Author: Ahmed Bougacha Date: 2024-06-21T10:20:15-07:00 New Revision: e23250ecb7e09170e584db60375100790f39fac9
URL: https://github.com/llvm/llvm-project/commit/e23250ecb7e09170e584db60375100790f39fac9 DIFF: https://github.com/llvm/llvm-project/commit/e23250ecb7e09170e584db60375100790f39fac9.diff LOG: [clang] Implement function pointer signing and authenticated function calls (#93906) The functions are currently always signed/authenticated with zero discriminator. Co-Authored-By: John McCall <rjmcc...@apple.com> Added: clang/lib/CodeGen/CGPointerAuthInfo.h clang/test/CodeGen/ptrauth-function-attributes.c clang/test/CodeGen/ptrauth-function-init-fail.c clang/test/CodeGen/ptrauth-function-init.c clang/test/CodeGen/ptrauth-function-lvalue-cast.c clang/test/CodeGen/ptrauth-function.c clang/test/CodeGen/ptrauth-weak_import.c clang/test/CodeGenCXX/ptrauth.cpp Modified: clang/include/clang/Basic/CodeGenOptions.h clang/include/clang/Basic/PointerAuthOptions.h clang/include/clang/Frontend/CompilerInvocation.h clang/lib/CodeGen/CGBuiltin.cpp clang/lib/CodeGen/CGCall.cpp clang/lib/CodeGen/CGCall.h clang/lib/CodeGen/CGExpr.cpp clang/lib/CodeGen/CGExprConstant.cpp clang/lib/CodeGen/CGPointerAuth.cpp clang/lib/CodeGen/CodeGenFunction.cpp clang/lib/CodeGen/CodeGenFunction.h clang/lib/CodeGen/CodeGenModule.h clang/lib/Frontend/CompilerInvocation.cpp clang/lib/Headers/ptrauth.h Removed: ################################################################################ diff --git a/clang/include/clang/Basic/CodeGenOptions.h b/clang/include/clang/Basic/CodeGenOptions.h index 00523a84d3895..f2a707a8ba8d7 100644 --- a/clang/include/clang/Basic/CodeGenOptions.h +++ b/clang/include/clang/Basic/CodeGenOptions.h @@ -13,6 +13,7 @@ #ifndef LLVM_CLANG_BASIC_CODEGENOPTIONS_H #define LLVM_CLANG_BASIC_CODEGENOPTIONS_H +#include "clang/Basic/PointerAuthOptions.h" #include "clang/Basic/Sanitizers.h" #include "clang/Basic/XRayInstr.h" #include "llvm/ADT/FloatingPointMode.h" @@ -391,6 +392,9 @@ class CodeGenOptions : public CodeGenOptionsBase { std::vector<std::string> Reciprocals; + /// Configuration for pointer-signing. + PointerAuthOptions PointerAuth; + /// The preferred width for auto-vectorization transforms. This is intended to /// override default transforms based on the width of the architected vector /// registers. diff --git a/clang/include/clang/Basic/PointerAuthOptions.h b/clang/include/clang/Basic/PointerAuthOptions.h index e5cdcc31ebfb7..aaad4a2b2b5ae 100644 --- a/clang/include/clang/Basic/PointerAuthOptions.h +++ b/clang/include/clang/Basic/PointerAuthOptions.h @@ -14,10 +14,144 @@ #ifndef LLVM_CLANG_BASIC_POINTERAUTHOPTIONS_H #define LLVM_CLANG_BASIC_POINTERAUTHOPTIONS_H +#include "clang/Basic/LLVM.h" +#include "clang/Basic/LangOptions.h" +#include "llvm/ADT/STLForwardCompat.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Target/TargetOptions.h" +#include <optional> + namespace clang { constexpr unsigned PointerAuthKeyNone = -1; +class PointerAuthSchema { +public: + enum class Kind : unsigned { + None, + ARM8_3, + }; + + /// Hardware pointer-signing keys in ARM8.3. + /// + /// These values are the same used in ptrauth.h. + enum class ARM8_3Key : unsigned { + ASIA = 0, + ASIB = 1, + ASDA = 2, + ASDB = 3 + }; + + /// Forms of extra discrimination. + enum class Discrimination : unsigned { + /// No additional discrimination. + None, + + /// Discriminate using a constant value. + Constant, + }; + +private: + Kind TheKind : 2; + unsigned IsAddressDiscriminated : 1; + unsigned IsIsaPointer : 1; + unsigned AuthenticatesNullValues : 1; + PointerAuthenticationMode SelectedAuthenticationMode : 2; + Discrimination DiscriminationKind : 2; + unsigned Key : 2; + unsigned ConstantDiscriminator : 16; + +public: + PointerAuthSchema() : TheKind(Kind::None) {} + + PointerAuthSchema( + ARM8_3Key Key, bool IsAddressDiscriminated, + PointerAuthenticationMode AuthenticationMode, + Discrimination OtherDiscrimination, + std::optional<uint16_t> ConstantDiscriminatorOrNone = std::nullopt, + bool IsIsaPointer = false, bool AuthenticatesNullValues = false) + : TheKind(Kind::ARM8_3), IsAddressDiscriminated(IsAddressDiscriminated), + IsIsaPointer(IsIsaPointer), + AuthenticatesNullValues(AuthenticatesNullValues), + SelectedAuthenticationMode(AuthenticationMode), + DiscriminationKind(OtherDiscrimination), Key(llvm::to_underlying(Key)) { + assert((getOtherDiscrimination() != Discrimination::Constant || + ConstantDiscriminatorOrNone) && + "constant discrimination requires a constant!"); + if (ConstantDiscriminatorOrNone) + ConstantDiscriminator = *ConstantDiscriminatorOrNone; + } + + PointerAuthSchema( + ARM8_3Key Key, bool IsAddressDiscriminated, + Discrimination OtherDiscrimination, + std::optional<uint16_t> ConstantDiscriminatorOrNone = std::nullopt, + bool IsIsaPointer = false, bool AuthenticatesNullValues = false) + : PointerAuthSchema(Key, IsAddressDiscriminated, + PointerAuthenticationMode::SignAndAuth, + OtherDiscrimination, ConstantDiscriminatorOrNone, + IsIsaPointer, AuthenticatesNullValues) {} + + Kind getKind() const { return TheKind; } + + explicit operator bool() const { return isEnabled(); } + + bool isEnabled() const { return getKind() != Kind::None; } + + bool isAddressDiscriminated() const { + assert(getKind() != Kind::None); + return IsAddressDiscriminated; + } + + bool isIsaPointer() const { + assert(getKind() != Kind::None); + return IsIsaPointer; + } + + bool authenticatesNullValues() const { + assert(getKind() != Kind::None); + return AuthenticatesNullValues; + } + + bool hasOtherDiscrimination() const { + return getOtherDiscrimination() != Discrimination::None; + } + + Discrimination getOtherDiscrimination() const { + assert(getKind() != Kind::None); + return DiscriminationKind; + } + + uint16_t getConstantDiscrimination() const { + assert(getOtherDiscrimination() == Discrimination::Constant); + return ConstantDiscriminator; + } + + unsigned getKey() const { + switch (getKind()) { + case Kind::None: + llvm_unreachable("calling getKey() on disabled schema"); + case Kind::ARM8_3: + return llvm::to_underlying(getARM8_3Key()); + } + llvm_unreachable("bad key kind"); + } + + PointerAuthenticationMode getAuthenticationMode() const { + return SelectedAuthenticationMode; + } + + ARM8_3Key getARM8_3Key() const { + assert(getKind() == Kind::ARM8_3); + return ARM8_3Key(Key); + } +}; + +struct PointerAuthOptions { + /// The ABI for C function pointers. + PointerAuthSchema FunctionPointers; +}; + } // end namespace clang #endif diff --git a/clang/include/clang/Frontend/CompilerInvocation.h b/clang/include/clang/Frontend/CompilerInvocation.h index 1a2a39411e58d..9daa0a1ecf948 100644 --- a/clang/include/clang/Frontend/CompilerInvocation.h +++ b/clang/include/clang/Frontend/CompilerInvocation.h @@ -305,6 +305,15 @@ class CompilerInvocation : public CompilerInvocationBase { /// executable), for finding the builtin compiler path. static std::string GetResourcesPath(const char *Argv0, void *MainAddr); + /// Populate \p Opts with the default set of pointer authentication-related + /// options given \p LangOpts and \p Triple. + /// + /// Note: This is intended to be used by tools which must be aware of + /// pointer authentication-related code generation, e.g. lldb. + static void setDefaultPointerAuthOptions(PointerAuthOptions &Opts, + const LangOptions &LangOpts, + const llvm::Triple &Triple); + /// Retrieve a module hash string that is suitable for uniquely /// identifying the conditions under which the module was built. std::string getModuleHash() const; diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp index 2516ed4508242..d11e7a95d833d 100644 --- a/clang/lib/CodeGen/CGBuiltin.cpp +++ b/clang/lib/CodeGen/CGBuiltin.cpp @@ -6015,8 +6015,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID, // If this is a predefined lib function (e.g. malloc), emit the call // using exactly the normal call path. if (getContext().BuiltinInfo.isPredefinedLibFunction(BuiltinID)) - return emitLibraryCall( - *this, FD, E, cast<llvm::Constant>(EmitScalarExpr(E->getCallee()))); + return emitLibraryCall(*this, FD, E, CGM.getRawFunctionPointer(FD)); // Check that a call to a target specific builtin has the correct target // features. diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp index a071b16fc37f9..2b301130ef7b7 100644 --- a/clang/lib/CodeGen/CGCall.cpp +++ b/clang/lib/CodeGen/CGCall.cpp @@ -5678,6 +5678,9 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo, !isa_and_nonnull<FunctionDecl>(TargetDecl)) EmitKCFIOperandBundle(ConcreteCallee, BundleList); + // Add