Merge pull request #508 from haberman/ubsan

Enabled ubsan tests and fixed ubsan failures.

.github/workflows/bazel_tests.yml

@@ -22,7 +22,8 @@ jobs:
           - { CC: clang, os: ubuntu-20.04, flags: "-c opt" }  # Some warnings only fire with -c opt
           - { CC: gcc, os: ubuntu-20.04, flags: "-c opt" }
           - { CC: clang, os: ubuntu-20.04, flags: "--//:fasttable_enabled=true -- -cmake:test_generated_files" }
-          - { CC: clang, os: ubuntu-20.04, flags: "--config=asan -- -benchmarks:benchmark -python/..." }
+          - { CC: clang, os: ubuntu-20.04, flags: "--config=asan -c dbg -- -benchmarks:benchmark -python/..." }
+          - { CC: clang, os: ubuntu-20.04, flags: "--config=ubsan -c dbg -- -benchmarks:benchmark -python/... -upb/bindings/lua/...", install: "libunwind-dev" }
           - { CC: clang, os: macos-11, flags: "" }
 
     steps:

upb/decode.c

@@ -1066,7 +1066,7 @@ upb_DecodeStatus upb_Decode(const char* buf, size_t size, void* msg,
 
   if (size <= 16) {
     memset(&state.patch, 0, 32);
-    memcpy(&state.patch, buf, size);
+    if (size) memcpy(&state.patch, buf, size);
     buf = state.patch;
     state.end = buf + size;
     state.limit = 0;

upb/encode.c

@@ -550,12 +550,14 @@ static void encode_message(upb_encstate* e, const upb_Message* msg,
     }
   }
 
-  const upb_MiniTable_Field* f = &m->fields[m->field_count];
-  const upb_MiniTable_Field* first = &m->fields[0];
-  while (f != first) {
-    f--;
-    if (encode_shouldencode(e, msg, m->subs, f)) {
-      encode_field(e, msg, m->subs, f);
+  if (m->field_count) {
+    const upb_MiniTable_Field* f = &m->fields[m->field_count];
+    const upb_MiniTable_Field* first = &m->fields[0];
+    while (f != first) {
+      f--;
+      if (encode_shouldencode(e, msg, m->subs, f)) {
+        encode_field(e, msg, m->subs, f);
+      }
     }
   }
 

upb/util/def_to_proto.c

@@ -453,14 +453,14 @@ static google_protobuf_FileDescriptorProto* filedef_toproto(
       google_protobuf_FileDescriptorProto_resize_public_dependency(proto, n,
                                                                    ctx->arena);
   const int32_t* public_dep_nums = _upb_FileDef_PublicDependencyIndexes(f);
-  memcpy(public_deps, public_dep_nums, n * sizeof(int32_t));
+  if (n) memcpy(public_deps, public_dep_nums, n * sizeof(int32_t));
 
   n = upb_FileDef_WeakDependencyCount(f);
   int32_t* weak_deps =
       google_protobuf_FileDescriptorProto_resize_weak_dependency(proto, n,
                                                                  ctx->arena);
   const int32_t* weak_dep_nums = _upb_FileDef_WeakDependencyIndexes(f);
-  memcpy(weak_deps, weak_dep_nums, n * sizeof(int32_t));
+  if (n) memcpy(weak_deps, weak_dep_nums, n * sizeof(int32_t));
 
   n = upb_FileDef_TopLevelMessageCount(f);
   google_protobuf_DescriptorProto** msgs =

upb/util/required_fields.c

@@ -216,8 +216,10 @@ static void upb_util_FindUnsetInMessage(upb_FindContext* ctx,
         // Append the contents of the stack to the out array, then
         // NULL-terminate.
         upb_FieldPathVector_Reserve(ctx, &ctx->out_fields, ctx->stack.size + 2);
-        memcpy(&ctx->out_fields.path[ctx->out_fields.size], ctx->stack.path,
-               ctx->stack.size * sizeof(*ctx->stack.path));
+        if (ctx->stack.size) {
+          memcpy(&ctx->out_fields.path[ctx->out_fields.size], ctx->stack.path,
+                 ctx->stack.size * sizeof(*ctx->stack.path));
+        }
         ctx->out_fields.size += ctx->stack.size;
         ctx->out_fields.path[ctx->out_fields.size++] =
             (upb_FieldPathEntry){.field = f};