972 lines
37 KiB
C++
972 lines
37 KiB
C++
/*
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* Compile LLVM bytecode to ClamAV bytecode.
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*
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* Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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* Copyright (C) 2009-2013 Sourcefire, Inc.
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*
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* Authors: Török Edvin, Kevin Lin
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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#define DEBUG_TYPE "clambc-rtcheck"
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#include "ClamBCModule.h"
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#include "ClamBCDiagnostics.h"
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#include "llvm30_compat.h" /* libclamav-specific */
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/ADT/PostOrderIterator.h"
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#include "llvm/ADT/SCCIterator.h"
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#include "llvm/Analysis/CallGraph.h"
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#if LLVM_VERSION < 32
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#include "llvm/Analysis/DebugInfo.h"
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#elif LLVM_VERSION < 35
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#include "llvm/DebugInfo.h"
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#else
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#include "llvm/IR/DebugInfo.h"
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#endif
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#if LLVM_VERSION < 35
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Analysis/Verifier.h"
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#else
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Verifier.h"
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#endif
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#include "llvm/Analysis/ConstantFolding.h"
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#if LLVM_VERSION < 29
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//#include "llvm/Analysis/LiveValues.h" (unused)
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#include "llvm/Analysis/PointerTracking.h"
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#else
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#include "llvm/Analysis/ValueTracking.h"
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#include "PointerTracking.h" /* included from old LLVM source */
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#endif
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#include "llvm/Analysis/ScalarEvolution.h"
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#include "llvm/Analysis/ScalarEvolutionExpressions.h"
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#include "llvm/Analysis/ScalarEvolutionExpander.h"
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#include "llvm/Config/config.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/CommandLine.h"
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#if LLVM_VERSION < 35
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#include "llvm/Support/DataFlow.h"
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#include "llvm/Support/InstIterator.h"
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#include "llvm/Support/GetElementPtrTypeIterator.h"
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#else
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#include "llvm/IR/InstIterator.h"
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#include "llvm/IR/GetElementPtrTypeIterator.h"
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#endif
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Support/Debug.h"
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#if LLVM_VERSION < 32
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#include "llvm/Target/TargetData.h"
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#elif LLVM_VERSION < 33
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#include "llvm/DataLayout.h"
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#else
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#include "llvm/IR/DataLayout.h"
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#endif
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#if LLVM_VERSION < 33
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#include "llvm/DerivedTypes.h"
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#include "llvm/Instructions.h"
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#include "llvm/IntrinsicInst.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/Module.h"
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#else
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/Intrinsics.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/Module.h"
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#endif
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#if LLVM_VERSION < 33
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#include "llvm/Support/InstVisitor.h"
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#elif LLVM_VERSION < 35
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#include "llvm/InstVisitor.h"
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#else
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#include "llvm/IR/InstVisitor.h"
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#endif
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#define DEFINEPASS(passname) passname() : FunctionPass(ID)
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using namespace llvm;
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#if LLVM_VERSION < 29
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/* function is succeeded in later LLVM with LLVM corresponding standalone */
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static Value *GetUnderlyingObject(Value *P, TargetData *TD)
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{
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return P->getUnderlyingObject();
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}
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#endif
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namespace llvm {
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class PtrVerifier;
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#if LLVM_VERSION >= 29
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void initializePtrVerifierPass(PassRegistry&);
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#endif
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class PtrVerifier : public FunctionPass {
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private:
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DenseSet<Function*> badFunctions;
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std::vector<Instruction*> delInst;
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#if LLVM_VERSION < 35
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CallGraphNode *rootNode;
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#else
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CallGraph *CG;
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#endif
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public:
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static char ID;
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#if LLVM_VERSION < 35
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DEFINEPASS(PtrVerifier), rootNode(0), PT(), TD(), SE(), expander(),
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#else
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DEFINEPASS(PtrVerifier), CG(0), PT(), TD(), SE(), expander(),
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#endif
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DT(), AbrtBB(), Changed(false), valid(false), EP() {
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#if LLVM_VERSION >= 29
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initializePtrVerifierPass(*PassRegistry::getPassRegistry());
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#endif
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}
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virtual bool runOnFunction(Function &F) {
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/*
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#ifndef CLAMBC_COMPILER
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// Bytecode was already verified and had stack protector applied.
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// We get called again because ALL bytecode functions loaded are part of
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// the same module.
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if (F.hasFnAttr(Attribute::StackProtectReq))
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return false;
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#endif
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*/
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DEBUG(errs() << "Running on " << F.getName() << "\n");
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DEBUG(F.dump());
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Changed = false;
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BaseMap.clear();
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BoundsMap.clear();
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delInst.clear();
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AbrtBB = 0;
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valid = true;
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#if LLVM_VERSION < 35
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if (!rootNode) {
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rootNode = getAnalysis<CallGraph>().getRoot();
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#else
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if (!CG) {
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CG = &getAnalysis<CallGraphWrapperPass>().getCallGraph();
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#endif
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// No recursive functions for now.
