Re: [PATCH 3.5 0/2] seccomp and vsyscall fixes

[Will Drewry]

On Tue, Jul 17, 2012 at 6:19 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> Apologies for the lateness of this stuff.  I was at a conference last
> week when the Chrome issue was discovered and I couldn't do this
> properly until I got back.
>
> Will, can you confirm that this version is okay and passes your tests?
> It passes mine.

I'll pull it and test it!

> While there are no known seccomp users that will have trouble,
> SECCOMP_RET_TRAP and SECCOMP_RET_TRACE currently interact oddly with
> emulated vsyscalls.  This might lead to ABI issues down the road (if
> something starts to rely on current behavior) or unexpected malfunctions
> (if something tries to change, say, sys_gettimeofday, into a different
> syscall and gets completely bogus results on a vsyscall-using distro.
>
> It's unlikely that fixing this later will cause issues, but it would be
> nice to nail down and document the vsyscall quirks for the first
> released kernel with seccomp mode 2 support.
>
> (Patch 2/2 is very much optional.  It fixes a strange corner case.  It
>  ought to be fine for 3.6, since I very much doubt that any real code
>  will hit that corner case and cause ABI problems.)
>
> Andy Lutomirski (2):
>   seccomp: Make syscall skipping and nr changes more consistent
>   seccomp: Future-proof against silly tracers
>
>  Documentation/prctl/seccomp_filter.txt |   74 ++++++++++++++++++++--
>  arch/x86/include/asm/syscall.h         |   11 +++
>  arch/x86/kernel/vsyscall_64.c          |  110 +++++++++++++++++---------------
>  kernel/seccomp.c                       |   28 +++++++-
>  4 files changed, 163 insertions(+), 60 deletions(-)
>
> --
> 1.7.7.6
>
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