nfsd_setuser() sets both the rqstp->cred and the current tasks uid, gid, and 
groups according to an exports squash rules (all_squash, root_squash). 
nfsd_setuser() is called in fh_verify() to correctly set the current's threads 
access to an export's directories and files.

setting the rqstp->cred is problematic for SETCLIENTID which is required to 
store the principal used for it's call, and whcih has client-wide scope, 
not export wide scope. under the current scheme, the rqstp->cred could
be set by nfsd_setuser or not, depending on the other previous NFSv4
operatios in the SETCLIENTID compound.
in order to pass confirmation of a clientid, SETCLIENTID_CONFIRM compares
the rqstp->cred with the credentials stored by SETCLIENTID. again, setting
the rqstp->cred with nfsd_user() is probelmatic.

this patch changes nfsd_setuser() to set only the current threads uid, gid,
and groups, leaving the rqstp->cred untouched.

"Signed-off-by: Andy Adamson <andros@citi.umich.edu>"
---

---


diff -puN fs/nfsd/auth.c~nfsd_setuser-fix fs/nfsd/auth.c
--- linux-2.6.16-rc4/fs/nfsd/auth.c~nfsd_setuser-fix	2006-03-01 19:16:34.000000000 -0500
+++ linux-2.6.16-rc4-andros/fs/nfsd/auth.c	2006-03-01 19:18:07.000000000 -0500
@@ -17,43 +17,43 @@ int nfsd_setuser(struct svc_rqst *rqstp,
 	struct svc_cred	*cred = &rqstp->rq_cred;
 	int i;
 	int ret;
+	uid_t luid = cred->cr_uid;
+	gid_t lgid = cred->cr_gid;
+	struct group_info *gi = NULL;
 
 	if (exp->ex_flags & NFSEXP_ALLSQUASH) {
-		cred->cr_uid = exp->ex_anon_uid;
-		cred->cr_gid = exp->ex_anon_gid;
-		put_group_info(cred->cr_group_info);
-		cred->cr_group_info = groups_alloc(0);
+		luid = exp->ex_anon_uid;
+		lgid = exp->ex_anon_gid;
+		gi = groups_alloc(0);
 	} else if (exp->ex_flags & NFSEXP_ROOTSQUASH) {
-		struct group_info *gi;
 		if (!cred->cr_uid)
-			cred->cr_uid = exp->ex_anon_uid;
+			luid = exp->ex_anon_uid;
 		if (!cred->cr_gid)
-			cred->cr_gid = exp->ex_anon_gid;
+			lgid = exp->ex_anon_gid;
 		gi = groups_alloc(cred->cr_group_info->ngroups);
-		if (gi)
-			for (i = 0; i < cred->cr_group_info->ngroups; i++) {
-				if (!GROUP_AT(cred->cr_group_info, i))
-					GROUP_AT(gi, i) = exp->ex_anon_gid;
-				else
-					GROUP_AT(gi, i) = GROUP_AT(cred->cr_group_info, i);
-			}
-		put_group_info(cred->cr_group_info);
-		cred->cr_group_info = gi;
+		if (!gi)
+			return -ENOMEM;
+		for (i = 0; i < cred->cr_group_info->ngroups; i++) {
+			if (!GROUP_AT(cred->cr_group_info, i))
+				GROUP_AT(gi, i) = exp->ex_anon_gid;
+			else
+				GROUP_AT(gi, i) = GROUP_AT(cred->cr_group_info, i);
+		}
 	}
 
-	if (cred->cr_uid != (uid_t) -1)
-		current->fsuid = cred->cr_uid;
+	if (luid != (uid_t) -1)
+		current->fsuid = luid;
 	else
 		current->fsuid = exp->ex_anon_uid;
-	if (cred->cr_gid != (gid_t) -1)
-		current->fsgid = cred->cr_gid;
+	if (lgid != (gid_t) -1)
+		current->fsgid = lgid;
 	else
 		current->fsgid = exp->ex_anon_gid;
 
-	if (!cred->cr_group_info)
-		return -ENOMEM;
-	ret = set_current_groups(cred->cr_group_info);
-	if ((cred->cr_uid)) {
+	if (!gi)
+		gi = cred->cr_group_info;
+	ret = set_current_groups(gi);
+	if ((luid)) {
 		cap_t(current->cap_effective) &= ~CAP_NFSD_MASK;
 	} else {
 		cap_t(current->cap_effective) |= (CAP_NFSD_MASK &
_