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// In the future we may insert runtime checks for stack depth.
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#if LLVM_VERSION < 35
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for (scc_iterator<CallGraphNode*> SCCI = scc_begin(rootNode),
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E = scc_end(rootNode); SCCI != E; ++SCCI) {
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#else
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for (scc_iterator<CallGraph*> SCCI = scc_begin(CG); !SCCI.isAtEnd(); ++SCCI) {
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#endif
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const std::vector<CallGraphNode*> &nextSCC = *SCCI;
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if (nextSCC.size() > 1 || SCCI.hasLoop()) {
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errs() << "INVALID: Recursion detected, callgraph SCC components: ";
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for (std::vector<CallGraphNode*>::const_iterator I = nextSCC.begin(),
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E = nextSCC.end(); I != E; ++I) {
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Function *FF = (*I)->getFunction();
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if (FF) {
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errs() << FF->getName() << ", ";
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badFunctions.insert(FF);
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}
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}
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if (SCCI.hasLoop())
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errs() << "(self-loop)";
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errs() << "\n";
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}
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// we could also have recursion via function pointers, but we don't
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// allow calls to unknown functions, see runOnFunction() below
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}
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}
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BasicBlock::iterator It = F.getEntryBlock().begin();
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while (isa<AllocaInst>(It) || isa<PHINode>(It)) ++It;
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EP = &*It;
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#if LLVM_VERSION < 32
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TD = &getAnalysis<TargetData>();
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#elif LLVM_VERSION < 35
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TD = &getAnalysis<DataLayout>();
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#else
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DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
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TD = DLP ? &DLP->getDataLayout() : 0;
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#endif
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SE = &getAnalysis<ScalarEvolution>();
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PT = &getAnalysis<PointerTracking>();
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#if LLVM_VERSION < 35
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DT = &getAnalysis<DominatorTree>();
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#else
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DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
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#endif
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expander = new SCEVExpander(*SE OPT("SCEVexpander"));
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std::vector<Instruction*> insns;
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BasicBlock *LastBB = 0;
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for (inst_iterator I=inst_begin(F),E=inst_end(F); I != E;++I) {
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Instruction *II = &*I;
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/* only appears in the libclamav version */
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if (II->getParent() != LastBB) {
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LastBB = II->getParent();
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if (DT->getNode(LastBB) == 0)
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continue;
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}
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/* end-block */
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if (isa<LoadInst>(II) || isa<StoreInst>(II) || isa<MemIntrinsic>(II))
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insns.push_back(II);
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else if (CallInst *CI = dyn_cast<CallInst>(II)) {
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Value *V = CI->getCalledValue()->stripPointerCasts();
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Function *F = dyn_cast<Function>(V);
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if (!F) {
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printLocation(CI, true);
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errs() << "Could not determine call target\n";
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valid = 0;
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continue;
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}
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// this statement disable checks on user-defined CallInst
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//if (!F->isDeclaration())
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//continue;
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insns.push_back(CI);
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}
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}
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for (unsigned Idx = 0; Idx < insns.size(); ++Idx) {
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Instruction *II = insns[Idx];
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DEBUG(dbgs() << "checking " << *II << "\n");
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if (LoadInst *LI = dyn_cast<LoadInst>(II)) {
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constType *Ty = LI->getType();
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valid &= validateAccess(LI->getPointerOperand(),
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TD->getTypeAllocSize(Ty), LI);
