From 7cb30b316eda0b2aa8adeaba28a8afe15fc58c28 Mon Sep 17 00:00:00 2001
From: Nicolas Iooss <nicolas.iooss@m4x.org>
Date: Sun, 14 Mar 2021 19:25:58 +0100
Subject: [PATCH] libsepol/cil: fix NULL pointer dereference in
 __cil_insert_name

OSS-Fuzz found a Null-dereference in __cil_insert_name when trying to
compile the following policy:

    (macro MACRO ()
        (classmap CLASS (PERM))
        (type TYPE)
        (typetransition TYPE TYPE CLASS "name" TYPE)
    )
    (call MACRO)

When using a macro with no argument, macro->params is NULL and
cil_list_for_each(item, macro->params) dereferenced a NULL pointer.
Fix this by checking that macro->params is not NULL before using it.

Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28565
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
---
 libsepol/cil/src/cil_resolve_ast.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libsepol/cil/src/cil_resolve_ast.c b/libsepol/cil/src/cil_resolve_ast.c
index ae334620..91e08633 100644
--- a/libsepol/cil/src/cil_resolve_ast.c
+++ b/libsepol/cil/src/cil_resolve_ast.c
@@ -82,7 +82,7 @@ static struct cil_name * __cil_insert_name(struct cil_db *db, hashtab_key_t key,
 	} else if (parent->flavor == CIL_MACRO) {
 		macro = parent->data;
 	}
-	if (macro != NULL) {
+	if (macro != NULL && macro->params != NULL) {
 		struct cil_list_item *item;
 		cil_list_for_each(item, macro->params) {
 			if (((struct cil_param*)item->data)->str == key) {
-- 
2.30.2