Elaborate on when `cred_store = ccache:...` should be used

[frozencemetery]

Current docs aren't very clear about when to use this. As a result, reasonable users often make the assumption that this should be something like cred_store = ccache:/tmp/krb5cc_%u or cred_store = ccache:KEYRING:%u or what have you.

We should make explicit what this is actually intended for and that it shouldn't be otherwise used.

[jbazik]

So, it shouldn't be this?

cred_store = ccache:FILE:/tmp/krb5cc_%U
allow_any_uid = yes

I was expecting gssproxy to chown the ccache to the user, which it doesn't do.

[jbazik]

I think I understand now that the cred_store ccache is for gssproxy's internal use. After I got things working, I could see in strace that gssd actually creates the ccache file in /tmp for the user. Or is it the interposer code that does that? I'm still not sure if or why I should set this setting, but I have it working.

[simo5]

@jbazik this i used by gss-proxy to perform operations like impersonation as they are split over multiple iterations and need a stored ccache to continue the operation.
It is not needed for all gss-proxy operations

[Saffa001]

Hello every one, Is there any document to validate GSSPROXY working? I have RHEL8 and Kerberos with GSSAPI and dotnet app.
It has been a Month i could not get it work. Any help would be appreciated. Thanks

[simo5]

What we have here: https://github.com/gssapi/gssproxy/tree/main/docs is all we have really.

[Saffa001]

Understood, Thank you. I was thinking maybe someone has knowledge base website to share so i may able to get this to work.

[mmoser-aires]

I'm likewise curious about the supported cache mechanisms that GSSProxy supports, which I think is what the OP was saying when this issue is opened.

man gssproxy.conf states:

The syntax of the cred_store parameter is as follows: cred_store = <cred_store_option>:<cred_store_value>

But it is unclear what valid options are i.e. FILE, KEYRING, KCM. All of the examples that I have seen have used:
cred_store = ccache:FILE:/var/lib/gssproxy/krb5cc_%U and what I (And I assume the OP) are trying to find out is if KCM and KEYRING are supported by gssproxy? Example:

cred_store = ccache:KCM:%U
cred_store = ccache:KEYRING:persistent:%U

Just starting out with GSSProxy, and am currently configuring services with KRB. It would be desirable to have GSSProxy support the same cache mechanisms the rest of the system is using if possible.

Thanks in advance.

[simo5]

GSSProxy is cache agnostic, it passes those values directly to the GSSAPI implementation on your system, so the answer is: whatever your system krb5/gssapi library supports.