view debian/README.runit @ 1788:1fc0012b9c38

Fix handling of replies to global requests (#112) The current code assumes that all global requests want / need a reply. This isn't always true and the request itself indicates if it wants a reply or not. It causes a specific problem with [email protected] messages. These are sent by OpenSSH after authentication to inform the client of potential other host keys for the host. This can be used to add a new type of host key or to rotate host keys. The initial information message from the server is sent as a global request, but with want_reply set to false. This means that the server doesn't expect an answer to this message. Instead the client needs to send a prove request as a reply if it wants to receive proof of ownership for the host keys. The bug doesn't cause any current problems with due to how OpenSSH treats receiving the failure message. It instead treats it as a keepalive message and further ignores it. Arguably this is a protocol violation though of Dropbear and it is only accidental that it doesn't cause a problem with OpenSSH. The bug was found when adding host keys support to libssh, which is more strict protocol wise and treats the unexpected failure message an error, also see https://gitlab.com/libssh/libssh-mirror/-/merge_requests/145 for more information. The fix here is to honor the want_reply flag in the global request and to only send a reply if the other side expects a reply.
author Dirkjan Bussink <d.bussink@gmail.com>
date Thu, 10 Dec 2020 16:13:13 +0100
parents 8c2d2edadf2a
children
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Using the dropbear SSH server with runit's services supervision
---------------------------------------------------------------

The dropbear SSH server is perfectly suited to be run under runit's
service supervision, and this package already has prepared an adequate
service directory.  Follow these steps to enable the dropbear service
using the runit package.

If not yet installed on your system, install the runit package, and make
sure its service supervision is enabled (it's by default)

 # apt-get install runit

Make sure the dropbear service normally handled through the sysv init
script is stopped

 # /etc/init.d/dropbear stop

Create the system user ``dropbearlog'' which will run the logger service,
and own the logs

 # adduser --system --home /var/log/dropbear --no-create-home dropbearlog

Create the log directory and make the newly created system user the owner
of this directory

 # mkdir -p /var/log/dropbear && chown dropbearlog /var/log/dropbear

Optionally adjust the configuration of the dropbear service by editing the
run script

 # vi /etc/dropbear/run

Finally enable the service through runit's update-service(8) program, the
service will be started within five seconds, and automatically at boot
time, and the sysv init script will automatically be disabled; see the
sv(8) program for information on how to control services handled by runit.
See the svlogd(8) program on how to configure the log service.

 # update-service --add /etc/dropbear

Optionally check the status of the service a few seconds later

 # sv status dropbear

 -- Gerrit Pape <[email protected]>, Fri, 02 Mar 2007 20:41:08 +0000