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Re: More GSSAPI on Windows: user auth hangs?
- Subject: Re: More GSSAPI on Windows: user auth hangs?
- From: Jakub Jelen <jjelen@xxxxxxxxxx>
- Reply-to: libssh@xxxxxxxxxx
- Date: Tue, 24 Aug 2021 09:08:17 +0200
- To: libssh@xxxxxxxxxx
On 8/23/21 6:10 PM, Kerrison, Adam wrote:
I’ve spent a while trying to test the GSSAPI support on Windows and I can’t make it work ☹I’ve attached a simple program which just tries to connect and authenticate with a server. It assumes you have a valid Kerberos configuration and a ticket.If I run this on Linux is just works. On Windows, it hangs in ssh_userauth_gssapi(). The program enables packet level logging and on Windows I see this before it hangs:[2021/08/23 17:01:39.112369, 4] ssh_socket_pollcallback: Poll callback on socket 756 (POLLIN ), out buffer 0[2021/08/23 17:01:39.112369, 3] ssh_packet_socket_callback: packet: read type 61 [len=176,padding=15,comp=160,payload=160][2021/08/23 17:01:39.113484, 3] ssh_packet_process: Dispatching handler for packet type 61Packet type 61 -> SSH2_MSG_USERAUTH_GSSAPI_TOKEN On Linux, I see the same message sequence but immediately followed by:[2021/08/23 17:05:07.856296, 3] ssh_packet_userauth_gssapi_token_client: Received SSH_MSG_USERAUTH_GSSAPI_TOKENI think this must be something about how I’ve built libssh but its odd as the first part of the GSSAPI auth definitely works (I see the GSSAPI: sending token message for example). I’d also expect things to crash if the function was missing (i.e. a NULL pointer)I’m not holding out a lot of hope that anyone will have a clue about what is going on here but I thought I’d ask anyway …
Hi,my guess is that on Linux you built libssh with server and on Windows without.
The packet number SSH2_MSG_USERAUTH_GSSAPI_TOKEN is shared with SSH2_MSG_USERAUTH_INFO_RESPONSE, which is implemented only if built with server, which is indeed wrong and should be fixed. See the following part of the code:
Feel free to test my theory and propose a fix. Regards, -- Jakub Jelen Crypto Team, Security Engineering Red Hat, Inc.
|More GSSAPI on Windows: user auth hangs?||"Kerrison, Adam" <Adam_Kerrison@xxxxxxx>|