Debian Bug report logs - #374705
adduser: creates incorrect mail spool files during new installation

serious

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Package: adduser
Version: 3.87
Severity: serious
Tags: d-i

After a new installation using Debian Installer, there are wrong mail 
files for several (system) users that are created during the 
installation:

# cd /target/var/spool/mail
# ls -l
---------- 1 root mail 0 2006-06-20 13:41 Debian-exim
---------- 1 root mail 0 2006-06-20 13:55 fjp
---------- 1 root mail 0 2006-06-20 13:41 identd
---------- 1 root mail 0 2006-06-20 13:41 statd

(fjp is the normal user created during this install)

Note that both the permissions and the ownership are broken. This breaks 
mail delivery for the installed system.
AFAIK there is actually no need to create mail spool files for new users?

I was able to create a similar file from the d-i debug shell:
# chroot /target adduser xxx
[...]
# ls -l xxx
---------- 1 root mail 0 2006-06-20 14:15 xxx

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I installed the desktop task on this laptop, then switched it to postfix
and installed a few other packages like nstxcd that also create users on
install. The result:

drwxr-xr-x 15 root root 4.0K Jun  2 08:22 ../
----------  1 root mail    0 Jun  2 07:49 BOGUS.joey.CY8W
----------  1 root mail    0 Jun  2 07:37 Debian-exim
----------  1 root mail    0 Jun  2 08:33 avahi
----------  1 root mail    0 Jun  2 10:03 dictd
----------  1 root mail    0 Jun  2 10:14 distccd
----------  1 root mail    0 Jun  2 10:14 distmp3
----------  1 root mail    0 Jun  2 10:15 fetchmail
----------  1 root mail    0 Jun  2 07:44 gdm
----------  1 root mail    0 Jun  2 07:39 hal
----------  1 root mail    0 Jun  2 07:37 identd
-rw-rw----  1 joey mail 3.2K Jun  2 11:42 joey
----------  1 root mail    0 Jun  2 07:38 messagebus
----------  1 root mail    0 Jun  2 10:17 mixmaster
----------  1 root mail    0 Jun  2 10:21 nstxd
----------  1 root mail    0 Jun  2 11:08 postfix
----------  1 root mail    0 Jun  2 10:23 saned
----------  1 root mail    0 Jun  2 08:35 sshd
----------  1 root mail    0 Jun  2 07:37 statd
----------  1 root mail    0 Jun  2 10:24 telnetd-ssl
----------  1 root mail    0 Jun  2 10:24 uml-net

I suspect that the BOGUS.joey.CY8W is from postfix moving the wrong
owner and permissions joey file out of the way when delivering mail
later.

-- 
see shy jo

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This one time, at band camp, Frans Pop said:
> After a new installation using Debian Installer, there are wrong mail 
> files for several (system) users that are created during the 
> installation:

[snip]

This one time, at band camp, Joey Hess said:
> I installed the desktop task on this laptop, then switched it to postfix
> and installed a few other packages like nstxcd that also create users on
> install. The result:

[snip]

I think the bug is in shadow, as there have been changes in this area
recently:

shadow (1:4.0.15-10) unstable; urgency=high

      + check the return value of fchown before fchmod when the mailbox is
        created by useradd
      + The patch also uses login.defs::MAIL_DIR instead of /var/mail.

 -- Christian Perrier <bubulle@debian.org>  Thu, 18 May 2006 01:44:56 -0500

adduser doesn't touch the mail spool when adding users.  I am not
reassigning yet, as I am not positive.  Can you test with an earlier
useradd and let me know if the bug is indeed there?

> I suspect that the BOGUS.joey.CY8W is from postfix moving the wrong
> owner and permissions joey file out of the way when delivering mail
> later.

I suspect it's procmail, but yes.  It's an MDA thing, and a feature at
that.

Thanks,
-- 
 -----------------------------------------------------------------
|   ,''`.                                            Stephen Gran |
|  : :' :                                        sgran@debian.org |
|  `. `'                        Debian user, admin, and developer |
|    `-                                     http://www.debian.org |
 -----------------------------------------------------------------

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reassign 374705 passwd
khtxbye

Hey all,

Can you take a look at this bug?  I see there have been recent changes
in how useradd handles the mailspool, and I suspect that it is
responsible for what is being seen here.  The bug was originally filed
against adduser, but adduser does not itself touch the mailspool, so I
believe the bug is in useradd (adduser does call useradd to create the
account).

Thanks,
-- 
 -----------------------------------------------------------------
|   ,''`.                                            Stephen Gran |
|  : :' :                                        sgran@debian.org |
|  `. `'                        Debian user, admin, and developer |
|    `-                                     http://www.debian.org |
 -----------------------------------------------------------------

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Confirmed that the bug was introduced with passwd 4.0.15-10.
After downgrading to 4.0.15-9 there is no longer a mail spool file created 
for a new user.