the pointer-authentication bundle. + EmitPointerAuthOperandBundle(ConcreteCallee.getPointerAuthInfo(), BundleList); + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CurFuncDecl)) if (FD->hasAttr<StrictFPAttr>()) // All calls within a strictfp function are marked strictfp diff --git a/clang/lib/CodeGen/CGCall.h b/clang/lib/CodeGen/CGCall.h index 6b676ac196db2..412b44a8c753a 100644 --- a/clang/lib/CodeGen/CGCall.h +++ b/clang/lib/CodeGen/CGCall.h @@ -14,6 +14,7 @@ #ifndef LLVM_CLANG_LIB_CODEGEN_CGCALL_H #define LLVM_CLANG_LIB_CODEGEN_CGCALL_H +#include "CGPointerAuthInfo.h" #include "CGValue.h" #include "EHScopeStack.h" #include "clang/AST/ASTFwd.h" @@ -69,6 +70,10 @@ class CGCallee { Last = Virtual }; + struct OrdinaryInfoStorage { + CGCalleeInfo AbstractInfo; + CGPointerAuthInfo PointerAuthInfo; + }; struct BuiltinInfoStorage { const FunctionDecl *Decl; unsigned ID; @@ -85,7 +90,7 @@ class CGCallee { SpecialKind KindOrFunctionPointer; union { - CGCalleeInfo AbstractInfo; + OrdinaryInfoStorage OrdinaryInfo; BuiltinInfoStorage BuiltinInfo; PseudoDestructorInfoStorage PseudoDestructorInfo; VirtualInfoStorage VirtualInfo; @@ -104,10 +109,13 @@ class CGCallee { /// Construct a callee. Call this constructor directly when this /// isn't a direct call. - CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr) + CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr, + /* FIXME: make parameter pointerAuthInfo mandatory */ + const CGPointerAuthInfo &pointerAuthInfo = CGPointerAuthInfo()) : KindOrFunctionPointer( SpecialKind(reinterpret_cast<uintptr_t>(functionPtr))) { - AbstractInfo = abstractInfo; + OrdinaryInfo.AbstractInfo = abstractInfo; + OrdinaryInfo.PointerAuthInfo = pointerAuthInfo; assert(functionPtr && "configuring callee without function pointer"); assert(functionPtr->getType()->isPointerTy()); } @@ -173,7 +181,11 @@ class CGCallee { if (isVirtual()) return VirtualInfo.MD; assert(isOrdinary()); - return AbstractInfo; + return OrdinaryInfo.AbstractInfo; + } + const CGPointerAuthInfo &getPointerAuthInfo() const { + assert(isOrdinary()); + return OrdinaryInfo.PointerAuthInfo; } llvm::Value *getFunctionPointer() const { assert(isOrdinary()); @@ -184,6 +196,10 @@ class CGCallee { KindOrFunctionPointer = SpecialKind(reinterpret_cast<uintptr_t>(functionPtr)); } + void setPointerAuthInfo(CGPointerAuthInfo PointerAuth) { + assert(isOrdinary()); + OrdinaryInfo.PointerAuthInfo = PointerAuth; + } bool isVirtual() const { return KindOrFunctionPointer == SpecialKind::Virtual; diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp index 3dfe5e09c778d..534f46da74862 100644 --- a/clang/lib/CodeGen/CGExpr.cpp +++ b/clang/lib/CodeGen/CGExpr.cpp @@ -2856,22 +2856,22 @@ static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF, return LV; } -static llvm::Constant *EmitFunctionDeclPointer(CodeGenModule &CGM, - GlobalDecl GD) { +llvm::Constant *CodeGenModule::getRawFunctionPointer(GlobalDecl GD, + llvm::Type *Ty) { const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); if (FD->hasAttr<WeakRefAttr>()) { - ConstantAddress aliasee = CGM.GetWeakRefReference(FD); + ConstantAddress aliasee = GetWeakRefReference(FD); return aliasee.getPointer(); } - llvm::Constant *V = CGM.GetAddrOfFunction(GD); + llvm::Constant *V = GetAddrOfFunction(GD, Ty); return V; } static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF, const Expr *E, GlobalDecl GD) { const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); - llvm::Value *V = EmitFunctionDeclPointer(CGF.CGM, GD); + llvm::Constant *V = CGF.CGM.getFunctionPointer(GD); CharUnits Alignment = CGF.getContext().getDeclAlign(FD); return CGF.MakeAddrLValue(V, E->getType(), Alignment, AlignmentSource::Decl); @@ -5506,7 +5506,7 @@ static CGCallee EmitDirectCallee(CodeGenFunction &CGF, GlobalDecl GD) { // name to make it clear it's not the actual builtin. if (CGF.CurFn->getName() != FDInlineName && OnlyHasInlineBuiltinDeclaration(FD)) { - llvm::Constant *CalleePtr = EmitFunctionDeclPointer(CGF.CGM, GD); + llvm::Constant *CalleePtr = CGF.CGM.getRawFunctionPointer(GD); llvm::Function *Fn = llvm::cast<llvm::Function>(CalleePtr); llvm::Module *M = Fn->getParent(); llvm::Function *Clone = M->getFunction(FDInlineName); @@ -5529,7 +5529,7 @@ static CGCallee EmitDirectCallee(CodeGenFunction &CGF, GlobalDecl GD) { return CGCallee::forBuiltin(builtinID, FD); } - llvm::Constant *CalleePtr = EmitFunctionDeclPointer(CGF.CGM, GD); + llvm::Constant *CalleePtr = CGF.CGM.getRawFunctionPointer(GD); if (CGF.CGM.getLangOpts().CUDA && !CGF.CGM.getLangOpts().CUDAIsDevice && FD->hasAttr<CUDAGlobalAttr>()) CalleePtr = CGF.CGM.getCUDARuntime().getKernelStub( @@ -5586,7 +5586,8 @@ CGCallee CodeGenFunction::EmitCallee(const Expr *E) { GD = GlobalDecl(VD); CGCalleeInfo calleeInfo(functionType->getAs<FunctionProtoType>(), GD); - CGCallee callee(calleeInfo, calleePtr); + CGPointerAuthInfo pointerAuth = CGM.getFunctionPointerAuthInfo(functionType); + CGCallee callee(calleeInfo, calleePtr, pointerAuth); return callee; } diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp index bc5f42d632bca..dffb8ce83b643 100644 --- a/clang/lib/CodeGen/CGExprConstant.cpp +++ b/clang/lib/CodeGen/CGExprConstant.cpp @@ -2024,8 +2024,25 @@ ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) { if (D->hasAttr<WeakRefAttr>()) return CGM.GetWeakRefReference(D).getPointer(); + auto PtrAuthSign = [&](llvm::Constant *C) { + CGPointerAuthInfo AuthInfo = CGM.getFunctionPointerAuthInfo(DestType); + + if (AuthInfo) { + if (hasNonZeroOffset()) + return ConstantLValue(nullptr); + + C = applyOffset(C); + C = CGM.getConstantSignedPointer( + C, AuthInfo.getKey(), nullptr, + cast_or_null<llvm::ConstantInt>(AuthInfo.getDiscriminator())); + return ConstantLValue(C, /*applied offset*/ true); + } + + return ConstantLValue(C); + }; + if (auto FD = dyn_cast<FunctionDecl>(D)) - return CGM.GetAddrOfFunction(FD); + return PtrAuthSign(CGM.getRawFunctionPointer(FD)); if (auto VD = dyn_cast<VarDecl>(D)) { // We can never refer to a variable with local storage. diff --git a/clang/lib/CodeGen/CGPointerAuth.cpp b/clang/lib/CodeGen/CGPointerAuth.cpp index e1fb0bdb85cfb..f0819b0467489 100644 --- a/clang/lib/CodeGen/CGPointerAuth.cpp +++ b/clang/lib/CodeGen/CGPointerAuth.cpp @@ -17,6 +17,24 @@ using namespace clang; using namespace CodeGen; +/// Return the abstract pointer authentication schema for a pointer to the given +/// function type. +CGPointerAuthInfo CodeGenModule::getFunctionPointerAuthInfo(QualType T) { + const auto &Schema = getCodeGenOpts().PointerAuth.FunctionPointers; + if (!Schema) + return CGPointerAuthInfo(); + + assert(!Schema.isAddressDiscriminated() && + "function pointers cannot use address-specific discrimination"); + + assert(!Schema.hasOtherDiscrimination() && + "function pointers don't support any discrimination yet"); + + return CGPointerAuthInfo(Schema.getKey(), Schema.getAuthenticationMode(), + /*IsaPointer=*/false, /*AuthenticatesNull=*/false, + /*Discriminator=*/nullptr); +} + llvm::Constant * CodeGenModule::getConstantSignedPointer(llvm::Constant *Pointer, unsigned Key, llvm::Constant *StorageAddress, @@ -41,3 +59,24 @@ CodeGenModule::getConstantSignedPointer(llvm::Constant *Pointer, unsigned Key, llvm::ConstantInt::get(Int32Ty, Key), IntegerDiscriminator, AddressDiscriminator); } + +llvm::Constant *CodeGenModule::getFunctionPointer(llvm::Constant *Pointer, + QualType FunctionType) { + assert(FunctionType->isFunctionType() || + FunctionType->isFunctionReferenceType() || + FunctionType->isFunctionPointerType()); + + if (auto PointerAuth = getFunctionPointerAuthInfo(FunctionType)) + return getConstantSignedPointer( + Pointer, PointerAuth.getKey(), /*StorageAddress=*/nullptr, + cast_or_null<llvm::ConstantInt>(PointerAuth.getDiscriminator())); + + return Pointer; +} + +llvm::Constant *CodeGenModule::getFunctionPointer(GlobalDecl GD, + llvm::Type *Ty) { + const auto *FD = cast<FunctionDecl>(GD.getDecl()); + QualType FuncType = FD->getType(); + return getFunctionPointer(getRawFunctionPointer(GD, Ty), FuncType); +} diff --git a/clang/lib/CodeGen/CGPointerAuthInfo.h b/clang/lib/CodeGen/CGPointerAuthInfo.h new file mode 100644 index 0000000000000..0a0c11fb423f2 --- /dev/null +++ b/clang/lib/CodeGen/CGPointerAuthInfo.h @@ -0,0 +1,99 @@ +//===----- CGPointerAuthInfo.h - -------------------------------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// Pointer auth info class. