dovecot - Feb 2013 - Imap process crash: assertion failed: (full_fs_access)

Any guess at what would cause this?

 	Feb  7 21:20:53 server dovecot: imap(user): Panic: file
 	mailbox-list-fs-iter.c: line 447 (fs_list_get_roots): assertion
 	failed: (full_fs_access)

 	(Sorry, no core dump)

According to my logs, this user couldn't start an IMAP session for a 2
hour stretch for hundreds of connections.  Then the problem seemed to
have went away.

I logged back as that user using a master password, but couldn't recreate
this problem.  The backtrace is just hex numbers (stripped executables)
and I didn't drop privileges, so it refused to drop core, so that's
no help.

Joseph Tam <jtam.home at gmail.com>

On Thu, 2013-02-07 at 23:59 -0800, Joseph Tam wrote:
> Any guess at what would cause this?
> 
>  	Feb  7 21:20:53 server dovecot: imap(user): Panic: file
>  	mailbox-list-fs-iter.c: line 447 (fs_list_get_roots): assertion
>  	failed: (full_fs_access)
LIST command that had invalid parameters that somehow got through the
first validity check. What namespace config do you have?

Timo Sirainen <tss at iki.fi> writes:
> > Any guess at what would cause this?
> > 
> >  	Feb  7 21:20:53 server dovecot: imap(user): Panic: file
> >  	mailbox-list-fs-iter.c: line 447 (fs_list_get_roots): assertion
> >  	failed: (full_fs_access)
> 
> LIST command that had invalid parameters that somehow got through the
> first validity check. What namespace config do you have?
I got more info from the user that had this problem.  He reported that he
was was setting up a new Email client (Nexus4 Android) and he sent me a
screenshot of his setup.  Everything look ordinary except perhaps the
IMAP prefix set to "mail".  My setup documents inform users to leave
it blank,
but sometimes they use "mail/", a holdover from the uw-imapd days.  I
provide
some aliases for that, but I don't know what would happen if you leave off
the trailing "/".

My namespace settings as reported by dovecot -n:

 	namespace {
 	  inbox = yes
 	  location  	  prefix  	  separator = /
 	}

 	(The following are aliases to keep backward compatibility)
 	namespace {
 	  alias_for  	  hidden = yes
 	  list = no
 	  location  	  prefix = /
 	  separator = /
 	}
 	namespace {
 	  alias_for  	  hidden = yes
 	  list = no
 	  location  	  prefix = mail/
 	  separator = /
 	}
 	namespace {
 	  alias_for  	  hidden = yes
 	  list = no
 	  location  	  prefix = ~/mail/
 	  separator = /
 	}
 	namespace {
 	  alias_for  	  hidden = yes
 	  list = no
 	  location  	  prefix = ~%u/mail/
 	  separator = /
 	}

I've asked the user to change his prefix, and he'll probably report
back.

Joseph Tam <jtam.home at gmail.com>

On 11.2.2013, at 12.20, Joseph Tam <jtam.home at gmail.com> wrote:
> 
> Timo Sirainen <tss at iki.fi> writes:
> 
>> > Any guess at what would cause this?
>> > >  	Feb  7 21:20:53 server dovecot: imap(user): Panic: file
>> >  	mailbox-list-fs-iter.c: line 447 (fs_list_get_roots): assertion
>> >  	failed: (full_fs_access)
>> LIST command that had invalid parameters that somehow got through the
>> first validity check. What namespace config do you have?
> 
> 	namespace {
> 	  alias_for > 	  hidden = yes
> 	  list = no
> 	  location > 	  prefix = /
> 	  separator = /
> 	}
This one causes these crashes. Fixed in v2.2 now:
http://hg.dovecot.org/dovecot-2.2/rev/fb367a977077

On Wed, 13 Feb 2013, dovecot-request at dovecot.org wrote:

Timo Sirainen <tss at iki.fi> writes:
>>>> Any guess at what would cause this?
>>>>>  	Feb  7 21:20:53 server dovecot: imap(user): Panic: file
>>>>  	mailbox-list-fs-iter.c: line 447 (fs_list_get_roots):
assertion
>>>>  	failed: (full_fs_access)
>>> LIST command that had invalid parameters that somehow got through
the
>>> first validity check. What namespace config do you have?
>>
>> 	namespace {
>> 	  alias_for >> 	  hidden = yes
>> 	  list = no
>> 	  location >> 	  prefix = /
>> 	  separator = /
>> 	}
>
> This one causes these crashes. Fixed in v2.2 now:
http://hg.dovecot.org/dovecot-2.2/rev/fb367a977077
Thanks for diagnosing this.  I'll probably remove this namespace or limp
along until 2.2 becomes the latest stable release.

I added this namespace alias in an abundance of caution:  this was to
prevent users from trying to peruse the entire file space e.g. /etc.
A poor man's chroot.  I didn't test this thoroughly to see if it
actually
did what it was supposed to.

Joseph Tam <jtam.home at gmail.com>