Author: Oliver Hunt Date: 2025-08-14T17:20:27-07:00 New Revision: fb14f91305dd512f28927ee17766c1b00ae114dc
URL: https://github.com/llvm/llvm-project/commit/fb14f91305dd512f28927ee17766c1b00ae114dc DIFF: https://github.com/llvm/llvm-project/commit/fb14f91305dd512f28927ee17766c1b00ae114dc.diff LOG: [clang][Obj-C][PAC] Make block descriptor pointer signing configurable (#153700) Pointer auth protection of the block descriptor pointer is only supported in some constrained environments so we do actually need it to be configurable. We had made it non configurable in the first PR to protect block metadata because we believed that was an option but subsequently realised it does need to remain configurable. This PR revives the flags that permit this. Added: Modified: clang/include/clang/Basic/Features.def clang/include/clang/Basic/LangOptions.def clang/include/clang/Driver/Options.td clang/lib/Frontend/CompilerInvocation.cpp clang/test/CodeGenObjC/ptrauth-block-descriptor-pointer.m clang/test/CodeGenObjC/ptrauth-block-isa.m Removed: ################################################################################ diff --git a/clang/include/clang/Basic/Features.def b/clang/include/clang/Basic/Features.def index 0f6cd005bfd03..b9efc6a6a2e9d 100644 --- a/clang/include/clang/Basic/Features.def +++ b/clang/include/clang/Basic/Features.def @@ -155,7 +155,7 @@ FEATURE(ptrauth_vtable_pointer_address_discrimination, LangOpts.PointerAuthVTPtr FEATURE(ptrauth_vtable_pointer_type_discrimination, LangOpts.PointerAuthVTPtrTypeDiscrimination) FEATURE(ptrauth_type_info_vtable_pointer_discrimination, LangOpts.PointerAuthTypeInfoVTPtrDiscrimination) FEATURE(ptrauth_member_function_pointer_type_discrimination, LangOpts.PointerAuthCalls) -FEATURE(ptrauth_signed_block_descriptors, LangOpts.PointerAuthCalls) +FEATURE(ptrauth_signed_block_descriptors, LangOpts.PointerAuthBlockDescriptorPointers) FEATURE(ptrauth_function_pointer_type_discrimination, LangOpts.PointerAuthFunctionTypeDiscrimination) FEATURE(ptrauth_indirect_gotos, LangOpts.PointerAuthIndirectGotos) FEATURE(ptrauth_init_fini, LangOpts.PointerAuthInitFini) diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def index 08d98a77e0252..f094ba112988f 100644 --- a/clang/include/clang/Basic/LangOptions.def +++ b/clang/include/clang/Basic/LangOptions.def @@ -136,6 +136,8 @@ LANGOPT(PointerAuthObjcInterfaceSel, 1, 0, NotCompatible, "authentication of SEL LANGOPT(PointerAuthObjcInterfaceSelKey, 16, 0, NotCompatible, "authentication key for SEL fields of ObjC interfaces") LANGOPT(PointerAuthObjcClassROPointers, 1, 0, Benign, "class_ro_t pointer authentication") +LANGOPT(PointerAuthBlockDescriptorPointers, 1, 0, NotCompatible, "enable signed block descriptors") + LANGOPT(DoubleSquareBracketAttributes, 1, 0, NotCompatible, "'[[]]' attributes extension for all language standard modes") LANGOPT(ExperimentalLateParseAttributes, 1, 0, NotCompatible, "experimental late parsing of attributes") diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index 7712a49cef154..858f37c392107 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -4546,6 +4546,7 @@ defm aarch64_jump_table_hardening: OptInCC1FFlag<"aarch64-jump-table-hardening", defm ptrauth_objc_isa : OptInCC1FFlag<"ptrauth-objc-isa", "Enable signing and authentication of Objective-C object's 'isa' field">; defm ptrauth_objc_interface_sel : OptInCC1FFlag<"ptrauth-objc-interface-sel", "Enable signing and authentication of Objective-C object's 