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_LIB_CODEGEN_CGPOINTERAUTHINFO_H +#define LLVM_CLANG_LIB_CODEGEN_CGPOINTERAUTHINFO_H + +#include "clang/AST/Type.h" +#include "clang/Basic/LangOptions.h" +#include "llvm/IR/Type.h" +#include "llvm/IR/Value.h" + +namespace clang { +namespace CodeGen { + +class CGPointerAuthInfo { +private: + PointerAuthenticationMode AuthenticationMode : 2; + unsigned IsIsaPointer : 1; + unsigned AuthenticatesNullValues : 1; + unsigned Key : 2; + llvm::Value *Discriminator; + +public: + CGPointerAuthInfo() + : AuthenticationMode(PointerAuthenticationMode::None), + IsIsaPointer(false), AuthenticatesNullValues(false), Key(0), + Discriminator(nullptr) {} + CGPointerAuthInfo(unsigned Key, PointerAuthenticationMode AuthenticationMode, + bool IsIsaPointer, bool AuthenticatesNullValues, + llvm::Value *Discriminator) + : AuthenticationMode(AuthenticationMode), IsIsaPointer(IsIsaPointer), + AuthenticatesNullValues(AuthenticatesNullValues), Key(Key), + Discriminator(Discriminator) { + assert(!Discriminator || Discriminator->getType()->isIntegerTy() || + Discriminator->getType()->isPointerTy()); + } + + explicit operator bool() const { return isSigned(); } + + bool isSigned() const { + return AuthenticationMode != PointerAuthenticationMode::None; + } + + unsigned getKey() const { + assert(isSigned()); + return Key; + } + llvm::Value *getDiscriminator() const { + assert(isSigned()); + return Discriminator; + } + + PointerAuthenticationMode getAuthenticationMode() const { + return AuthenticationMode; + } + + bool isIsaPointer() const { return IsIsaPointer; } + + bool authenticatesNullValues() const { return AuthenticatesNullValues; } + + bool shouldStrip() const { + return AuthenticationMode == PointerAuthenticationMode::Strip || + AuthenticationMode == PointerAuthenticationMode::SignAndStrip; + } + + bool shouldSign() const { + return AuthenticationMode == PointerAuthenticationMode::SignAndStrip || + AuthenticationMode == PointerAuthenticationMode::SignAndAuth; + } + + bool shouldAuth() const { + return AuthenticationMode == PointerAuthenticationMode::SignAndAuth; + } + + friend bool operator!=(const CGPointerAuthInfo &LHS, + const CGPointerAuthInfo &RHS) { + return LHS.Key != RHS.Key || LHS.Discriminator != RHS.Discriminator || + LHS.AuthenticationMode != RHS.AuthenticationMode; + } + + friend bool operator==(const CGPointerAuthInfo &LHS, + const CGPointerAuthInfo &RHS) { + return !(LHS != RHS); + } +}; + +} // end namespace CodeGen +} // end namespace clang + +#endif diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp index 200c40da8bc43..650c5662539f9 100644 --- a/clang/lib/CodeGen/CodeGenFunction.cpp +++ b/clang/lib/CodeGen/CodeGenFunction.cpp @@ -861,6 +861,11 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, FD->getBody()->getStmtClass() == Stmt::CoroutineBodyStmtClass) SanOpts.Mask &= ~SanitizerKind::Null; + // Add pointer authentication attributes. + const CodeGenOptions &CodeGenOpts = CGM.getCodeGenOpts(); + if (CodeGenOpts.PointerAuth.FunctionPointers) + Fn->addFnAttr("ptrauth-calls"); + // Apply xray attributes to the function (as a string, for now) bool AlwaysXRayAttr = false; if (const auto *XRayAttr = D ? D->getAttr<XRayInstrumentAttr>() : nullptr) { @@ -3042,3 +3047,19 @@ llvm::Value *CodeGenFunction::emitBoolVecConversion(llvm::Value *SrcVec, return Builder.CreateShuffleVector(SrcVec, ShuffleMask, Name); } + +void CodeGenFunction::EmitPointerAuthOperandBundle( + const CGPointerAuthInfo &PointerAuth, + SmallVectorImpl<llvm::OperandBundleDef> &Bundles) { + if (!PointerAuth.isSigned()) + return; + + auto *Key = Builder.getInt32(PointerAuth.getKey()); + + llvm::Value *Discriminator = PointerAuth.getDiscriminator(); + if (!Discriminator) + Discriminator = Builder.getSize(0); + + llvm::Value *Args[] = {Key, Discriminator}; + Bundles.emplace_back("ptrauth", Args); +} diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h index cdb5ae6663405..a9c497bde6871 100644 --- a/clang/lib/CodeGen/CodeGenFunction.h +++ b/clang/lib/CodeGen/CodeGenFunction.h @@ -4417,6 +4417,10 @@ class CodeGenFunction : public CodeGenTypeCache { bool isPointerKnownNonNull(const Expr *E); + void EmitPointerAuthOperandBundle( + const CGPointerAuthInfo &Info, + SmallVectorImpl<llvm::OperandBundleDef> &Bundles); + // Return