Messages in this thread | | | Date | Fri, 14 Dec 2012 15:48:26 -0800 | From | John Stultz <> | Subject | Re: [CRIU] [PATCH] Add VDSO time function support for x86 32-bit kernel |
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On 12/14/2012 02:48 PM, H. Peter Anvin wrote: > On 12/14/2012 02:43 PM, Cyrill Gorcunov wrote: >> On Fri, Dec 14, 2012 at 02:27:08PM -0800, H. Peter Anvin wrote: >> >> >> This won't help in case of scenario you've been pointing in >> previous email (where c/r happens in a middle of vdso), >> would it? Because we still need somehow to be sure we're not >> checkpointing in a middle of signal handler which will return >> to some vdso place. > It is okay if and only if those vdso places never change... which I > think is doable if they only contain trival system call wrappers, i.e. > something like: > > movl $__SYS_gettimeofday, %eax > syscall > ret
Though doesn't this make it easier for exploits (somewhat undoing ASLR)? I know Andi always wanted to avoid having syscall instructions at a fixed location for the old vsyscall code (though I know we had it none-the-less for awhile). But maybe I'm confusing issues here?
thanks -john
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