Troubleshooting local GSSAPI connections is fairly straight-forward. This page will cover both major Linux distribution sets.
Contents
1. System Preparation
1.1. Installing the Kerberos GSSAPI client and server utility
1.1.1. RedHat, CentOS or Scientific Linux
On RedHat, CentOS or Scientific Linux, install the Kerberos GSSAPI utilities by running the following command:
$ yum install krb5-devel
1.1.2. Debian or Ubuntu
On Debian or Ubuntu, install the Kerberos GSSAPI utilities by running the following command:
$ apt-get install krb5-gss-samples
2. Troubleshooting
To troubleshoot a GSSAPI connection, you require two separate terminals.
2.1. Window 1 - As root
In the first window, as root, run the following command:
$ gss-server -verbose host@localhost
You should now have the following output with no prompt:
starting...
2.2. Window 2 - As your test user
In the second window, as your test user, run the following command:
$ gss-client -spnego localhost host@localhost foo
In a non-X environment (and no display forwarding), the identity is selected from the
.gss_eap_idfile in the test user's home directory. Create this file with the following content:[full NAI of your identity, e.g. steve@localdomain] [password for the identity]
- In X, you should now be prompted to select an identity in the the Moonshot Identity Selector. Choose one that will authenticate locally.
2.3. GSS Output
After selecting your identity, you should now see output in both windows.
2.3.1. Successful output
In Window 1, the output should scroll rapidly with a lot of hex text before ending with something similar to the following:
: : 73 74 80 00 00 0e 00 00 00 0c 4e fd c8 f7 af 37 18 bc 23 47 6a 5b context flag: GSS_C_MUTUAL_FLAG context flag: GSS_C_REPLAY_FLAG context flag: GSS_C_SEQUENCE_FLAG context flag: GSS_C_CONF_FLAG context flag: GSS_C_INTEG_FLAG Accepted connection using mechanism OID { 1 3 6 1 5 5 15 1 1 17 }. Attribute urn:ietf:params:gss:radius-attribute 79 Authenticated Complete 03070004 Attribute urn:ietf:params:gss:radius-attribute 80 Authenticated Complete 7982a7cd93fbaef973e8d6ccac5e850b Accepted connection: "" Message token (flags=228): 05 04 02 ff 00 00 00 00 00 00 00 00 00 00 00 00 ef 58 6b 46 bd 60 26 d1 c1 4a 58 b0 88 91 49 34 2c 32 fa 93 e7 9d f2 29 e3 f8 09 e6 25 05 12 f2 4e c5 31 71 ba 01 94 8a cb d7 cf 73 05 87 3d Received message: "foo" NOOP tokenIn Window 2, the output looks similar to the below:
Sending init_sec_context token (size=81)...continue needed... Sending init_sec_context token (size=64)...continue needed... Sending init_sec_context token (size=261)...continue needed... Sending init_sec_context token (size=42)...continue needed... Sending init_sec_context token (size=42)...continue needed... Sending init_sec_context token (size=181)...continue needed... Sending init_sec_context token (size=169)...continue needed... Sending init_sec_context token (size=185)...continue needed... Sending init_sec_context token (size=42)...continue needed... Sending init_sec_context token (size=60)...continue needed... context flag: GSS_C_MUTUAL_FLAG context flag: GSS_C_REPLAY_FLAG context flag: GSS_C_SEQUENCE_FLAG context flag: GSS_C_CONF_FLAG context flag: GSS_C_INTEG_FLAG "steve@debian7x64.localdomain" to "host/localhost", lifetime -1, flags 13e, locally initiated, open Name type of source name is { 1 2 840 113554 1 2 1 1 }. Mechanism { 1 3 6 1 5 5 2 } supports 4 names 0: { 1 2 840 113554 1 2 1 1 } 1: { 1 2 840 113554 1 2 1 2 } 2: { 1 2 840 113554 1 2 1 3 } 3: { 1 2 840 113554 1 2 1 4 } Signature verified.
2.3.2. Failed output
If the GSSAPI connection failed, you may see one or more errors in either window.
In Window 1, you should see one or more messages similar to the below:
reading token flags: 0 bytes read reading token flags: 0 bytes read
In Window 2, you should see one or more error messages similar to the below:
GSS-API error initializing context: Unspecified GSS failure. Minor code may provide more information GSS-API error initializing context:
Now you will need to diagnose why the error occurred.