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freebsd/sys/rpc/auth_unix.c
Doug Rabson a9148abd9d 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
2008-11-03 10:38:00 +00:00

380 lines
9.6 KiB
C

/* $NetBSD: auth_unix.c,v 1.18 2000/07/06 03:03:30 christos Exp $ */
/*
* Sun RPC is a product of Sun Microsystems, Inc. and is provided for
* unrestricted use provided that this legend is included on all tape
* media and as a part of the software program in whole or part. Users
* may copy or modify Sun RPC without charge, but are not authorized
* to license or distribute it to anyone else except as part of a product or
* program developed by the user.
*
* SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
* WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
*
* Sun RPC is provided with no support and without any obligation on the
* part of Sun Microsystems, Inc. to assist in its use, correction,
* modification or enhancement.
*
* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
* OR ANY PART THEREOF.
*
* In no event will Sun Microsystems, Inc. be liable for any lost revenue
* or profits or other special, indirect and consequential damages, even if
* Sun has been advised of the possibility of such damages.
*
* Sun Microsystems, Inc.
* 2550 Garcia Avenue
* Mountain View, California 94043
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char *sccsid2 = "@(#)auth_unix.c 1.19 87/08/11 Copyr 1984 Sun Micro";
static char *sccsid = "@(#)auth_unix.c 2.2 88/08/01 4.0 RPCSRC";
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* auth_unix.c, Implements UNIX style authentication parameters.
*
* Copyright (C) 1984, Sun Microsystems, Inc.
*
* The system is very weak. The client uses no encryption for it's
* credentials and only sends null verifiers. The server sends backs
* null verifiers or optionally a verifier that suggests a new short hand
* for the credentials.
*
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/hash.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/pcpu.h>
#include <sys/refcount.h>
#include <sys/sx.h>
#include <sys/ucred.h>
#include <rpc/types.h>
#include <rpc/xdr.h>
#include <rpc/auth.h>
#include <rpc/clnt.h>
#include <rpc/rpc_com.h>
/* auth_unix.c */
static void authunix_nextverf (AUTH *);
static bool_t authunix_marshal (AUTH *, uint32_t, XDR *, struct mbuf *);
static bool_t authunix_validate (AUTH *, uint32_t, struct opaque_auth *,
struct mbuf **);
static bool_t authunix_refresh (AUTH *, void *);
static void authunix_destroy (AUTH *);
static void marshal_new_auth (AUTH *);
static struct auth_ops authunix_ops = {
.ah_nextverf = authunix_nextverf,
.ah_marshal = authunix_marshal,
.ah_validate = authunix_validate,
.ah_refresh = authunix_refresh,
.ah_destroy = authunix_destroy,
};
/*
* This struct is pointed to by the ah_private field of an auth_handle.
*/
struct audata {
TAILQ_ENTRY(audata) au_link;
TAILQ_ENTRY(audata) au_alllink;
volatile u_int au_refs;
struct xucred au_xcred;
struct opaque_auth au_origcred; /* original credentials */
struct opaque_auth au_shcred; /* short hand cred */
u_long au_shfaults; /* short hand cache faults */
char au_marshed[MAX_AUTH_BYTES];
u_int au_mpos; /* xdr pos at end of marshed */
AUTH *au_auth; /* link back to AUTH */
};
TAILQ_HEAD(audata_list, audata);
#define AUTH_PRIVATE(auth) ((struct audata *)auth->ah_private)
#define AUTH_UNIX_HASH_SIZE 16
#define AUTH_UNIX_MAX 256
static struct audata_list auth_unix_cache[AUTH_UNIX_HASH_SIZE];
static struct audata_list auth_unix_all;
static struct sx auth_unix_lock;
static int auth_unix_count;
static void
authunix_init(void *dummy)
{
int i;
for (i = 0; i < AUTH_UNIX_HASH_SIZE; i++)
TAILQ_INIT(&auth_unix_cache[i]);
TAILQ_INIT(&auth_unix_all);
sx_init(&auth_unix_lock, "auth_unix_lock");
}
SYSINIT(authunix_init, SI_SUB_KMEM, SI_ORDER_ANY, authunix_init, NULL);
/*
* Create a unix style authenticator.
