From 8dbbf3578a9a5d063232b59e558e5fe46e2cd42c Mon Sep 17 00:00:00 2001 From: Naomi Musgrave Date: Wed, 12 Aug 2015 21:37:40 +0000 Subject: [PATCH] Implement poisoning of only class members in dtor, as opposed to also poisoning fields inherited from base classes. Verify emitted code for derived class with virtual destructor sanitizes its members only once. Changed emission order for dtor callback, so only the last dtor for a class emits the sanitizing callback, while ensuring that class members are poisoned before base class destructors are invoked. Skip poisoning of members, if class has no fields. Removed patch file containing extraneous changes. Summary: Poisoning applied to only class members, and before dtors for base class invoked Reviewers: eugenis, kcc Differential Revision: http://reviews.llvm.org/D11951 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@244819 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/CGClass.cpp | 39 +++++++++--- test/CodeGenCXX/sanitize-dtor-callback.cpp | 9 ++- .../sanitize-dtor-derived-class.cpp | 62 +++++++++++++++++++ .../CodeGenCXX/sanitize-dtor-fn-attribute.cpp | 9 ++- 4 files changed, 107 insertions(+), 12 deletions(-) create mode 100644 test/CodeGenCXX/sanitize-dtor-derived-class.cpp diff --git a/lib/CodeGen/CGClass.cpp b/lib/CodeGen/CGClass.cpp index 740cd4ab4e..fea72f6818 100644 --- a/lib/CodeGen/CGClass.cpp +++ b/lib/CodeGen/CGClass.cpp @@ -1376,9 +1376,30 @@ static void EmitDtorSanitizerCallback(CodeGenFunction &CGF, const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Dtor->getParent()); + // Nothing to poison + if(Layout.getFieldCount() == 0) + return; + + // Construct pointer to region to begin poisoning, and calculate poison + // size, so that only members declared in this class are poisoned. + llvm::Value *OffsetPtr; + CharUnits::QuantityType PoisonSize; + ASTContext &Context = CGF.getContext(); + + llvm::ConstantInt *OffsetSizePtr = llvm::ConstantInt::get( + CGF.SizeTy, Context.toCharUnitsFromBits(Layout.getFieldOffset(0)). + getQuantity()); + + OffsetPtr = CGF.Builder.CreateGEP(CGF.Builder.CreateBitCast( + CGF.LoadCXXThis(), CGF.Int8PtrTy), OffsetSizePtr); + + PoisonSize = Layout.getSize().getQuantity() - + Context.toCharUnitsFromBits(Layout.getFieldOffset(0)).getQuantity(); + llvm::Value *Args[] = { - CGF.Builder.CreateBitCast(CGF.LoadCXXThis(), CGF.VoidPtrTy), - llvm::ConstantInt::get(CGF.SizeTy, Layout.getSize().getQuantity())}; + CGF.Builder.CreateBitCast(OffsetPtr, CGF.VoidPtrTy), + llvm::ConstantInt::get(CGF.SizeTy, PoisonSize)}; + llvm::Type *ArgTypes[] = {CGF.VoidPtrTy, CGF.SizeTy}; llvm::FunctionType *FnType = @@ -1386,6 +1407,8 @@ static void EmitDtorSanitizerCallback(CodeGenFunction &CGF, llvm::Value *Fn = CGF.CGM.CreateRuntimeFunction(FnType, "__sanitizer_dtor_callback"); + // Disables tail call elimination, to prevent the current stack frame from + // disappearing from the stack trace. CGF.CurFn->addFnAttr("disable-tail-calls", "true"); CGF.EmitNounwindRuntimeCall(Fn, Args); } @@ -1468,6 +1491,13 @@ void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) { // the caller's body. if (getLangOpts().AppleKext) CurFn->addFnAttr(llvm::Attribute::AlwaysInline); + + // Insert memory-poisoning instrumentation, before final clean ups, + // to ensure this class's members are protected from invalid access. + if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor + && SanOpts.has(SanitizerKind::Memory)) + EmitDtorSanitizerCallback(*this, Dtor); + break; } @@ -1477,11 +1507,6 @@ void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) { // Exit the try if applicable. if (isTryBody) ExitCXXTryStmt(*cast(Body), true); - - // Insert memory-poisoning instrumentation. - if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor - && SanOpts.has(SanitizerKind::Memory)) - EmitDtorSanitizerCallback(*this, Dtor); } void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) { diff --git a/test/CodeGenCXX/sanitize-dtor-callback.cpp b/test/CodeGenCXX/sanitize-dtor-callback.cpp index a3ecbcbdd8..078efe88ca 100644 --- a/test/CodeGenCXX/sanitize-dtor-callback.cpp +++ b/test/CodeGenCXX/sanitize-dtor-callback.cpp @@ -7,7 +7,8 @@ struct Simple { Simple s; // Simple internal member is poisoned by compiler-generated dtor // CHECK-LABEL: define {{.*}}SimpleD1Ev -// CHECK: call void @__sanitizer_dtor_callback +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: call void {{.