Endless loop of directories

Hi,
I am trying to log to a Unix server. Everything seems ok until Winscp tries to get the directory structure. It start reading in an endless loop.
What could be causing this?


. --------------------------------------------------------------------------
. WinSCP Version 3.5.0 (Build 204)
. Login time: 23 janvier 2004 09:23:01
. --------------------------------------------------------------------------
. Session name: webadmin@bismo.qc
. Host name: bismo.qc (Port: 22)
. User name: webadmin (Password: Yes, Key file: No)
. Transfer Protocol: SFTP
. SSH protocol version: 2; Compression: No
. Agent forwarding: No; TIS/CryptoCard: No; KI: Yes
. Ciphers: blowfish,3des,aes,WARN,des; Ssh2DES: No
. Ping type: N, Ping interval: 30 sec; Timeout: 10 sec
. SSH Bugs: +,+,+,+,+,+,+,+,
. Proxy: none
. Return code variable: Autodetect; Lookup user groups: No
. Shell: default, EOL: 1
. Local directory: C:\, Remote directory: /software, Update: No, Cache: No
. Cache directory changes: No, Permanent: No
. Clear aliases: No, Unset nat.vars: No, Resolve symlinks: No
. Alias LS: No, Ign LS warn: No, Scp1 Comp: No
. --------------------------------------------------------------------------
. Looking up host "bismo.qc"
. Connecting to 142.117.21.237 port 22
. Server version: SSH-1.99-OpenSSH_2.3.0p1
. We claim version: SSH-2.0-WinSCP-release-3.5
. Using SSH protocol version 2
. Doing Diffie-Hellman group exchange
. Doing Diffie-Hellman key exchange
. Host key fingerprint is:
. ssh-dss 1024 59:ff:03:96:2b:7d:ce:2a:69:d3:93:b7:e8:b5:f0:f0
. Initialised Blowfish client->server encryption
. Initialised Blowfish server->client encryption
! Using username "webadmin".
. Session password prompt (webadmin@bismo.qc's password: )
. Using stored password.
. Sent password
. Access granted
. Opened channel for session
. Started a shell/command
. --------------------------------------------------------------------------
. Using SFTP protocol.
. Doing startup conversation with host.
> Type: SSH_FXP_INIT, Size: 5, Number: -1
< Type: SSH_FXP_VERSION, Size: 5, Number: -1
. SFTP version 2 negotiated.
. Changing directory to "/software".
. Getting real path for '/software'
> Type: SSH_FXP_REALPATH, Size: 18, Number: 16
< Type: SSH_FXP_NAME, Size: 39, Number: 16
. Real path is '/software'
. Trying to open directory "/software".
> Type: SSH_FXP_OPENDIR, Size: 18, Number: 267
< Type: SSH_FXP_HANDLE, Size: 10, Number: 267
> Type: SSH_FXP_CLOSE, Size: 10, Number: 516
< Type: SSH_FXP_STATUS, Size: 9, Number: 516
< Status/error code: 0
. Getting current directory name.
. Listing directory "/software".
> Type: SSH_FXP_OPENDIR, Size: 18, Number: 779
< Type: SSH_FXP_HANDLE, Size: 10, Number: 779
> Type: SSH_FXP_READDIR, Size: 10, Number: 1036
< Type: SSH_FXP_NAME, Size: 2724, Number: 1036
> Type: SSH_FXP_READDIR, Size: 10, Number: 1292
< Type: SSH_FXP_NAME, Size: 9, Number: 1292
> Type: SSH_FXP_READDIR, Size: 10, Number: 1548
< Type: SSH_FXP_NAME, Size: 9, Number: 1548
> Type: SSH_FXP_READDIR, Size: 10, Number: 1804
< Type: SSH_FXP_NAME, Size: 9, Number: 1804
> Type: SSH_FXP_READDIR, Size: 10, Number: 2060
< Type: SSH_FXP_NAME, Size: 9, Number: 2060
> Type: SSH_FXP_READDIR, Size: 10, Number: 2316
< Type: SSH_FXP_NAME, Size: 9, Number: 2316
> Type: SSH_FXP_READDIR, Size: 10, Number: 2572
< Type: SSH_FXP_NAME, Size: 9, Number: 2572
> Type: SSH_FXP_READDIR, Size: 10, Number: 2828
< Type: SSH_FXP_NAME, Size: 9, Number: 2828
> Type: SSH_FXP_READDIR, Size: 10, Number: 3084
< Type: SSH_FXP_NAME, Size: 9, Number: 3084
> Type: SSH_FXP_READDIR, Size: 10, Number: 3340
< Type: SSH_FXP_NAME, Size: 9, Number: 3340
> Type: SSH_FXP_READDIR, Size: 10, Number: 3596
< Type: SSH_FXP_NAME, Size: 9, Number: 3596
> Type: SSH_FXP_READDIR, Size: 10, Number: 3852
< Type: SSH_FXP_NAME, Size: 9, Number: 3852

