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Re: RFC: Shadow Stack support in glibc
- From: Szabolcs Nagy <szabolcs dot nagy at arm dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: nd at arm dot com, Yu-cheng Yu <yu-cheng dot yu at intel dot com>, Florian Weimer <fweimer at redhat dot com>, GNU C Library <libc-alpha at sourceware dot org>, Igor Tsimbalist <tigor dot tools at gmail dot com>, "Shanbhogue, Vedvyas" <vedvyas dot shanbhogue at intel dot com>
- Date: Fri, 09 Jun 2017 12:21:58 +0100
- Subject: Re: RFC: Shadow Stack support in glibc
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On 09/06/17 12:15, Szabolcs Nagy wrote:
> On 09/06/17 12:13, H.J. Lu wrote:
>> On Fri, Jun 9, 2017 at 2:05 AM, Szabolcs Nagy <email@example.com> wrote:
>>> fixing setjmp/longjmp is non-trivial since jmpbuf size is abi,
>>> it may be possible to do without saving ssp into jmpbuf though.
>> Shadow stack is enabled at run-time only if all sources are compiled
>> with shadow stack enabled compiler against shadow stack enabled
>> glibc. setjmp/longjmp are implemented with IFUNC, which uses
>> the old setjmp/longjmp if shadow stack is off and uses the new
>> setjmp/longjmp if shadow stack is on.
> that is not enough.
> jmpbuf may be used in user code independently of setjmp/longjmp.
oh wait, are you saying shadow stack is a new abi
and all libraries on the system need to be compiled
for that abi?