1 /*
2 * Copyright 2014, 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 "bcc/Renderscript/RSTransforms.h"
18 #include "bcc/Support/Log.h"
19 #include "RSStubsWhiteList.h"
20
21 #include <cstdlib>
22
23 #include <llvm/IR/Instructions.h>
24 #include <llvm/IR/Module.h>
25 #include <llvm/IR/Function.h>
26 #include <llvm/Pass.h>
27
28 namespace { // anonymous namespace
29
30 // Create a Module pass that screens all the global functions in the
31 // module and check if any disallowed external function is accessible
32 // and potentially callable.
33 class RSScreenFunctionsPass : public llvm::ModulePass {
34 private:
35 static char ID;
36
37 std::vector<std::string> &whiteList = stubList;
38
isPresent(std::vector<std::string> & list,std::string name)39 bool isPresent(std::vector<std::string> &list, std::string name) {
40 auto lower = std::lower_bound(list.begin(),
41 list.end(),
42 name);
43
44 if (lower != list.end() && name.compare(*lower) == 0)
45 return true;
46 return false;
47 }
48
isLegal(llvm::Function & F)49 bool isLegal(llvm::Function &F) {
50 // A global function symbol is legal if
51 // a. it has a body, i.e. is not empty or
52 // b. its name starts with "llvm." or
53 // c. it is present in the whitelist
54
55 if (!F.empty())
56 return true;
57
58 llvm::StringRef FName = F.getName();
59 if (FName.startswith("llvm."))
60 return true;
61
62 if (isPresent(whiteList, FName.str()))
63 return true;
64
65 return false;
66 }
67
68 public:
RSScreenFunctionsPass()69 RSScreenFunctionsPass()
70 : ModulePass (ID) {
71 std::sort(whiteList.begin(), whiteList.end());
72 }
73
getAnalysisUsage(llvm::AnalysisUsage & AU) const74 virtual void getAnalysisUsage(llvm::AnalysisUsage &AU) const override {
75 AU.setPreservesAll();
76 }
77
runOnModule(llvm::Module & M)78 bool runOnModule(llvm::Module &M) override {
79 bool failed = false;
80
81 auto &FunctionList(M.getFunctionList());
82 for(auto &F: FunctionList) {
83 if (!isLegal(F)) {
84 ALOGE("Call to function %s from RenderScript is disallowed\n",
85 F.getName().str().c_str());
86 failed = true;
87 }
88 }
89
90 if (failed) {
91 llvm::report_fatal_error("Use of undefined external function");
92 }
93
94 return false;
95 }
96
97 };
98
99 }
100
101 char RSScreenFunctionsPass::ID = 0;
102
103 namespace bcc {
104
105 llvm::ModulePass *
createRSScreenFunctionsPass()106 createRSScreenFunctionsPass() {
107 return new RSScreenFunctionsPass();
108 }
109
110 }
111