Bug 18046 - Another security hole in usermode/glibc
Summary: Another security hole in usermode/glibc
Alias: None
Product: Red Hat Linux
Classification: Retired
Component: usermode
Version: 7.0
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Nalin Dahyabhai
QA Contact:
URL: http://www.securityfocus.com/archive/...
Keywords: Security
Depends On:
TreeView+ depends on / blocked
Reported: 2000-10-02 00:47 UTC by Chris Evans
Modified: 2008-05-01 15:37 UTC (History)
1 user (show)

Clone Of:
Last Closed: 2000-10-16 17:09:39 UTC

Attachments (Terms of Use)

Description Chris Evans 2000-10-02 00:47:17 UTC

Please see the local root exploit posted to Bugtraq,


Issue is usermode passing untrusted user environment down to the programs
it launches.

Of course, it would be nice if glibc were more paranoid about ".." in
locale paths.

Comment 1 Nalin Dahyabhai 2000-10-02 05:20:00 UTC
We're going to have to add a whitelist and use execle() to run the right
program, but we need to preserve a sane LANG rather than let the default "C" be
used.  Might have to make a specific exception for LANG, though.

Comment 2 Jakub Jelinek 2000-10-03 08:23:48 UTC
Actually, glibc takes care about slashes, not .. in locale paths. Anyway, I
don't think glibc should restrict LANG/LC_ALL for non-setuid root, maybe it
should remove LC_*/LANG from environment for setuid programs if it contains
/,  I'll talk with Ulrich. Anyway, IMHO all suid/sgid apps which exec something
should be careful by themselves.
In ftp://ultra.linux.cz/private/usermode/ are updated usermode RPMs, Nalin,
could you please retest the bugtraq exploit with it and issue erratas ASAP
(like today) for all distributions shipping usermode? This is really serious.
And we should check all suid/sgid apps which ever exec for this kind of thing
as well.

Comment 3 Nalin Dahyabhai 2000-10-05 18:33:58 UTC
Still not sure what to do about other distributions, but usermode with a couple
of minor bug fixes is now in the pipeline.

Comment 4 Chris Evans 2000-10-16 17:09:36 UTC
Errata is released - fancy marking the bug RESOLVED + ERRATA?

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