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195246 |
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01-Jul-2009 |
rmacklem |
When unmounting an NFS mount using sec=krb5[ip], the umount system call could get hung sleeping on "gsssta" if the credentials for a user that had been accessing the mount point have expired. This happened because rpc_gss_destroy_context() would end up calling itself when the "destroy context" RPC was attempted, trying to refresh the credentials. This patch just checks for this case in rpc_gss_refresh() and returns without attempting the refresh, which avoids the recursive call to rpc_gss_destroy_context() and the subsequent hang.
Reviewed by: dfr Approved by: re (Ken Smith), kib (mentor)
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194878 |
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24-Jun-2009 |
rmacklem |
If the initial attempt to refresh credentials in the RPCSEC_GSS client side fails, the entry in the cache is left with no valid context (gd_ctx == GSS_C_NO_CONTEXT). As such, subsequent hits on the cache will result in persistent authentication failure, even after the user has done a kinit or similar and acquired a new valid TGT. This patch adds a test for that case upon a cache hit and calls rpc_gss_init() to make another attempt at getting valid credentials. It also moves the setting of gc_proc to before the import of the principal name to ensure that, if that case fails, it will be detected as a failure after going to "out:".
Reviewed by: dfr Approved by: kib (mentor)
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184588 |
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03-Nov-2008 |
dfr |
Implement support for RPCSEC_GSS authentication to both the NFS client and server. This replaces the RPC implementation of the NFS client and server with the newer RPC implementation originally developed (actually ported from the userland sunrpc code) to support the NFS Lock Manager. I have tested this code extensively and I believe it is stable and that performance is at least equal to the legacy RPC implementation.
The NFS code currently contains support for both the new RPC implementation and the older legacy implementation inherited from the original NFS codebase. The default is to use the new implementation - add the NFS_LEGACYRPC option to fall back to the old code. When I merge this support back to RELENG_7, I will probably change this so that users have to 'opt in' to get the new code.
To use RPCSEC_GSS on either client or server, you must build a kernel which includes the KGSSAPI option and the crypto device. On the userland side, you must build at least a new libc, mountd, mount_nfs and gssd. You must install new versions of /etc/rc.d/gssd and /etc/rc.d/nfsd and add 'gssd_enable=YES' to /etc/rc.conf.
As long as gssd is running, you should be able to mount an NFS filesystem from a server that requires RPCSEC_GSS authentication. The mount itself can happen without any kerberos credentials but all access to the filesystem will be denied unless the accessing user has a valid ticket file in the standard place (/tmp/krb5cc_<uid>). There is currently no support for situations where the ticket file is in a different place, such as when the user logged in via SSH and has delegated credentials from that login. This restriction is also present in Solaris and Linux. In theory, we could improve this in future, possibly using Brooks Davis' implementation of variant symlinks.
Supporting RPCSEC_GSS on a server is nearly as simple. You must create service creds for the server in the form 'nfs/<fqdn>@<REALM>' and install them in /etc/krb5.keytab. The standard heimdal utility ktutil makes this fairly easy. After the service creds have been created, you can add a '-sec=krb5' option to /etc/exports and restart both mountd and nfsd.
The only other difference an administrator should notice is that nfsd doesn't fork to create service threads any more. In normal operation, there will be two nfsd processes, one in userland waiting for TCP connections and one in the kernel handling requests. The latter process will create as many kthreads as required - these should be visible via 'top -H'. The code has some support for varying the number of service threads according to load but initially at least, nfsd uses a fixed number of threads according to the value supplied to its '-n' option.
Sponsored by: Isilon Systems MFC after: 1 month
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