ This plugin adds support for multi-lingual wikis, translated with gettext, using [po4a](http://po4a.alioth.debian.org/). It depends on the Perl `Locale::Po4a::Po` library (`apt-get install po4a`). +As detailed bellow in the security section, `po4a` is subject to +denial-of-service attacks before version 0.35. [[!toc levels=2]] @@ -31,6 +33,12 @@ Example: `bla/page.fr.po` is the PO "message catalog" used to translate `bla/page.mdwn` into French; if `usedirs` is enabled, it is rendered as `bla/page/index.fr.html`, else as `bla/page.fr.html` +(In)Compatibility +================= + +This plugin does not support the `indexpages` mode. If you don't know +what it is, you probably don't care. + Configuration ============= @@ -47,7 +55,7 @@ Supported languages languages, such as: po_slave_languages => { 'fr' => 'Français', - 'es' => 'Castellano', + 'es' => 'Español', 'de' => 'Deutsch', } @@ -64,39 +72,40 @@ worry about excluding them explicitly from this [[ikiwiki/PageSpec]]. Internal links -------------- +### Links targets + The `po_link_to` option in `ikiwiki.setup` is used to decide how internal links should be generated, depending on web server features and site-specific preferences. -### Default linking behavior +#### Default linking behavior If `po_link_to` is unset, or set to `default`, ikiwiki's default linking behavior is preserved: `\[[destpage]]` links to the master language's page. -### Link to current language +#### Link to current language If `po_link_to` is set to `current`, `\[[destpage]]` links to the `destpage`'s version written in the current page's language, if available, *i.e.*: -- `foo/destpage/index.LL.html` if `usedirs` is enabled -- `foo/destpage.LL.html` if `usedirs` is disabled +* `foo/destpage/index.LL.html` if `usedirs` is enabled +* `foo/destpage.LL.html` if `usedirs` is disabled -### Link to negotiated language +#### Link to negotiated language If `po_link_to` is set to `negotiated`, `\[[page]]` links to the negotiated preferred language, *i.e.* `foo/page/`. (In)compatibility notes: -- if `usedirs` is disabled, it does not make sense to set `po_link_to` +* if `usedirs` is disabled, it does not make sense to set `po_link_to` to `negotiated`; this option combination is neither implemented nor allowed. -- if the web server does not support Content Negotiation, setting +* if the web server does not support Content Negotiation, setting `po_link_to` to `negotiated` will produce a unusable website. - Server support ============== @@ -105,7 +114,8 @@ Apache Using Apache `mod_negotiation` makes it really easy to have Apache serve any page in the client's preferred language, if available. -This is the default Debian Apache configuration. + +Add 'Options MultiViews' to the wiki directory's configuration in Apache. When `usedirs` is enabled, one has to set `DirectoryIndex index` for the wiki context. @@ -114,6 +124,8 @@ Setting `DefaultLanguage LL` (replace `LL` with your default MIME language code) for the wiki context can help to ensure `bla/page/index.en.html` is served as `Content-Language: LL`. +For details, see [Apache's documentation](http://httpd.apache.org/docs/2.2/content-negotiation.html). + lighttpd -------- @@ -141,43 +153,21 @@ display things only on translatable or translation pages. The `OTHERLANGUAGES` loop provides ways to display other languages' versions of the same page, and the translations' status. -One typically adds the following code to `templates/page.tmpl`: - - -
- -
-
- -The following variables are available inside the loop (for every page in): - -- `URL` - url to the page -- `CODE` - two-letters language code -- `LANGUAGE` - language name (as defined in `po_slave_languages`) -- `MASTER` - is true (1) if, and only if the page is a "master" page -- `PERCENT` - for "slave" pages, is set to the translation completeness, in percents +An example of its use can be found in the default +`templates/page.tmpl`. In case you want to customize it, the following +variables are available inside the loop (for every page in): + +* `URL` - url to the page +* `CODE` - two-letters language code +* `LANGUAGE` - language name (as defined in `po_slave_languages`) +* `MASTER` - is true (1) if, and only if the page is a "master" page +* `PERCENT` - for "slave" pages, is set to the translation completeness, in percents ### Display the current translation status The `PERCENTTRANSLATED` variable is set to the translation -completeness, expressed in percent, on "slave" pages. - -One can use it this way: - - -