This may not mean endless loop. In SFTP protocol, client must issue SSH_FXP_READDIR several times until the server replyies that there are no more files. So if the directory is very large, it may require tens (even hundreds) requests. Does it help if you start in different folder (see Environment tab of login dialog)?

martin wrote:

This may not mean endless loop. In SFTP protocol, client must issue SSH_FXP_READDIR several times until the server replyies that there are no more files. So if the directory is very large, it may require tens (even hundreds) requests. Does it help if you start in different folder (see Environment tab of login dialog)?

No. Even If I specify the full path of a directory with only 2 files, it still seems to 'loop'

. Getting current directory name.
. Listing directory "/software/AribaBuyer7/CoreServer/ariba/base/core".
> Type: SSH_FXP_OPENDIR, Size: 57, Number: 779
< Type: SSH_FXP_HANDLE, Size: 10, Number: 779
> Type: SSH_FXP_READDIR, Size: 10, Number: 1036
< Type: SSH_FXP_NAME, Size: 365, Number: 1036
> Type: SSH_FXP_READDIR, Size: 10, Number: 1292
< Type: SSH_FXP_NAME, Size: 9, Number: 1292
> Type: SSH_FXP_READDIR, Size: 10, Number: 1548
< Type: SSH_FXP_NAME, Size: 9, Number: 1548
> Type: SSH_FXP_READDIR, Size: 10, Number: 1804
< Type: SSH_FXP_NAME, Size: 9, Number: 1804
> Type: SSH_FXP_READDIR, Size: 10, Number: 2060
< Type: SSH_FXP_NAME, Size: 9, Number: 2060
> Type: SSH_FXP_READDIR, Size: 10, Number: 2316
< Type: SSH_FXP_NAME, Size: 9, Number: 2316
> Type: SSH_FXP_READDIR, Size: 10, Number: 2572
< Type: SSH_FXP_NAME, Size: 9, Number: 2572
> Type: SSH_FXP_READDIR, Size: 10, Number: 2828
< Type: SSH_FXP_NAME, Size: 9, Number: 2828
> Type: SSH_FXP_READDIR, Size: 10, Number: 3084
< Type: SSH_FXP_NAME, Size: 9, Number: 3084
> Type: SSH_FXP_READDIR, Size: 10, Number: 3340
< Type: SSH_FXP_NAME, Size: 9, Number: 3340

PierreBelanger wrote:

No. Even If I specify the full path of a directory with only 2 files, it still seems to 'loop'

It seems like a bug in your server. Because when listing ends it should reply SSH_FXP_STATUS with code EOF, but it keep replying SSH_FXP_NAME. Have you tried other SFTP client? Can I have a test account on your server?

martin wrote:

PierreBelanger wrote:

No. Even If I specify the full path of a directory with only 2 files, it still seems to 'loop'

It seems like a bug in your server. Because when listing ends it should reply SSH_FXP_STATUS with code EOF, but it keep replying SSH_FXP_NAME. Have you tried other SFTP client? Can I have a test account on your server?

I did not try it elsewhere (This is the only SFTP client I use). But I can connect without problem with version 5.3 of F-Secure-SSH. Unfortunately, this server cannot be accessed from outside the network.

PierreB wrote:

I did not try it elsewhere (This is the only SFTP client I use). But I can connect without problem with version 5.3 of F-Secure-SSH. Unfortunately, this server cannot be accessed from outside the network.

F-Secure-SSH is only SSH terminal or SFTP client? Can you PSFTP from Putty package? It is command line client, just try to list directory.

martin wrote:

PierreB wrote:

I did not try it elsewhere (This is the only SFTP client I use). But I can connect without problem with version 5.3 of F-Secure-SSH. Unfortunately, this server cannot be accessed from outside the network.

