Merge pull request #12008 from ncteisen/fuzz-direct-leak-in-malloc

Fix leak if duplicated static metadata

src/core/lib/surface/call.c

@@ -825,7 +825,7 @@ uint32_t grpc_call_test_only_get_encodings_accepted_by_peer(grpc_call *call) {
   return encodings_accepted_by_peer;
 }
 
-static grpc_linked_mdelem *linked_from_md(grpc_metadata *md) {
+static grpc_linked_mdelem *linked_from_md(const grpc_metadata *md) {
   return (grpc_linked_mdelem *)&md->internal_data;
 }
 
@@ -849,7 +849,7 @@ static int prepare_application_metadata(
   for (i = 0; i < total_count; i++) {
     const grpc_metadata *md =
         get_md_elem(metadata, additional_metadata, i, count);
-    grpc_linked_mdelem *l = (grpc_linked_mdelem *)&md->internal_data;
+    grpc_linked_mdelem *l = linked_from_md(md);
     GPR_ASSERT(sizeof(grpc_linked_mdelem) == sizeof(md->internal_data));
     if (!GRPC_LOG_IF_ERROR("validate_metadata",
                            grpc_validate_header_key_is_legal(md->key))) {
@@ -866,7 +866,7 @@ static int prepare_application_metadata(
     for (int j = 0; j < i; j++) {
       const grpc_metadata *md =
           get_md_elem(metadata, additional_metadata, j, count);
-      grpc_linked_mdelem *l = (grpc_linked_mdelem *)&md->internal_data;
+      grpc_linked_mdelem *l = linked_from_md(md);
       GRPC_MDELEM_UNREF(exec_ctx, l->md);
     }
     return 0;
@@ -884,9 +884,12 @@ static int prepare_application_metadata(
   }
   for (i = 0; i < total_count; i++) {
     grpc_metadata *md = get_md_elem(metadata, additional_metadata, i, count);
-    GRPC_LOG_IF_ERROR(
+    grpc_linked_mdelem *l = linked_from_md(md);
-        "prepare_application_metadata",
+    grpc_error *error = grpc_metadata_batch_link_tail(exec_ctx, batch, l);
-        grpc_metadata_batch_link_tail(exec_ctx, batch, linked_from_md(md)));
+    if (error != GRPC_ERROR_NONE) {
+      GRPC_MDELEM_UNREF(exec_ctx, l->md);
+    }
+    GRPC_LOG_IF_ERROR("prepare_application_metadata", error);
   }
   call->send_extra_metadata_count = 0;
 

tools/run_tests/generated/tests.json

@@ -92736,6 +92736,29 @@
     ], 
     "uses_polling": false
   }, 
+  {
+    "args": [
+      "test/core/end2end/fuzzers/api_fuzzer_corpus/clusterfuzz-testcase-minimized-4688823906729984"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "api_fuzzer_one_entry", 
+    "platforms": [
+      "mac", 
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
   {
     "args": [
       "test/core/end2end/fuzzers/api_fuzzer_corpus/clusterfuzz-testcase-minimized-5175380371570688"