Re: documentation bug (uid resetting in posix mode)

[Stefano Lattarini]

Hi Chet.

On 10/30/2012 07:10 PM, Chet Ramey wrote:
> On 10/30/12 1:53 PM, Stefano Lattarini wrote:
>> On 10/30/2012 06:28 PM, Andreas Schwab wrote:
>>> Stefano Lattarini <stefano.lattarini@gmail.com> writes:
>>>
>>>>   $ ./system-suid
>>>>   [8204] ruid = 1000, euid = 0, suid = 0
>>>
>>> Looks like your /bin/sh is broken.
>>>
>> How "broken" exactly?  Honest question.
> 
> It's not unheard of for vendors to make their own changes and ship the
> result.  This has happened a number of times in the past.
>
You're right;  I see this in the bash_4.2-5.diff file applied by Debian:

  --- bash-4.2.orig/debian/patches/privmode.diff
  +++ bash-4.2/debian/patches/privmode.diff
  @@ -0,0 +1,19 @@
  # DP: XXX missing description
  # DP:
  # DP: Comment from Chet Ramey <chet@nike.ins.cwru.edu>:
  # DP:
  # DP: Nope.  This will allow setuid scripts if not called as `sh' and not
  # DP: called with the -p option.  I won't install this.

  --- a/bash/shell.c
  +++ b/bash/shell.c
  @@ -486,7 +486,7 @@
     if (dump_translatable_strings)
       read_but_dont_execute = 1;

  -  if (running_setuid && privileged_mode == 0)
  +  if (running_setuid && privileged_mode == 0 && act_like_sh == 0)
       disable_priv_mode ();

So the behaviour I'm seeing is only due to the Debian patches, and
there's no bug in the Bash documentation.

Thanks, and sorry for the noise,
  Stefano