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} else if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
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constType *Ty = SI->getOperand(0)->getType();
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valid &= validateAccess(SI->getPointerOperand(),
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TD->getTypeAllocSize(Ty), SI);
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} else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) {
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valid &= validateAccess(MI->getDest(), MI->getLength(), MI);
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if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
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valid &= validateAccess(MTI->getSource(), MI->getLength(), MI);
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}
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} else if (CallInst *CI = dyn_cast<CallInst>(II)) {
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Value *V = CI->getCalledValue()->stripPointerCasts();
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Function *F = cast<Function>(V);
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constFunctionType *FTy = F->getFunctionType();
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CallSite CS(CI);
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if (F->getName().equals("memcmp") && FTy->getNumParams() == 3) {
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valid &= validateAccess(CS.getArgument(0), CS.getArgument(2), CI);
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valid &= validateAccess(CS.getArgument(1), CS.getArgument(2), CI);
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continue;
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}
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unsigned i;
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#ifdef CLAMBC_COMPILER
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i = 0;
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#else
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i = 1;// skip hidden ctx*
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#endif
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for (;i<FTy->getNumParams();i++) {
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if (isa<PointerType>(FTy->getParamType(i))) {
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Value *Ptr = CS.getArgument(i);
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if (i+1 >= FTy->getNumParams()) {
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printLocation(CI, false);
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errs() << "Call to external function with pointer parameter last"
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" cannot be analyzed\n";
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errs() << *CI << "\n";
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valid = 0;
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break;
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}
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Value *Size = CS.getArgument(i+1);
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if (!Size->getType()->isIntegerTy()) {
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printLocation(CI, false);
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errs() << "Pointer argument must be followed by integer argument"
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" representing its size\n";
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errs() << *CI << "\n";
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valid = 0;
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break;
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}
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valid &= validateAccess(Ptr, Size, CI);
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}
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}
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}
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}
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if (badFunctions.count(&F))
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valid = 0;
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if (!valid) {
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DEBUG(F.dump());
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ClamBCModule::stop("Verification found errors!", &F);
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// replace function with call to abort
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std::vector<constType*>args;
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FunctionType* abrtTy = FunctionType::get(Type::getVoidTy(F.getContext()),args,false);
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Constant *func_abort = F.getParent()->getOrInsertFunction("abort", abrtTy);
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BasicBlock *BB = &F.getEntryBlock();
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Instruction *I = &*BB->begin();
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Instruction *UI = new UnreachableInst(F.getContext(), I);
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CallInst *AbrtC = CallInst::Create(func_abort, "", UI);
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AbrtC->setCallingConv(CallingConv::C);
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AbrtC->setTailCall(true);
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#if LLVM_VERSION < 32
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AbrtC->setDoesNotReturn(true);
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AbrtC->setDoesNotThrow(true);
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#else
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AbrtC->setDoesNotReturn();
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AbrtC->setDoesNotThrow();
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#endif
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// remove all instructions from entry
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BasicBlock::iterator BBI = I, BBE=BB->end();
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while (BBI != BBE) {
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if (!BBI->use_empty())
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BBI->replaceAllUsesWith(UndefValue::get(BBI->getType()));
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BB->getInstList().erase(BBI++);
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}
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}
