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Re: [PATCH 0/2] Multiarch hooks for memcpy variants
On Monday 14 August 2017 06:50 PM, Szabolcs Nagy wrote:
> i only proposed plt for this specific case on
> the grounds that i expect _chk to be obsoleted
> and instead the check will be in user code
> (which has the same semantics as if plt was
> used in libc, the memcpy call is interposable)
Right, but the test case puts in a blanket override, so it becomes
useless for testing any future inadvertent PLT introductions.
>> usage for memcpy, which we don't want. Hence my patch is probably the
>> best compromise, especially since there is precedent for the approach in
>> x86.
>
> it is probably best from performance point
> of view.
>
> but i'm not yet convinced that __memcpy_chk is
> performance critical, if not, then i'd rather
> not add ifuncs.
>
> does anyone know how commonly distros build
> with _FORTIFY_SOURCE?
Fedora does it by default:
-14: __global_compiler_flags -O2 -g -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong
--param=ssp-buffer-size=4 -grecord-gcc-switches %{_hardened_cflags}
Siddhesh