Mercurial > dropbear
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