F-Secure-SSH is only SSH terminal or SFTP client? Can you PSFTP from Putty package? It is command line client, just try to list directory.

F-Secure-SSH works in both modes. Cypher: 3des-cbc-hmac-sha1.

I tried FPFTP from Putty. The server key fingerprint was installed correctly. But when I try to connect I get:

C:\aribajava>psftp -v webadmin@myserver.intranet.ca
Looking up host "myserver.intranet.ca"
Connecting to 216.210.81.40 port 22
Server version: SSH-1.99-OpenSSH_2.3.0p1
We claim version: SSH-2.0-PuTTY-Release-0.53b
Using SSH protocol version 2
Doing Diffie-Hellman group exchange
Doing Diffie-Hellman key exchange
Host key fingerprint is:
ssh-dss 1024 0f:e2:c6:1b:ae:e0:d7:51:61:73:1c:89:38:aa:65:06
Incoming packet was garbled on decryption
Fatal:Incoming packet was garbled on decryption

I checked this error message in Putty. The documentation states that:

Versions below 2.0.11 of the SSH server software from ssh.com compute the keys for the session encryption incorrectly. This problem can cause various error messages, such as "Incoming packet was garbled on decryption", or possibly even "Out of memory".

If this bug is detected, PuTTY will compute its encryption keys in the same way as the buggy server, so that communication will still be possible. If this bug is enabled when talking to a correct server, communication will fail.

This is an SSH2-specific bug.

Could this be the problem?

Pierre wrote:

I tried FPFTP from Putty. The server key fingerprint was installed correctly. But when I try to connect I get:

....

Incoming packet was garbled on decryption
Fatal:Incoming packet was garbled on decryption

Try rather latest development snapshot not the last release 0.53b, which is very old.

I'll try to prepare debug version of WinSCP to trace what's going on on your server. I'll contact you then.

I have maybe found a cause of the problem.

First some details about SFTP protocol:
Every request issued by the client (WinSCP here) to server has associated ID (number). The server send back same ID with the response to the request. The purpose of the ID is that client uses it to match response to the original request (There may be more outstanding requests and the server can respond in different order).

Typically clients increment the ID with each request. The same does WinSCP. But by my mistake it does not for subsequest list directory requests. All requests are with the same ID.

I believe that this is not against the SFTP specification, becuase it does not forbid reusing the same ID. However obviously it is agains common sense, so I'll change it in the next release.

I believe that the same ID of all requests makes your server always respond with the same response (first part of the directory listing). And it leads to endless loop.

Hi,
The modification did not correct the problem. Could the SFTP Protocol version used (version 2) be the cause. What version does WinSCP support?