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// bb#9967 - deleting obsolete termination instructions
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for (unsigned i = 0; i < delInst.size(); ++i)
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delInst[i]->eraseFromParent();
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delete expander;
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return Changed;
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}
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virtual void releaseMemory() {
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badFunctions.clear();
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}
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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#if LLVM_VERSION < 32
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AU.addRequired<TargetData>();
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#elif LLVM_VERSION < 35
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AU.addRequired<DataLayout>();
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#else
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AU.addRequired<DataLayoutPass>();
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#endif
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#if LLVM_VERSION < 35
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AU.addRequired<DominatorTree>();
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#else
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AU.addRequired<DominatorTreeWrapperPass>();
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#endif
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AU.addRequired<ScalarEvolution>();
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AU.addRequired<PointerTracking>();
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#if LLVM_VERSION < 35
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AU.addRequired<CallGraph>();
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#else
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AU.addRequired<CallGraphWrapperPass>();
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#endif
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}
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bool isValid() const { return valid; }
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private:
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PointerTracking *PT;
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#if LLVM_VERSION < 32
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TargetData *TD;
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#elif LLVM_VERSION < 35
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DataLayout *TD;
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#else
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const DataLayout *TD;
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#endif
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ScalarEvolution *SE;
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SCEVExpander *expander;
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DominatorTree *DT;
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DenseMap<Value*, Value*> BaseMap;
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DenseMap<Value*, Value*> BoundsMap;
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BasicBlock *AbrtBB;
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bool Changed;
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bool valid;
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Instruction *EP;
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Instruction *getInsertPoint(Value *V)
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{
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BasicBlock::iterator It = EP;
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if (Instruction *I = dyn_cast<Instruction>(V)) {
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It = I;
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++It;
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}
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return &*It;
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}
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Value *getPointerBase(Value *Ptr)
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{
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if (BaseMap.count(Ptr))
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return BaseMap[Ptr];
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Value *P = Ptr->stripPointerCasts();
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if (BaseMap.count(P)) {
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return BaseMap[Ptr] = BaseMap[P];
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}
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Value *P2 = GetUnderlyingObject(P, TD);
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if (P2 != P) {
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Value *V = getPointerBase(P2);
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return BaseMap[Ptr] = V;
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}
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constType *P8Ty =
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PointerType::getUnqual(Type::getInt8Ty(Ptr->getContext()));
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if (PHINode *PN = dyn_cast<PHINode>(Ptr)) {
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BasicBlock::iterator It = PN;
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++It;
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PHINode *newPN = PHINode::Create(P8Ty, HINT(PN->getNumIncomingValues()) ".verif.base", &*It);
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Changed = true;
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BaseMap[Ptr] = newPN;
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for (unsigned i=0;i<PN->getNumIncomingValues();i++) {
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Value *Inc = PN->getIncomingValue(i);
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Value *V = getPointerBase(Inc);
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newPN->addIncoming(V, PN->getIncomingBlock(i));
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}
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return newPN;
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}
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if (SelectInst *SI = dyn_cast<SelectInst>(Ptr)) {
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BasicBlock::iterator It = SI;
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++It;