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Quoting Frans Pop (elendil@planet.nl):
> Confirmed that the bug was introduced with passwd 4.0.15-10.
> After downgrading to 4.0.15-9 there is no longer a mail spool file created 
> for a new user.

Very likely to be this:

  * Upstream bugs or fixes fixed in upstream releases or CVS:
    - Fix for CERT VU#312962
      + check the return value of fchown before fchmod when the mailbox is
        created by useradd
      + The patch also uses login.defs::MAIL_DIR instead of /var/mail.


Tomasz, Nicolas, I need you here.....



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Hey all,

I think I might have found the problem.  The mail spool is open()ed, and
then the fd is checked to see if there is an error (as is proper).  The
problem is, the fchown/fchmod calls happen in the same logic path as
error handling, not in an else block.  The attached patch should fix it.

I have to note in passing, though, that I had to change the line

if (strcasecmp (create_mail_spool, "yes") == 0) {

to 

if (strcasecmp (def_create_mail_spool, "yes") == 0) {

to even enter this block in the first place - is there an incomplete
variable name transition, or am I doing something wrong?

--- src/useradd.c~      2006-06-21 10:51:01.000000000 +0100
+++ src/useradd.c       2006-06-21 10:51:17.000000000 +0100
@@ -1599,6 +1599,7 @@
                if (fd < 0) {
                        perror (_("Creating mailbox file"));
                        return;
+               } else {

                        gr = getgrnam ("mail");
                        if (!gr) {

Take care,
-- 
 -----------------------------------------------------------------
|   ,''`.                                            Stephen Gran |
|  : :' :                                        sgran@debian.org |
|  `. `'                        Debian user, admin, and developer |
|    `-                                     http://www.debian.org |
 -----------------------------------------------------------------

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Tomasz, you probably already saw this contribution by Stephen Gran
about http://bugs.debian.org/374705 (see the whole story there: as
this bug was reassigned to shadow we didn't have the originating bug
report in our mailing list).

Just sending this directly to you to properly record the "forwarded"
status in our BTS...and also to get attention..:-)

The bug seems related to the following change which appeared in 4.0.16
for you, but which we applied in 4.0.15-10 in Debian:

  * Upstream bugs or fixes fixed in upstream releases or CVS:
    - Fix for CERT VU#312962
      + check the return value of fchown before fchmod when the mailbox is
        created by useradd


----- Forwarded message from Stephen Gran <sgran@debian.org> -----

Date: Wed, 21 Jun 2006 10:55:36 +0100
From: Stephen Gran <sgran@debian.org>
To: 374705@bugs.debian.org
Subject: [Pkg-shadow-devel] Bug#374705: tentative patch
Reply-To: Stephen Gran <sgran@debian.org>, 374705@bugs.debian.org
X-CRM114-Status: SPAM  ( pR: -7.2743 )

Hey all,

I think I might have found the problem.  The mail spool is open()ed, and
then the fd is checked to see if there is an error (as is proper).  The
problem is, the fchown/fchmod calls happen in the same logic path as
error handling, not in an else block.  The attached patch should fix it.

I have to note in passing, though, that I had to change the line

if (strcasecmp (create_mail_spool, "yes") == 0) {

to 

if (strcasecmp (def_create_mail_spool, "yes") == 0) {

to even enter this block in the first place - is there an incomplete
variable name transition, or am I doing something wrong?

--- src/useradd.c~      2006-06-21 10:51:01.000000000 +0100
+++ src/useradd.c       2006-06-21 10:51:17.000000000 +0100
@@ -1599,6 +1599,7 @@
                if (fd < 0) {
                        perror (_("Creating mailbox file"));
                        return;
+               } else {

                        gr = getgrnam ("mail");
                        if (!gr) {

Take care,
-- 
 -----------------------------------------------------------------
|   ,''`.                                            Stephen Gran |
|  : :' :                                        sgran@debian.org |
|  `. `'                        Debian user, admin, and developer |
|    `-                                     http://www.debian.org |
 -----------------------------------------------------------------



_______________________________________________
Pkg-shadow-devel mailing list
Pkg-shadow-devel@lists.alioth.debian.org
http://lists.alioth.debian.org/mailman/listinfo/pkg-shadow-devel


----- End forwarded message -----




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Tomasz,

On Wed, Jun 21, 2006 at 10:55:36AM +0100, Stephen Gran wrote:
> Hey all,
> 
> I think I might have found the problem.  The mail spool is open()ed, and
> then the fd is checked to see if there is an error (as is proper).  The
> problem is, the fchown/fchmod calls happen in the same logic path as
> error handling, not in an else block.  The attached patch should fix it.

