Re: ssh_pki_import_privkey_file always returns -1

[Andreas Schneider <asn@xxxxxxxxxxxxxx>]

On Monday, 17 April 2017 18:30:46 CEST Eric Lemasson wrote:
> Hello
> 
> I hope this is the right place to ask this kind of question, apologizes in
> advance if I should send my question somewhere else. I am new to libssh and
> trying to use it properly in a windows application that needs to do sftp. I
> have followed samples found online (mostly in the tutorial section of
> libssh website) and came up with the following piece of code:
> 
>                 ssh_session my_ssh_session = ssh_new();
>                 if (my_ssh_session == NULL) {
>                                 exit(-1);
>                 }
>                 ssh_options_set(my_ssh_session, SSH_OPTIONS_HOST,
> serverIP.GetBuffer()); ssh_options_set(my_ssh_session,
> SSH_OPTIONS_LOG_VERBOSITY, &verbosity); ssh_options_set(my_ssh_session,
> SSH_OPTIONS_PORT, &port); ssh_options_set(my_ssh_session, SSH_OPTIONS_USER,
> User.GetBuffer());
> 
>                 rc = ssh_connect(my_ssh_session);
>                 if (rc != SSH_OK)
>                 {
>                                 ssh_free(my_ssh_session);
>                                 exit(-1);
>                 }
>                 if (verify_knownhost(my_ssh_session) < 0)
>                 {
>                                 ssh_disconnect(my_ssh_session);
>                                 ssh_free(my_ssh_session);
>                                 exit(-1);
>                 }
>                 rc = ssh_userauth_publickey_auto(my_ssh_session, NULL,
> NULL); if (rc != SSH_AUTH_SUCCESS)
>                 {
>                                 ssh_key pubKey, privKey;
>                                 rc =
> ssh_pki_import_pubkey_file("C:\\Users\\XXXX\\.ssh\\key.pub", &pubKey); if
> (rc == SSH_OK) {
>                                                 rc =
> ssh_userauth_try_publickey(my_ssh_session, NULL, pubKey); if (rc ==
> SSH_AUTH_SUCCESS) { rc =
> ssh_pki_import_privkey_file("C:\\Users\\XXXX\\.ssh\\key", NULL, NULL, NULL,
> &privKey); if (rc == SSH_OK) { rc = ssh_userauth_publickey(my_ssh_session,
> NULL, privKey); ssh_key_free(privKey); }
>                                                 }
>                                                 ssh_key_free(pubKey);
>                                 }
>                                 if (!authenticated) {
>                                                 rc =
> ssh_userauth_password(my_ssh_session, NULL, password.GetBuffer()); if (rc
> != SSH_AUTH_SUCCESS) {
>                                                                
> ssh_disconnect(my_ssh_session); ssh_free(my_ssh_session); exit(-1); }
>                                 }
>                 }
> 
> The key pair have been generated with puttygen tool, and I understand that
> putty uses a different format to store the private key, so I have used the
> Conversion / Export OpenSSH key (force new file format) option to have the
> private key in standard format. The public key has been added to the
> authorized_key file on the remote server and the manual connection using
> putty works fine, using a password, or using the putty key agent (pageant)
> without having to enter a password.
> 
> In my code above, the call to the function ssh_pki_import_privkey_file
> always return -1. I have tried different key type but I still get the same
> thing. Also tried to remove the line (--- BEGIN OPENSSH PRIVATE KEY ----)
> in the key file but no luck. I know that on linux / unix, permission
> checking on key files are very strict in .ssh directory and may be a reason
> for failing to authenticate.
> 
> The fact that I am getting SSH_ERROR and not SSH_EOF tells me that it is
> able to find the file, so I am thinking it is a file format or a file
> permission issue.
> 
> I don't know if the same permission checks are done on Windows and if so,
> what the permission should be.
> 
> The password authentication in the code works fine so I am still able to
> connect to the server but I would like to have the key method to work.
> 
> If you have any suggestion or tips, that would be greatly appreciated,

Turn on debug messages and it will give you some hints :)

http://api.libssh.org/master/
group__libssh__session.html#ga7a801b85800baa3f4e16f5b47db0a73d


	Andreas


-- 
Andreas Schneider                   GPG-ID: CC014E3D
www.cryptomilk.org                asn@xxxxxxxxxxxxxx