Common subdirectories: orig/auth and src/auth
diff -ru orig/auth/passdb-pam.c src/auth/passdb-pam.c
--- orig/auth/passdb-pam.c	ti. okt. 14 12:04:16 2014
+++ src/auth/passdb-pam.c	ti. okt. 14 12:02:28 2014
@@ -85,6 +85,8 @@
 			string = strdup(ctx->request->user);
 			if (string == NULL)
 				i_fatal_status(FATAL_OUTOFMEM, "Out of memory");
+			if (strlen(string) == 0)
+				i_fatal_status(FATAL_OUTOFMEM, "NO USER?");
 			break;
 		case PAM_PROMPT_ECHO_OFF:
 			/* Assume we're asking for password */