the copy constructor name with the prefix "__copy_constructor_" // removed. static std::string getNonTrivialCopyConstructorStr(QualType QT, diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h index 04e1a392ef5d1..9913304757caa 100644 --- a/clang/lib/CodeGen/CodeGenModule.h +++ b/clang/lib/CodeGen/CodeGenModule.h @@ -69,6 +69,7 @@ class Expr; class Stmt; class StringLiteral; class NamedDecl; +class PointerAuthSchema; class ValueDecl; class VarDecl; class LangOptions; @@ -937,6 +938,25 @@ class CodeGenModule : public CodeGenTypeCache { // Return the function body address of the given function. llvm::Constant *GetFunctionStart(const ValueDecl *Decl); + /// Return a function pointer for a reference to the given function. + /// This correctly handles weak references, but does not apply a + /// pointer signature. + llvm::Constant *getRawFunctionPointer(GlobalDecl GD, + llvm::Type *Ty = nullptr); + + /// Return the ABI-correct function pointer value for a reference + /// to the given function. This will apply a pointer signature if + /// necessary, caching the result for the given function. + llvm::Constant *getFunctionPointer(GlobalDecl GD, llvm::Type *Ty = nullptr); + + /// Return the ABI-correct function pointer value for a reference + /// to the given function. This will apply a pointer signature if + /// necessary. + llvm::Constant *getFunctionPointer(llvm::Constant *Pointer, + QualType FunctionType); + + CGPointerAuthInfo getFunctionPointerAuthInfo(QualType T); + llvm::Constant * getConstantSignedPointer(llvm::Constant *Pointer, unsigned Key, llvm::Constant *StorageAddress, diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index cde4a84673b6e..a6d9f42ace9cc 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -1458,6 +1458,29 @@ static void setPGOUseInstrumentor(CodeGenOptions &Opts, Opts.setProfileUse(CodeGenOptions::ProfileClangInstr); } +void CompilerInvocation::setDefaultPointerAuthOptions( + PointerAuthOptions &Opts, const LangOptions &LangOpts, + const llvm::Triple &Triple) { + assert(Triple.getArch() == llvm::Triple::aarch64); + if (LangOpts.PointerAuthCalls) { + using Key = PointerAuthSchema::ARM8_3Key; + using Discrimination = PointerAuthSchema::Discrimination; + // If you change anything here, be sure to update <ptrauth.h>. + Opts.FunctionPointers = + PointerAuthSchema(Key::ASIA, false, Discrimination::None); + } +} + +static void parsePointerAuthOptions(PointerAuthOptions &Opts, + const LangOptions &LangOpts, + const llvm::Triple &Triple, + DiagnosticsEngine &Diags) { + if (!LangOpts.PointerAuthCalls) + return; + + CompilerInvocation::setDefaultPointerAuthOptions(Opts, LangOpts, Triple); +} + void CompilerInvocationBase::GenerateCodeGenArgs(const CodeGenOptions &Opts, ArgumentConsumer Consumer, const llvm::Triple &T, @@ -2153,6 +2176,9 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, Opts.EmitVersionIdentMetadata = Args.hasFlag(OPT_Qy, OPT_Qn, true); + if (!LangOpts->CUDAIsDevice) + parsePointerAuthOptions(Opts.PointerAuth, *LangOpts, T, Diags); + if (Args.hasArg(options::OPT_ffinite_loops)) Opts.FiniteLoops = CodeGenOptions::FiniteLoopsKind::Always; else if (Args.hasArg(options::OPT_fno_finite_loops)) diff --git a/clang/lib/Headers/ptrauth.h b/clang/lib/Headers/ptrauth.h index 6aad9efb7a652..1a4bd02933ea2 100644 --- a/clang/lib/Headers/ptrauth.h +++ b/clang/lib/Headers/ptrauth.h @@ -28,6 +28,12 @@ typedef enum { /* A process-specific key which can be used to sign data pointers. */ ptrauth_key_process_dependent_data = ptrauth_key_asdb, + /* The key used to sign C function pointers. + The extra data is always 0. */ + ptrauth_key_function_pointer = ptrauth_key_process_independent_code, + + /* Other pointers signed under the ABI use private ABI rules. */ + } ptrauth_key; /* An integer type of the appropriate size for a discriminator argument. */ @@ -131,6 +137,27 @@ typedef __UINTPTR_TYPE__ ptrauth_generic_signature_t; __builtin_ptrauth_auth_and_resign(__value, __old_key, __old_data, __new_key, \ __new_data) +/* Authenticate a pointer using one scheme and resign it as a C + function pointer. + + If the result is subsequently authenticated using the new scheme, that + authentication is guaranteed to fail if and only if the initial + authentication failed. + + The value must be an expression of function pointer type. + The key must be a constant expression of type ptrauth_key. + The extra data must be an expression of pointer or integer type; + if an integer, it will be coerced to ptrauth_extra_data_t. + The result will have the same type as the original value. + + This operation is guaranteed to not leave the intermediate value + available for attack before it is re-signed. Additionally, if this + expression is used syntactically as the function expression in a + call, only a single authentication will be performed. */ +#define ptrauth_auth_function(__value, __old_key, __old_data) \ + ptrauth_auth_and_resign(__value, __old_key, __old_data, \ + ptrauth_key_function_pointer, 0) + /* Authenticate a data pointer. The value must be an expression of non-function pointer type. @@ -217,6 +244,13 @@ typedef __UINTPTR_TYPE__ ptrauth_generic_signature_t; __value; \ }) +#define ptrauth_auth_function(__value, __old_key, __old_data) \ + ({ \ + (void)__old_key; \ + (void)__old_data; \ + __value; \ + }) + #define ptrauth_auth_data(__value, __old_key, __old_data) \ ({ \ (void)__old_key; \ diff --git a/clang/test/CodeGen/ptrauth-function-attributes.c b/clang/test/CodeGen/ptrauth-function-attributes.c new file mode 100644 index 0000000000000..7ec30498b9d35 --- /dev/null +++ b/clang/test/CodeGen/ptrauth-function-attributes.c @@ -0,0 +1,13 @@ +// RUN: %clang_cc1 -triple arm64e-apple-ios -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,OFF +// RUN: %clang_cc1 -triple aarch64-linux-gnu -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,OFF + +// RUN: %clang_cc1 -triple arm64-apple-ios -fptrauth-calls -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,CALLS +// RUN: %clang_cc1 -triple aarch64-linux-gnu -fptrauth-calls -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,CALLS + +// ALL: define {{(dso_local )?}}void @test() #0 +void test() { +} + +// CALLS: attributes #0 = {{{.*}} "ptrauth-calls" {{.*}}} + +// OFF-NOT: attributes {{.*}} "ptrauth- diff --git a/clang/test/CodeGen/ptrauth-function-init-fail.c b/clang/test/CodeGen/ptrauth-function-init-fail.c new file mode 100644 index 0000000000000..4522f6a14c4a8 --- /dev/null +++ b/clang/test/CodeGen/ptrauth-function-init-fail.c @@ -0,0 +1,7 @@ +// RUN: %clang_cc1 -triple arm64e-apple-ios -fptrauth-calls %s -verify -emit-llvm -o - +// RUN: %clang_cc1 -triple aarch64-linux-gnu -fptrauth-calls %s -verify -emit-llvm -o - + +void f(void); + +// FIXME: We need a better diagnostic here. +int *pf = (int *)&f + 1; // expected-error{{cannot compile this static initializer yet}} diff --git a/clang/test/CodeGen/ptrauth-function-init.c b/clang/test/CodeGen/ptrauth-function-init.c new file mode 100644 index 0000000000000..bf8ee53364ecc --- /dev/null +++ b/clang/test/CodeGen/ptrauth-function-init.c @@ -0,0 +1,36 @@ +// RUN: %clang_cc1 %s -triple arm64e-apple-ios13 -fptrauth-calls -fptrauth-intrinsics -disable-llvm-passes -emit-llvm -o- | FileCheck %s +// RUN: %clang_cc1 %s -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics -disable-llvm-passes -emit-llvm -o- | FileCheck %s +// RUN: %clang_cc1 -xc++ %s -triple arm64e-apple-ios13 -fptrauth-calls -fptrauth-intrinsics -disable-llvm-passes -emit-llvm -o- | FileCheck %s --check-prefixes=CHECK,CXX +// RUN: %clang_cc1 -xc++ %s -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics -disable-llvm-passes -emit-llvm -o- | FileCheck %s --check-prefixes=CHECK,CXX + +#ifdef __cplusplus +extern "C" { +#endif + +void f(void); + +#ifdef __cplusplus + +// CXX: define {{(dso_local )?}}internal void @__cxx_global_var_init() +// CXX: store ptr getelementptr inbounds (i32, ptr ptrauth (ptr @f, i32 0), i64 2), ptr @_ZL2fp, align 8 + +// This is rejected in C mode as adding a non-zero constant to a signed pointer +// is unrepresentable in relocations. In C++ mode, this can be done dynamically +// by the global constructor. +__attribute__((used)) +void (*const fp)(void) = (void (*)(void))((int *)&f + 2); + +#endif + +// CHECK: define {{(dso_local )?}}void @t1() +void t1() { + // CHECK: [[PF:%.