From 5f3dc9220d92088a1d942de3c676f725cf18999c Mon Sep 17 00:00:00 2001
From: kotori0 <admin@0x.mk>
Date: Sun, 20 Dec 2020 00:55:56 +0800
Subject: [PATCH] Properly handle GetOatQuickMethodHeader

---
 .../main/cpp/external/yahfa/src/HookMain.cpp  |  5 ++--
 .../cpp/main/include/art/runtime/art_method.h | 25 +++++++++++--------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/edxp-core/src/main/cpp/external/yahfa/src/HookMain.cpp b/edxp-core/src/main/cpp/external/yahfa/src/HookMain.cpp
index 0a1c270f..3b1c1561 100644
--- a/edxp-core/src/main/cpp/external/yahfa/src/HookMain.cpp
+++ b/edxp-core/src/main/cpp/external/yahfa/src/HookMain.cpp
@@ -125,19 +125,18 @@ void *getEntryPoint(void* method) {
 static int replaceMethod(void *fromMethod, void *toMethod, int isBackup) {
     // replace entry point
     void *newEntrypoint = nullptr;
+    void* fromEntrypoint = (char *) fromMethod + OFFSET_entry_point_from_quick_compiled_code_in_ArtMethod;
     if(isBackup) {
         void *originEntrypoint = readAddr((char *) toMethod + OFFSET_entry_point_from_quick_compiled_code_in_ArtMethod);
         // entry point hardcoded
         newEntrypoint = genTrampoline(toMethod, originEntrypoint);
+        replaced_entrypoint[fromMethod] = newEntrypoint;
     }
     else {
         // entry point from ArtMethod struct
         newEntrypoint = genTrampoline(toMethod, nullptr);
     }
 
-    void* fromEntrypoint = (char *) fromMethod + OFFSET_entry_point_from_quick_compiled_code_in_ArtMethod;
-    replaced_entrypoint[fromMethod] = newEntrypoint;
-
     LOGI("replace entry point from %p to %p",
          readAddr(fromEntrypoint),
          newEntrypoint
diff --git a/edxp-core/src/main/cpp/main/include/art/runtime/art_method.h b/edxp-core/src/main/cpp/main/include/art/runtime/art_method.h
index da39bb60..d91106bf 100644
--- a/edxp-core/src/main/cpp/main/include/art/runtime/art_method.h
+++ b/edxp-core/src/main/cpp/main/include/art/runtime/art_method.h
@@ -16,19 +16,22 @@ namespace art {
         inline static size_t oat_header_length;
         inline static int32_t oat_header_code_length_offset;
         CREATE_HOOK_STUB_ENTRIES(void *, GetOatQuickMethodHeader, void *thiz, uintptr_t pc) {
-            LOGD("GetOatQuickMethodHeader called");
+            // LOGD("GetOatQuickMethodHeader called, thiz=%p", thiz);
             // This is a partial copy from AOSP. We only touch them if they are hooked.
             if (LIKELY(edxp::isHooked(thiz))) {
-                LOGD("GetOatQuickMethodHeader: isHooked=true, thiz=%p", thiz);
-                char* thiz_ = static_cast<char *>(thiz);
-                char* code_length_loc = thiz_ + oat_header_code_length_offset;
-                uint32_t code_length = *reinterpret_cast<uint32_t *>(code_length_loc);
-                uintptr_t original_ep = reinterpret_cast<uintptr_t>(
-                        getOriginalEntryPointFromTargetMethod(thiz));
-                if (original_ep <= pc <= original_ep + code_length) return thiz_ - oat_header_length;
-                // If PC is not in range, we mark it as not found.
-                LOGD("GetOatQuickMethodHeader: PC not found in current method.");
-                return nullptr;
+                uintptr_t original_ep = reinterpret_cast<uintptr_t>(getOriginalEntryPointFromTargetMethod(thiz));
+                if(original_ep) {
+                    char* code_length_loc = reinterpret_cast<char *>(original_ep) + oat_header_code_length_offset;
+                    uint32_t code_length = *reinterpret_cast<uint32_t *>(code_length_loc) & ~0x80000000;
+                    LOGD("GetOatQuickMethodHeader: isHooked=true, original_ep=0x%x, code_length=0x%x, pc=0x%x", original_ep, code_length, pc);
+                    if (original_ep <= pc && pc <= original_ep + code_length)
+                        return reinterpret_cast<void *>(original_ep - oat_header_length);
+                    // If PC is not in range, we mark it as not found.
+                    LOGD("GetOatQuickMethodHeader: PC not found in current method.");
+                    return nullptr;
+                } else {
+                    LOGD("GetOatQuickMethodHeader: isHooked but not backup, fallback to system");
+                }
             }
             return GetOatQuickMethodHeaderBackup(thiz, pc);
         }