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Value *TrueB = getPointerBase(SI->getTrueValue());
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Value *FalseB = getPointerBase(SI->getFalseValue());
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if (TrueB && FalseB) {
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SelectInst *NewSI = SelectInst::Create(SI->getCondition(), TrueB,
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FalseB, ".select.base", &*It);
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Changed = true;
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return BaseMap[Ptr] = NewSI;
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}
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}
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if (Ptr->getType() != P8Ty) {
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if (Constant *C = dyn_cast<Constant>(Ptr))
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Ptr = ConstantExpr::getPointerCast(C, P8Ty);
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else {
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Instruction *I = getInsertPoint(Ptr);
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Ptr = new BitCastInst(Ptr, P8Ty, "", I);
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}
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}
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return BaseMap[Ptr] = Ptr;
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}
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Value* getValAtIdx(Function *F, unsigned Idx) {
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Value *Val= NULL;
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// check if accessed Idx is within function parameter list
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if (Idx < F->arg_size()) {
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Function::arg_iterator It = F->arg_begin();
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Function::arg_iterator ItEnd = F->arg_end();
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for (unsigned i = 0; i < Idx; ++i, ++It) {
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// redundant check, should not be possible
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if (It == ItEnd) {
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// Houston, the impossible has become possible
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//printDiagnostic("Idx is outside of Function parameters", F);
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errs() << "Idx is outside of Function parameters\n";
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errs() << *F << "\n";
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//valid = 0;
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break;
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}
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}
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// retrieve value ptr of argument of F at Idx
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Val = &(*It);
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}
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else {
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// Idx is outside function parameter list
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//printDiagnostic("Idx is outside of Function parameters", F);
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errs() << "Idx is outside of Function parameters\n";
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errs() << *F << "\n";
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//valid = 0;
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}
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return Val;
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}
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Value* getPointerBounds(Value *Base) {
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if (BoundsMap.count(Base))
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return BoundsMap[Base];
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constType *I64Ty =
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Type::getInt64Ty(Base->getContext());
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|
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#ifndef CLAMBC_COMPILER
|
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// first arg is hidden ctx
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if (Argument *A = dyn_cast<Argument>(Base)) {
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if (A->getArgNo() == 0) {
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constType *Ty = cast<PointerType>(A->getType())->getElementType();
|
|
return ConstantInt::get(I64Ty, TD->getTypeAllocSize(Ty));
|
|
} else if (Base->getType()->isPointerTy()) {
|
|
Function *F = A->getParent();
|
|
const FunctionType *FT = F->getFunctionType();
|
|
|
|
bool checks = true;
|
|
// last argument check
|
|
if (A->getArgNo() == (FT->getNumParams()-1)) {
|
|
//printDiagnostic("pointer argument cannot be last argument", F);
|
|
errs() << "pointer argument cannot be last argument\n";
|
|
errs() << *F << "\n";
|
|
checks = false;
|
|
}
|
|
|
|
// argument after pointer MUST be a integer (unsigned probably too)
|
|
if (checks && !FT->getParamType(A->getArgNo()+1)->isIntegerTy()) {
|
|
//printDiagnostic("argument following pointer argument is not an integer", F);
|
|
errs() << "argument following pointer argument is not an integer\n";
|
|
errs() << *F << "\n";
|
|
checks = false;
|
|
}
|
|
|
|
if (checks)
|
|
return BoundsMap[Base] = getValAtIdx(F, A->getArgNo()+1);
|
|
}
|
|
}
|
|
if (LoadInst *LI = dyn_cast<LoadInst>(Base)) {
|
|
Value *V = GetUnderlyingObject(LI->getPointerOperand()->stripPointerCasts(), TD);
|
|
if (Argument *A = dyn_cast<Argument>(V)) {
|
|
if (A->getArgNo() == 0) {
|
|
// pointers from hidden ctx are trusted to be at least the
|
|
// size they say they are
|
|
constType *Ty = cast<PointerType>(LI->getType())->getElementType();
|
|
return ConstantInt::get(I64Ty, TD->getTypeAllocSize(Ty));
|
|
}
|
|
}
|
|
}
|
|
#else
|
|
if (Base->getType()->isPointerTy()) {
|
|
if (Argument *A = dyn_cast<Argument>(Base)) {
|
|
Function *F = A->getParent();
|
|
const FunctionType *FT = F->getFunctionType();
|
|
|
|
bool checks = true;
|
|
// last argument check
|
|
if (A->getArgNo() == (FT->getNumParams()-1)) {
|
|
//printDiagnostic("pointer argument cannot be last argument", F);
|
|
errs() << "pointer argument cannot be last argument\n";
|
|
errs() << *F << "\n";
|
|
checks = false;
|
|
}
|
|
|
|
// argument after pointer MUST be a integer (unsigned probably too)
|
|
if (checks && !FT->getParamType(A->getArgNo()+1)->isIntegerTy()) {
