linux-kernel - Re: [patch] i386: remove IOPL check on task switch

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 4 Nov 2006 21:02:12 +0100
From:	Andi Kleen <ak@...e.de>
To:	Zachary Amsden <zach@...are.com>
Cc:	Chuck Ebbert <76306.1226@...puserve.com>,
	Andrew Morton <akpm@...l.org>,
	Linus Torvalds <torvalds@...l.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [patch] i386: remove IOPL check on task switch

 
> Ok, checking shows Linus put it back to stop NT leakage. 

It is also needed to stop AC leakage

> This is  
> correct, but unlikely.  Would be nice to avoid it unless absolutely 
> necessary.  Perhaps xor eflags old and new and only set_system_eflags() 
> if non-ALU bits have changed.

If it's worth it...

If it's worth for the context switch i think it would make 
more sense to do it for the normal restore_flags() etc. which are much
more common (and could be actually handled in most cases with test + jump + sti)

-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/