ssh and sshd hanging

["Martin Haltmayer" <cygwin at 0800-einwahl dot de>]

Hello all,

WinXP SP 3, Cygwin1.dll 1.7.7 (latest stable download), sshd and ssh  
latest stable. I created a root user (!), empty /var/empty that belongs to  
root, but deviate (by ssh-host-config) from the standard by

Port 22
StrictModes no
UsePrivilegeSeparation no
Compression no
Subsystem       sftp    /usr/sbin/sftp-server

I did my


mkpasswd -l > /etc/passwd
mkgroup -l > /etc/group


Connection establishes but I cannot continue to work (note the line  
"debug1: Connection established"):


martin@martin004 ~
$ cygrunsrv --start sshd

martin@martin004 ~
$ strace -f -o /tmp/strace.out ssh -vvv martin@192.168.178.2
OpenSSH_5.6p1, OpenSSL 0.9.8q 2 Dec 2010
debug1: Reading configuration data /etc/ssh_config
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.178.2 [192.168.178.2] port 22.
debug1: Connection established.
debug1: identity file /home/martin/.ssh/id_rsa type -1
debug1: identity file /home/martin/.ssh/id_rsa-cert type -1
debug3: Not a RSA1 key file /home/martin/.ssh/id_dsa.
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
debug1: identity file /home/martin/.ssh/id_dsa type 2
debug1: ssh_dss_verify: signature correct
debug1: identity file /home/martin/.ssh/id_dsa-cert type 4


Funnily enough, /tmp/strace.out shows (less with line numbers)


   1024    90  285650 [main] ssh 928 fhandler_base::set_flags: flags  
0x100000, supplied_bin 0x10000
   1025    36  285686 [main] ssh 928 fhandler_base::set_flags: filemode  
set to text
   1026    38  285724 [main] ssh 928 fhandler_base::open: 0 = NtCreateFile  
(0x5D0, 80100000, \??\C:\cygwin\home\martin\.ssh\id_dsa-c
o, NULL, 0, 7, 1, 4020, NULL, 0)
   1027   338  286062 [main] ssh 928 fhandler_base::open: 1 =  
fhandler_base::open (\??\C:\cygwin\home\martin\.ssh\id_dsa-cert.pub, 0
   1028    49  286111 [main] ssh 928 fhandler_base::open_fs: 1 =  
fhandler_disk_file::open (\??\C:\cygwin\home\martin\.ssh\id_dsa-cer
)
   1029    40  286151 [main] ssh 928 open: 4 = open  
(/home/martin/.ssh/id_dsa-cert.pub, 0x0)
   1030   177  286328 [main] ssh 928 _cygwin_istext_for_stdio: fd 4:  
defaulting to text
   1031   235  286563 [main] ssh 928 cygpsid::debug_print: get_sids_info:  
owner SID = S-1-5-21-484763869-823518204-682003330-1005
   1032    48  286611 [main] ssh 928 cygpsid::debug_print: get_sids_info:  
group SID = S-1-5-21-484763869-823518204-682003330-513
   1033    42  286653 [main] ssh 928 get_info_from_sd: ACL 1A4, uid 1005,  
gid 513
   1034    45  286698 [main] ssh 928 fhandler_base::fstat_helper: 0 =  
fstat (\??\C:\cygwin\home\martin\.ssh\id_dsa-cert.pub, 0x23831
e=4D2B76EC st_size=1605, st_mode=0x81A4, st_ino=125256364636259231,  
sizeof=96
   1035    64  286762 [main] ssh 928 fstat64: 0 = fstat (4, 0x238318)
   1036    61  286823 [main] ssh 928 fhandler_base::set_flags: flags  
0x110000, supplied_bin 0x0
   1037    34  286857 [main] ssh 928 fhandler_base::set_flags:  
O_TEXT/O_BINARY set in flags 0x10000
   1038    41  286898 [main] ssh 928 fhandler_base::set_flags: filemode  
set to binary
   1039    41  286939 [main] ssh 928 setmode:  
(4<\??\C:\cygwin\home\martin\.ssh\id_dsa-cert.pub>, 0x10000) returning text
   1040    37  286976 [main] ssh 928 readv: readv (4, 0x238334, 1)  
blocking, sigcatchers 0
   1041    94  287070 [main] ssh 928 fhandler_base::read: returning 1605,  
binary mode
   1042    31  287101 [main] ssh 928 readv: 1605 = readv (4, 0x238334, 1),  
errno 2
   1043    38  287139 [main] ssh 928 fhandler_base::set_flags: flags  
0x120000, supplied_bin 0x0
   1044    41  287180 [main] ssh 928 fhandler_base::set_flags:  
O_TEXT/O_BINARY set in flags 0x20000
   1045    38  287218 [main] ssh 928 fhandler_base::set_flags: filemode  
set to text
   1046    32  287250 [main] ssh 928 setmode:  
(4<\??\C:\cygwin\home\martin\.ssh\id_dsa-cert.pub>, 0x20000) returning  
binary
   1047 10227  297477 [main] ssh 928 fhandler_console::write: 237E88, 43
   1048    58  297535 [main] ssh 928 fhandler_console::write: at 100(d)  
state is 0
   1049   180  297715 [main] ssh 928 fhandler_console::write: at 10(0x20)  
state is 0
   1050    73  297788 [main] ssh 928 fhandler_console::write: 43 =  
fhandler_console::write (,..43)
   1051   934  298722 [main] ssh 928 close: close (4)
   1052    41  298763 [main] ssh 928 fhandler_base::close: closing  
'/home/martin/.ssh/id_dsa-cert.pub' handle 0x5D0
   1053   520  299283 [main] ssh 928 close: 0 = close (4)
   1054   320  299603 [main] ssh 928 fhandler_console::write: 23B088, 60
   1055    37  299640 [main] ssh 928 fhandler_console::write: at 100(d)  
state is 0
   1056   142  299782 [main] ssh 928 fhandler_console::write: at 10(0x20)  
state is 0
   1057    74  299856 [main] ssh 928 fhandler_console::write: 60 =  
fhandler_console::write (,..60)
   1058   389  300245 [main] ssh 928 sig_send: sendsig 0x748, pid 928,  
signal -34, its_me 1
   1059   137  300382 [main] ssh 928 sig_send: wakeup 0x5D4
   1060    55  300437 [main] ssh 928 sig_send: Waiting for pack.wakeup  
0x5D4
   1061    54  300491 [sig] ssh 928 wait_sig: signalling pack.wakeup 0x5D4
   1062    44  300535 [main] ssh 928 sig_send: returning 0x0 from sending  
signal -34
   1063    42  300577 [main] ssh 928 sigaction_worker: signal 13, newact  
0x0, oa 0x0
   1064    31  300608 [main] ssh 928 sig_send: sendsig 0x748, pid 928,  
signal -34, its_me 1
   1065    39  300647 [main] ssh 928 sig_send: wakeup 0x5D4
   1066    42  300689 [main] ssh 928 sig_send: Waiting for pack.wakeup  
0x5D4
   1067    44  300733 [sig] ssh 928 wait_sig: signalling pack.wakeup 0x5D4
   1068    36  300769 [main] ssh 928 sig_send: returning 0x0 from sending  
signal -34
   1069    31  300800 [main] ssh 928 sigaction_worker: signal 13, newact  
0x23B4AC (handler 0x1), oa 0x0
   1070    29  300829 [main] ssh 928 sig_send: sendsig 0x748, pid 928,  
signal -13, its_me 1
   1071    35  300864 [main] ssh 928 sig_send: wakeup 0x5D4
   1072    33  300897 [main] ssh 928 sig_send: Waiting for pack.wakeup  
0x5D4
   1073    42  300939 [sig] ssh 928 wait_sig: signalling pack.wakeup 0x5D4
   1074   225  301164 [main] ssh 928 sig_send: returning 0x0 from sending  
signal -13
   1075   124  301288 [main] ssh 928 readv: readv (3, 0x23B194, 1)  
blocking, sigcatchers 0