* Returns an auth handle with the given stuff in it.
*/
AUTH *
authunix_create(struct ucred *cred)
{
uint32_t h, th;
struct xucred xcr;
char mymem[MAX_AUTH_BYTES];
XDR xdrs;
AUTH *auth;
struct audata *au, *tau;
struct timeval now;
uint32_t time;
int len;
if (auth_unix_count > AUTH_UNIX_MAX) {
while (auth_unix_count > AUTH_UNIX_MAX) {
sx_xlock(&auth_unix_lock);
tau = TAILQ_FIRST(&auth_unix_all);
th = HASHSTEP(HASHINIT, tau->au_xcred.cr_uid)
% AUTH_UNIX_HASH_SIZE;
TAILQ_REMOVE(&auth_unix_cache[th], tau, au_link);
TAILQ_REMOVE(&auth_unix_all, tau, au_alllink);
auth_unix_count--;
sx_xunlock(&auth_unix_lock);
AUTH_DESTROY(tau->au_auth);
}
}
/*
* Hash the uid to see if we already have an AUTH with this cred.
*/
h = HASHSTEP(HASHINIT, cred->cr_uid) % AUTH_UNIX_HASH_SIZE;
cru2x(cred, &xcr);
again:
sx_slock(&auth_unix_lock);
TAILQ_FOREACH(au, &auth_unix_cache[h], au_link) {
if (!memcmp(&xcr, &au->au_xcred, sizeof(xcr))) {
refcount_acquire(&au->au_refs);
if (sx_try_upgrade(&auth_unix_lock)) {
/*
* Keep auth_unix_all LRU sorted.
*/
TAILQ_REMOVE(&auth_unix_all, au, au_alllink);
TAILQ_INSERT_TAIL(&auth_unix_all, au,
au_alllink);
sx_xunlock(&auth_unix_lock);
} else {
sx_sunlock(&auth_unix_lock);
}
return (au->au_auth);
}
}
sx_sunlock(&auth_unix_lock);
/*
* Allocate and set up auth handle
*/
au = NULL;
auth = mem_alloc(sizeof(*auth));
au = mem_alloc(sizeof(*au));
auth->ah_ops = &authunix_ops;
auth->ah_private = (caddr_t)au;
auth->ah_verf = au->au_shcred = _null_auth;
refcount_init(&au->au_refs, 1);
au->au_xcred = xcr;
au->au_shfaults = 0;
au->au_origcred.oa_base = NULL;
au->au_auth = auth;
getmicrotime(&now);
time = now.tv_sec;
/*
* Serialize the parameters into origcred
*/
xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE);
cru2x(cred, &xcr);
if (! xdr_authunix_parms(&xdrs, &time, &xcr))
panic("authunix_create: failed to encode creds");
au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs);
au->au_origcred.oa_flavor = AUTH_UNIX;
au->au_origcred.oa_base = mem_alloc((u_int) len);
memcpy(au->au_origcred.oa_base, mymem, (size_t)len);
/*
* set auth handle to reflect new cred.
*/
auth->ah_cred = au->au_origcred;
marshal_new_auth(auth);
sx_xlock(&auth_unix_lock);
TAILQ_FOREACH(tau, &auth_unix_cache[h], au_link) {
if (!memcmp(&xcr, &tau->au_xcred, sizeof(xcr))) {
/*
* We lost a race to create the AUTH that
* matches this cred.
