Messages in this thread | | | Date | Thu, 13 Jul 2006 07:23:52 -0400 | From | Jeff Dike <> | Subject | Re: [patch] let CONFIG_SECCOMP default to n |
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On Thu, Jul 13, 2006 at 05:16:14AM +0200, Andrea Arcangeli wrote: > On Thu, Jul 13, 2006 at 12:19:11AM +0200, Ingo Molnar wrote: > > attacked ptrace, implicitly weakening the security perception of other > > syscall filtering based projects like User Mode Linux. Now what we have > > Note that UML had a security weakness already that allowed to escape > the jail, see bugtraq. Infact his complexity is huge regardless of > ptrace, the security hole probably wasn't even ptrace related (I don't > remember the exact details).
Not hardly. If you did remember the exact details, you'd remember that it was in 2000, and someone "discovered" that tt mode didn't allow kernel memory to be protected from userspace. It had always been well documented that tt mode had this problem and you shouldn't be using it if you needed a secure VM.
See http://www.securityfocus.com/bid/3973/info
Now, there were a couple of ways to legitimately escape from UML, and they *did* involve ptrace. Things like single-stepping a system call instruction or putting a breakpoint on a system call instruction and single-stepping from the breakpoint. As far as I know, these were discovered and fixed by UML developers before there was any outside awareness of these bugs.
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