From 58c1ea1fa2ab5c69075ecb8b9a71f87f1b708d26 Mon Sep 17 00:00:00 2001
From: Fred Gylys-Colwell <fredgc@google.com>
Date: Thu, 24 Jun 2021 03:28:19 +0000
Subject: [PATCH] Cache security level

Merge from Widevine repo of http://go/wvgerrit/127743

There was some confusion about who owned the OEMCrypto security level
string in a multithreaded environment. This is solved by caching the
security level at initialization time.

Bug: 188706160
Test: ran unit tests on bonito
Change-Id: I93af3bb2e5a8bf190627ee568f752b5ea9543306
---
 .../core/src/oemcrypto_adapter_dynamic.cpp    | 32 +++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/libwvdrmengine/cdm/core/src/oemcrypto_adapter_dynamic.cpp b/libwvdrmengine/cdm/core/src/oemcrypto_adapter_dynamic.cpp
index 194b2ee6..51e2c119 100644
--- a/libwvdrmengine/cdm/core/src/oemcrypto_adapter_dynamic.cpp
+++ b/libwvdrmengine/cdm/core/src/oemcrypto_adapter_dynamic.cpp
@@ -35,6 +35,7 @@
 #include "metrics_collections.h"
 #include "properties.h"
 #include "wv_cdm_constants.h"
+#include "wv_cdm_types.h"
 
 using namespace wvoec3;
 using video_widevine::ProvisioningResponse;
@@ -319,6 +320,7 @@ typedef OEMCryptoResult (*L1_LoadProvisioning_t)(
 typedef uint32_t (*L1_MinorAPIVersion_t)();
 
 struct FunctionPointers {
+  wvcdm::CdmSecurityLevel security_level;
   uint32_t version;
   L1_Initialize_t Initialize;
   L1_SetSandbox_t SetSandbox;
@@ -690,6 +692,7 @@ class Adapter {
 
     level1_ = FunctionPointers();  // start with all null pointers.
     level3_ = FunctionPointers();  // start with all null pointers.
+    level3_.security_level = wvcdm::kSecurityLevelL3;
     LoadLevel3();
     WatchDog* watcher = new WatchDog(sandbox_id_);
     watcher->CheckForPreviousFailure(&metrics);
@@ -782,6 +785,7 @@ class Adapter {
       return false;
     }
     level1_.version = level1_.APIVersion();
+    level1_.security_level = wvcdm::kSecurityLevelUninitialized;
     metrics->SetL1ApiVersion(level1_.version);
     metrics->SetL1MinApiVersion(kMinimumVersion);
 
@@ -895,6 +899,22 @@ class Adapter {
           level1_library_, "OEMCrypto_FreeSecureBuffer");
     }
 
+    if (level1_.SecurityLevel) {
+      const char* level = level1_.SecurityLevel();
+      if (strncmp(level, "L1", 2) == 0) {
+        level1_.security_level = wvcdm::kSecurityLevelL1;
+      } else if (strncmp(level, "L3", 2) == 0) {
+        // It is possible that the dynamically loaded OEMCrypto is really L3.
+        // We might want to use it if it has better performance than the built
+        // in L3.
+        LOGW("L1 OEMCrypto is really L3");
+        level1_.security_level = wvcdm::kSecurityLevelL3;
+      } else {
+        LOGE("Unknown security level %.2s", level);
+        level1_.security_level = wvcdm::kSecurityLevelUnknown;
+      }
+    }
+
     // TODO(119830252): make the code below available to a static adapter.
     // Check if the keybox or oem certificate is valid, if so, we are finished
     // with initialization.
@@ -1219,8 +1239,16 @@ const char* OEMCrypto_SecurityLevel(SecurityLevel level) {
   if (!gAdapter) return "";
   const FunctionPointers* fcn = gAdapter->GetFunctionPointers(level);
   if (!fcn) return "";
-  if (fcn->SecurityLevel == nullptr) return "";
-  return fcn->SecurityLevel();
+  switch (fcn->security_level) {
+    case kSecurityLevelL1:
+      return "L1";
+    case kSecurityLevelL2:
+      return "L2";
+    case kSecurityLevelL3:
+      return "L3";
+    default:
+      return "";
+  }
 }
 
 OEMCryptoResult OEMCrypto_GetHDCPCapability(