libsepol/cil: Return error when identifier declared as both type and …

…attribute

CIL allows a type to be redeclared when using the multiple declarations
option ("-m" or "--muliple-decls"), but make it an error for an identifier
to be declared as both a type and an attribute.

Change the error message so that it always gives the location and flavor
of both declarations. The flavors will be the same in all other cases,
but in this case they explain why there is an error even if multiple
declartions are allowed.

Fixes: Commit fafe4c2 ("libsepol: cil: Add ability to redeclare types[attributes]")
Reported-by: Topi Miettinen <toiwoton@gmail.com>
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>

libsepol/cil/src/cil_build_ast.c

@@ -87,16 +87,20 @@ int cil_fill_list(struct cil_tree_node *current, enum cil_flavor flavor, struct
  * datum, given the new datum and the one already present in a given symtab.
  */
 int cil_is_datum_multiple_decl(__attribute__((unused)) struct cil_symtab_datum *cur,
-                               __attribute__((unused)) struct cil_symtab_datum *old,
+                               struct cil_symtab_datum *old,
                                enum cil_flavor f)
 {
 	int rc = CIL_FALSE;
 
 	switch (f) {
 	case CIL_TYPE:
 	case CIL_TYPEATTRIBUTE:
-		/* type and typeattribute statements insert empty datums, ret true */
-		rc = CIL_TRUE;
+		if (!old || f != FLAVOR(old)) {
+			rc = CIL_FALSE;
+		} else {
+			/* type and typeattribute statements insert empty datums */
+			rc = CIL_TRUE;
+		}
 		break;
 	default:
 		break;
@@ -126,19 +130,20 @@ int cil_gen_node(struct cil_db *db, struct cil_tree_node *ast_node, struct cil_s
 	if (symtab != NULL) {
 		rc = cil_symtab_insert(symtab, (hashtab_key_t)key, datum, ast_node);
 		if (rc == SEPOL_EEXIST) {
+			rc = cil_symtab_get_datum(symtab, (hashtab_key_t)key, &prev);
+			if (rc != SEPOL_OK) {
+				cil_log(CIL_ERR, "Re-declaration of %s %s, but previous declaration could not be found\n",cil_node_to_string(ast_node), key);
+				goto exit;
+			}
 			if (!db->multiple_decls ||
-			    cil_symtab_get_datum(symtab, (hashtab_key_t)key, &prev) != SEPOL_OK ||
 			    !cil_is_datum_multiple_decl(datum, prev, nflavor)) {
-
 				/* multiple_decls not ok, ret error */
+				struct cil_tree_node *node = NODE(prev);
 				cil_log(CIL_ERR, "Re-declaration of %s %s\n",
 					cil_node_to_string(ast_node), key);
-				if (cil_symtab_get_datum(symtab, key, &datum) == SEPOL_OK) {
-					if (sflavor == CIL_SYM_BLOCKS) {
-						struct cil_tree_node *node = datum->nodes->head->data;
-						cil_tree_log(node, CIL_ERR, "Previous declaration");
-					}
-				}
+				cil_tree_log(node, CIL_ERR, "Previous declaration of %s",
+					cil_node_to_string(node));
+				rc = SEPOL_ERR;
 				goto exit;
 			}
 			/* multiple_decls is enabled and works for this datum type, add node */
@@ -169,7 +174,6 @@ int cil_gen_node(struct cil_db *db, struct cil_tree_node *ast_node, struct cil_s
 	return SEPOL_OK;
 
 exit:
-	cil_log(CIL_ERR, "Failed to create node\n");
 	return rc;
 }