What I don't understand, is why the mail box is created if this bloc of
code cannot be reached (due to the issue described below).

> I have to note in passing, though, that I had to change the line
> 
> if (strcasecmp (create_mail_spool, "yes") == 0) {
> 
> to 
> 
> if (strcasecmp (def_create_mail_spool, "yes") == 0) {

Tomasz, create_mail_spool is never set. It should either be removed, or
set somewhere (e.g. like the other similar variables in process_flags,
even if there is no flags for this value).

> to even enter this block in the first place - is there an incomplete
> variable name transition, or am I doing something wrong?
> 
> --- src/useradd.c~      2006-06-21 10:51:01.000000000 +0100
> +++ src/useradd.c       2006-06-21 10:51:17.000000000 +0100
> @@ -1599,6 +1599,7 @@
>                 if (fd < 0) {
>                         perror (_("Creating mailbox file"));
>                         return;
> +               } else {
> 
>                         gr = getgrnam ("mail");
>                         if (!gr) {

Thanks for the patch. This also looks correct.

I'm attaching another patch, which fixes this issue, the other issue
mentionned by Stephen and another issue (def_create_mail_spool should
never be set to CREATE_MAIL_SPOOL).

Note: I still don't understand the Debian bug and can't reproduce it. I
will look closer later.

Kind Regards,
-- 
Nekral

[useradd.c.diff (text/plain, attachment)]
On Wed, Jun 21, 2006 at 09:57:04PM +0200, Nicolas François wrote:

> Note: I still don't understand the Debian bug and can't reproduce it. I
> will look closer later.

I checked the code of 4.0.15-10.
The bug is present in this version.
However, I think the issue is not present in the 4.0.16 versions (according
to my tests and according to the code).

Can somebody else confirm?

I also wonder whether we should make a special note for this bug (to
inform the users who created users with 4.0.15-10).

Kind Regards,
-- 
Nekral



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On Wednesday 21 June 2006 22:26, you wrote:
> However, I think the issue is not present in the 4.0.16 versions
> (according to my tests and according to the code).
>
> Can somebody else confirm?

Confirmed. If I do a new install of unstable, the mail spool dir is clean.

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Quoting Frans Pop (elendil@planet.nl):
> On Wednesday 21 June 2006 22:26, you wrote:
> > However, I think the issue is not present in the 4.0.16 versions
> > (according to my tests and according to the code).
> >
> > Can somebody else confirm?
> 
> Confirmed. If I do a new install of unstable, the mail spool dir is clean.


So, this is probably because there were some differences in the patch
we temporarily applied in Debian to cover the security issue
supposedly fixed by 4.0.15-10 and the one that was really applied by
Tomasz in 4.0.16.

Hence, closing the bug with "Version: 4.0.16-1" seems fair.

4.0.16-2 is now in testing anyway.

Waiting for others input....



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Dnia 21-06-2006, śro o godzinie 10:55 +0100, Stephen Gran napisał(a):
> --- src/useradd.c~      2006-06-21 10:51:01.000000000 +0100
> +++ src/useradd.c       2006-06-21 10:51:17.000000000 +0100
> @@ -1599,6 +1599,7 @@
>                 if (fd < 0) {
>                         perror (_("Creating mailbox file"));
>                         return;
> +               } else {
> 
>                         gr = getgrnam ("mail");
>                         if (!gr) {
> 

Above is return so instead "else" can be placed by only "}".
OK. I'll ASAP commit neccessary changes.
Probaly in comming monday will be good release 4.0.17.

kloczek





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This one time, at band camp, Christian Perrier said:
> Quoting Frans Pop (elendil@planet.nl):
> > On Wednesday 21 June 2006 22:26, you wrote:
> > > However, I think the issue is not present in the 4.0.16 versions
> > > (according to my tests and according to the code).
> > >
> > > Can somebody else confirm?
> > 
> > Confirmed. If I do a new install of unstable, the mail spool dir is clean.
> 
> 
> So, this is probably because there were some differences in the patch
> we temporarily applied in Debian to cover the security issue
> supposedly fixed by 4.0.15-10 and the one that was really applied by
> Tomasz in 4.0.16.
> 
> Hence, closing the bug with "Version: 4.0.16-1" seems fair.
> 
> 4.0.16-2 is now in testing anyway.

steve@gashuffer:~/source/shadow-4.0.16$ head -n 1 debian/changelog
shadow (1:4.0.16-2) unstable; urgency=low
steve@gashuffer:~/source/shadow-4.0.16$ grep -B 17 fchown src/useradd.c
                fd = open (file, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0);
                if (fd < 0) {
                        perror (_("Creating mailbox file"));
                        return;

