[lkml]   [2011]   [Jun]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v3 08/10] x86-64: Emulate legacy vsyscalls
On Wed, Jun 1, 2011 at 7:54 AM, Brian Gerst <> wrote:
> On Tue, May 31, 2011 at 9:16 AM, Andy Lutomirski <> wrote:
>> There's a fair amount of code in the vsyscall page.  It contains a
>> syscall instruction (in the gettimeofday fallback) and who knows
>> what will happen if an exploit jumps into the middle of some other
>> code.
>> Reduce the risk by replacing the vsyscalls with short magic
>> incantations that cause the kernel to emulate the real vsyscalls.
>> These incantations are useless if entered in the middle.
> How about remapping the vsyscall page into a random page in the
> modules area, and make the fixed page simply have stubs that jump to
> the code in that page.  That would solve the fixed address syscall
> problem without any more overhead.

It wouldn't give any protection against local attacks, though.


> --
> Brian Gerst
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2011-06-01 14:39    [W:0.051 / U:0.480 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site