1 files changed, 56 insertions, 39 deletions

diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c
index 294992e9bf69..0184fe9b514c 100644
--- a/fs/nfsd/auth.c
+++ b/fs/nfsd/auth.c
@@ -27,53 +27,70 @@ int nfsexp_flags(struct svc_rqst *rqstp, struct svc_export *exp)
 
 int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
 {
-        struct svc_cred cred = rqstp->rq_cred;
+        struct group_info *rqgi;
+        struct group_info *gi;
+        struct cred *new;
         int i;
         int flags = nfsexp_flags(rqstp, exp);
         int ret;
 
+        /* discard any old override before preparing the new set */
+        revert_creds(get_cred(current->real_cred));
+        new = prepare_creds();
+        if (!new)
+                return -ENOMEM;
+
+        new->fsuid = rqstp->rq_cred.cr_uid;
+        new->fsgid = rqstp->rq_cred.cr_gid;
+
+        rqgi = rqstp->rq_cred.cr_group_info;
+
         if (flags & NFSEXP_ALLSQUASH) {
-                cred.cr_uid = exp->ex_anon_uid;
-                cred.cr_gid = exp->ex_anon_gid;
-                cred.cr_group_info = groups_alloc(0);
+                new->fsuid = exp->ex_anon_uid;
+                new->fsgid = exp->ex_anon_gid;
+                gi = groups_alloc(0);
         } else if (flags & NFSEXP_ROOTSQUASH) {
-                struct group_info *gi;
-                if (!cred.cr_uid)
-                        cred.cr_uid = exp->ex_anon_uid;
-                if (!cred.cr_gid)
-                        cred.cr_gid = 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);
-                        }
-                cred.cr_group_info = gi;
-        } else
-                get_group_info(cred.cr_group_info);
-
-        if (cred.cr_uid != (uid_t) -1)
-                current->fsuid = cred.cr_uid;
-        else
-                current->fsuid = exp->ex_anon_uid;
-        if (cred.cr_gid != (gid_t) -1)
-                current->fsgid = cred.cr_gid;
-        else
-                current->fsgid = exp->ex_anon_gid;
+                if (!new->fsuid)
+                        new->fsuid = exp->ex_anon_uid;
+                if (!new->fsgid)
+                        new->fsgid = exp->ex_anon_gid;
 
-        if (!cred.cr_group_info)
-                return -ENOMEM;
-        ret = set_current_groups(cred.cr_group_info);
-        put_group_info(cred.cr_group_info);
-        if ((cred.cr_uid)) {
-                current->cap_effective =
-                        cap_drop_nfsd_set(current->cap_effective);
+                gi = groups_alloc(rqgi->ngroups);
+                if (!gi)
+                        goto oom;
+
+                for (i = 0; i < rqgi->ngroups; i++) {
+                        if (!GROUP_AT(rqgi, i))
+                                GROUP_AT(gi, i) = exp->ex_anon_gid;
+                        else
+                                GROUP_AT(gi, i) = GROUP_AT(rqgi, i);
+                }
         } else {
-                current->cap_effective =
-                        cap_raise_nfsd_set(current->cap_effective,
-                                           current->cap_permitted);
+                gi = get_group_info(rqgi);
         }
+
+        if (new->fsuid == (uid_t) -1)
+                new->fsuid = exp->ex_anon_uid;
+        if (new->fsgid == (gid_t) -1)
+                new->fsgid = exp->ex_anon_gid;
+
+        ret = set_groups(new, gi);
+        put_group_info(gi);
+        if (!ret)
+                goto error;
+
+        if (new->uid)
+                new->cap_effective = cap_drop_nfsd_set(new->cap_effective);
+        else
+                new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
+                                                        new->cap_permitted);
+        put_cred(override_creds(new));
+        return 0;
+
+oom:
+        ret = -ENOMEM;
+error:
+        abort_creds(new);
         return ret;
 }
+