This is a partial log generated:
. --------------------------------------------------------------------------
. WinSCP Version 3.5.0 (Build 206)
. Login time: 28 janvier 2004 09:21:39
. --------------------------------------------------------------------------
. Session name: webadmin@blmcdv.qc.bell.ca
. Host name: blmcdv.qc.bell.ca (Port: 22)
. User name: webadmin (Password: Yes, Key file: No)
. Transfer Protocol: SFTP
. SSH protocol version: 2; Compression: No
. Agent forwarding: No; TIS/CryptoCard: No; KI: Yes
. Ciphers: blowfish,3des,aes,WARN,des; Ssh2DES: No
. Ping type: N, Ping interval: 30 sec; Timeout: 10 sec
. SSH Bugs: +,+,+,+,+,+,+,+,
. Proxy: none
. Return code variable: Autodetect; Lookup user groups: No
. Shell: default, EOL: 0
. Local directory: C:\, Remote directory: /software/AribaBuyer7/CoreServer/ariba/base/core, Update: No, Cache: No
. Cache directory changes: No, Permanent: No
. Clear aliases: No, Unset nat.vars: No, Resolve symlinks: No
. Alias LS: No, Ign LS warn: No, Scp1 Comp: No
. --------------------------------------------------------------------------
. Looking up host "blmcdv.qc.bell.ca"
. Connecting to 142.117.21.237 port 22
. Server version: SSH-1.99-OpenSSH_2.3.0p1
. We claim version: SSH-2.0-WinSCP-release-3.5
. Using SSH protocol version 2
. Doing Diffie-Hellman group exchange
. Doing Diffie-Hellman key exchange
. Host key fingerprint is:
. ssh-dss 1024 59:ff:03:96:2b:7d:ce:2a:69:d3:93:b7:e8:b5:f0:f0
. Initialised Blowfish client->server encryption
. Initialised Blowfish server->client encryption
! Using username "webadmin".
. Session password prompt (webadmin@blmcdv.qc.bell.ca's password: )
. Using stored password.
. Sent password
. Access granted
. Opened channel for session
. Started a shell/command
. --------------------------------------------------------------------------
. Using SFTP protocol.
. Doing startup conversation with host.
> Type: SSH_FXP_INIT, Size: 5, Number: -1
< Type: SSH_FXP_VERSION, Size: 5, Number: -1
. SFTP version 2 negotiated.
. Changing directory to "/software/AribaBuyer7/CoreServer/ariba/base/core".
. Getting real path for '/software/AribaBuyer7/CoreServer/ariba/base/core'
> Type: SSH_FXP_REALPATH, Size: 57, Number: 16
< Type: SSH_FXP_NAME, Size: 117, Number: 16
. Real path is '/software/AribaBuyer7/CoreServer/ariba/base/core'
. Trying to open directory "/software/AribaBuyer7/CoreServer/ariba/base/core".
> Type: SSH_FXP_OPENDIR, Size: 57, Number: 267
< Type: SSH_FXP_HANDLE, Size: 10, Number: 267
> Type: SSH_FXP_CLOSE, Size: 10, Number: 516
< Type: SSH_FXP_STATUS, Size: 9, Number: 516
< Status/error code: 0
. Getting current directory name.
. Listing directory "/software/AribaBuyer7/CoreServer/ariba/base/core".
> Type: SSH_FXP_OPENDIR, Size: 57, Number: 779
< Type: SSH_FXP_HANDLE, Size: 10, Number: 779
> Type: SSH_FXP_READDIR, Size: 10, Number: 1036
< Type: SSH_FXP_NAME, Size: 365, Number: 1036
> Type: SSH_FXP_READDIR, Size: 10, Number: 1548
< Type: SSH_FXP_NAME, Size: 9, Number: 1548
> Type: SSH_FXP_READDIR, Size: 10, Number: 2060
< Type: SSH_FXP_NAME, Size: 9, Number: 2060
> Type: SSH_FXP_READDIR, Size: 10, Number: 2572
< Type: SSH_FXP_NAME, Size: 9, Number: 2572
> Type: SSH_FXP_READDIR, Size: 10, Number: 3084
< Type: SSH_FXP_NAME, Size: 9, Number: 3084
> Type: SSH_FXP_READDIR, Size: 10, Number: 3596
< Type: SSH_FXP_NAME, Size: 9, Number: 3596

Pierre wrote:

The modification did not correct the problem. Could the SFTP Protocol version used (version 2) be the cause. What version does WinSCP support?

:-(
WinSCP should support all versions of SFTP (0 to 4). Unfortunately I have no SFTP server that supports versions below 3 to test it by myself. However from the specification I know that directory reading was changed only between versions 3 and 4.

OK, so I'll try more, I'll contact you soon. Meanwhile, please try other SFTP client, like PSFTP (command-line). Let me know if it works.

Thanks for your patience. I would really like to solve this!

Martin,

I tried sending the file at your email address but it seems your box is full!

