Bug#569683: linux-image-2.6.26-2-686: /proc/pid/maps is empty for all processes

[maximilian attems <max@stro.at>]

On Sat, Feb 13, 2010 at 01:32:36PM +0100, Ine Ya wrote:
> Package: linux-2.6
> Version: 2.6.26-21
> Severity: normal
> Tags: patch
> 
> /proc/pid/maps is empty for all processes, only /proc/self/maps works.
> 
> The following patch helped me to fix the problem:
> --- linux-2.6-2.6.26/fs/proc/base.c     2008-07-13 16:51:29.000000000 -0500
> +++ linux/fs/proc/base.c        2009-12-26 02:14:58.000000000 -0600
> @@ -251,7 +251,8 @@
>         task_lock(task);
>         if (task->mm != mm)
>                 goto out;
> -       if (task->mm != current->mm && __ptrace_may_attach(task) < 0)
> +       if (task->mm != current->mm && ((mm->flags & MMF_IN_EXEC) ||
> +                                       __ptrace_may_attach(task) < 0))
>                 goto out;
>         task_unlock(task);
>         return mm;
> 
> I'm writing this report from modified kernel, which contains this
> patch, and I test like 'cat /proc/1/maps' works now.

looks like mm_for_maps() had several fixes since the last security
update that got applied to lenny, see 704b836c for example.

dannf please evaluate if it is severity important. thanks