Bug 382

Summary: Privilege Separation breaks HostbasedAuthentication
Product: Portable OpenSSH Reporter: Russ LeBar <rlebar>
Component: sshdAssignee: OpenSSH Bugzilla mailing list <openssh-bugs>
Status: CLOSED FIXED    
Severity: major    
Priority: P2    
Version: -current   
Hardware: SPARC   
OS: Solaris   

Description Russ LeBar 2002-08-08 04:03:12 AEST 
With privsep disabled (UsePrivilegeSeparation no) HostbasedAuthenticatoin 
works. With it turned on below is what I get from sshd. Note the 
mm_answer_keyverify: bad signature data blob
 near the end. Also note that our OpenSSH is compiled with the config directory 
as /opt/erac/etc.

-----8<-----------------------------------------------------------------

debug3: Seeding PRNG from /opt/erac//libexec/ssh-rand-helper
This platform does not support both privilege separation and compression
Compression disabled
debug1: sshd version OpenSSH_3.4p1
debug3: Not a RSA1 key file /opt/erac/etc/ssh_host_rsa_key.
debug1: read PEM private key done: type RSA
debug1: private host key: #0 type 1 RSA
debug3: Not a RSA1 key file /opt/erac/etc/ssh_host_dsa_key.
debug1: read PEM private key done: type DSA
debug1: private host key: #1 type 2 DSA
debug1: Bind to port 22 on 0.0.0.0.
Server listening on 0.0.0.0 port 22.
debug1: Server will not fork when running in debugging mode.
Connection from 10.49.191.9 port 34890
debug1: Client protocol version 2.0; client software version OpenSSH_3.4p1
debug1: match: OpenSSH_3.4p1 pat OpenSSH*
Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.4p1
debug3: privsep user:group 60001:1
debug1: list_hostkey_types: ssh-rsa,ssh-dss
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-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,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: none
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-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,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: none
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: client->server aes128-cbc hmac-md5 none
debug2: mac_init: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST received
debug3: mm_request_send entering: type 0
debug3: mm_choose_dh: waiting for MONITOR_ANS_MODULI
debug3: mm_request_receive_expect entering: type 1
debug3: mm_request_receive entering
debug2: Network child is on pid 3990
debug3: preauth child monitor started
debug3: mm_request_receive entering
debug3: monitor_read: checking request 0
debug3: mm_answer_moduli: got parameters: 1024 2048 8192
WARNING: /opt/erac/etc/moduli does not exist, using old modulus
debug3: mm_request_send entering: type 1
debug3: mm_choose_dh: remaining 0
debug1: SSH2_MSG_KEX_DH_GEX_GROUP sent
debug1: dh_gen_key: priv key bits set: 139/256
debug1: bits set: 469/1024
debug1: expecting SSH2_MSG_KEX_DH_GEX_INIT
debug2: monitor_read: 0 used once, disabling now
debug3: mm_request_receive entering
debug1: bits set: 547/1024
debug3: mm_key_sign entering
debug3: mm_request_send entering: type 4
debug3: mm_key_sign: waiting for MONITOR_ANS_SIGN
debug3: mm_request_receive_expect entering: type 5
debug3: mm_request_receive entering
debug3: monitor_read: checking request 4
debug3: mm_answer_sign
debug3: mm_answer_sign: signature 121938(143)
debug3: mm_request_send entering: type 5
debug2: monitor_read: 4 used once, disabling now
debug3: mm_request_receive entering
debug1: SSH2_MSG_KEX_DH_GEX_REPLY sent
debug1: kex_derive_keys
debug1: newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: waiting for SSH2_MSG_NEWKEYS
debug1: newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: KEX done
debug1: userauth-request for user rjl01 service ssh-connection method none
debug1: attempt 0 failures 0
debug3: mm_getpwnamallow entering
debug3: mm_request_send entering: type 6
debug3: mm_getpwnamallow: waiting for MONITOR_ANS_PWNAM
debug3: mm_request_receive_expect entering: type 7
debug3: mm_request_receive entering
debug3: monitor_read: checking request 6
debug3: mm_answer_pwnamallow
debug3: mm_answer_pwnamallow: sending MONITOR_ANS_PWNAM: 1
debug3: mm_request_send entering: type 7
debug2: monitor_read: 6 used once, disabling now
debug3: mm_request_receive entering
debug2: input_userauth_request: setting up authctxt for rjl01
debug3: mm_start_pam entering
debug3: mm_request_send entering: type 37
debug3: mm_inform_authserv entering
debug3: mm_request_send entering: type 3
debug2: input_userauth_request: try method none
debug3: mm_auth_password entering
debug3: mm_request_send entering: type 10
debug3: mm_auth_password: waiting for MONITOR_ANS_AUTHPASSWORD
debug3: mm_request_receive_expect entering: type 11
debug3: mm_request_receive entering
debug3: monitor_read: checking request 37
debug1: Starting up PAM with username "rjl01"
debug3: Trying to reverse map address 10.49.191.9.
