When multihop executes dbclient it should only add -i arguments
from the original commandline, not the default id_dropbear key.
Otherwise multiple -i arguments keep getting added which
results in servers disconnecting with too many auth attempts
When dropbear is used in a very restricted environment (such as in a
initrd), the default user shell is often also very restricted
and doesn't take care of setting the PATH so the user ends up
with the PATH set by dropbear. Unfortunately, dropbear always
sets "/usr/bin:/bin" as default PATH even for the root user
which should have /usr/sbin and /sbin too.
For a concrete instance of this problem, see the "Remote Unlocking"
section in this tutorial: https://paxswill.com/blog/2013/11/04/encrypted-raspberry-pi/
It speaks of a bug in the initramfs script because it's written "blkid"
instead of "/sbin/blkid"... this is just because the scripts from the
initramfs do not expect to have a PATH without the sbin directories and
because dropbear is not setting the PATH appropriately for the root user.
I'm thus suggesting to use the attached patch to fix this misbehaviour (I
did not test it, but it's easy enough). It might seem anecdotic but
multiple Kali users have been bitten by this.
From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=903403
For the time being Dropbear will only allow SK auth with default
parameters, user-presence needs to be set.
In future handling of authorized_keys option "no-touch-required" can be
added.
This code would also be refactored to share between ecdsa and ed25519
once I get hardware/emulation to test ed25519.
Why:
Running dropbear as a user (rootless) is aided if
files and programs can be saved/removed without
needing sudo.
What:
Use the same convention as DROPBEAR_DEFAULT_CLI_AUTHKEY;
if not starting with '/', then is relative to hedge's /home/hedge:
*_PRIV_FILENAME
DROPBEAR_PIDFILE
SFTPSERVER_PATH
default_options.h commentary added.
Changes kept to a minimum, so log entry in svr_kex.c#163
is refactored.
From:
Generated hostkey is <path> ... <finger-print>
to:
Generated hostkey path is <path>
Generated hostkey fingerprint is <fp>
Otherwise the unexpanded path was reported.
Patch modified by Matt Johnston
Signed-off-by: Begley Brothers Inc <begleybrothers@gmail.com>
SHA256 is always compiled and only enable SHA1 when needed. Fingerprints
are always SHA256: base64 format, md5 and sha1 are removed. dbrandom now
uses sha256 its hash function.
This introduces buf_put_ed25519_priv_ossh and buf_get_ed25519_priv_ossh
to handle OpenSSH internal private key format. Previously writing
OpenSSH format keys didn't write the private part correctly.
This reverts git commit f972813ecd.
The sk algorithms need to remain in the sigalgs list so that they
are included in the server-sig-algs ext-info message sent by
the server. RFC8308 for server-sig-algs requires that all algorithms are
listed (though OpenSSH client 8.4p1 tested doesn't require that)
