Re: [patch 3/4] c/r: procfs: add arg_start/end, env_start/end andexit_code members to /proc/$pid/stat

From: Kees Cook
Date: Mon Jan 23 2012 - 15:42:29 EST


On Mon, Jan 23, 2012 at 6:20 AM, Cyrill Gorcunov <gorcunov@xxxxxxxxxx> wrote:
> We would like to have an ability to restore command line
> arguments and envirion pointers so the task being restored
> would print appropriate values in /proc/pid/cmdline and
> /proc/pid/envirion. The exit_code is needed to restore
> zombie tasks.
>
> Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
> Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
> Cc: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Andrew Vagin <avagin@xxxxxxxxxx>
> Cc: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>
> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> ---
>  fs/proc/array.c |   10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> Index: linux-2.6.git/fs/proc/array.c
> ===================================================================
> --- linux-2.6.git.orig/fs/proc/array.c
> +++ linux-2.6.git/fs/proc/array.c
> @@ -464,7 +464,8 @@ static int do_task_stat(struct seq_file
>
>        seq_printf(m, "%d (%s) %c %d %d %d %d %d %u %lu \
>  %lu %lu %lu %lu %lu %ld %ld %ld %ld %d 0 %llu %lu %ld %lu %lu %lu %lu %lu \
> -%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu %lu %ld %lu %lu %lu\n",
> +%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu %lu %ld %lu %lu %lu \
> +%lu %lu %lu %lu %d\n",
>                pid_nr_ns(pid, ns),
>                tcomm,
>                state,
> @@ -514,7 +515,12 @@ static int do_task_stat(struct seq_file
>                cputime_to_clock_t(cgtime),
>                (mm && permitted) ? mm->start_data : 0,
>                (mm && permitted) ? mm->end_data : 0,
> -               (mm && permitted) ? mm->start_brk : 0);
> +               (mm && permitted) ? mm->start_brk : 0,
> +               (mm && permitted) ? mm->arg_start : 0,
> +               (mm && permitted) ? mm->arg_end : 0,
> +               (mm && permitted) ? mm->env_start : 0,
> +               (mm && permitted) ? mm->env_end : 0,
> +               task->exit_code);
>        if (mm)
>                mmput(mm);
>        return 0;

You're not exposing auxv here? In your testing, what situations ended
up using auxv after initial startup? Or is your intention to be able
to freeze a process potentially before libc has examined auxv?

-Kees

--
Kees Cook
ChromeOS Security
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