OpenSSH can't open known_hosts and id_rsa, but the files are clearly accessible

Question

It seems my openssh client (OpenSSH_4.6p1, OpenSSL 0.9.8e 23 Feb 2007) is unable to open known\_hosts or the id\_rsa file, even though I can see them just fine by looking at their content with a 'type' command. This is being run as the 'SYSTEM' user for a Hudson instance which is running as a service. Notably, if I set the %HOME% environment variable to use another folder, such as c:\git, everything works just fine. This points to a permission issue, but the 'type' command seems to disprove that. What's going on, and how can I further diagnose this?

C:\hudson\jobs\blah\workspace>type C:\Windows\System32\config\systemprofile\.ssh\known_hosts 
git,10.3.11.91 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEA00Er2Sidyjm+wf0X4Ck/Yld85HedJTJAwlQg9KoWL1rJYyA90Zcdm6qhjsZs+9yXvpoRALeUBBYa07aRpU9PwYQodhuAoE31c3WytKXPQ7XnwL+hCnsZckdmLFgX0Vptto/PZ0uZY5KhmvHN+shRovHbg9yfe979wAG7V5HaSRs=

C:\hudson\jobs\blah\workspace>type C:\Windows\System32\config\systemprofile\.ssh\id_rsa 
-----BEGIN RSA PRIVATE KEY-----
-----private key content was here-----
-----END RSA PRIVATE KEY-----

C:\hudson\jobs\blah\workspace>"c:\program files (x86)\git\bin\ssh" -T -vvv git@git ls 
OpenSSH_4.6p1, OpenSSL 0.9.8e 23 Feb 2007
debug2: ssh_connect: needpriv 0
debug1: Connecting to git [10.3.11.91] port 22.
debug1: Connection established.
debug1: identity file /c/Windows/System32/config/systemprofile/.ssh/identity type -1
debug1: identity file /c/Windows/System32/config/systemprofile/.ssh/id_rsa type -1
debug1: identity file /c/Windows/System32/config/systemprofile/.ssh/id_dsa type -1
debug1: Remote protocol version 1.99, remote software version OpenSSH_4.2
debug1: match: OpenSSH_4.2 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.6
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
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@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@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
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,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib@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-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@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@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
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,zlib@openssh.com
debug2: kex_parse_kexinit: none,zlib@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: 130/256
debug2: bits set: 489/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: filename /c/Windows/System32/config/systemprofile/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 1
debug3: check_host_in_hostfile: filename /c/Windows/System32/config/systemprofile/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 1
debug1: Host 'qvtgit' is known and matches the RSA host key.
debug1: Found key in /c/Windows/System32/config/systemprofile/.ssh/known_hosts:1
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: /c/Windows/System32/config/systemprofile/.ssh/identity (0x0)
debug2: key: /c/Windows/System32/config/systemprofile/.ssh/id_rsa (0x0)
debug2: key: /c/Windows/System32/config/systemprofile/.ssh/id_dsa (0x0)
debug1: Authentications that can continue: publickey,keyboard-interactive
debug3: start over, passed a different list publickey,keyboard-interactive
debug3: preferred 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: Trying private key: /c/Windows/System32/config/systemprofile/.ssh/identity
debug3: no such identity: /c/Windows/System32/config/systemprofile/.ssh/identity
debug1: Trying private key: /c/Windows/System32/config/systemprofile/.ssh/id_rsa
debug3: no such identity: /c/Windows/System32/config/systemprofile/.ssh/id_rsa
debug1: Trying private key: /c/Windows/System32/config/systemprofile/.ssh/id_dsa
debug3: no such identity: /c/Windows/System32/config/systemprofile/.ssh/id_dsa
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
debug2: input_userauth_info_req
debug2: input_userauth_info_req: num_prompts 1

Start each line with 4 spaces for
-like formatting
– Mark Biek Jul 14 '09 at 21:52 — Mark Biek, Jul 14 '09 at 21:52

Zanchey · Answer 1 · 2009-07-15T13:32:43.960

3

OpenSSH refuses to use private keys that are readable by anyone other than their owner - check that the only account with permissions to that file is the SYSTEM account.

(Further inspection indicates this is not the problem in your case.)

edited Jul 15 '09 at 13:32

answered Jul 15 '09 at 09:21

Zanchey

3,051
22
28

also can be picky about who can write to these files (and I believe the parent folder too, though could be wrong there). Try with the least set of permissions, rather than the most. – Tom Newton Jul 15 '09 at 10:07
I believe openssh is pretty communicative when ignoring a file that is too open. Were this the problem, I should see a message like "Permissions 0644 for '/cygdrive/c/Users/Paul/.ssh/id_rsa' are too open." – Michael Donohue Jul 15 '09 at 13:24

score 2 · Answer 2 · answered Jul 15 '09 at 13:42

Inspection of the OpenSSH source shows that this error message is only ever printed in conditions where the stat(2) function call fails: see line 1224 of sshconnect2.c. It would be interesting to see the output of 'whoami && stat /c/Windows/System32/config/systemprofile/.ssh/id_dsa' from the Cygwin environment.

Alternatively, try a tool like Process Monitor to see what is going on at the API level - perhaps the error message returned when the identity files are accessed will give you a clue.

score 1 · Answer 3 · answered Jul 15 '09 at 12:37

It could also be the Virtual Store mechanism in Vista, which creates an overlay over directories not usually accessible for the user, where the user can write.

If the files were copied there by a non-admin account, it's possible they've ended up in

%USERPROFILE%\AppData\Local\VirtualStore

I.e. you copied the keys with your user to the path(s) specified, vista created an overlay in your users VirtualStore containing those files. However, when invoked as another user, that user will not see the changes contained in your users VirtualStore.

That does sound pretty plausible, but I can't find a corresponding directory structure in the VirtualStore folder, so I don't think that's it. — Michael Donohue, Jul 16 '09 at 21:41

OpenSSH can't open known_hosts and id_rsa, but the files are clearly accessible

3 Answers3