. WinSCP Version 3.5.0 (Build 206)
. Login time: 29 janvier 2004 09:49:14
. --------------------------------------------------------------------------
. Session name: webadmin@blmcdv.qc.bell.ca
. Host name: blmcdv.qc.bell.ca (Port: 22)
. User name: webadmin (Password: Yes, Key file: No)
. Transfer Protocol: SFTP
. SSH protocol version: 2; Compression: No
. Agent forwarding: No; TIS/CryptoCard: No; KI: Yes
. Ciphers: blowfish,3des,aes,WARN,des; Ssh2DES: No
. Ping type: N, Ping interval: 30 sec; Timeout: 10 sec
. SSH Bugs: +,+,+,+,+,+,+,+,
. Proxy: none
. Return code variable: Autodetect; Lookup user groups: No
. Shell: default, EOL: 0
. Local directory: C:\, Remote directory: /software/AribaBuyer7/CoreServer/ariba/base/core, Update: No, Cache: No
. Cache directory changes: No, Permanent: No
. Clear aliases: No, Unset nat.vars: No, Resolve symlinks: No
. Alias LS: No, Ign LS warn: No, Scp1 Comp: No
. --------------------------------------------------------------------------
. Looking up host "blmcdv.qc.bell.ca"
. Connecting to 142.117.21.237 port 22
. Server version: SSH-1.99-OpenSSH_2.3.0p1
. We claim version: SSH-2.0-WinSCP-release-3.5
. Using SSH protocol version 2
. Doing Diffie-Hellman group exchange
. Doing Diffie-Hellman key exchange
. Host key fingerprint is:
. ssh-dss 1024 59:ff:03:96:2b:7d:ce:2a:69:d3:93:b7:e8:b5:f0:f0
. Initialised Blowfish client->server encryption
. Initialised Blowfish server->client encryption
! Using username "webadmin".
. Session password prompt (webadmin@blmcdv.qc.bell.ca's password: )
. Using stored password.
. Sent password
. Access granted
. Opened channel for session
. Started a shell/command
. --------------------------------------------------------------------------
. Using SFTP protocol.
. Doing startup conversation with host.
> Type: SSH_FXP_INIT, Size: 5, Number: -1
> 01,00,00,00,04,
< Type: SSH_FXP_VERSION, Size: 5, Number: -1
< 02,00,00,00,02,
. SFTP version 2 negotiated.
. Changing directory to "/software/AribaBuyer7/CoreServer/ariba/base/core".
. Getting real path for '/software/AribaBuyer7/CoreServer/ariba/base/core'
> Type: SSH_FXP_REALPATH, Size: 57, Number: 16
> 10,00,00,00,10,00,00,00,30,2F,73,6F,66,74,77,61,72,65,2F,41,72,69,62,61,42,
> 75,79,65,72,37,2F,43,6F,72,65,53,65,72,76,65,72,2F,61,72,69,62,61,2F,62,61,
> 73,65,2F,63,6F,72,65,
< Type: SSH_FXP_NAME, Size: 117, Number: 16
< 68,00,00,00,10,00,00,00,01,00,00,00,30,2F,73,6F,66,74,77,61,72,65,2F,41,72,
< 69,62,61,42,75,79,65,72,37,2F,43,6F,72,65,53,65,72,76,65,72,2F,61,72,69,62,
< 61,2F,62,61,73,65,2F,63,6F,72,65,00,00,00,30,2F,73,6F,66,74,77,61,72,65,2F,
< 41,72,69,62,61,42,75,79,65,72,37,2F,43,6F,72,65,53,65,72,76,65,72,2F,61,72,
< 69,62,61,2F,62,61,73,65,2F,63,6F,72,65,00,00,00,00,
. Real path is '/software/AribaBuyer7/CoreServer/ariba/base/core'
. Trying to open directory "/software/AribaBuyer7/CoreServer/ariba/base/core".
> Type: SSH_FXP_OPENDIR, Size: 57, Number: 267
> 0B,00,00,01,0B,00,00,00,30,2F,73,6F,66,74,77,61,72,65,2F,41,72,69,62,61,42,