|
|
//printDiagnostic("argument following pointer argument is not an integer", F);
|
|
errs() << "argument following pointer argument is not an integer\n";
|
|
errs() << *F << "\n";
|
|
checks = false;
|
|
}
|
|
|
|
if (checks)
|
|
return BoundsMap[Base] = getValAtIdx(F, A->getArgNo()+1);
|
|
}
|
|
}
|
|
#endif
|
|
if (PHINode *PN = dyn_cast<PHINode>(Base)) {
|
|
BasicBlock::iterator It = PN;
|
|
++It;
|
|
PHINode *newPN = PHINode::Create(I64Ty, HINT(PN->getNumIncomingValues()) ".verif.bounds", &*It);
|
|
Changed = true;
|
|
BoundsMap[Base] = newPN;
|
|
|
|
bool good = true;
|
|
for (unsigned i=0;i<PN->getNumIncomingValues();i++) {
|
|
Value *Inc = PN->getIncomingValue(i);
|
|
Value *B = getPointerBounds(Inc);
|
|
if (!B) {
|
|
good = false;
|
|
B = ConstantInt::get(newPN->getType(), 0);
|
|
DEBUG(dbgs() << "bounds not found while solving phi node: " << *Inc
|
|
<< "\n");
|
|
}
|
|
newPN->addIncoming(B, PN->getIncomingBlock(i));
|
|
}
|
|
if (!good)
|
|
newPN = 0;
|
|
return BoundsMap[Base] = newPN;
|
|
}
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Base)) {
|
|
BasicBlock::iterator It = SI;
|
|
++It;
|
|
Value *TrueB = getPointerBounds(SI->getTrueValue());
|
|
Value *FalseB = getPointerBounds(SI->getFalseValue());
|
|
if (TrueB && FalseB) {
|
|
SelectInst *NewSI = SelectInst::Create(SI->getCondition(), TrueB,
|
|
FalseB, ".select.bounds", &*It);
|
|
Changed = true;
|
|
return BoundsMap[Base] = NewSI;
|
|
}
|
|
}
|
|
|
|
constType *Ty;
|
|
Value *V = PT->computeAllocationCountValue(Base, Ty);
|
|
if (!V) {
|
|
Base = Base->stripPointerCasts();
|
|
if (CallInst *CI = dyn_cast<CallInst>(Base)) {
|
|
Function *F = CI->getCalledFunction();
|
|
constFunctionType *FTy = F->getFunctionType();
|
|
// last operand is always size for this API call kind
|
|
if (F->isDeclaration() && FTy->getNumParams() > 0) {
|
|
CallSite CS(CI);
|
|
if (FTy->getParamType(FTy->getNumParams()-1)->isIntegerTy())
|
|
V = CS.getArgument(FTy->getNumParams()-1);
|
|
}
|
|
}
|
|
if (!V)
|
|
return BoundsMap[Base] = 0;
|
|
} else {
|
|
unsigned size = TD->getTypeAllocSize(Ty);
|
|
if (size > 1) {
|
|
Constant *C = cast<Constant>(V);
|
|
C = ConstantExpr::getMul(C,
|
|
ConstantInt::get(Type::getInt32Ty(C->getContext()),
|
|
size));
|
|
V = C;
|
|
}
|
|
}
|
|
if (V->getType() != I64Ty) {
|
|
if (Constant *C = dyn_cast<Constant>(V))
|
|
V = ConstantExpr::getZExt(C, I64Ty);
|
|
else {
|
|
Instruction *I = getInsertPoint(V);
|
|
V = new ZExtInst(V, I64Ty, "", I);
|
|
}
|
|
}
|
|
return BoundsMap[Base] = V;
|
|
}
|
|
|
|
MDNode *getLocation(Instruction *I, bool &Approximate, unsigned MDDbgKind)
|
|
{
|
|
Approximate = false;
|
|
if (MDNode *Dbg = I->getMetadata(MDDbgKind))
|
|
return Dbg;
|
|
if (!MDDbgKind)
|
|
return 0;
|
|
Approximate = true;
|
|
BasicBlock::iterator It = I;
|
|
while (It != I->getParent()->begin()) {
|
|
--It;
|
|
if (MDNode *Dbg = It->getMetadata(MDDbgKind))
|
|
return Dbg;
|
|
}
|
|
BasicBlock *BB = I->getParent();
|
|
while ((BB = BB->getUniquePredecessor())) {
|
|
It = BB->end();
|
|
while (It != BB->begin()) {
|
|
--It;
|
|
if (MDNode *Dbg = It->getMetadata(MDDbgKind))
|
|
return Dbg;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
bool insertCheck(const SCEV *Idx, const SCEV *Limit, Instruction *I,
|
|
bool strict)
|
|
{
|
|
if (isa<SCEVCouldNotCompute>(Idx) && isa<SCEVCouldNotCompute>(Limit)) {
|
|
errs() << "Could not compute the index and the limit!: \n" << *I << "\n";
|
|
return false;
|
|
}
|
|
if (isa<SCEVCouldNotCompute>(Idx)) {
|
|
errs() << "Could not compute index: \n" << *I << "\n";
|
|
return false;
|
|
}
|
|
if (isa<SCEVCouldNotCompute>(Limit)) {
|
|
errs() << "Could not compute limit: " << *I << "\n";
|
|
return false;
|
|
}
|
|
BasicBlock *BB = I->getParent();
|
|
BasicBlock::iterator It = I;
|
|
BasicBlock *newBB = SplitBlock(BB, &*It, this);
|
|
PHINode *PN;
|
|
unsigned MDDbgKind = I->getContext().getMDKindID("dbg");
|
|
//verifyFunction(*BB->getParent());
|
|
if (!AbrtBB) {
|
|
std::vector<constType*>args;
|
|
FunctionType* abrtTy = FunctionType::get(Type::getVoidTy(BB->getContext()),args,false);
|
|
args.push_back(Type::getInt32Ty(BB->getContext()));
|
|
FunctionType* rterrTy = FunctionType::get(Type::getInt32Ty(BB->getContext()),args,false);
|
|
Constant *func_abort = BB->getParent()->getParent()->getOrInsertFunction("abort", abrtTy);
|
|
Constant *func_rterr = BB->getParent()->getParent()->getOrInsertFunction("bytecode_rt_error",
|
|
rterrTy);
|
|
AbrtBB = BasicBlock::Create(BB->getContext(), "rterr.trig", BB->getParent());
|
|
|
|
PN = PHINode::Create(Type::getInt32Ty(BB->getContext()),HINT(1) "",
|
|
AbrtBB);
|
|
if (MDDbgKind) {
|
|
CallInst *RtErrCall = CallInst::Create(func_rterr, PN, "", AbrtBB);
|
|
RtErrCall->setCallingConv(CallingConv::C);
|
|
RtErrCall->setTailCall(true);
|
|
#if LLVM_VERSION < 32
|
|
RtErrCall->setDoesNotThrow(true);
|
|
#else
|
|
RtErrCall->setDoesNotThrow();
|
|
#endif
|
|
}
|
|
CallInst* AbrtC = CallInst::Create(func_abort, "", AbrtBB);
|
|
AbrtC->setCallingConv(CallingConv::C);
|
|
AbrtC->setTailCall(true);
|
|
#if LLVM_VERSION < 32
|
|
AbrtC->setDoesNotReturn(true);
|
|
AbrtC->setDoesNotThrow(true);
|
|
#else
|
|
AbrtC->setDoesNotReturn();
|
|
AbrtC->setDoesNotThrow();
|
|
#endif
|
|
new UnreachableInst(BB->getContext(), AbrtBB);
|
|
DT->addNewBlock(AbrtBB, BB);
|
|
//verifyFunction(*BB->getParent());
|
|
} else {
|
|
PN = cast<PHINode>(AbrtBB->begin());
|
|
}
|
|
unsigned locationid = 0;
|
|
bool Approximate;
|
|
if (MDNode *Dbg = getLocation(I, Approximate, MDDbgKind)) {
|
|
DILocation Loc(Dbg);
|
|
locationid = Loc.getLineNumber() << 8;
|
|
unsigned col = Loc.getColumnNumber();
|
|
if (col > 254)
|
|
col = 254;
|
|
if (Approximate)
|
|
col = 255;
|
|
locationid |= col;
|
|
}
|
|
PN->addIncoming(ConstantInt::get(Type::getInt32Ty(BB->getContext()),
|
|
locationid), BB);
|
|
TerminatorInst *TI = BB->getTerminator();
|
|
Value *IdxV = expander->expandCodeFor(Idx, Limit->getType(), TI);
|
|
Value *LimitV = expander->expandCodeFor(Limit, Limit->getType(), TI);
|
|
if (isa<Instruction>(IdxV) &&
|
|
!DT->dominates(cast<Instruction>(IdxV)->getParent(),I->getParent())) {
|
|
printLocation(I, true);
|
|
errs() << "basic block with value [ " << IdxV->getName();
|
|
errs() << " ] with limit [ " << LimitV->getName();
|
|
errs() << " ] does not dominate" << *I << "\n";
|
|
return false;
|
|
}
|
|
if (isa<Instruction>(LimitV) &&
|
|
!DT->dominates(cast<Instruction>(LimitV)->getParent(),I->getParent())) {
|
|
printLocation(I, true);
|
|
errs() << "basic block with limit [" << LimitV->getName();
|
|
errs() << " ] on value [ " << IdxV->getName();
|
|
errs() << " ] does not dominate" << *I << "\n";
|
|
return false;
|
|
}
|
|
Value *Cond = new ICmpInst(TI, strict ?