If I search backwards for " 3 = open ", I find


    383    29  170778 [main] ssh 928 open: 3 = open (/dev/urandom, 0x1C000)
    384    28  170806 [main] ssh 928 fhandler_base::fstat: here
    385    29  170835 [main] ssh 928 time: 1294694125 = time (0)
    386    44  170879 [main] ssh 928 fstat64: 0 = fstat (3, 0x23B320)

In this state, sshd forked a process that occupies a complete cpu. Trying  
strace -p does not reveal much:


$ strace -p 3432
Windows process 2052 attached
**********************************************
Program name: C:\cygwin\usr\sbin\sshd.exe (pid 3432, ppid 1888)
App version:  1007.7, api: 0.230
DLL version:  1007.7, api: 0.230
DLL build:    2010-08-31 09:58
OS version:   Windows NT-5.1
Heap size:    402653184
Date/Time:    2011-01-10 23:04:01
**********************************************

and no more output. So it looks like a busy loop. Similar holds for the  
ssh strace when it hangs. It looks like


$ strace -p 3312
Windows process 3784 attached
**********************************************
Program name: C:\cygwin\bin\ssh.exe (pid 3312, ppid 3876)
App version:  1007.7, api: 0.230
DLL version:  1007.7, api: 0.230
DLL build:    2010-08-31 09:58
OS version:   Windows NT-5.1
Heap size:    402653184
Date/Time:    2011-01-10 23:14:20
**********************************************

I tried the same with SyslogFacility LOCAL0 and LogLevel DEBUG3 in  
/etc/sshd_config. /var/log/sshd.log is created but it remains empty. Can I  
get more info? Unluckily, I did not find further info about the  
SyslogFacility destinations.

Anybody any pointers where to look and what to look for?

Thanks for your time and enlightenment.

Where do I search further? Or does somebody even have a solution for my  
problem?


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