r13492: As noone objected on the mailing-list:

Fix parse_domain_user to fail when splitting a full name like "DOM\user"
when "winbind use default domain" and "winbind trusted domains only" are
not enabled.

This allows pam_winbind to behave correctly when more modules are
stacked in the "account" or "password" PAM facility. pam_winbindd calls
WINBINDD_GETPWNAM which can decide whether or not a user is a winbind
user and return correct PAM error codes.

Guenther
(This used to be commit e6d52c1e9d)

source3/nsswitch/pam_winbind.c

@@ -566,10 +566,38 @@ static int winbind_chauthtok_request(pam_handle_t * pamh,
  *	 0  = OK
  * 	-1  = System error
  */
-static int valid_user(const char *user)
+static int valid_user(const char *user, pam_handle_t *pamh, int ctrl)
 {
-	if (getpwnam(user)) return 0;
-	return 1;
+	/* check not only if the user is available over NSS calls, also make
+	 * sure it's really a winbind user, this is important when stacking PAM
+	 * modules in the 'account' or 'password' facility. */
+
+	struct passwd *pwd = NULL;
+	struct winbindd_request request;
+	struct winbindd_response response;
+	int ret;
+
+	ZERO_STRUCT(request);
+	ZERO_STRUCT(response);
+
+	pwd = getpwnam(user);
+	if (pwd == NULL) {
+		return 1;
+	}
+
+	fstrcpy(request.data.username, user);
+
+	ret = pam_winbind_request_log(pamh, ctrl, WINBINDD_GETPWNAM, &request, &response, user);
+
+	switch (ret) {
+		case PAM_USER_UNKNOWN:
+			return 1;
+		case PAM_SUCCESS:
+			return 0;
+		default:
+			break;
+	}
+	return -1;
 }
 
 static char *_pam_delete(register char *xx)
@@ -897,7 +925,7 @@ int pam_sm_acct_mgmt(pam_handle_t *pamh, int flags,
 	}
 
 	/* Verify the username */
-	retval = valid_user(username);
+	retval = valid_user(username, pamh, ctrl);
 	switch (retval) {
 	case -1:
 		/* some sort of system error. The log was already printed */
@@ -1123,6 +1151,17 @@ int pam_sm_chauthtok(pam_handle_t * pamh, int flags,
 		return retval;
 	}
 
+	/* check if this is really a user in winbindd, not only in NSS */
+	retval = valid_user(user, pamh, ctrl);
+	switch (retval) {
+		case 1:
+			return PAM_USER_UNKNOWN;
+		case -1:
+			return PAM_SYSTEM_ERR;
+		default:
+			break;
+	}
+		
 	/*
 	 * obtain and verify the current password (OLDAUTHTOK) for
 	 * the user.

source3/nsswitch/winbindd_group.c

@@ -992,7 +992,7 @@ void winbindd_getgroups(struct winbindd_cli_state *state)
 	if (!parse_domain_user_talloc(state->mem_ctx,
 				      state->request.data.username,
 				      &s->domname, &s->username)) {
-		DEBUG(0, ("Could not parse domain user: %s\n",
+		DEBUG(5, ("Could not parse domain user: %s\n",
 			  state->request.data.username));
 		request_error(state);
 		return;

source3/nsswitch/winbindd_pam.c

@@ -633,8 +633,17 @@ void winbindd_pam_auth(struct winbindd_cli_state *state)
 
 	/* Parse domain and username */
 	
-	parse_domain_user(state->request.data.auth.user,
-			  name_domain, name_user);
+	if (!parse_domain_user(state->request.data.auth.user,
+			       name_domain, name_user)) {
+		set_auth_errors(&state->response, NT_STATUS_NO_SUCH_USER);
+		DEBUG(5, ("Plain text authentication for %s returned %s "
+			  "(PAM: %d)\n",
+			  state->request.data.auth.user, 
+			  state->response.data.auth.nt_status_string,
+			  state->response.data.auth.pam_error));
+		request_error(state);
+		return;
+	}
 
 	domain = find_auth_domain(state, name_domain);
 

source3/nsswitch/winbindd_user.c

@@ -337,7 +337,7 @@ void winbindd_getpwnam(struct winbindd_cli_state *state)
 
 	if (!parse_domain_user(state->request.data.username, domname,
 			       username)) {
-		DEBUG(0, ("Could not parse domain user: %s\n",
+		DEBUG(5, ("Could not parse domain user: %s\n",
 			  state->request.data.username));
 		request_error(state);
 		return;

source3/nsswitch/winbindd_util.c

@@ -835,10 +835,9 @@ BOOL parse_domain_user(const char *domuser, fstring domain, fstring user)
 		if ( assume_domain(lp_workgroup())) {
 			fstrcpy(domain, lp_workgroup());
 		} else {
-			fstrcpy( domain, get_global_sam_name() ); 
+			return False;
 		}
-	} 
-	else {
+	} else {
 		fstrcpy(user, p+1);
 		fstrcpy(domain, domuser);
 		domain[PTR_DIFF(p, domuser)] = 0;
@@ -853,7 +852,9 @@ BOOL parse_domain_user_talloc(TALLOC_CTX *mem_ctx, const char *domuser,
 			      char **domain, char **user)
 {
 	fstring fstr_domain, fstr_user;
-	parse_domain_user(domuser, fstr_domain, fstr_user);
+	if (!parse_domain_user(domuser, fstr_domain, fstr_user)) {
+		return False;
+	}
 	*domain = talloc_strdup(mem_ctx, fstr_domain);
 	*user = talloc_strdup(mem_ctx, fstr_user);
 	return ((*domain != NULL) && (*user != NULL));