> 75,79,65,72,37,2F,43,6F,72,65,53,65,72,76,65,72,2F,61,72,69,62,61,2F,62,61,
> 73,65,2F,63,6F,72,65,
< Type: SSH_FXP_HANDLE, Size: 10, Number: 267
< 66,00,00,01,0B,00,00,00,01,30,
> Type: SSH_FXP_CLOSE, Size: 10, Number: 516
> 04,00,00,02,04,00,00,00,01,30,
< Type: SSH_FXP_STATUS, Size: 9, Number: 516
< 65,00,00,02,04,00,00,00,00,
< Status/error code: 0
. Getting current directory name.
. Listing directory "/software/AribaBuyer7/CoreServer/ariba/base/core".
> Type: SSH_FXP_OPENDIR, Size: 57, Number: 779
> 0B,00,00,03,0B,00,00,00,30,2F,73,6F,66,74,77,61,72,65,2F,41,72,69,62,61,42,
> 75,79,65,72,37,2F,43,6F,72,65,53,65,72,76,65,72,2F,61,72,69,62,61,2F,62,61,
> 73,65,2F,63,6F,72,65,
< Type: SSH_FXP_HANDLE, Size: 10, Number: 779
< 66,00,00,03,0B,00,00,00,01,30,
. DEBUG Handle: 30
> Type: SSH_FXP_READDIR, Size: 10, Number: 1036
> 0C,00,00,04,0C,00,00,00,01,30,
< Type: SSH_FXP_NAME, Size: 365, Number: 1036
< 68,00,00,04,0C,00,00,00,04,00,00,00,01,2E,00,00,00,1F,30,34,32,37,37,35,20,
< 31,30,32,20,32,30,20,31,30,32,34,20,31,30,30,36,32,30,31,35,31,30,20,2E,00,
< 00,00,0F,00,00,00,00,00,00,04,00,00,00,00,66,00,00,00,14,00,00,45,FD,40,19,
< 1E,C3,3B,F9,6A,A6,00,00,00,02,2E,2E,00,00,00,1D,30,34,32,37,37,35,20,31,30,
< 32,20,32,30,20,39,36,20,39,39,37,34,37,39,34,32,37,20,2E,2E,00,00,00,0F,00,
< 00,00,00,00,00,00,60,00,00,00,66,00,00,00,14,00,00,45,FD,40,18,CE,38,3B,74,
< 54,03,00,00,00,08,42,61,73,65,2E,61,6D,6C,00,00,00,27,30,31,30,30,37,37,35,
< 20,31,30,32,20,32,30,20,32,34,35,38,33,20,39,39,37,34,37,39,34,32,36,20,42,
< 61,73,65,2E,61,6D,6C,00,00,00,0F,00,00,00,00,00,00,60,07,00,00,00,66,00,00,
< 00,14,00,00,81,FD,40,11,7A,D2,3B,74,54,02,00,00,00,1C,4D,75,6C,74,69,4C,69,
< 6E,67,75,61,6C,53,74,72,69,6E,67,2E,63,6C,61,73,73,2E,50,30,33,00,00,00,3A,
< 30,31,30,30,36,34,34,20,31,30,32,20,32,30,20,37,39,34,31,20,39,38,31,31,33,
< 36,32,36,39,20,4D,75,6C,74,69,4C,69,6E,67,75,61,6C,53,74,72,69,6E,67,2E,63,
< 6C,61,73,73,2E,50,30,33,00,00,00,0F,00,00,00,00,00,00,1F,05,00,00,00,66,00,
< 00,00,14,00,00,81,A4,40,11,7A,D2,3A,7A,F3,8D,
> Type: SSH_FXP_READDIR, Size: 10, Number: 1292
> 0C,00,00,05,0C,00,00,00,01,30,
. DEBUG File count 4
. DEBUG File 0: .
. DEBUG File 1: ..
. DEBUG File 2: Base.aml
. DEBUG File 3: MultiLingualString.class.P03
. DEBUG isEOF: 0
< Type: SSH_FXP_NAME, Size: 9, Number: 1292
< 68,00,00,05,0C,00,00,00,00,
> Type: SSH_FXP_READDIR, Size: 10, Number: 1548
> 0C,00,00,06,0C,00,00,00,01,30,
. DEBUG File count 0
. DEBUG isEOF: 0
< Type: SSH_FXP_NAME, Size: 9, Number: 1548
< 68,00,00,06,0C,00,00,00,00,
> Type: SSH_FXP_READDIR, Size: 10, Number: 1804
> 0C,00,00,07,0C,00,00,00,01,30,
. DEBUG File count 0
. DEBUG isEOF: 0
< Type: SSH_FXP_NAME, Size: 9, Number: 1804
< 68,00,00,07,0C,00,00,00,00,
> Type: SSH_FXP_READDIR, Size: 10, Number: 2060
> 0C,00,00,08,0C,00,00,00,01,30,
. DEBUG File count 0
. DEBUG isEOF: 0
< Type: SSH_FXP_NAME, Size: 9, Number: 2060
< 68,00,00,08,0C,00,00,00,00,
> Type: SSH_FXP_READDIR, Size: 10, Number: 2316
> 0C,00,00,09,0C,00,00,00,01,30,
. DEBUG File count 0
. DEBUG isEOF: 0