On 2013-08-02 14:25, Timo Sirainen wrote:
On Tue, 2013-07-30 at 14:55 +0200, Frerich Raabe wrote:
I'm running Dovecot 2.1.7 on Debian. Exim is the MTA. I was recently
made aware of the fact that the way in which Exim invokes
dovecot-lda is
prone to code injection:
dovecot_virtual_delivery:
driver = pipe
command = HOME=/home/vmail/\$local_part
/usr/lib/dovecot/dovecot-lda
-f \$sender_address
use_shell
..
I.e. a command is executed via the shell, and Exim uses
non-sanitized
user input (mail header fields) to construct the command.
Now, the reason I invoked dovecot like that is to pass a plausible
value for the HOME environment variable, so that dovecot-lda can
determine where the Maildir directory of the recipient is. Is there
any
way to achieve this without requiring HOME to be set correctly? I
looked
at the -m switch but as far as I can see that merely defines the
destination mailbox, but not the path to the Maildir directory,
correct?
Maybe set mail_home = /home/vmail/%n ?
Sorry for the late reply, I totally forgot to follow-up on this.
Setting mail_home
didn't seem to help (according to 'doveadm user' the home directory was
already
computed corretly). It turned out that what *did* help was to pass '-d
$local_part'
to dovecot-lda. Apparently that makes it do a userdb lookup which in
turn makes it
figure out the home directory.
--
Frerich Raabe - ra...@froglogic.com
www.froglogic.com - Multi-Platform GUI Testing