- -
-
+completeness, expressed in percent, on "slave" pages. It is used by +the default `templates/page.tmpl`. Additional PageSpec tests ------------------------- @@ -222,8 +212,8 @@ preferred `$EDITOR`, without needing to be online. Markup languages support ------------------------ -Markdown is well supported. Some other markup languages supported by -ikiwiki mostly work, but some pieces of syntax are not rendered +[[Markdown|mdwn]] is well supported. Some other markup languages supported +by ikiwiki mostly work, but some pieces of syntax are not rendered correctly on the slave pages: * [[reStructuredText|rst]]: anonymous hyperlinks and internal @@ -234,272 +224,101 @@ correctly on the slave pages: could be used to support them, but they would need a security audit * other markup languages have not been tested. +Security +======== -TODO -==== - -Security checks ---------------- - -### Security history - -The only past security issues I could find in GNU gettext and po4a -are: - -- [CVE-2004-0966](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-0966), - *i.e.* [Debian bug #278283](http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=278283): - the autopoint and gettextize scripts in the GNU gettext package - 1.14 and later versions, as used in Trustix Secure Linux 1.5 - through 2.1 and other operating systems, allows local users to - overwrite files via a symlink attack on temporary files. -- [CVE-2007-4462](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-4462): - `lib/Locale/Po4a/Po.pm` in po4a before 0.32 allows local users to - overwrite arbitrary files via a symlink attack on the - gettextization.failed.po temporary file. - -**FIXME**: check whether this plugin would have been a possible attack -vector to exploit these vulnerabilities. - -Depending on my mood, the lack of found security issues can either -indicate that there are none, or reveal that no-one ever bothered to -find (and publish) them. - -### PO file features - -Can any sort of directives be put in po files that will cause mischief -(ie, include other files, run commands, crash gettext, whatever)? - -> No [documented](http://www.gnu.org/software/gettext/manual/gettext.html#PO-Files) -> directive is supposed to do so. [[--intrigeri]] - -### Running po4a on untrusted content - -Are there any security issues on running po4a on untrusted content? - -To say the least, this issue is not well covered, at least publicly: - -- the documentation does not talk about it; -- grep'ing the source code for `security` or `trust` gives no answer. - -On the other hand, a po4a developer answered my questions in -a convincing manner, stating that processing untrusted content was not -an initial goal, and analysing in detail the possible issues. - -#### Already checked - -- the core (`Po.pm`, `Transtractor.pm`) should be safe -- po4a source code was fully checked for other potential symlink - attacks, after discovery of one such issue -- the only external program run by the core is `diff`, in `Po.pm` (in - parts of its code we don't use) -- `Locale::gettext`: only used to display translated error messages -- Nicolas François "hopes" `DynaLoader` is safe, and has "no reason to - think that `Encode` is not safe" -- Nicolas François has "no reason to think that `Encode::Guess` is not - safe". The po plugin nevertheless avoids using it by defining the - input charset (`file_in_charset`) before asking `Transtractor` to - read any file. NB: this hack depends on po4a internals to stay - the same. - -##### Locale::Po4a modules - -The modules we want to use have to be checked, as not all are safe -(e.g. the LaTeX module's behaviour is changed by commands included in -the content); they may use regexps generated from the content. - -`Chooser.pm` only loads the plugin we tell it too: currently, this -means the `Text` module only. - -`Text` module (I checked the CVS version): - -- it does not run any external program -- only `do_paragraph()` builds regexp's that expand untrusted - variables; they seem safe to me, but someone more expert than me - will need to check. Joey? - - > 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. - -> 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 +[[po/discussion]] contains a detailed security analysis of this plugin +and its dependencies. -`Term::ReadKey` is not a hard dependency in our case, *i.e.