debug1: PAM setting rhost to "evereska.wan.erac.com"
debug2: monitor_read: 37 used once, disabling now
debug3: mm_request_receive entering
debug3: monitor_read: checking request 3
debug3: mm_answer_authserv: service=ssh-connection, style=
debug2: monitor_read: 3 used once, disabling now
debug3: mm_request_receive entering
debug3: monitor_read: checking request 10
debug3: mm_answer_authpassword: sending result 0
debug3: mm_request_send entering: type 11
Failed none for rjl01 from 10.49.191.9 port 34890 ssh2
debug3: mm_request_receive entering
debug3: mm_auth_password: user not authenticated
Failed none for rjl01 from 10.49.191.9 port 34890 ssh2
debug1: userauth-request for user rjl01 service ssh-connection method hostbased
debug1: attempt 1 failures 1
debug2: input_userauth_request: try method hostbased
debug1: userauth_hostbased: cuser rjl01 chost evereska. pkalg ssh-dss slen 55
debug3: mm_key_allowed entering
debug3: mm_request_send entering: type 20
debug3: mm_key_allowed: waiting for MONITOR_ANS_KEYALLOWED
debug3: mm_request_receive_expect entering: type 21
debug3: mm_request_receive entering
debug3: monitor_read: checking request 20
debug3: mm_answer_keyallowed entering
debug3: mm_answer_keyallowed: key_from_blob: 1245e0
debug2: userauth_hostbased: chost evereska. resolvedname evereska.wan.erac.com 
ipaddr 10.49.191.9
debug2: auth_rhosts2: clientuser rjl01 hostname evereska. ipaddr evereska.
debug1: temporarily_use_uid: 503/5005 (e=0)
debug1: restore_uid
debug2: userauth_hostbased: access allowed by auth_rhosts2
debug3: check_host_in_hostfile: filename /opt/erac/etc/ssh_known_hosts
debug1: temporarily_use_uid: 503/5005 (e=0)
debug3: check_host_in_hostfile: filename /export/home/rjl01/.ssh/known_hosts
debug1: restore_uid
debug2: check_key_in_hostfiles: key not found for evereska.
debug3: check_host_in_hostfile: filename /opt/erac/etc/ssh_known_hosts2
debug3: key_read: type mismatch
debug1: temporarily_use_uid: 503/5005 (e=0)
debug3: check_host_in_hostfile: filename /export/home/rjl01/.ssh/known_hosts2
debug1: restore_uid
debug2: check_key_in_hostfiles: key not found for evereska.
debug3: mm_answer_keyallowed: key 1245e0 is disallowed
debug3: mm_append_debug: Appending debug messages for child
debug3: mm_request_send entering: type 21
debug3: mm_request_receive entering
debug3: mm_send_debug: Sending debug: Accepted for evereska. [evereska.] 
by /opt/erac/etc/shosts.equiv.
debug2: userauth_hostbased: authenticated 0
Failed hostbased for rjl01 from 10.49.191.9 port 34890 ssh2
debug1: userauth-request for user rjl01 service ssh-connection method hostbased
debug1: attempt 2 failures 2
debug2: input_userauth_request: try method hostbased
debug1: userauth_hostbased: cuser rjl01 chost evereska. pkalg ssh-rsa slen 143
debug3: mm_key_allowed entering
debug3: mm_request_send entering: type 20
debug3: mm_key_allowed: waiting for MONITOR_ANS_KEYALLOWED
debug3: mm_request_receive_expect entering: type 21
debug3: mm_request_receive entering
debug3: monitor_read: checking request 20
debug3: mm_answer_keyallowed entering
debug3: mm_answer_keyallowed: key_from_blob: 1245e0
debug2: userauth_hostbased: chost evereska. resolvedname evereska.wan.erac.com 
ipaddr 10.49.191.9
debug2: auth_rhosts2: clientuser rjl01 hostname evereska. ipaddr evereska.
debug1: temporarily_use_uid: 503/5005 (e=0)
debug1: restore_uid
debug2: userauth_hostbased: access allowed by auth_rhosts2
debug3: check_host_in_hostfile: filename /opt/erac/etc/ssh_known_hosts
debug1: temporarily_use_uid: 503/5005 (e=0)
debug3: check_host_in_hostfile: filename /export/home/rjl01/.ssh/known_hosts
debug1: restore_uid
debug2: check_key_in_hostfiles: key not found for evereska.
debug3: check_host_in_hostfile: filename /opt/erac/etc/ssh_known_hosts2
debug3: check_host_in_hostfile: match line 2
debug2: check_key_in_hostfiles: key ok for evereska.
debug3: mm_answer_keyallowed: key 1245e0 is allowed
debug3: mm_append_debug: Appending debug messages for child
debug3: mm_request_send entering: type 21
debug3: mm_request_receive entering
debug3: mm_send_debug: Sending debug: Accepted for evereska. [evereska.] 
by /opt/erac/etc/shosts.equiv.
debug3: mm_key_verify entering
debug3: mm_request_send entering: type 22
debug3: mm_key_verify: waiting for MONITOR_ANS_KEYVERIFY
debug3: mm_request_receive_expect entering: type 23
debug3: mm_request_receive entering
debug3: monitor_read: checking request 22
mm_answer_keyverify: bad signature data blob
debug1: Calling cleanup 0x38d24(0x0)
debug1: Calling cleanup 0x53eb0(0x0)
debug1: Calling cleanup 0x53eb0(0x0)
Comment 1 Markus Friedl 2002-09-11 08:18:30 AEST 
this should be fixed in -current (use-after-free in ssh-keysign)

please test current and reopen if the bug is still there.
Comment 2 Damien Miller 2004-04-14 12:24:18 AEST 
Mass change of RESOLVED bugs to CLOSED