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      1 /*
      2  * Copyright (C) 2018 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11   * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "precise_hidden_api_finder.h"
     18 
     19 #include "dex/code_item_accessors-inl.h"
     20 #include "dex/dex_instruction-inl.h"
     21 #include "dex/dex_file.h"
     22 #include "dex/method_reference.h"
     23 #include "flow_analysis.h"
     24 #include "hidden_api.h"
     25 #include "resolver.h"
     26 #include "veridex.h"
     27 
     28 #include <iostream>
     29 
     30 namespace art {
     31 
     32 void PreciseHiddenApiFinder::RunInternal(
     33     const std::vector<std::unique_ptr<VeridexResolver>>& resolvers,
     34     const std::function<void(VeridexResolver*, const ClassDataItemIterator&)>& action) {
     35   for (const std::unique_ptr<VeridexResolver>& resolver : resolvers) {
     36     const DexFile& dex_file = resolver->GetDexFile();
     37     size_t class_def_count = dex_file.NumClassDefs();
     38     for (size_t class_def_index = 0; class_def_index < class_def_count; ++class_def_index) {
     39       const DexFile::ClassDef& class_def = dex_file.GetClassDef(class_def_index);
     40       const uint8_t* class_data = dex_file.GetClassData(class_def);
     41       if (class_data == nullptr) {
     42         // Empty class.
     43         continue;
     44       }
     45       ClassDataItemIterator it(dex_file, class_data);
     46       it.SkipAllFields();
     47       for (; it.HasNextMethod(); it.Next()) {
     48         const DexFile::CodeItem* code_item = it.GetMethodCodeItem();
     49         if (code_item == nullptr) {
     50           continue;
     51         }
     52         action(resolver.get(), it);
     53       }
     54     }
     55   }
     56 }
     57 
     58 void PreciseHiddenApiFinder::AddUsesAt(const std::vector<ReflectAccessInfo>& accesses,
     59                                        MethodReference ref) {
     60   for (const ReflectAccessInfo& info : accesses) {
     61     if (info.IsConcrete()) {
     62       concrete_uses_[ref].push_back(info);
     63     } else {
     64       abstract_uses_[ref].push_back(info);
     65     }
     66   }
     67 }
     68 
     69 void PreciseHiddenApiFinder::Run(const std::vector<std::unique_ptr<VeridexResolver>>& resolvers) {
     70   // Collect reflection uses.
     71   RunInternal(resolvers, [this] (VeridexResolver* resolver, const ClassDataItemIterator& it) {
     72     FlowAnalysisCollector collector(resolver, it);
     73     collector.Run();
     74     AddUsesAt(collector.GetUses(), MethodReference(&resolver->GetDexFile(), it.GetMemberIndex()));
     75   });
     76 
     77   // For non-final reflection uses, do a limited fixed point calculation over the code to try
     78   // substituting them with final reflection uses.
     79   // We limit the number of times we iterate over the code as one run can be long.
     80   static const int kMaximumIterations = 10;
     81   uint32_t i = 0;
     82   while (!abstract_uses_.empty() && (i++ < kMaximumIterations)) {
     83     // Fetch and clear the worklist.
     84     std::map<MethodReference, std::vector<ReflectAccessInfo>> current_uses
     85         = std::move(abstract_uses_);
     86     RunInternal(resolvers,
     87                 [this, current_uses] (VeridexResolver* resolver, const ClassDataItemIterator& it) {
     88       FlowAnalysisSubstitutor substitutor(resolver, it, current_uses);
     89       substitutor.Run();
     90       AddUsesAt(substitutor.GetUses(),
     91                 MethodReference(&resolver->GetDexFile(), it.GetMemberIndex()));
     92     });
     93   }
     94 }
     95 
     96 void PreciseHiddenApiFinder::Dump(std::ostream& os, HiddenApiStats* stats) {
     97   static const char* kPrefix = "       ";
     98   std::map<std::string, std::vector<MethodReference>> named_uses;
     99   for (auto it : concrete_uses_) {
    100     MethodReference ref = it.first;
    101     for (const ReflectAccessInfo& info : it.second) {
    102       std::string cls(info.cls.ToString());
    103       std::string name(info.name.ToString());
    104       std::string full_name = cls + "->" + name;
    105       HiddenApiAccessFlags::ApiList api_list = hidden_api_.GetApiList(full_name);
    106       if (api_list != HiddenApiAccessFlags::kWhitelist) {
    107         named_uses[full_name].push_back(ref);
    108       }
    109     }
    110   }
    111 
    112   for (auto it : named_uses) {
    113     ++stats->reflection_count;
    114     const std::string& full_name = it.first;
    115     HiddenApiAccessFlags::ApiList api_list = hidden_api_.GetApiList(full_name);
    116     stats->api_counts[api_list]++;
    117     os << "#" << ++stats->count << ": Reflection " << api_list << " " << full_name << " use(s):";
    118     os << std::endl;
    119     for (const MethodReference& ref : it.second) {
    120       os << kPrefix << HiddenApi::GetApiMethodName(ref) << std::endl;
    121     }
    122     os << std::endl;
    123   }
    124 }
    125 
    126 }  // namespace art
    127