* po4a -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. +When using po4a older than 0.35, it is recommended to uninstall +`Text::WrapI18N` (Debian package `libtext-wrapi18n-perl`), in order to +avoid a potential denial of service. -`Term::ReadKey` has too far reaching implications for us to -be able to guarantee anything wrt. security. - -> 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". I did not manage to crash it with `zzuf`, nor was able to find -any past security holes. - -### msgfmt - -`isvalidpo()` runs this external program. - -* 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. - -### Fuzzing input - -Test conditions: - -- a 21M file containing 100 concatenated copies of all the files in my - `/usr/share/common-licenses/`; I had no existing PO file or - translated versions at hand, which renders these tests - quite incomplete. -- po4a was the Debian 0.34-2 package; the same tests were also run - after replacing the `Text` module with the CVS one (the core was not - changed in CVS since 0.34-2 was released), without any significant - difference in the results. -- Perl 5.10.0-16 - -#### po4a-gettextize - -`po4a-gettextize` uses more or less the same po4a features as our -`refreshpot` function. - -Without specifying an input charset, zzuf'ed `po4a-gettextize` quickly -errors out, complaining it was not able to detect the input charset; -it leaves no incomplete file on disk. - -So I had to pretend the input was in UTF-8, as does the po plugin. - -Two ways of crashing were revealed by this command-line: - - zzuf -vc -s 0:100 -r 0.1:0.5 \ - po4a-gettextize -f text -o markdown -M utf-8 -L utf-8 \ - -m LICENSES >/dev/null - -They are: - - Malformed UTF-8 character (UTF-16 surrogate 0xdcc9) in substitution iterator at /usr/share/perl5/Locale/Po4a/Po.pm line 1443. - Malformed UTF-8 character (fatal) at /usr/share/perl5/Locale/Po4a/Po.pm line 1443. - -and - - Malformed UTF-8 character (UTF-16 surrogate 0xdcec) in substitution (s///) at /usr/share/perl5/Locale/Po4a/Po.pm line 1443. - Malformed UTF-8 character (fatal) at /usr/share/perl5/Locale/Po4a/Po.pm line 1443. - -Perl seems to exit cleanly, and an incomplete PO file is written on -disk. I not sure whether if this is a bug in Perl or in `Po.pm`. - -> It's fairly standard perl behavior when fed malformed utf-8. As long as it doesn't -> crash ikiwiki, it's probably acceptable. Ikiwiki can do some similar things itself when fed malformed utf-8 (doesn't crash tho) --[[Joey]] - -#### po4a-translate - -`po4a-translate` uses more or less the same po4a features as our -`filter` function. +TODO +==== -Without specifying an input charset, same behaviour as -`po4a-gettextize`, so let's specify UTF-8 as input charset as of now. +Better links +------------ - zzuf -cv \ - po4a-translate -d -f text -o markdown -M utf-8 -L utf-8 \ - -k 0 -m LICENSES -p LICENSES.fr.po -l test.fr +Once the fix to +[[bugs/pagetitle_function_does_not_respect_meta_titles]] from +[[intrigeri]]'s `meta` branch is merged into ikiwiki upstream, the +generated links' text will be optionally based on the page titles set +with the [[meta|plugins/meta]] plugin, and will thus be translatable. +It will also allow displaying the translation status in links to slave +pages. Both were implemented, and reverted in commit +ea753782b222bf4ba2fb4683b6363afdd9055b64, which should be reverted +once [[intrigeri]]'s `meta` branch is merged. + +An integration branch, called `meta-po`, merges [[intrigeri]]'s `po` +and `meta` branches, and thus has this additional features. + +Language display order +---------------------- + +Jonas pointed out that one might want to control the order that links to +other languages are listed, for various reasons. Currently, there is no +order, as `po_slave_languages` is a hash. It would need to be converted +to an array to support this. (If twere done, twere best done quickly.) +--[[Joey]] + +Pagespecs +--------- -... prints tons of occurences of the following error, but a complete -translated document is written (obviously with some weird chars -inside): +I was suprised that, when using the map directive, a pagespec of "*" +listed all the translated pages as well as regular pages. That can +make a big difference to an existing wiki when po is turned on, +and seems generally not wanted. +(OTOH, you do want to match translated pages by +default when locking