Fix undefined behavior

1 files changed, 13 insertions, 6 deletions

diff --git a/src/core/ext/client_config/subchannel_index.c b/src/core/ext/client_config/subchannel_index.c
index ab8d9bd91d..b77632bba3 100644
--- a/src/core/ext/client_config/subchannel_index.c
+++ b/src/core/ext/client_config/subchannel_index.c
@@ -77,9 +77,14 @@ static grpc_subchannel_key *create_key(
   grpc_subchannel_key *k = gpr_malloc(sizeof(*k));
   k->connector = grpc_connector_ref(connector);
   k->args.filter_count = args->filter_count;
-  k->args.filters = gpr_malloc(sizeof(*k->args.filters) * k->args.filter_count);
-  memcpy((grpc_channel_filter *)k->args.filters, args->filters,
-         sizeof(*k->args.filters) * k->args.filter_count);
+  if (k->args.filter_count > 0) {
+    k->args.filters =
+        gpr_malloc(sizeof(*k->args.filters) * k->args.filter_count);
+    memcpy((grpc_channel_filter *)k->args.filters, args->filters,
+           sizeof(*k->args.filters) * k->args.filter_count);
+  } else {
+    k->args.filters = NULL;
+  }
   k->args.addr_len = args->addr_len;
   k->args.addr = gpr_malloc(args->addr_len);
   memcpy(k->args.addr, args->addr, k->args.addr_len);
@@ -106,9 +111,11 @@ static int subchannel_key_compare(grpc_subchannel_key *a,
   if (c != 0) return c;
   c = memcmp(a->args.addr, b->args.addr, a->args.addr_len);
   if (c != 0) return c;
-  c = memcmp(a->args.filters, b->args.filters,
-             a->args.filter_count * sizeof(*a->args.filters));
-  if (c != 0) return c;
+  if (a->args.filter_count > 0) {
+    c = memcmp(a->args.filters, b->args.filters,
+               a->args.filter_count * sizeof(*a->args.filters));
+    if (c != 0) return c;
+  }
   return grpc_channel_args_compare(a->args.args, b->args.args);
 }