Re: [logs] Charset selection (Was: Re: EventLog library)

betat_private

2003-01-08T20:34:34 Darren Reed:
> Is there a compelling reason to keep traffic between log daemons in
> "text strings" rather than wrap them up in something else with byte
> counts and no CR-LF stuff and just exchange typed data in a manner
> that allows you to be ignorant of what character set is in use ?

I'd argue rather that if we aren't going to ignore this issue, we
should settle it by mandating strict 7-bit US-ASCII printables
in the normal 8bit embedding. If we produce a specification or
implementation that's tolerant of 8bit messages, we're setting
ourselves up for a bomb to go off under our kiesters down the
road, when different log text processors apply radically different
interpretations to the exact same logged message --- and some of
those interpretations tickle bugs causing security problems.

If instead we force people who want to syslog kanji, or accented
characters, or anything else outside of strict 7bit US-ASCII to go
with some encoding onto US-ASCII, like e.g. SGML entity references;
then we'd have the characteristic that implementations would have
the privilege of being blind to charsets without running a risk of
introducing security problems.

This isn't a critique of the appropriateness of the general concept
of being binary-transparent and letting people pick interpretations
that suit 'em; in many venues that works really well. But logging
tends to lie fairly near to security concerns, and right now
charsets are a fraught area, with different people advocating
different solutions, applying different interpretations to
8-bit-binary data, and in some cases opening unexpected ways to
slip dangerous embedded characters past screeners trying to block
them.

Suppose someone wants to write a nice generic logfile viewer, that
presents sliced-n-diced log data to a web browser. They're already
going to be having to escape "<", ">", and "&" in the logged text
before croaking it out at the browser. Let's not force them to also
know every possible way anyone can ever invent to encode those in
any possible multibyte charset.

-Bennett