Re: [Qemu-devel] [PATCH v3 0/3] seccomp fixes

[Eduardo Otubo]

On 22/08/2018 - 16:29:53, Marc-André Lureau wrote:
> Hi,
> 
> This series fixes 2 issues with -sandbox:
> 
> - The seccomp action SCMP_ACT_KILL results in immediate termination of
>   the thread that made the bad system call. However, qemu being
>   multi-threaded, it keeps running. There is no easy way for parent
>   process / management layer (libvirt) to know about that situation.
> 
>   Instead, the default SIGSYS handler when invoked with SCMP_ACT_TRAP
>   will terminate the program and core dump.
> 
>   This may not be the most secure solution, but probably better than
>   just killing the offending thread. SCMP_ACT_KILL_PROCESS has been
>   added in Linux 4.14 to improve the situation, which I propose to use
>   by default if available.
> 
>   Related to:
>   https://bugzilla.redhat.com/show_bug.cgi?id=1594456
> 
> - The seccomp filter isn't applied to all threads. We can solve the
>   issue by using SECCOMP_FILTER_FLAG_TSYNC since libseccomp 2.2.0 and
>   kernel >= 3.17. The issue remains on older kernels or older
>   libseccomp. I chose to report an error by default, but we may want
>   it to fail instead.
> 
> v3:
> - modify qemu_seccomp() to set errno=ENOSYS
> - add patch "seccomp: set the seccomp filter to all threads"
> 
> v2:
> - fix clang unused inline warning
> - add acked-by/r-b tags
> 
> Marc-André Lureau (3):
>   seccomp: use SIGSYS signal instead of killing the thread
>   seccomp: prefer SCMP_ACT_KILL_PROCESS if available
>   seccomp: set the seccomp filter to all threads
> 
>  qemu-seccomp.c  | 96 +++++++++++++++++++++++++++++++++++++++++++++++--
>  qemu-options.hx |  2 ++
>  2 files changed, 95 insertions(+), 3 deletions(-)
> 
> -- 
> 2.18.0.547.g1d89318c48
> 
Acked-by: Eduardo Otubo <address@hidden>

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