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)
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)
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