pages.) --[[Joey]] - Use of uninitialized value in string ne at /usr/share/perl5/Locale/Po4a/TransTractor.pm line 854. - Use of uninitialized value in string ne at /usr/share/perl5/Locale/Po4a/TransTractor.pm line 840. - Use of uninitialized value in pattern match (m//) at /usr/share/perl5/Locale/Po4a/Po.pm line 1002. +Edit links on untranslated pages +-------------------------------- -While: +If a page is not translated yet, the "translated" version of it +displays wikilinks to other, existing (but not yet translated?) +pages as edit links, as if those pages do not exist. - zzuf -cv -s 0:10 -r 0.001:0.3 \ - po4a-translate -d -f text -o markdown -M utf-8 -L utf-8 \ - -k 0 -m LICENSES -p LICENSES.fr.po -l test.fr +That's really confusing, especially as clicking such a link +brings up an edit form to create a new, english page. -... seems to lose the fight, at the `readpo(LICENSES.fr.po)` step, -against some kind of infinite loop, deadlock, or any similar beast. +This is with po_link_to=current or negotiated. With default, it doesn't +happen.. -The root of this bug lies in `Text::WrapI18N`, see above for -possible solutions. +Also, this may only happen if the page being linked to is coming from an +underlay, and the underlays lack translation to a given language. +--[[Joey]] -gettext/po4a rough corners +Double commits of po files -------------------------- -- fix infinite loop when synchronizing two ikiwiki (when checkouts - live in different directories): say bla.fr.po has been updated in - repo2; pulling repo2 from repo1 seems to trigger a PO update, that - changes bla.fr.po in repo1; then pushing repo1 to repo2 triggers - a PO update, that changes bla.fr.po in repo2; etc.; quickly fixed in - `629968fc89bced6727981c0a1138072631751fee`, by disabling references - in Pot files. Using `Locale::Po4a::write_if_needed` might be - a cleaner solution. (warning: this function runs the external - `diff` program, have to check security) -- new translations created in the web interface must get proper - charset/encoding gettext metadata, else the next automatic PO update - removes any non-ascii chars; possible solution: put such metadata - into the Pot file, and let it propagate; should be fixed in - `773de05a7a1ee68d2bed173367cf5e716884945a`, time will tell. +When adding a new english page, the po files are created, committed, +and then committed again. The second commit makes this change: -Better links ------------- + -"Content-Type: text/plain; charset=utf-8\n" + -"Content-Transfer-Encoding: ENCODING" + +"Content-Type: text/plain; charset=UTF-8\n" + +"Content-Transfer-Encoding: ENCODING\n" -### Page title in links - -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 into ikiwiki upstream, though. +Same thing happens when a change to an existing page triggers a po file +update. --[[Joey]] -Robustness tests ----------------- +Ugly messages with empty files +------------------------------ -### Enabling/disabling the plugin +If there are empty .mdwn files, the po plugin displays some ugly messages. -- enabling the plugin with `po_translatable_pages` set -- enabling the plugin without `po_translatable_pages` set: **OK** -- disabling the plugin: **OK** - -### Changing the plugin config - -- adding existing pages to `po_translatable_pages`: **OK** -- removing existing pages from `po_translatable_pages`: **OK** -- adding a language to `po_slave_languages`: **OK** -- removing a language from `po_slave_languages`: **OK** -- changing `po_master_language`: **OK** -- replacing `po_master_language` with a language previously part of - `po_slave_languages`: needs two rebuilds, but **OK** (this is quite - a perverse test actually) - -### Creating/deleting/renaming pages +Translation of directives +------------------------- -All cases of master/slave page creation/deletion/rename, both via RCS -and via CGI, have been tested. +If a translated page contains a directive, it may expand to some english +text, or text in whatever single language ikiwiki is configured to "speak". -### Misc +Maybe there could be a way to switch ikiwiki to speaking another language +when building a non-english page? Then the directives would get translated. -- general test with `usedirs` disabled: **OK** -- general test with `indexpages` enabled -- general test with `po_link_to=default` +(We also will need this in order to use translated templates, when they are +available.) Documentation -------------