|
|
ICmpInst::ICMP_ULT :
|
|
ICmpInst::ICMP_ULE, IdxV, LimitV);
|
|
BranchInst::Create(newBB, AbrtBB, Cond, TI);
|
|
//TI->eraseFromParent();
|
|
delInst.push_back(TI);
|
|
// Update dominator info
|
|
BasicBlock *DomBB =
|
|
DT->findNearestCommonDominator(BB, DT->getNode(AbrtBB)->getIDom()->getBlock());
|
|
DT->changeImmediateDominator(AbrtBB, DomBB);
|
|
return true;
|
|
}
|
|
|
|
static void MakeCompatible(ScalarEvolution *SE, const SCEV*& LHS, const SCEV*& RHS)
|
|
{
|
|
if (const SCEVZeroExtendExpr *ZL = dyn_cast<SCEVZeroExtendExpr>(LHS))
|
|
LHS = ZL->getOperand();
|
|
if (const SCEVZeroExtendExpr *ZR = dyn_cast<SCEVZeroExtendExpr>(RHS))
|
|
RHS = ZR->getOperand();
|
|
|
|
constType* LTy = SE->getEffectiveSCEVType(LHS->getType());
|
|
constType *RTy = SE->getEffectiveSCEVType(RHS->getType());
|
|
if (SE->getTypeSizeInBits(RTy) > SE->getTypeSizeInBits(LTy))
|
|
LTy = RTy;
|
|
LHS = SE->getNoopOrZeroExtend(LHS, LTy);
|
|
RHS = SE->getNoopOrZeroExtend(RHS, LTy);
|
|
}
|
|
|
|
bool checkCond(Instruction *ICI, Instruction *I, bool equal)
|
|
{
|
|
#if LLVM_VERSION < 35
|
|
for (Value::use_iterator JU=ICI->use_begin(),JUE=ICI->use_end();
|
|
JU != JUE; ++JU) {
|
|
#else
|
|
for (Value::user_iterator JU=ICI->user_begin(),JUE=ICI->user_end();
|
|
JU != JUE; ++JU) {
|
|
#endif
|
|
Value *JU_V = *JU;
|
|
if (BranchInst *BI = dyn_cast<BranchInst>(JU_V)) {
|
|
if (!BI->isConditional())
|
|
continue;
|
|
BasicBlock *S = BI->getSuccessor(equal);
|
|
if (DT->dominates(S, I->getParent()))
|
|
return true;
|
|
}
|
|
if (BinaryOperator *BI = dyn_cast<BinaryOperator>(JU_V)) {
|
|
if (BI->getOpcode() == Instruction::Or &&
|
|
checkCond(BI, I, equal))
|
|
return true;
|
|
if (BI->getOpcode() == Instruction::And &&
|
|
checkCond(BI, I, !equal))
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool checkCondition(Instruction *CI, Instruction *I)
|
|
{
|
|
#if LLVM_VERSION < 35
|
|
for (Value::use_iterator U=CI->use_begin(),UE=CI->use_end();
|
|
U != UE; ++U) {
|
|
#else
|
|
for (Value::user_iterator U=CI->user_begin(),UE=CI->user_end();
|
|
U != UE; ++U) {
|
|
#endif
|
|
Value *U_V = *U;
|
|
if (ICmpInst *ICI = dyn_cast<ICmpInst>(U_V)) {
|
|
if (ICI->getOperand(0)->stripPointerCasts() == CI &&
|
|
isa<ConstantPointerNull>(ICI->getOperand(1))) {
|
|
if (checkCond(ICI, I, ICI->getPredicate() == ICmpInst::ICMP_EQ))
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool validateAccess(Value *Pointer, Value *Length, Instruction *I)
|
|
{
|
|
// get base
|
|
Value *Base = getPointerBase(Pointer);
|
|
|
|
Value *SBase = Base->stripPointerCasts();
|
|
// get bounds
|
|
Value *Bounds = getPointerBounds(SBase);
|
|
if (!Bounds) {
|
|
printLocation(I, true);
|
|
errs() << "no bounds for base ";
|
|
printValue(SBase);
|
|
errs() << " while checking access to ";
|
|
printValue(Pointer);
|
|
errs() << " of length ";
|
|
printValue(Length);
|
|
errs() << "\n";
|
|
|
|
return false;
|
|
}
|
|
|
|
// checks if a NULL pointer check (returned from function) is made:
|
|
if (CallInst *CI = dyn_cast<CallInst>(Base->stripPointerCasts())) {
|
|
// by checking if use is in the same block (i.e. no branching decisions)
|
|
if (I->getParent() == CI->getParent()) {
|
|
printLocation(I, true);
|
|
errs() << "no null pointer check of pointer ";
|
|
printValue(Base, false, true);
|
|
errs() << " obtained by function call";
|
|
errs() << " before use in same block\n";
|
|
return false;
|
|
}
|
|
// by checking if a conditional contains the values in question somewhere
|
|
// between their usage
|
|
if (!checkCondition(CI, I)) {
