From 692cb259f39f6791f39addc1d74f926c54e3b6fe Mon Sep 17 00:00:00 2001
From: Jacob Trimble <modmaker@google.com>
Date: Wed, 4 Oct 2023 17:32:16 +0000
Subject: [PATCH] Fix dynamic adapter with provisioning

Bug: 302721191
Change-Id: Icdc003ed903142129eb1f89d109f447ea6dc2079
---
 .../core/src/oemcrypto_adapter_dynamic.cpp    | 46 +++++++++++++------
 1 file changed, 32 insertions(+), 14 deletions(-)

diff --git a/libwvdrmengine/cdm/core/src/oemcrypto_adapter_dynamic.cpp b/libwvdrmengine/cdm/core/src/oemcrypto_adapter_dynamic.cpp
index 73d5061e..8562d5b7 100644
--- a/libwvdrmengine/cdm/core/src/oemcrypto_adapter_dynamic.cpp
+++ b/libwvdrmengine/cdm/core/src/oemcrypto_adapter_dynamic.cpp
@@ -2108,6 +2108,20 @@ extern "C" OEMCryptoResult OEMCrypto_PrepAndSignRenewalRequest(
   return OEMCrypto_ERROR_NOT_IMPLEMENTED;
 }
 
+template <size_t N>
+std::vector<uint8_t> MakeContext(const char (&key_label)[N],
+                                 const uint8_t* context, size_t context_length,
+                                 uint32_t suffix) {
+  // TODO(b/299343035): Use ODK methods.
+  std::vector<uint8_t> ret;
+  ret.insert(ret.end(), key_label, key_label + N);
+  ret.insert(ret.end(), context, context + context_length);
+  const uint32_t suffix_net = htonl(suffix);
+  auto* ptr = reinterpret_cast<const uint8_t*>(&suffix_net);
+  ret.insert(ret.end(), ptr, ptr + sizeof(suffix_net));
+  return ret;
+}
+
 extern "C" OEMCryptoResult OEMCrypto_PrepAndSignProvisioningRequest(
     OEMCrypto_SESSION session, uint8_t* message, size_t message_length,
     size_t* core_message_length, uint8_t* signature, size_t* signature_length) {
@@ -2115,6 +2129,24 @@ extern "C" OEMCryptoResult OEMCrypto_PrepAndSignProvisioningRequest(
   LevelSession pair = gAdapter->GetSession(session);
   if (!pair.fcn) return OEMCrypto_ERROR_INVALID_SESSION;
   if (pair.fcn->PrepAndSignProvisioningRequest != nullptr) {
+    if (pair.fcn->version < 19 &&
+        pair.fcn->GenerateDerivedKeys_V18 != nullptr) {
+      if (!core_message_length || *core_message_length > message_length) {
+        return OEMCrypto_ERROR_INVALID_CONTEXT;
+      }
+
+      const std::vector<uint8_t> mac_context =
+          MakeContext("AUTHENTICATION", message + *core_message_length,
+                      message_length - *core_message_length, 0x200);
+      const std::vector<uint8_t> enc_context =
+          MakeContext("ENCRYPTION", message + *core_message_length,
+                      message_length - *core_message_length, 0x80);
+      const OEMCryptoResult result = pair.fcn->GenerateDerivedKeys_V18(
+          pair.session, mac_context.data(), mac_context.size(),
+          enc_context.data(), enc_context.size());
+      if (result != OEMCrypto_SUCCESS) return result;
+    }
+
     return pair.fcn->PrepAndSignProvisioningRequest(
         pair.session, message, message_length, core_message_length, signature,
         signature_length);
@@ -2141,20 +2173,6 @@ const uint8_t* PointerOrNull(const uint8_t* pointer, size_t length) {
   return length ? pointer : nullptr;
 }
 
-template <size_t N>
-std::vector<uint8_t> MakeContext(const char (&key_label)[N],
-                                 const uint8_t* context, size_t context_length,
-                                 uint32_t suffix) {
-  // TODO(b/299343035): Use ODK methods.
-  std::vector<uint8_t> ret;
-  ret.insert(ret.end(), key_label, key_label + N);
-  ret.insert(ret.end(), context, context + context_length);
-  const uint32_t suffix_net = htonl(suffix);
-  auto* ptr = reinterpret_cast<const uint8_t*>(&suffix_net);
-  ret.insert(ret.end(), ptr, ptr + sizeof(suffix_net));
-  return ret;
-}
-
 extern "C" OEMCryptoResult OEMCrypto_LoadLicense(
     OEMCrypto_SESSION session, const uint8_t* context, size_t context_length,
     const uint8_t* derivation_key, size_t derivation_key_length,