sshfs error when mounting "remote host has disconnected"

thew00t · 03-19-2007, 05:27 PM

Hi all, recently a server I maintain running
$ cat /etc/redhat-release
Red Hat Enterprise Linux ES release 4 (Nahant Update 4)

with kernel version
$ uname -r
2.6.9-42.0.2.ELsmp

and I've been trying to connect from a remote host with sshfs command:
$ sudo sshfs someuser@someserver.com:/dir/to/mount /mount/point

and immediately after entering my sudo'er password, I get
remote host has disconnected

if I pass -1 and -d like so
$ sudo sshfs someuser@someserver.com:/dir/to/mount /mount/point -1 -d

then I get promted for a password as I should, but upon entering the proper password I get booted with the same error. strace doesn't seem to help much:

$ sudo strace sshfs someuser@someserver.com:/dir/to/mount /mount/point -1 -d
... (cut off the beginning of output

Code:

set_tid_address(0xb7dba6f8)             = 7081
rt_sigaction(SIGRTMIN, {0xb7f8f720, [], SA_SIGINFO}, NULL, 8) = 0
rt_sigaction(SIGRT_1, {0xb7f8f640, [], SA_RESTART|SA_SIGINFO}, NULL, 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0
getrlimit(RLIMIT_STACK, {rlim_cur=8192*1024, rlim_max=RLIM_INFINITY}) = 0
_sysctl({{CTL_KERN, KERN_VERSION}, 2, 0xbfc57100, 34, (nil), 0}) = 0
brk(0)                                  = 0x8053000
brk(0x8074000)                          = 0x8074000
gettimeofday({1174342571, 232739}, NULL) = 0
pipe([3, 4])                            = 0
pipe([5, 6])                            = 0
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb7dba6f8) = 7082
--- SIGCHLD (Child exited) @ 0 (0) ---
waitpid(7082, NULL, 0)                  = 7082
close(4)                                = 0
close(5)                                = 0
writev(6, [{"\0\0\0\5\1\0\0\0\3", 9}], 1) = 9
read(3, someuser@somehost.com's password: 
"", 5)                          = 0
write(2, "remote host has disconnected\n", 29remote host has disconnected
) = 29
exit_group(1)                           = ?

any thoughts? I know I can SSH/SFTP to the host fine, and I know that the source dir and the target mountpoint both exist

syg00 · 03-19-2007, 07:58 PM

Done any maint on that box ???. Maybe the sshd_config has been reset to the default.
(Don't know how RHEL works, so this may be irrelvant).

thew00t · 03-19-2007, 08:16 PM

Oh yes, the system was recently wiped but I made sure that sshd_config had the right path to the sftp subsystem. Are there other directives I should have in my config? Here is what it says:

Code:

#       $OpenBSD: sshd_config,v 1.65 2003/08/28 12:54:34 markus Exp $

# This is the sshd server system-wide configuration file.  See
# sshd_config(5) for more information.

# This sshd was compiled with PATH=/usr/bin:/bin:/usr/sbin:/sbin

# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented.  Uncommented options change a
# default value.

#Port 22
#Protocol 2,1
#ListenAddress 0.0.0.0
#ListenAddress ::

# HostKey for protocol version 1
#HostKey /etc/ssh/ssh_host_key
# HostKeys for protocol version 2
#HostKey /etc/ssh/ssh_host_rsa_key
#HostKey /etc/ssh/ssh_host_dsa_key

# Lifetime and size of ephemeral version 1 server key
#KeyRegenerationInterval 1h
#ServerKeyBits 768

# Logging
#obsoletes QuietMode and FascistLogging
#SyslogFacility AUTH
LogLevel INFO

# Authentication:

LoginGraceTime 2m
PermitRootLogin no
#StrictModes yes

#RSAAuthentication yes
#PubkeyAuthentication yes
#AuthorizedKeysFile     .ssh/authorized_keys

# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
#RhostsRSAAuthentication no
# similar for protocol version 2
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# RhostsRSAAuthentication and HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes

# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no

# Change to no to disable s/key passwords
#ChallengeResponseAuthentication yes

# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCreds yes

# Set this to 'yes' to enable PAM authentication (via challenge-response)
# and session processing. Depending on your PAM configuration, this may
# bypass the setting of 'PasswordAuthentication'
#UsePAM yes

#AllowTcpForwarding yes
#GatewayPorts no
#X11Forwarding no
#X11DisplayOffset 10
#X11UseLocalhost yes
#PrintMotd yes
#PrintLastLog yes
#KeepAlive yes
#UseLogin no
#UsePrivilegeSeparation yes
#PermitUserEnvironment no
#Compression yes
#ClientAliveInterval 0
#ClientAliveCountMax 3
#UseDNS yes
#PidFile /var/run/sshd.pid
#MaxStartups 10

# no default banner path
#Banner /some/path

# override default of no subsystems
Subsystem       sftp    /usr/libexec/openssh/sftp-server

lordroger · 04-14-2007, 06:32 AM

Try running sshfs with the sshfs debug option:

"(sudo) sshfs (-o allow_other) -o sshfs_debug user@computer:/mountpoint /localmountpoint"

See if there is any problem with RSA/DSA keys. If you changed things on the server, keys may have changed.

If so, in the client, edit /root/.ssh/known_hosts and remove the line in which the server key appears. Or simply remove the entire file if you can't find the specific line.

Then try sshfs again, it will prompt you to accept the server's key.

This happened to me, and until I didn't use the debug option I didn't see my mistake.

Good luck!