On Mon, Apr 04, 2005 at 05:35:26PM -0700, Steve Langasek wrote: > On Mon, Apr 04, 2005 at 05:11:20PM +0200, Peter 'p2' De Schrijver wrote: > > http://thread.gmane.org/gmane.linux.kernel/205839 has the patch. Note > > that 486 stepping A processors have a wrong opcode for cmpxchg. This > > means emulation of cmpxchg is necessary for 486 stepping A as well. As > > to the security hole, either the patch needs some fixes (ie using get_user > > etc.) > > or a userland emulation hooking SIGILL needs to be implemented. > > Yes, I think everyone involved is aware of that. Are you volunteering to > implement this? >
I got from Andreas that not everyone was aware 486 stepping A CPUs are affected as well. But 486 stepping A CPUs actually do have cmpxchg, but with other opcodes if I get it correctly. So the emulation could be much simpeler here. As to implementing this, not in the first weeks and I don't have any of the affected CPUs. I guess one hacking weekend with a few knowledgeable people and a crate of club-mate should do though. Cheers, Peter (p2).
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