11927 Log, or optionally panic, on zero-length kmem allocations
Reviewed by: Dan McDonald <danmcd@joyent.com>
Reviewed by: Jason King <jason.brian.king@gmail.com>

*** 21,30 ****
--- 21,31 ----
  
  /*
   * Copyright 2016 Nexenta Systems, Inc.  All rights reserved.
   * Copyright (c) 1995, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2015 by Delphix. All rights reserved.
+  * Copyright (c) 2015 Joyent, Inc.  All rights reserved.
   */
  
  #include <sys/param.h>
  #include <sys/errno.h>
  #include <sys/vfs.h>
*** 559,573 ****
          switch (res.stat) {
                  case NFSAUTH_DR_OKAY:
                          *access = res.ares.auth_perm;
                          *srv_uid = res.ares.auth_srv_uid;
                          *srv_gid = res.ares.auth_srv_gid;
!                         *srv_gids_cnt = res.ares.auth_srv_gids.len;
!                         *srv_gids = kmem_alloc(*srv_gids_cnt * sizeof (gid_t),
!                             KM_SLEEP);
                          bcopy(res.ares.auth_srv_gids.val, *srv_gids,
                              *srv_gids_cnt * sizeof (gid_t));
                          break;
  
                  case NFSAUTH_DR_EFAIL:
                  case NFSAUTH_DR_DECERR:
                  case NFSAUTH_DR_BADCMD:
--- 560,579 ----
          switch (res.stat) {
                  case NFSAUTH_DR_OKAY:
                          *access = res.ares.auth_perm;
                          *srv_uid = res.ares.auth_srv_uid;
                          *srv_gid = res.ares.auth_srv_gid;
! 
!                         if ((*srv_gids_cnt = res.ares.auth_srv_gids.len) != 0) {
!                                 *srv_gids = kmem_alloc(*srv_gids_cnt *
!                                     sizeof (gid_t), KM_SLEEP);
                                  bcopy(res.ares.auth_srv_gids.val, *srv_gids,
                                      *srv_gids_cnt * sizeof (gid_t));
+                         } else {
+                                 *srv_gids = NULL;
+                         }
+ 
                          break;
  
                  case NFSAUTH_DR_EFAIL:
                  case NFSAUTH_DR_DECERR:
                  case NFSAUTH_DR_BADCMD:
*** 1052,1065 ****
                  if (uid != NULL)
                          *uid = p->auth_srv_uid;
                  if (gid != NULL)
                          *gid = p->auth_srv_gid;
                  if (ngids != NULL && gids != NULL) {
!                         *ngids = p->auth_srv_ngids;
!                         *gids = kmem_alloc(*ngids * sizeof (gid_t), KM_SLEEP);
!                         bcopy(p->auth_srv_gids, *gids, *ngids * sizeof (gid_t));
                  }
  
                  access = p->auth_access;
  
                  if ((refresh > NFSAUTH_CACHE_REFRESH) &&
                      p->auth_state == NFS_AUTH_FRESH) {
--- 1058,1075 ----
                  if (uid != NULL)
                          *uid = p->auth_srv_uid;
                  if (gid != NULL)
                          *gid = p->auth_srv_gid;
                  if (ngids != NULL && gids != NULL) {
!                         if ((*ngids = p->auth_srv_ngids) != 0) {
!                                 size_t sz = *ngids * sizeof (gid_t);
!                                 *gids = kmem_alloc(sz, KM_SLEEP);
!                                 bcopy(p->auth_srv_gids, *gids, sz);
!                         } else {
!                                 *gids = NULL;
                          }
+                 }
  
                  access = p->auth_access;
  
                  if ((refresh > NFSAUTH_CACHE_REFRESH) &&
                      p->auth_state == NFS_AUTH_FRESH) {