'SEL' fields">; defm ptrauth_objc_class_ro : OptInCC1FFlag<"ptrauth-objc-class-ro", "Enable signing and authentication for ObjC class_ro pointers">; +defm ptrauth_block_descriptor_pointers : OptInCC1FFlag<"ptrauth-block-descriptor-pointers", "Enable signing and authentication of block descriptors">; } def fenable_matrix : Flag<["-"], "fenable-matrix">, Group<f_Group>, diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index a4d18966be35f..da96352e1d82c 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -1548,9 +1548,10 @@ void CompilerInvocation::setDefaultPointerAuthOptions( PointerAuthSchema(Key::ASIA, true, Discrimination::None); Opts.BlockByrefHelperFunctionPointers = PointerAuthSchema(Key::ASIA, true, Discrimination::None); - Opts.BlockDescriptorPointers = - PointerAuthSchema(Key::ASDA, true, Discrimination::Constant, - BlockDescriptorConstantDiscriminator); + if (LangOpts.PointerAuthBlockDescriptorPointers) + Opts.BlockDescriptorPointers = + PointerAuthSchema(Key::ASDA, true, Discrimination::Constant, + BlockDescriptorConstantDiscriminator); Opts.ObjCMethodListFunctionPointers = PointerAuthSchema(Key::ASIA, true, Discrimination::None); @@ -3608,6 +3609,8 @@ static void GeneratePointerAuthArgs(const LangOptions &Opts, GenerateArg(Consumer, OPT_fptrauth_objc_interface_sel); if (Opts.PointerAuthObjcClassROPointers) GenerateArg(Consumer, OPT_fptrauth_objc_class_ro); + if (Opts.PointerAuthBlockDescriptorPointers) + GenerateArg(Consumer, OPT_fptrauth_block_descriptor_pointers); } static void ParsePointerAuthArgs(LangOptions &Opts, ArgList &Args, @@ -3631,6 +3634,8 @@ static void ParsePointerAuthArgs(LangOptions &Opts, ArgList &Args, Opts.PointerAuthELFGOT = Args.hasArg(OPT_fptrauth_elf_got); Opts.AArch64JumpTableHardening = Args.hasArg(OPT_faarch64_jump_table_hardening); + Opts.PointerAuthBlockDescriptorPointers = + Args.hasArg(OPT_fptrauth_block_descriptor_pointers); Opts.PointerAuthObjcIsa = Args.hasArg(OPT_fptrauth_objc_isa); Opts.PointerAuthObjcClassROPointers = Args.hasArg(OPT_fptrauth_objc_class_ro); Opts.PointerAuthObjcInterfaceSel = diff --git a/clang/test/CodeGenObjC/ptrauth-block-descriptor-pointer.m b/clang/test/CodeGenObjC/ptrauth-block-descriptor-pointer.m index 559cddfd4e866..b51670fd6459a 100644 --- a/clang/test/CodeGenObjC/ptrauth-block-descriptor-pointer.m +++ b/clang/test/CodeGenObjC/ptrauth-block-descriptor-pointer.m @@ -1,6 +1,11 @@ -// RUN: %clang_cc1 -fobjc-arc -fblocks -fptrauth-calls -triple arm64e-apple-ios -emit-llvm -o - %s | FileCheck %s +// RUN: %clang_cc1 -fobjc-arc -fblocks -fptrauth-calls -fptrauth-block-descriptor-pointers -triple arm64e-apple-ios -emit-llvm -o - %s | FileCheck %s +// RUN: %clang_cc1 -fobjc-arc -fblocks -fptrauth-calls -triple arm64e-apple-ios -DNO_BLOCK_DESC_AUTH -emit-llvm -o - %s | FileCheck %s --check-prefix=NODESCRIPTORAUTH +#ifndef NO_BLOCK_DESC_AUTH _Static_assert(__has_feature(ptrauth_signed_block_descriptors), "-fptrauth-block-descriptor-pointers should set ptrauth_signed_block_descriptors"); +#else +_Static_assert(!__has_feature(ptrauth_signed_block_descriptors), "-fptrauth-block-descriptor-pointers should not be enabled by default"); +#endif void a() { // Test out a global block. @@ -8,9 +13,11 @@ void a() { } // CHECK: [[BLOCK_DESCRIPTOR_NAME:@"__block_descriptor_.