*]] = alloca ptr + // CHECK: store ptr getelementptr inbounds (i32, ptr ptrauth (ptr @f, i32 0), i64 2), ptr [[PF]] + + void (*pf)(void) = (void (*)(void))((int *)&f + 2); + (void)pf; +} + +#ifdef __cplusplus +} +#endif diff --git a/clang/test/CodeGen/ptrauth-function-lvalue-cast.c b/clang/test/CodeGen/ptrauth-function-lvalue-cast.c new file mode 100644 index 0000000000000..8d8af18fcafbe --- /dev/null +++ b/clang/test/CodeGen/ptrauth-function-lvalue-cast.c @@ -0,0 +1,24 @@ +// RUN: %clang_cc1 %s -triple arm64e-apple-ios13 -fptrauth-calls -fptrauth-intrinsics -emit-llvm -o- | FileCheck %s +// RUN: %clang_cc1 %s -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics -emit-llvm -o- | FileCheck %s + +typedef void (*fptr_t)(void); + +char *cptr; +void (*fptr)(void); + +// CHECK: define {{(dso_local )?}}void @test1 +void test1() { + // CHECK: [[LOAD:%.*]] = load ptr, ptr @cptr + // CHECK: call void [[LOAD]]() [ "ptrauth"(i32 0, i64 0) ] + // CHECK: ret void + + (*(fptr_t)cptr)(); +} + +// CHECK: define {{(dso_local )?}}i8 @test2 +char test2() { + return *(char *)fptr; + // CHECK: [[LOAD:%.*]] = load ptr, ptr @fptr + // CHECK: [[LOAD1:%.*]] = load i8, ptr [[LOAD]] + // CHECK: ret i8 [[LOAD1]] +} diff --git a/clang/test/CodeGen/ptrauth-function.c b/clang/test/CodeGen/ptrauth-function.c new file mode 100644 index 0000000000000..eea3f7ed73747 --- /dev/null +++ b/clang/test/CodeGen/ptrauth-function.c @@ -0,0 +1,38 @@ +// RUN: %clang_cc1 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics -emit-llvm %s -o - | FileCheck -check-prefix=CHECK %s +// RUN: %clang_cc1 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics -emit-llvm %s -o - | FileCheck -check-prefix=CHECK %s + +void test_call(); + +// CHECK: define {{(dso_local )?}}void @test_direct_call() +void test_direct_call() { + // CHECK: call void @test_call(){{$}} + test_call(); +} + +// CHECK: define {{(dso_local )?}}void @test_indirect_call(ptr noundef %[[FP:.*]]) +void test_indirect_call(void (*fp(void))) { + // CHECK: %[[FP_ADDR:.*]] = alloca ptr, align 8 + // CHECK: store ptr %[[FP]], ptr %[[FP_ADDR]], align 8 + // CHECK: %[[V0:.*]] = load ptr, ptr %[[FP_ADDR]], align 8 + // CHECK: %[[CALL:.*]] = call ptr %[[V0]]() [ "ptrauth"(i32 0, i64 0) ] + fp(); +} + +void abort(); +// CHECK: define {{(dso_local )?}}void @test_direct_builtin_call() +void test_direct_builtin_call() { + // CHECK: call void @abort() {{#[0-9]+$}} + abort(); +} + +// CHECK-LABEL: define {{(dso_local )?}}void @test_memcpy_inline( +// CHECK-NOT: call{{.*}}memcpy + +extern inline __attribute__((__always_inline__)) +void *memcpy(void *d, const void *s, unsigned long) { + return 0; +} + +void test_memcpy_inline(char *d, char *s) { + memcpy(d, s, 4); +} diff --git a/clang/test/CodeGen/ptrauth-weak_import.c b/clang/test/CodeGen/ptrauth-weak_import.c new file mode 100644 index 0000000000000..1f53747a2640e --- /dev/null +++ b/clang/test/CodeGen/ptrauth-weak_import.c @@ -0,0 +1,12 @@ +// RUN: %clang_cc1 -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics -emit-llvm %s -o - | FileCheck %s +// RUN: %clang_cc1 -triple aarch64-linux-gnu -fptrauth-calls -fptrauth-intrinsics -emit-llvm %s -o - | FileCheck %s + +extern void foo() __attribute__((weak_import)); + +// CHECK: define {{(dso_local )?}}void @bar() +// CHECK: [[TMP1:%.*]] = icmp ne ptr ptrauth (ptr @foo, i32 0), null +// CHECK: br i1 [[TMP1]], label +void bar() { + if (foo) + foo(); +} diff --git a/clang/test/CodeGenCXX/ptrauth.cpp b/clang/test/CodeGenCXX/ptrauth.cpp new file mode 100644 index 0000000000000..b0c069f43969b --- /dev/null +++ b/clang/test/CodeGenCXX/ptrauth.cpp @@ -0,0 +1,25 @@ +// RUN: %clang_cc1 -triple arm64-apple-ios -fptrauth-calls -emit-llvm -std=c++11 -fexceptions -fcxx-exceptions -o - %s | FileCheck %s +// RUN: %clang_cc1 -triple aarch64-linux-gnu -fptrauth-calls -emit-llvm -std=c++11 -fexceptions -fcxx-exceptions -o - %s | FileCheck %s + +void f(void); +auto &f_ref = f; + +// CHECK: define {{(dso_local )?}}void @_Z1gv( +// CHECK: call void ptrauth (ptr @_Z1fv, i32 0)() [ "ptrauth"(i32 0, i64 0) ] + +void g() { f_ref(); } + +void foo1(); + +void test_terminate() noexcept { + foo1(); +} + +// CHECK: define {{(dso_local )?}}void @_ZSt9terminatev() #[[ATTR4:.*]] { + +namespace std { + void terminate() noexcept { + } +} + +// CHECK: attributes #[[ATTR4]] = {{{.*}}"ptrauth-calls"{{.*}}} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
