NEX-2842 SMB client authentication fails in adt_set_user() with IDMU enabled

@@ -19,10 +19,11 @@
  * CDDL HEADER END
  */
 
 /*
  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
  * Copyright 2017 OmniOS Community Edition (OmniOSce) Association.
  */
 
 #include <bsm/adt.h>
 #include <bsm/adt_event.h>

@@ -189,31 +190,40 @@
 
         if (auditstate & AUC_DISABLED) {
                 /* c2audit excluded */
                 mask->am_success = 0;
                 mask->am_failure = 0;
-        } else if (uid <= MAXUID) {
+                return (0);
+        }
+
+        if (uid <= MAXUID) {
                 if ((buff_sz = sysconf(_SC_GETPW_R_SIZE_MAX)) == -1) {
                         adt_write_syslog("couldn't determine maximum size of "
                             "password buffer", errno);
                         return (-1);
                 }
                 if ((pwd_buff = calloc(1, (size_t)++buff_sz)) == NULL) {
                         return (-1);
                 }
-                if (getpwuid_r(uid, &pwd, pwd_buff, (int)buff_sz) == NULL) {
-                        errno = EINVAL; /* user doesn't exist */
-                        free(pwd_buff);
-                        return (-1);
-                }
+                /*
+                 * Ephemeral id's and id's that exist in a name service we
+                 * don't have configured (LDAP, NIS) can't be looked up,
+                 * but either way it's not an error.
+                 */
+                if (getpwuid_r(uid, &pwd, pwd_buff, (int)buff_sz) != NULL) {
                 if (au_user_mask(pwd.pw_name, mask)) {
                         free(pwd_buff);
                         errno = EFAULT; /* undetermined failure */
                         return (-1);
                 }
                 free(pwd_buff);
-        } else if (auditon(A_GETKMASK, (caddr_t)mask, sizeof (*mask)) == -1) {
+                        return (0);
+                }
+                free(pwd_buff);
+        }
+
+        if (auditon(A_GETKMASK, (caddr_t)mask, sizeof (*mask)) == -1) {
                         return (-1);
         }
 
         return (0);
 }