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Re: [RESEND PATCH v9] Mutex: Add pthread mutex tunables
- From: Florian Weimer <fweimer at redhat dot com>
- To: Carlos O'Donell <carlos at redhat dot com>
- Cc: Kemi Wang <kemi dot wang at intel dot com>, Glibc alpha <libc-alpha at sourceware dot org>
- Date: Tue, 11 Dec 2018 12:13:43 +0100
- Subject: Re: [RESEND PATCH v9] Mutex: Add pthread mutex tunables
- References: <1542851105-16956-1-git-send-email-kemi.wang@intel.com> <87h8g02bfx.fsf@oldenburg.str.redhat.com> <82342cea-60ea-f8ea-4735-007144641f7a@redhat.com>
* Carlos O'Donell:
> On 11/29/18 9:41 AM, Florian Weimer wrote:
>> * Kemi Wang:
>>
>>> +# SXID_ERASE: (default) Don't read for AT_SECURE binaries and
>>> +# removed so that child processes can't read it.
>>
>> I think this will not work as intended for libpthread tunables because
>> if libpthread is not linked in, no code in nptl/nptl-init.c ever runs.
>>
>> I think we need to move the tunable to elf/dl-tunables.list, parse it
>> there, and communicate the result to libpthread, possibly via
>> _rtld_global_ro.
>
> This is a fairly arcane issue with tunables, are we certain this is a
> problem?
My concern is about the quoted part, from a new file added in this
patch. The security controls will not work reliably in this context
because libpthread may never be loaded and the promised removal never
happens.
Thanks,
Florian