NCDESTROY(1) BSD General Commands Manual NCDESTROY(1)NAMEncdestroy — Destroy kernel NFS credentials
SYNOPSISncdestroy [-v] [-P] [path [path...]]
DESCRIPTIONncdestroy invalidates the caller's kernel GSS credentials for any of the
specified path's associated NFS mounts. If no paths are specified then
all the caller's associated credentials for all NFS file systems are
destroyed.
When a nfs file system is mounted using a GSS mechanism (currently only
Kerberos is supported) through the “sec=” option or by the export speci‐
fied on the server, the resulting session context is stored in a table
for each mount. If the user decides to finish his or her session or
chooses to use a different credential, then ncdestroy can be called to
invalidate those credentials in the kernel. New credentials can be obtain
(typically by calling kinit) and those credentials can be used when
accessing the mount.
The options are as follows:
-v Be verbose and show what file system is being operated on and any
resulting errors.
-P If the trailing component resolves to a symbolic link do not
resolve the link but use the current path to determine any asso‐
ciate NFS file system.
EXAMPLES
If leaving for the day:
$ kdestroy -A
$ ncdestroy
Lets say a user does
$ kinit user@FOO.COM
And through the automounter access a path /Network/Serves/some‐
server/Sources/foo/bar where the mount of /Network/Servers/some‐
server/Sources/foo was done with user@FOO.COM.
$ cat /Network/Servers/someserver/Sources/foo/bar
cat: /Network/Servers/someserver/Sources/foo/bar: Permission denied
The user realizes that in order to have access on the server his identity
should be user2@BAR.COM. So:
$ kdestroy -A
$ kinit user2@BAR.COM
$ ncdestroy /Network/Servers/someserver/Sources/foo
Now the local user can access bar
NOTES
In the above example the user destroyed all credentials so the only cre‐
dential to choose was new credential user2@BAR.COM. However, if accessing
the server with user@FOO.COM was done by getting a cross realm TGT to
obtain the service ticket nfs/some.server.fqdn@BAR.COM, then it won't be
necessary to use kdestroy. The GSS infrastructure will prefer to use cre‐
dentials in the same realm as the service.
DIAGNOSTICS
The ncdestroy command will exit with 1 if any of the supplied paths don't
exist. If all paths exist or no paths are given the exit status will be
0.
SEE ALSOkinit(1), kdestroy(1), mount_nfs(8)BUGS
There should be an option to kdestroy to destroy cached nfs contexts.
BSD December 10, 2012 BSD
