I've received this message from a Linux list, since I don't own a Pentiu
m
I'm unable to test this.
        Forgive me to put this OT on the list, my intention is not to start anot
her
endless OT tread.

Ricardo Seixas.

----------------------------------------------------------------------------
-------

>>
>> There is a SERIOUS bug in all pentium CPUs. The following
>> code will crash any machine running on a pentium CPU, MMX or no
>> MMX, any speed, regardless of OS (crash as in instant seize, hard
>> reboot the only cure):
>>
>> char x [5] = { 0xf0, 0x0f, 0xc7, 0xc8 };
>>
>> main ()
>> {
>>        void (*f)() = x;
>>        f();
>> }
>>
>> This require no special permissions to run, it works fine with
>> average-joe-userspace permissions. I have verified this, it works.
>> Demand a new CPU from Intel.
>>

>Curious, I compiled that under Linux OS. Linux freezed. Dead.
>Without *any* warning.

>My machine is a Genuine Intel 166 MHZ Pentium MMX.

>Then I rebooted Windows NT. Compiled it with my compiler system (lcc-win32).
>Windows NT freezed. DEAD. Without *any* warning.

>Then, I ported the code to my old faithful 486-DX33 with linux. Compiled it.
>When it run it traps with 'illegal instruction'

>This means that anybody can crash anytime any OS that runs under a Pentium
CPU.
>As the poster said, no special permissions are needed, the pentium runs under
>ring 3 permissions!!!!

>This means that no secure system can ever be built that uses the pentium
CPU. No
>protected system. The OS receives NO TRAP!!!

>This is absolutely incredible.

>Bugs are impossible to avoid. Not even with huge corporations like Intel.
>I will *not* start screaming at Intel now. Myself, I have done more bugs
>than Intel ever will. As somene said before:

>Those that are free of sin, throw the first stone...

>For any user of pentium cpus in a multiuser system this means that
>anybody that can execute a program can freeze the system dead. I repeat:
>NO ROOT PERMISSIONS ARE NEEDED.