Re: [Qemu-devel] [PATCH v3 3/6] seccomp: add elevateprivileges argument to command line

[Thomas Huth <thuth@redhat.com>]

On 28.07.2017 14:10, Eduardo Otubo wrote:
> This patch introduces the new argument
> [,elevateprivileges=allow|deny|children] to the `-sandbox on'. It allows
> or denies Qemu process to elevate its privileges by blacklisting all
> set*uid|gid system calls. The 'children' option will let forks and
> execves run unprivileged.
> 
> Signed-off-by: Eduardo Otubo <otubo@redhat.com>
> ---
>  include/sysemu/seccomp.h |  1 +
>  qemu-options.hx          |  9 ++++++---
>  qemu-seccomp.c           | 29 +++++++++++++++++++++++++++++
>  vl.c                     | 22 ++++++++++++++++++++++
>  4 files changed, 58 insertions(+), 3 deletions(-)
> 
> diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
> index 7a7bde246b..e6e78d85ce 100644
> --- a/include/sysemu/seccomp.h
> +++ b/include/sysemu/seccomp.h
> @@ -16,6 +16,7 @@
>  #define QEMU_SECCOMP_H
>  
>  #define OBSOLETE    0x0001
> +#define PRIVILEGED  0x0010
>  
>  #include <seccomp.h>
>  
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 54e492f36a..34d33a812e 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -4004,17 +4004,20 @@ Old param mode (ARM only).
>  ETEXI
>  
>  DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
> -    "-sandbox on[,obsolete=allow]  Enable seccomp mode 2 system call filter (default 'off').\n" \
> -    "                obsolete: Allow obsolete system calls\n",
> +    "-sandbox on[,obsolete=allow][,elevateprivileges=allow|deny|children]  Enable seccomp mode 2 system call filter (default 'off').\n" \

Most other boolean-like options use "on|off" as possible values ...
maybe it would be nicer to use "on|off" instead of "allow|deny" here, too?

> +    "                obsolete: Allow obsolete system calls\n"
> +    "                elevateprivileges: allows or denies Qemu process to elevate its privileges by blacklisting all set*uid|gid system calls. 'children' will deny set*uid|gid system calls for main Qemu process but will allow forks and execves to run unprivileged\n",

Correct spelling is "QEMU" with all capital letters, not "Qemu"

>      QEMU_ARCH_ALL)
>  STEXI
> -@item -sandbox @var{arg}[,obsolete=@var{string}]
> +@item -sandbox @var{arg}[,obsolete=@var{string}][,elevateprivileges=@var{string}]
>  @findex -sandbox
>  Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will
>  disable it.  The default is 'off'.
>  @table @option
>  @item obsolete=@var{string}
>  Enable Obsolete system calls
> +@item elevateprivileges=@var{string}
> +Disable set*uid|gid systema calls

s/systema/system/

 Thomas