Connection issue in OpenBMC image

Fri Sep 18 19:47:32 AEST 2020

Classification: HCL Internal

Hello Patrick,

I saw the post about dropbear, but that commit was updated on July16 and my target is connecting till August last week image. I don't think that will be an issue. Also on working image, I tried with 'ssh -vvv ' and I got below information.

OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 58: Applying options for *
debug2: resolving "10.0.128.108" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 10.0.128.108 [10.0.128.108] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.4
debug1: Remote protocol version 2.0, remote software version dropbear_2020.80
debug1: no match: dropbear_2020.80
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 10.0.128.108:22 as 'root'
debug3: hostkeys_foreach: reading file "/root/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /root/.ssh/known_hosts:68
debug3: load_hostkeys: loaded 1 keys from 10.0.128.108
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01 at openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa
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,diffie-hellman-group1-sha1,ext-info-c
debug2: host key algorithms: ssh-rsa-cert-v01 at openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256-cert-v01 at openssh.com,ecdsa-sha2-nistp384-cert-v01 at openssh.com,ecdsa-sha2-nistp521-cert-v01 at openssh.com,ssh-ed25519-cert-v01 at openssh.com,ssh-dss-cert-v01 at openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,ssh-dss
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,kexguess2 at matt.ucc.asn.au
debug2: host key algorithms: rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305 at openssh.com,aes128-ctr,aes256-ctr
debug2: ciphers stoc: chacha20-poly1305 at openssh.com,aes128-ctr,aes256-ctr
debug2: MACs ctos: hmac-sha1,hmac-sha2-256
debug2: MACs stoc: 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: rsa-sha2-256
debug1: kex: server->client cipher: chacha20-poly1305 at openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305 at openssh.com MAC: <implicit> compression: none
debug1: kex: curve25519-sha256 need=64 dh_need=64
debug1: kex: curve25519-sha256 need=64 dh_need=64
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-rsa SHA256:3WwhPmIIxzrw0+cm/0vN3hifY4kh9sJhClVNw6zrJ7Y
debug3: hostkeys_foreach: reading file "/root/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /root/.ssh/known_hosts:68
debug3: load_hostkeys: loaded 1 keys from 10.0.128.108
debug1: Host '10.0.128.108' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:68
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug2: key: /root/.ssh/id_rsa (0x558ea3ad3640), agent
debug2: key: /root/.ssh/id_rsa ((nil))
debug2: key: /root/.ssh/id_dsa ((nil))
debug2: key: /root/.ssh/id_ecdsa ((nil))
debug2: key: /root/.ssh/id_ed25519 ((nil))
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,rsa-sha2-256,ssh-rsa,ssh-dss>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /root/.ssh/id_rsa
debug3: send_pubkey_test
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /root/.ssh/id_rsa
debug3: sign_and_send_pubkey: RSA SHA256:YfteufmWUV8W7EQEycZ+38skgUWGDTYFHw93a7SwwLM
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /root/.ssh/id_dsa
debug3: no such identity: /root/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /root/.ssh/id_ecdsa
debug3: no such identity: /root/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /root/.ssh/id_ed25519
debug3: no such identity: /root/.ssh/id_ed25519: No such file or directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password

In non-working image, the logs are stopped after below lines and it is not providing any errors.

debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.4

Also one more observation in UART-Console, after flashing latest image.

1. reboot command is not working.
2. systemctl status <service_name> is not providing any status. ( Failed to get properties: Connection timed out)
3. I can able to ping the ip address but scp is not working.

Thanks,
Jayashree

-----Original Message-----
From: Patrick Williams <patrick at stwcx.xyz>
Sent: Thursday, September 17, 2020 9:16 PM
To: Jayashree D <jayashree-d at hcl.com>
Cc: Konstantin Klubnichkin <kitsok at yandex-team.ru>; openbmc at lists.ozlabs.org
Subject: Re: Connection issue in OpenBMC image

Hello Jayashree,

I saw an output `ssh -v` from you earlier, but there really wasn't any useful information there.  It looked like the connection was being made and keys were exchanged and then the log just stopped abruptly.  This tells me it likely isn't a networking issue but an issue in the handshake between the ssh-client (your computer) and ssh-server (dropbear).  You can continue to add '-v' parameters up to `ssh -vvv` and you'll get increasingly more information.

Joseph Reynolds recently posted a reminder about dropbear disabling weak ciphers[1].  Is it possible that your client is using an old cipher?

On Wed, Sep 16, 2020 at 11:35:28AM +0000, Jayashree D wrote:
> root at tiogapass:~# journalctl | grep drop
...
> Jan 01 00:15:28 tiogapass systemd[1]: dropbear at 0-10.0.128.108:22-10.0.0.1:51810.service: Succeeded.
> Jan 01 00:15:44 tiogapass dropbear[2753]: Child connection from
> ::ffff:10.0.0.1:51944 Jan 01 00:15:50 tiogapass dropbear[2753]: PAM
> password auth succeeded for 'root' from ::ffff:10.0.0.1:51944

This looks like a valid connection was established.

> 15.09.2020, 16:12, "Jayashree D" <jayashree-d at hcl.com<mailto:jayashree-d at hcl.com>>:
>
> OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
> debug1: Reading configuration data /etc/ssh/ssh_config
> debug1: /etc/ssh/ssh_config line 58: Applying options for *
> debug1: Connecting to 10.0.128.108 [10.0.128.108] port 22.
> debug1: Connection established.
> debug1: permanently_set_uid: 0/0
> debug1: key_load_public: No such file or directory
> debug1: identity file /root/.ssh/id_rsa type -1
> debug1: key_load_public: No such file or directory
> debug1: identity file /root/.ssh/id_rsa-cert type -1
> debug1: key_load_public: No such file or directory
> debug1: identity file /root/.ssh/id_dsa type -1
> debug1: key_load_public: No such file or directory
> debug1: identity file /root/.ssh/id_dsa-cert type -1
> debug1: key_load_public: No such file or directory
> debug1: identity file /root/.ssh/id_ecdsa type -1
> debug1: key_load_public: No such file or directory
> debug1: identity file /root/.ssh/id_ecdsa-cert type -1
> debug1: key_load_public: No such file or directory
> debug1: identity file /root/.ssh/id_ed25519 type -1
> debug1: key_load_public: No such file or directory
> debug1: identity file /root/.ssh/id_ed25519-cert type -1
> debug1: Enabling compatibility mode for protocol 2.0
> debug1: Local version string SSH-2.0-OpenSSH_7.4

This is the log that also looks like a good connection.  Identity files were attempted to be exchanged.  Version strings were exchanged.  And then the log just abruptly stops.  Was the connection dropped?  Is it hung?

1. https://lists.ozlabs.org/pipermail/openbmc/2020-September/023071.html

--
Patrick Williams
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