Dropbear 2018.76

[Peter Krefting]

Matt Johnston:

> Yes it should. I can't immediately reproduce it here, what
> flags are you giving to Dropbear? Is
> /mnt/nv/dropbear_ecdsa_host_key specified with -r or as a
> default config path, and are there other keyfiles?

The daemon is started with "dropbear -R", and the keyfiles are 
specified at compile-time, using localoptions.h. The full file is 
included below.

> ssh -vvv will print the full set of negotiated algorithms,
> you could send that to me (off-list if you want).

I have included the output below

> The relevant revision for that changelog note is
> https://secure.ucc.asn.au/hg/dropbear/rev/016b86f03e21
> you could try reverting that to confirm.

That does not seem to fix the issue, it aborts in the same location, 
so it seems something else is going on here.


===[ localoptions.h ]===
/* Put host keys in non-volatile storage */
#define DSS_PRIV_FILENAME "/mnt/nv/dropbear_dss_host_key"
#define RSA_PRIV_FILENAME "/mnt/nv/dropbear_rsa_host_key"
#define ECDSA_PRIV_FILENAME "/mnt/nv/dropbear_ecdsa_host_key"

/* Disable inetd mode */
#define INETD_MODE 0

/* Disable X11 forwarding as we do not have any X11. */
#define DROPBEAR_X11FWD 0

/* Disable port forwarding and proxying and agent forwarding. */
#define DROPBEAR_CLI_LOCALTCPFWD 0
#define DROPBEAR_CLI_REMOTETCPFWD 0
#define DROPBEAR_SVR_LOCALTCPFWD 0
#define DROPBEAR_SVR_REMOTETCPFWD 0
#define DROPBEAR_SVR_AGENTFWD 0
#define DROPBEAR_CLI_AGENTFWD 0
#define DROPBEAR_CLI_PROXYCMD 0
#define DROPBEAR_CLI_NETCAT 0

/* Disable Twofish to save about 10 kilobytes. */
#define DROPBEAR_TWOFISH256 0
#define DROPBEAR_TWOFISH128 0

/* Disable /etc/motd support since nothing else on the target uses it. */
#define DO_MOTD 0

/* Put client keys in non-volatile storage */
#define DROPBEAR_DEFAULT_CLI_AUTHKEY "/mnt/nv/id_dropbear"

/* Disable sftp support (as we do not have a binary for sftp 
installed). */
#define DROPBEAR_SFTPSERVER 0

/* Patch it to use the same default PATH as the telnet daemon. This will
  * fix scripts that assume certain tools are in the path. */
  #define DEFAULT_PATH 
"/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin"
===[ end localoptions.h ]===

===[ output from ssh -vvvv ]===
$ ssh -vvvv root at 10.0.30.175
OpenSSH_7.4p1 Debian-10+deb9u2, OpenSSL 1.0.2l  25 May 2017
debug1: Reading configuration data /home/peter/.ssh/config
debug1: /home/peter/.ssh/config line 54: Applying options for 
10.0.30.175
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "10.0.30.175" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 10.0.30.175 [10.0.30.175] port 22.
debug1: Connection established.
debug1: identity file /home/peter/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /home/peter/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/peter/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/peter/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/peter/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/peter/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/peter/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/peter/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.4p1 Debian-10+deb9u2
debug1: Remote protocol version 2.0, remote software version 
dropbear_2018.76
debug1: no match: dropbear_2018.76
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 10.0.30.175:22 as 'root'
debug3: hostkeys_foreach: reading file "/home/peter/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file 
/home/peter/.ssh/known_hosts:126
debug3: load_hostkeys: loaded 1 keys from 10.0.30.175
debug3: order_hostkeyalgs: prefer hostkeyalgs: 
ecdsa-sha2-nistp256-cert-v01 at openssh.com,ecdsa-sha2-nistp384-cert-v01 at openssh.com,ecdsa-sha2-nistp521-cert-v01 at openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: 
curve25519-sha256,curve25519-sha256 at libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: 
ecdsa-sha2-nistp256-cert-v01 at openssh.com,ecdsa-sha2-nistp384-cert-v01 at openssh.com,ecdsa-sha2-nistp521-cert-v01 at openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519-cert-v01 at openssh.com,ssh-rsa-cert-v01 at openssh.com,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: 
chacha20-poly1305 at openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at openssh.com,aes256-gcm at openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: ciphers stoc: 
chacha20-poly1305 at openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at openssh.com,aes256-gcm at openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: MACs ctos: 
umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: 
umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib at openssh.com,zlib
debug2: compression stoc: none,zlib at openssh.com,zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: 
curve25519-sha256,curve25519-sha256 at libssh.org,ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,kexguess2 at matt.ucc.asn.au
debug2: host key algorithms: 
ecdsa-sha2-nistp256,ecdsa-sha2-nistp521,ssh-rsa,ssh-dss
debug2: ciphers ctos: 
aes128-ctr,aes256-ctr,aes128-cbc,aes256-cbc,3des-ctr,3des-cbc
debug2: ciphers stoc: 
aes128-ctr,aes256-ctr,aes128-cbc,aes256-cbc,3des-ctr,3des-cbc
debug2: MACs ctos: hmac-sha1-96,hmac-sha1,hmac-sha2-256
debug2: MACs stoc: hmac-sha1-96,hmac-sha1,hmac-sha2-256
debug2: compression ctos: zlib at openssh.com,none
debug2: compression stoc: zlib at openssh.com,none
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: aes128-ctr MAC: hmac-sha2-256 
compression: none
debug1: kex: client->server cipher: aes128-ctr MAC: hmac-sha2-256 
compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
Connection closed by 10.0.30.175 port 22
===[ end output from ssh -vvvv ]===

-- 
\\// Peter - http://www.softwolves.pp.se/