On Sun, Dec 28, 2025 at 11:44:05PM +0100, Dennis Camera wrote:
> >Synopsis: OpenSSH 10.2: Illegal instruction in AES-256-GCM cipher on i686
> >Category: user
> >Environment:
> System : OpenBSD 7.8
> Details : OpenBSD 7.8 (GENERIC) #113: Sun Oct 12 15:23:27 MDT 2025
>
> [email protected]:/usr/src/sys/arch/i386/compile/GENERIC
>
> Architecture: OpenBSD.i386
> Machine : i386
> >Description:
> When the OpenSSH client is used on i686 (Intel Pentium 2)
> the ssh process crashes due to an Illegal instruction.
>
> A similar problem also occurs when a client tries to
> connect to an OpenSSH server running on i686 using the
> [email protected] cipher.
> cpu0: Intel Celeron ("GenuineIntel" 686-class, 256KB L2 cache) 367 MHz,
> 06-06-0a, patch 0000000d
> cpu0:
> FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PSE36,MMX,FXSR,PERF,MELTDOWN
This is a pure MMX machine without SSE and therefore is the same bug as
reported here two weeks ago:
https://marc.info/?l=libressl&m=176581546511021&w=2
Recent logic changes made a mistake due to misleading naming of the i386
perlasm routines where the MMX routines also use SSE instructions.
The fix is to use this code only for machines with MMX + SSE. My
understanding is that jsing has a fix in mind, which he should land.