*/
sx_xunlock(&auth_unix_lock);
AUTH_DESTROY(auth);
goto again;
}
}
auth_unix_count++;
TAILQ_INSERT_TAIL(&auth_unix_cache[h], au, au_link);
TAILQ_INSERT_TAIL(&auth_unix_all, au, au_alllink);
refcount_acquire(&au->au_refs); /* one for the cache, one for user */
sx_xunlock(&auth_unix_lock);
return (auth);
}
/*
* authunix operations
*/
/* ARGSUSED */
static void
authunix_nextverf(AUTH *auth)
{
/* no action necessary */
}
static bool_t
authunix_marshal(AUTH *auth, uint32_t xid, XDR *xdrs, struct mbuf *args)
{
struct audata *au;
au = AUTH_PRIVATE(auth);
if (!XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos))
return (FALSE);
xdrmbuf_append(xdrs, args);
return (TRUE);
}
static bool_t
authunix_validate(AUTH *auth, uint32_t xid, struct opaque_auth *verf,
struct mbuf **mrepp)
{
struct audata *au;
XDR txdrs;
if (!verf)
return (TRUE);
if (verf->oa_flavor == AUTH_SHORT) {
au = AUTH_PRIVATE(auth);
xdrmem_create(&txdrs, verf->oa_base, verf->oa_length,
XDR_DECODE);
if (au->au_shcred.oa_base != NULL) {
mem_free(au->au_shcred.oa_base,
au->au_shcred.oa_length);
au->au_shcred.oa_base = NULL;
}
if (xdr_opaque_auth(&txdrs, &au->au_shcred)) {
auth->ah_cred = au->au_shcred;
} else {
txdrs.x_op = XDR_FREE;
(void)xdr_opaque_auth(&txdrs, &au->au_shcred);
au->au_shcred.oa_base = NULL;
auth->ah_cred = au->au_origcred;
}
marshal_new_auth(auth);
}
return (TRUE);
}
static bool_t
authunix_refresh(AUTH *auth, void *dummy)
{
struct audata *au = AUTH_PRIVATE(auth);
struct xucred xcr;
uint32_t time;
struct timeval now;
XDR xdrs;
int stat;
if (auth->ah_cred.oa_base == au->au_origcred.oa_base) {
/* there is no hope. Punt */
return (FALSE);
}
au->au_shfaults ++;
/* first deserialize the creds back into a struct ucred */
xdrmem_create(&xdrs, au->au_origcred.oa_base,
au->au_origcred.oa_length, XDR_DECODE);
stat = xdr_authunix_parms(&xdrs, &time, &xcr);
if (! stat)
goto done;
/* update the time and serialize in place */
getmicrotime(&now);
time = now.tv_sec;
xdrs.x_op = XDR_ENCODE;
XDR_SETPOS(&xdrs, 0);
stat = xdr_authunix_parms(&xdrs, &time, &xcr);
if (! stat)
goto done;
auth->ah_cred = au->au_origcred;
marshal_new_auth(auth);
done:
XDR_DESTROY(&xdrs);
return (stat);
}
static void
authunix_destroy(AUTH *auth)
{
struct audata *au;
au = AUTH_PRIVATE(auth);
if (!refcount_release(&au->au_refs))
return;
mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length);
if (au->au_shcred.oa_base != NULL)
mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length);
mem_free(auth->ah_private, sizeof(struct audata));
if (auth->ah_verf.oa_base != NULL)
mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length);
mem_free(auth, sizeof(*auth));
}
/*
* Marshals (pre-serializes) an auth struct.
* sets private data, au_marshed and au_mpos
*/
static void
marshal_new_auth(AUTH *auth)
{
XDR xdr_stream;
XDR *xdrs = &xdr_stream;
struct audata *au;
au = AUTH_PRIVATE(auth);
xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE);
if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) ||
(! xdr_opaque_auth(xdrs, &(auth->ah_verf))))
printf("auth_none.c - Fatal marshalling problem");
else
au->au_mpos = XDR_GETPOS(xdrs);
XDR_DESTROY(xdrs);
}