*"]] = linkonce_odr hidden unnamed_addr constant { i64, i64, ptr, ptr } { i64 0, i64 32, ptr @.str, ptr null } +// CHECK: @__block_literal_global = internal constant { ptr, i32, i32, ptr, ptr } { ptr @_NSConcreteGlobalBlock, i32 1342177280, i32 0, ptr ptrauth (ptr @__a_block_invoke, i32 0, i64 0, ptr getelementptr inbounds ({ ptr, i32, i32, ptr, ptr }, ptr @__block_literal_global, i32 0, i32 3)), ptr ptrauth (ptr [[BLOCK_DESCRIPTOR_NAME]], i32 2, i64 49339, ptr getelementptr inbounds ({ ptr, i32, i32, ptr, ptr }, ptr @__block_literal_global, i32 0, i32 4)) } +// NODESCRIPTORAUTH: [[BLOCK_DESCRIPTOR_NAME:@"__block_descriptor_.*"]] = linkonce_odr hidden unnamed_addr constant { i64, i64, ptr, ptr } { i64 0, i64 32, ptr @.str, ptr null } +// NODESCRIPTORAUTH: @__block_literal_global = internal constant { ptr, i32, i32, ptr, ptr } { ptr @_NSConcreteGlobalBlock, i32 1342177280, i32 0, ptr ptrauth (ptr @__a_block_invoke, i32 0, i64 0, ptr getelementptr inbounds ({ ptr, i32, i32, ptr, ptr }, ptr @__block_literal_global, i32 0, i32 3)), ptr [[BLOCK_DESCRIPTOR_NAME]] } -// CHECK: @__block_literal_global = internal constant { ptr, i32, i32, ptr, ptr } { ptr @_NSConcreteGlobalBlock, i32 1342177280, i32 0, ptr ptrauth (ptr @__a_block_invoke, i32 0, i64 0, ptr getelementptr inbounds ({ ptr, i32, i32, ptr, ptr }, ptr @__block_literal_global, i32 0, i32 3)), ptr ptrauth (ptr @"__block_descriptor_32_e5_v8\01?0l", i32 2, i64 49339, ptr getelementptr inbounds ({ ptr, i32, i32, ptr, ptr }, ptr @__block_literal_global, i32 0, i32 4)) } void b(int p) { // CHECK-LABEL: define void @b @@ -25,4 +32,8 @@ void b(int p) { // CHECK: [[SIGNED_REF:%.*]] = call i64 @llvm.ptrauth.sign(i64 ptrtoint (ptr @"__block_descriptor_36_e5_v8\01?0l" to i64), i32 2, i64 [[BLENDED]]) // CHECK: [[SIGNED_REF_PTR:%.*]] = inttoptr i64 [[SIGNED_REF]] to ptr // CHECK: store ptr [[SIGNED_REF_PTR]], ptr [[BLOCK_DESCRIPTOR_REF]] + + // NODESCRIPTORAUTH: [[BLOCK:%.*]] = alloca <{ ptr, i32, i32, ptr, ptr, i32 }> + // NODESCRIPTORAUTH: [[BLOCK_DESCRIPTOR_REF:%.*]] = getelementptr inbounds nuw <{ {{.*}} }>, ptr [[BLOCK]], i32 0, i32 4 + // NODESCRIPTORAUTH: store ptr @"__block_descriptor_36_e5_v8\01?0l", ptr [[BLOCK_DESCRIPTOR_REF]] } diff --git a/clang/test/CodeGenObjC/ptrauth-block-isa.m b/clang/test/CodeGenObjC/ptrauth-block-isa.m index c37fe8b0d7fec..248e57769ba1e 100644 --- a/clang/test/CodeGenObjC/ptrauth-block-isa.m +++ b/clang/test/CodeGenObjC/ptrauth-block-isa.m @@ -2,7 +2,7 @@ void (^globalblock)(void) = ^{}; // CHECK: [[BLOCK_DESCRIPTOR_NAME:@"__block_descriptor_.*"]] = linkonce_odr hidden unnamed_addr constant { i64, i64, ptr, ptr } { i64 0, i64 32, ptr @.str, ptr null }, comdat, align 8 -// CHECK: @__block_literal_global = internal constant { ptr, i32, i32, ptr, ptr } { ptr ptrauth (ptr @_NSConcreteGlobalBlock, i32 2, i64 27361, ptr @__block_literal_global), i32 1342177280, i32 0, ptr ptrauth (ptr @globalblock_block_invoke, i32 0, i64 0, ptr getelementptr inbounds ({ ptr, i32, i32, ptr, ptr }, ptr @__block_literal_global, i32 0, i32 3)), ptr ptrauth (ptr [[BLOCK_DESCRIPTOR_NAME]], i32 2, i64 49339, ptr getelementptr inbounds ({ ptr, i32, i32, ptr, ptr }, ptr @__block_literal_global, i32 0, i32 4)) } +// CHECK: @__block_literal_global = internal constant { ptr, i32, i32, ptr, ptr } { ptr ptrauth (ptr @_NSConcreteGlobalBlock, i32 2, i64 27361, ptr @__block_literal_global), i32 1342177280, i32 0, ptr ptrauth (ptr @globalblock_block_invoke, i32 0, i64 0, ptr getelementptr inbounds ({ ptr, i32, i32, ptr, ptr }, ptr @__block_literal_global, i32 0, i32 3)), ptr [[BLOCK_DESCRIPTOR_NAME]] } @interface A - (int) count; 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