Author: Daniil Kovalev Date: 2025-08-01T09:04:25+02:00 New Revision: 614544048c713209b619f7a93763ce66dde620d3
URL: https://github.com/llvm/llvm-project/commit/614544048c713209b619f7a93763ce66dde620d3 DIFF: https://github.com/llvm/llvm-project/commit/614544048c713209b619f7a93763ce66dde620d3.diff LOG: [PAC][compiler-rt] Fix init/fini array signing schema (#150691) When `ptrauth_calls` is present but `ptrauth_init_fini` is not, compiler emits raw unsigned pointers in `.init_array`/`.fini_array` sections. Previously, `__do_init`/`__do_fini` pointers, which are explicitly added to the sections, were implicitly signed (due to the presense of `ptrauth_calls`), while all the other pointers in the sections were implicitly added by the compiler and thus non-signed.. As a result, the sections contained a mix of unsigned function pointers and function pointers signed with default signing schema. This patch introduces use of inline assembly for this particular case, so we can manually specify that we do not want to sign the pointers. Note that we cannot use `__builtin_ptrauth_strip` for this purpose since its result is not a constant expression. (cherry picked from commit 19ba224fb8a925d095d84836bc9896bf564dfd99) Added: Modified: compiler-rt/lib/builtins/crtbegin.c Removed: ################################################################################ diff --git a/compiler-rt/lib/builtins/crtbegin.c b/compiler-rt/lib/builtins/crtbegin.c index d5f7756308b09..447474bd0b692 100644 --- a/compiler-rt/lib/builtins/crtbegin.c +++ b/compiler-rt/lib/builtins/crtbegin.c @@ -54,22 +54,33 @@ static void __attribute__((used)) __do_init(void) { } #ifdef CRT_HAS_INITFINI_ARRAY -#if __has_feature(ptrauth_init_fini) +# if __has_feature(ptrauth_init_fini) // TODO: use __ptrauth-qualified pointers when they are supported on clang side -#if __has_feature(ptrauth_init_fini_address_discrimination) +# if __has_feature(ptrauth_init_fini_address_discrimination) __attribute__((section(".init_array"), used)) static void *__init = ptrauth_sign_constant(&__do_init, ptrauth_key_init_fini_pointer, ptrauth_blend_discriminator( &__init, __ptrauth_init_fini_discriminator)); -#else +# else __attribute__((section(".init_array"), used)) static void *__init = ptrauth_sign_constant(&__do_init, ptrauth_key_init_fini_pointer, __ptrauth_init_fini_discriminator); -#endif -#else +# endif +# elif __has_feature(ptrauth_calls) +# ifdef __aarch64__ +// If ptrauth_init_fini feature is not present, compiler emits raw unsigned +// pointers in .init_array. Use inline assembly to avoid implicit signing of +// __do_init function pointer with ptrauth_calls enabled. +__asm__(".pushsection .init_array,\"aw\",@init_array\n\t" + ".xword __do_init\n\t" + ".popsection"); +# else +# error "ptrauth_calls is only supported for AArch64" +# endif +# else __attribute__((section(".init_array"), used)) static void (*__init)(void) = __do_init; -#endif +# endif #elif defined(__i386__) || defined(__x86_64__) __asm__(".pushsection .init,\"ax\",@progbits\n\t" "call __do_init\n\t" @@ -125,22 +136,33 @@ static void __attribute__((used)) __do_fini(void) { } #ifdef CRT_HAS_INITFINI_ARRAY -#if __has_feature(ptrauth_init_fini) +# if __has_feature(ptrauth_init_fini) // TODO: use __ptrauth-qualified pointers when they are supported on clang side -#if __has_feature(ptrauth_init_fini_address_discrimination) +# if __has_feature(ptrauth_init_fini_address_discrimination) __attribute__((section(".fini_array"), used)) static void *__fini = ptrauth_sign_constant(&__do_fini, ptrauth_key_init_fini_pointer, ptrauth_blend_discriminator( &__fini, __ptrauth_init_fini_discriminator)); -#else +# else __attribute__((section(".fini_array"), used)) static void *__fini = ptrauth_sign_constant(&__do_fini, ptrauth_key_init_fini_pointer, __ptrauth_init_fini_discriminator); -#endif -#else +# endif +# elif __has_feature(ptrauth_calls) +# ifdef __aarch64__ +// If ptrauth_init_fini feature is not present, compiler emits raw unsigned +// pointers in .fini_array. Use inline assembly to avoid implicit signing of +// __do_fini function pointer with ptrauth_calls enabled. +__asm__(".pushsection .fini_array,\"aw\",@fini_array\n\t" + ".xword __do_fini\n\t" + ".popsection"); +# else +# error "ptrauth_calls is only supported for AArch64" +# endif +# else __attribute__((section(".fini_array"), used)) static void (*__fini)(void) = __do_fini; -#endif +# endif #elif defined(__i386__) || defined(__x86_64__) __asm__(".pushsection .fini,\"ax\",@progbits\n\t" "call __do_fini\n\t" _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
