Date: Tue, 17 May 2011 02:26:42 +0400 From: "Dmitry V. Levin" <ldv@...linux.org> To: oss-security@...ts.openwall.com Subject: Re: Multiple libraries privilege checking 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 Content of type "application/pgp-signature" skipped
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