-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.
-
-#### To be checked
-
-##### 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; we
- currently only use the `Text` module
-- the `Text` module does not run any external program
-- check that no module is loaded by `Chooser.pm`, when we tell it to
- load the `Text` one
-- `nsgmls` is used by `Sgml.pm`
-
-##### 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]]
-
-##### Term::ReadKey
-
-`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.
-
-If `$ENV{COLUMNS}` is not set, `Locale::Po4a::Common` uses
-`Term::ReadKey::GetTerminalSize()` to get the terminal size. How safe
-is this?
-
-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]]
-
-### msgmerge
-
-`refreshpofiles()` runs this external program. A po4a developer
-answered he does "not expect any security issues from it".
-
-### Fuzzing input
-
-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]]
-
-> po4a was not fuzzy-tested, but according to one of its developers,
-> "it would be really appreciated". [[--intrigeri]]
-
-gettext/po4a rough corners
---------------------------
-
-- 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.
-
-Misc. improvements
-------------------
sipb-www / ikiwiki.git / blobdiff