                        gr = getgrnam ("mail");
                        if (!gr) {
                                fprintf (stderr,
                                         _
                                         ("Group 'mail' not found. Creating the user mailbox file with 0600 mode.\n"));
                                gid = user_gid;
                                mode = 0600;
                        } else {
                                gid = gr->gr_gid;
                                mode = 0660;
                        }

                        if (fchown (fd, user_id, gid) || fchmod (fd, mode))

The bug is present in 1:4.0.16-2.  Unless I'm missing something?
-- 
 -----------------------------------------------------------------
|   ,''`.                                            Stephen Gran |
|  : :' :                                        sgran@debian.org |
|  `. `'                        Debian user, admin, and developer |
|    `-                                     http://www.debian.org |
 -----------------------------------------------------------------

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Dnia 22-06-2006, czw o godzinie 11:18 +0100, Stephen Gran napisał(a):
[..]
> The bug is present in 1:4.0.16-2.  Unless I'm missing something?

Please test patch from:
http://cvs.pld.org.pl/shadow/src/useradd.c?r1=1.97&r2=1.99

kloczek





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This one time, at band camp, Tomasz K??oczko said:
> Dnia 22-06-2006, czw o godzinie 11:18 +0100, Stephen Gran napisa??(a):
> [..]
> > The bug is present in 1:4.0.16-2.  Unless I'm missing something?
> 
> Please test patch from:
> http://cvs.pld.org.pl/shadow/src/useradd.c?r1=1.97&r2=1.99

steve@gashuffer:~/source/shadow-4.0.16$ sudo src/useradd -d /home/xxx -g xxx -s /bin/bash -u 1007 xxx
steve@gashuffer:~/source/shadow-4.0.16$ ll /var/mail/
-rw-rw---- 1 xxx         mail 0 2006-06-22 13:36 xxx

That looks fine.

Thanks,
-- 
 -----------------------------------------------------------------
|   ,''`.                                            Stephen Gran |
|  : :' :                                        sgran@debian.org |
|  `. `'                        Debian user, admin, and developer |
|    `-                                     http://www.debian.org |
 -----------------------------------------------------------------

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tags 374705 fixed-upstream
thanks

> Above is return so instead "else" can be placed by only "}".
> OK. I'll ASAP commit neccessary changes.
> Probaly in comming monday will be good release 4.0.17.


OK, so you will release with this fix. If that's completely sure, then
I think that I will not try to upload a 4.0.16-3 release in Debian in
the meantime....as long as I'm completely sure that the issue is fixed
very soon in upstream.

For the sake of it, I commit this patch in our SVN.



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package passwd
clone 374705 -1
retitle -1 useradd do not create the mail spool (even with CREATE_MAIL_SPOOL=yes in /etc/default/useradd)
severity -1 normal
thanks


Hello Stephen,

On Thu, Jun 22, 2006 at 11:18:44AM +0100, Stephen Gran wrote:
> 
> The bug is present in 1:4.0.16-2.  Unless I'm missing something?

Well, the bug present in 1:4.0.16-2 is a little bit different:
no mail spools are created - even when CREATE_MAIL_SPOOL is set to yes

So I'm cloning this bug. The new bug is pending and fixed upstream, with a
normal severity.

I will close 374705 with the 1:4.0.16-1 version of passwd.

Kind Regards,
-- 
Nekral



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This one time, at band camp, Nicolas François said:
> Hello Stephen,
> 
> On Thu, Jun 22, 2006 at 11:18:44AM +0100, Stephen Gran wrote:
> > 
> > The bug is present in 1:4.0.16-2.  Unless I'm missing something?
> 
> Well, the bug present in 1:4.0.16-2 is a little bit different:
> no mail spools are created - even when CREATE_MAIL_SPOOL is set to yes
> 
> So I'm cloning this bug. The new bug is pending and fixed upstream, with a
> normal severity.
> 
> I will close 374705 with the 1:4.0.16-1 version of passwd.

Well it's really, no mail spools are created, but if they were, this
bug would be present, but I see your point :)

Glad it's fixed now.  Take care,
-- 
 -----------------------------------------------------------------
|   ,''`.                                            Stephen Gran |
|  : :' :                                        sgran@debian.org |
|  `. `'                        Debian user, admin, and developer |
|    `-                                     http://www.debian.org |
 -----------------------------------------------------------------

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Version: 1:4.0.16-1

As mentionned in the bug's log, this bug was only present in the last
version of 4.0.15, and was fixed by 4.0.16.

Kind Regards,
-- 
Nekral




Debian Bug report logs - #374705 adduser: creates incorrect mail spool files during new installation

Debian Bug report logs - #374705
adduser: creates incorrect mail spool files during new installation