bug(?) with OpenSSH 4.4+ and large DSA ID keys

downtime at slagheap.net downtime at slagheap.net
Fri Feb 9 06:17:24 EST 2007 

Please pardon me if this is the wrong place, or operator error/ 
retardation is involved.  Any help is sincerely appreciated.

fatal: mm_request_receive_expect: read: rtype 12 != type 24

For some reason, three (two OpenBSD/i386 and one OpenBSD/sparc64) of  
my four identically-configured SSH daemons cough up the above error  
when I try to authenticate using a big (4096-bit) DSA key from the  
same OpenSSH 4.2 client.  Note that I said three out of four -  
strangely one works, and this would ordinarily make me suspect my own  
incompetence, but I haven't done anything funny and all of them have  
default, vanilla configuration files.

One of them (i386), for some unbeknownst reason, works just fine.   
This was working just fine before I changed to a 4096 bit key.   
Upgrading the server to OpenSSH 4.5 allows for fallback to password  
authentication to work; upgrading the client produces no change  
whatsoever.  Other OpenSSH 4.2 and 4.3 servers I have seem not to be  
affected.  Going back to a 2048-bit DSA key fixes it.

Shell transcript follows, including debug output.  The key parsing  
errors are especially weird, but these seem to happen with the  
working client and a 2048-bit DSA key, too.

aurora65% ssh northstar
Connection closed by 192.168.99.2
aurora66% ssh root at northstar
root at northstar's password:
Last login: Thu Nov  2 00:31:48 2006
OpenBSD 4.0 (GENERIC) #2: Tue Jan 16 12:33:34 PST 2007

/usr/X11R6/bin/xauth:  creating new authority file /root/.Xauthority
Terminal type? [xterm]
# tail /var/log/authlog
Feb  6 03:00:01 northstar newsyslog[18751]: logfile turned over
Feb  7 14:54:26 northstar sshd[30539]: fatal:  
mm_request_receive_expect: read: rtype 12 != type 24
Feb  7 15:22:49 northstar sshd[10863]: fatal:  
mm_request_receive_expect: read: rtype 12 != type 24
Feb  7 16:34:03 northstar sshd[21238]: fatal:  
mm_request_receive_expect: read: rtype 12 != type 24
Feb  7 16:34:12 northstar sshd[24866]: Accepted password for root  
from 192.168.69.34 port 49715 ssh2
# exit
aurora69% ssh -vvv northstar
OpenSSH_4.2p1, OpenSSL 0.9.7l 28 Sep 2006
debug1: Reading configuration data /etc/ssh_config
debug2: ssh_connect: needpriv 0
debug1: Connecting to northstar [192.168.99.2] port 22.
debug1: Connection established.
debug1: identity file /Users/peter/.ssh/identity type 0
debug3: Not a RSA1 key file /Users/peter/.ssh/id_rsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug2: key_type_from_name: unknown key type 'Proc-Type:'
debug3: key_read: missing keytype
debug2: key_type_from_name: unknown key type 'DEK-Info:'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /Users/peter/.ssh/id_rsa type 1
debug3: Not a RSA1 key file /Users/peter/.ssh/id_dsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug2: key_type_from_name: unknown key type 'Proc-Type:'
debug3: key_read: missing keytype
debug2: key_type_from_name: unknown key type 'DEK-Info:'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /Users/peter/.ssh/id_dsa type 2
debug1: Remote protocol version 1.99, remote software version  
OpenSSH_4.4
debug1: match: OpenSSH_4.4 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.2
debug2: fd 3 setting O_NONBLOCK
debug1: An invalid name was supplied
Configuration file does not specify default realm

debug1: An invalid name was supplied
A parameter was malformed
Validation error

debug1: An invalid name was supplied
Configuration file does not specify default realm

debug1: An invalid name was supplied
A parameter was malformed
Validation error

debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie- 
hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128- 
cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael- 
cbc at lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128- 
cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael- 
cbc at lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac- 
ripemd160 at openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac- 
ripemd160 at openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib at openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib at openssh.com,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: diffie-hellman-group-exchange- 
sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14- 
sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128- 
cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael- 
cbc at lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128- 
cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael- 
cbc at lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac- 
ripemd160 at openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac- 
ripemd160 at openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib at openssh.com
debug2: kex_parse_kexinit: none,zlib at openssh.com
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_init: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug2: mac_init: found hmac-md5
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug2: dh_gen_key: priv key bits set: 121/256
debug2: bits set: 502/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: filename /Users/peter/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 148
debug3: check_host_in_hostfile: filename /Users/peter/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 148
debug1: Host 'northstar' is known and matches the RSA host key.
debug1: Found key in /Users/peter/.ssh/known_hosts:148
debug2: bits set: 511/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /Users/peter/.ssh/id_rsa (0x307930)
debug2: key: /Users/peter/.ssh/id_dsa (0x3078a0)
debug1: Authentications that can continue:  
publickey,password,keyboard-interactive
debug3: start over, passed a different list  
publickey,password,keyboard-interactive
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 public key: /Users/peter/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue:  
publickey,password,keyboard-interactive
debug1: Offering public key: /Users/peter/.ssh/id_dsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-dss blen 1587
debug2: input_userauth_pk_ok: fp blah:blah:blah
debug3: sign_and_send_pubkey
debug1: Authentications that can continue:  
publickey,password,keyboard-interactive
debug2: we did not send a packet, disable method
debug3: authmethod_lookup keyboard-interactive
debug3: remaining preferred: password
debug3: authmethod_is_enabled keyboard-interactive
debug1: Next authentication method: keyboard-interactive
debug2: userauth_kbdint
debug2: we sent a keyboard-interactive packet, wait for reply
Connection closed by 192.168.99.2

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