Author: Oliver Hunt Date: 2025-08-22T14:18:22+02:00 New Revision: ad7bb1cc45a253d873198b9143fbe9c1e5d97aa5
URL: https://github.com/llvm/llvm-project/commit/ad7bb1cc45a253d873198b9143fbe9c1e5d97aa5 DIFF: https://github.com/llvm/llvm-project/commit/ad7bb1cc45a253d873198b9143fbe9c1e5d97aa5.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 16604057d2da7..b040181beaffd 100644 --- a/clang/include/clang/Basic/Features.def +++ b/clang/include/clang/Basic/Features.def @@ -157,7 +157,7 @@ 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 f5a5d84eefb80..25f4575a54257 100644 --- a/clang/include/clang/Basic/LangOptions.def +++ b/clang/include/clang/Basic/LangOptions.def @@ -138,6 +138,8 @@ 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 18e4ab406ce4e..958d0d05ade29 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -4527,6 +4527,7 @@ 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 88886bf945aeb..08f3b7a7fcc49 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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