|
|
printLocation(I, true);
|
|
errs() << "no null pointer check of pointer ";
|
|
printValue(Base, false, true);
|
|
errs() << " obtained by function call";
|
|
errs() << " before use\n";
|
|
return false;
|
|
}
|
|
}
|
|
|
|
constType *I64Ty =
|
|
Type::getInt64Ty(Base->getContext());
|
|
const SCEV *SLen = SE->getSCEV(Length);
|
|
const SCEV *OffsetP = SE->getMinusSCEV(SE->getSCEV(Pointer),
|
|
SE->getSCEV(Base));
|
|
SLen = SE->getNoopOrZeroExtend(SLen, I64Ty);
|
|
OffsetP = SE->getNoopOrZeroExtend(OffsetP, I64Ty);
|
|
const SCEV *Limit = SE->getSCEV(Bounds);
|
|
Limit = SE->getNoopOrZeroExtend(Limit, I64Ty);
|
|
|
|
DEBUG(dbgs() << "Checking access to " << *Pointer << " of length " <<
|
|
*Length << "\n");
|
|
if (OffsetP == Limit) {
|
|
printLocation(I, true);
|
|
errs() << "OffsetP == Limit: " << *OffsetP << "\n";
|
|
errs() << " while checking access to ";
|
|
printValue(Pointer);
|
|
errs() << " of length ";
|
|
printValue(Length);
|
|
errs() << "\n";
|
|
return false;
|
|
}
|
|
|
|
if (SLen == Limit) {
|
|
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(OffsetP)) {
|
|
if (SC->isZero())
|
|
return true;
|
|
}
|
|
errs() << "SLen == Limit: " << *SLen << "\n";
|
|
errs() << " while checking access to " << *Pointer << " of length "
|
|
<< *Length << " at " << *I << "\n";
|
|
return false;
|
|
}
|
|
|
|
bool valid = true;
|
|
SLen = SE->getAddExpr(OffsetP, SLen);
|
|
// check that offset + slen <= limit;
|
|
// umax(offset+slen, limit) == limit is a sufficient (but not necessary
|
|
// condition)
|
|
const SCEV *MaxL = SE->getUMaxExpr(SLen, Limit);
|
|
if (MaxL != Limit) {
|
|
DEBUG(dbgs() << "MaxL != Limit: " << *MaxL << ", " << *Limit << "\n");
|
|
valid &= insertCheck(SLen, Limit, I, false);
|
|
}
|
|
|
|
//TODO: nullpointer check
|
|
const SCEV *Max = SE->getUMaxExpr(OffsetP, Limit);
|
|
if (Max == Limit)
|
|
return valid;
|
|
DEBUG(dbgs() << "Max != Limit: " << *Max << ", " << *Limit << "\n");
|
|
|
|
// check that offset < limit
|
|
valid &= insertCheck(OffsetP, Limit, I, true);
|
|
return valid;
|
|
}
|
|
|
|
bool validateAccess(Value *Pointer, unsigned size, Instruction *I)
|
|
{
|
|
return validateAccess(Pointer,
|
|
ConstantInt::get(Type::getInt32Ty(Pointer->getContext()),
|
|
size), I);
|
|
}
|
|
|
|
};
|
|
char PtrVerifier::ID;
|
|
|
|
} /* end namespace llvm */
|
|
#if LLVM_VERSION >= 29
|
|
INITIALIZE_PASS_BEGIN(PtrVerifier, "", "", false, false)
|
|
#if LLVM_VERSION < 32
|
|
INITIALIZE_PASS_DEPENDENCY(TargetData)
|
|
#elif LLVM_VERSION < 35
|
|
INITIALIZE_PASS_DEPENDENCY(DataLayout)
|
|
#else
|
|
INITIALIZE_PASS_DEPENDENCY(DataLayoutPass)
|
|
#endif
|
|
#if LLVM_VERSION < 35
|
|
INITIALIZE_PASS_DEPENDENCY(DominatorTree)
|
|
#else
|
|
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
|
|
#endif
|
|
INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
|
|
#if LLVM_VERSION < 34
|
|
INITIALIZE_AG_DEPENDENCY(CallGraph)
|
|
#elif LLVM_VERSION < 35
|
|
INITIALIZE_PASS_DEPENDENCY(CallGraph)
|
|
#else
|
|
INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
|
|
#endif
|
|
INITIALIZE_PASS_DEPENDENCY(PointerTracking)
|
|
INITIALIZE_PASS_END(PtrVerifier, "clambc-rtchecks", "ClamBC RTchecks", false, false)
|
|
#endif
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llvm::Pass *createClamBCRTChecks()
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{
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return new PtrVerifier();
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}
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