ANDROID: fuzz: Check for NULL property during walk

When fdt_get_property_by_offset() fails, it returns NULL so prevent the
fuzzer from dereferencing the pointer, in that case.

Bug: 240841657
Test: SANITIZE_HOST=address m libfdt_fuzzer
Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
Change-Id: Idcd187993fce0140038b61589a183b16d822004b

1 files changed, 2 insertions, 0 deletions

diff --git a/fuzzing/libfdt_fuzzer.c b/fuzzing/libfdt_fuzzer.c
index b433bbc..f89f1b4 100644
--- a/fuzzing/libfdt_fuzzer.c
+++ b/fuzzing/libfdt_fuzzer.c
@@ -62,6 +62,8 @@ static void walk_node_properties(const void *device_tree, int node) {
   fdt_for_each_property_offset(property, device_tree, node) {
     const struct fdt_property *prop = fdt_get_property_by_offset(device_tree,
                                                                  property, &len);
+    if (!prop)
+      continue;
     check_mem(prop->data, fdt32_to_cpu(prop->len));
   }
 }