oss-sec mailing list archives
Re: Multiple libraries privilege checking
From: "Dmitry V. Levin" <ldv () altlinux org>
Date: Tue, 17 May 2011 02:26:42 +0400
On Mon, May 16, 2011 at 10:56:37PM +0400, Solar Designer wrote:
On Mon, May 16, 2011 at 04:27:41PM +0200, Sebastian Krahmer wrote:Its probably about time to review libraries that are commonly linked to (formerly-) suid programs, such as libldap, libssl etc. In near future, in the advent of file caps they are often lacking proper checks.Good idea.They usually just compare uid against euid (not even gid sometimes) and do not check the dumpable flag or AT_SECURE (dont know whether glibc exports a proper function to easily check that at all).glibc exports the __libc_enable_secure variable, which is initialized based on AT_* including AT_SECURE. It also exports __secure_getenv().
There is a problem: in upstream glibc, __libc_enable_secure is placed into GLIBC_PRIVATE section, thus making it unavailable in most of rpm-based distros. This is surely not the case in Owl and ALT Linux, where __libc_enable_secure is legal interface for use in applications, and some essential libraries are already patched to use __libc_enable_secure instead of uid comparisons. -- ldv
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Current thread:
- Multiple libraries privilege checking Sebastian Krahmer (May 16)
- Re: Multiple libraries privilege checking Solar Designer (May 16)
- Re: Multiple libraries privilege checking Dmitry V. Levin (May 16)
- Re: Multiple libraries privilege checking Sebastian Krahmer (May 17)
- Re: Multiple libraries privilege checking Solar Designer (May 18)
- Re: Multiple libraries privilege checking Sebastian Krahmer (May 22)
- Re: Multiple libraries privilege checking yersinia (May 18)
- Re: Multiple libraries privilege checking Solar Designer (May 18)
- Re: Multiple libraries privilege checking Solar Designer (May 16)
- Re: Multiple libraries privilege checking Florian Weimer (Jun 19)