*}}SimpleD2Ev // CHECK-NOT: call void @__sanitizer_dtor_callback // CHECK: ret void @@ -17,7 +18,8 @@ struct Inlined { Inlined i; // Simple internal member is poisoned by compiler-generated dtor // CHECK-LABEL: define {{.*}}InlinedD1Ev -// CHECK: call void @__sanitizer_dtor_callback +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: call void {{.*}}InlinedD2Ev // CHECK-NOT: call void @__sanitizer_dtor_callback // CHECK: ret void @@ -44,7 +46,8 @@ Defaulted_Non_Trivial def_non_trivial; // By including a Simple member in the struct, the compiler is // forced to generate a non-trivial destructor. // CHECK-LABEL: define {{.*}}Defaulted_Non_TrivialD1Ev -// CHECK: call void @__sanitizer_dtor_callback +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: call void {{.*}}Defaulted_Non_TrivialD2 // CHECK-NOT: call void @__sanitizer_dtor_callback // CHECK: ret void diff --git a/test/CodeGenCXX/sanitize-dtor-derived-class.cpp b/test/CodeGenCXX/sanitize-dtor-derived-class.cpp new file mode 100644 index 0000000000..2084d530bc --- /dev/null +++ b/test/CodeGenCXX/sanitize-dtor-derived-class.cpp @@ -0,0 +1,62 @@ +// RUN: %clang_cc1 -fsanitize=memory -fsanitize-memory-use-after-dtor -disable-llvm-optzns -std=c++11 -triple=x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s +// RUN: %clang_cc1 -O1 -fsanitize=memory -fsanitize-memory-use-after-dtor -disable-llvm-optzns -std=c++11 -triple=x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s + +class Base { + public: + int x; + Base() { + x = 5; + } + virtual ~Base() { + x += 1; + } +}; + +class Derived : public Base { + public: + int y; + Derived() { + y = 10; + } + ~Derived() { + y += 1; + } +}; + +Derived d; + +// CHECK-LABEL: define {{.*}}DerivedD1Ev +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: call void {{.*}}DerivedD2Ev +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: ret void + +// CHECK-LABEL: define {{.*}}DerivedD0Ev +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: call void {{.*}}DerivedD1Ev +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: ret void + +// CHECK-LABEL: define {{.*}}BaseD1Ev +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: call void {{.*}}BaseD2Ev +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: ret void + +// CHECK-LABEL: define {{.*}}BaseD0Ev +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: call void {{.*}}BaseD1Ev +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: ret void + +// CHECK-LABEL: define {{.*}}BaseD2Ev +// CHECK: call void @__sanitizer_dtor_callback +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: ret void + +// CHECK-LABEL: define {{.*}}DerivedD2Ev +// CHECK: call void @__sanitizer_dtor_callback +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: call void {{.*}}BaseD2Ev +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: ret void diff --git a/test/CodeGenCXX/sanitize-dtor-fn-attribute.cpp b/test/CodeGenCXX/sanitize-dtor-fn-attribute.cpp index 8a9e477cf1..8d190e09f3 100644 --- a/test/CodeGenCXX/sanitize-dtor-fn-attribute.cpp +++ b/test/CodeGenCXX/sanitize-dtor-fn-attribute.cpp @@ -26,22 +26,27 @@ int main() { // Repressing the sanitization attribute results in no msan // instrumentation of the destructor // CHECK: define {{.*}}No_SanD1Ev{{.*}} [[ATTRIBUTE:#[0-9]+]] +// CHECK-NOT: call void @__sanitizer_dtor_callback // CHECK: call void {{.*}}No_SanD2Ev -// CHECK: call void @__sanitizer_dtor_callback +// CHECK-NOT: call void @__sanitizer_dtor_callback // CHECK: ret void // CHECK-ATTR: define {{.*}}No_SanD1Ev{{.*}} [[ATTRIBUTE:#[0-9]+]] +// CHECK-ATTR-NOT: call void @__sanitizer_dtor_callback // CHECK-ATTR: call void {{.*}}No_SanD2Ev // CHECK-ATTR-NOT: call void @__sanitizer_dtor_callback // CHECK-ATTR: ret void // CHECK: define {{.*}}No_SanD2Ev{{.*}} [[ATTRIBUTE:#[0-9]+]] -// CHECK: call void {{.*}}Vector // CHECK: call void @__sanitizer_dtor_callback +// CHECK-NOT: call void @__sanitizer_dtor_callback +// CHECK: call void {{.*}}Vector +// CHECK-NOT: call void @__sanitizer_dtor_callback // CHECK: ret void // CHECK-ATTR: define {{.*}}No_SanD2Ev{{.*}} [[ATTRIBUTE:#[0-9]+]] +// CHECK-ATTR-NOT: call void @__sanitizer_dtor_callback // CHECK-ATTR: call void {{.*}}Vector // CHECK-ATTR-NOT: call void @__sanitizer_dtor_callback // CHECK-ATTR: ret void -- 2.40.0