diff options
| -rw-r--r-- | libc/arch-arm64/include/machine/elf_machdep.h | 1 | ||||
| -rw-r--r-- | libc/arch-x86/include/machine/elf_machdep.h | 1 | ||||
| -rw-r--r-- | libc/arch-x86_64/include/machine/elf_machdep.h | 2 | ||||
| -rw-r--r-- | linker/dlfcn.cpp | 4 | ||||
| -rw-r--r-- | linker/linker.cpp | 174 | ||||
| -rw-r--r-- | linker/linker.h | 8 | ||||
| -rw-r--r-- | tests/Android.build.mk | 4 | ||||
| -rw-r--r-- | tests/dlfcn_test.cpp | 14 | ||||
| -rw-r--r-- | tests/libs/Android.mk | 10 | ||||
| -rw-r--r-- | tests/libs/dlopen_testlib_ifunc.c | 11 |
10 files changed, 95 insertions, 134 deletions
diff --git a/libc/arch-arm64/include/machine/elf_machdep.h b/libc/arch-arm64/include/machine/elf_machdep.h index 2bf8189..6eab313 100644 --- a/libc/arch-arm64/include/machine/elf_machdep.h +++ b/libc/arch-arm64/include/machine/elf_machdep.h @@ -99,6 +99,7 @@ #define R_AARCH64_RELATIVE 1027 /* Adjust by program base. */ #define R_AARCH64_TLS_TPREL64 1030 #define R_AARCH64_TLS_DTPREL32 1031 +#define R_AARCH64_IRELATIVE 1032 #define R_TYPE(name) __CONCAT(R_AARCH64_,name) diff --git a/libc/arch-x86/include/machine/elf_machdep.h b/libc/arch-x86/include/machine/elf_machdep.h index 442c561..4bce933 100644 --- a/libc/arch-x86/include/machine/elf_machdep.h +++ b/libc/arch-x86/include/machine/elf_machdep.h @@ -59,5 +59,6 @@ #define R_386_TLS_GOTDESC 39 #define R_386_TLS_DESC_CALL 40 #define R_386_TLS_DESC 41 +#define R_386_IRELATIVE 42 #define R_TYPE(name) __CONCAT(R_386_,name) diff --git a/libc/arch-x86_64/include/machine/elf_machdep.h b/libc/arch-x86_64/include/machine/elf_machdep.h index 20f8c6d..bf1f273 100644 --- a/libc/arch-x86_64/include/machine/elf_machdep.h +++ b/libc/arch-x86_64/include/machine/elf_machdep.h @@ -46,6 +46,8 @@ #define R_X86_64_GOTTPOFF 22 #define R_X86_64_TPOFF32 23 +#define R_X86_64_IRELATIVE 37 + #define R_TYPE(name) __CONCAT(R_X86_64_,name) #else /* !__i386__ */ diff --git a/linker/dlfcn.cpp b/linker/dlfcn.cpp index 3024b3c..9801fa1 100644 --- a/linker/dlfcn.cpp +++ b/linker/dlfcn.cpp @@ -118,7 +118,7 @@ void* dlsym(void* handle, const char* symbol) { unsigned bind = ELF_ST_BIND(sym->st_info); if ((bind == STB_GLOBAL || bind == STB_WEAK) && sym->st_shndx != 0) { - return reinterpret_cast<void*>(sym->st_value + found->load_bias); + return reinterpret_cast<void*>(found->resolve_symbol_address(sym)); } __bionic_format_dlerror("symbol found but not global", symbol); @@ -148,7 +148,7 @@ int dladdr(const void* addr, Dl_info* info) { ElfW(Sym)* sym = dladdr_find_symbol(si, addr); if (sym != nullptr) { info->dli_sname = si->strtab + sym->st_name; - info->dli_saddr = reinterpret_cast<void*>(si->load_bias + sym->st_value); + info->dli_saddr = reinterpret_cast<void*>(si->resolve_symbol_address(sym)); } return 1; diff --git a/linker/linker.cpp b/linker/linker.cpp index f436e85..1b4fb62 100644 --- a/linker/linker.cpp +++ b/linker/linker.cpp @@ -470,32 +470,6 @@ soinfo::soinfo(const char* name, const struct stat* file_stat) { } } -void soinfo::resolve_ifunc_symbols() { - if (!get_has_ifuncs()) { - return; - } - - phdr_table_unprotect_segments(phdr, phnum, load_bias); - - TRACE_TYPE(IFUNC, "CHECKING FOR IFUNCS AND PERFORMING SYMBOL UPDATES"); - - for (size_t i = 0; i < nchain; ++i) { - ElfW(Sym)* s = &symtab[i]; - if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC) { - // The address of the ifunc in the symbol table is the address of the - // function that chooses the function to which the ifunc will refer. - // In order to return the proper value, we run the choosing function - // in the linker and then return its result (minus the base offset). - TRACE_TYPE(IFUNC, "FOUND IFUNC"); - ElfW(Addr) (*ifunc_ptr)(); - ifunc_ptr = reinterpret_cast<ElfW(Addr)(*)()>(s->st_value + base); - s->st_value = (ifunc_ptr() - base); - TRACE_TYPE(IFUNC, "NEW VALUE IS %p", (void*)s->st_value); - } - } - phdr_table_protect_segments(phdr, phnum, load_bias); -} - static unsigned elfhash(const char* _name) { const unsigned char* name = reinterpret_cast<const unsigned char*>(_name); unsigned h = 0, g; @@ -1111,52 +1085,14 @@ void do_dlclose(soinfo* si) { protect_data(PROT_READ); } -// ifuncs are only defined for x86 -#if defined(__i386__) -static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count) { - for (size_t idx = 0; idx < count; ++idx, ++rel) { - ElfW(Sym)* s; - soinfo* lsi; - unsigned type = ELFW(R_TYPE)(rel->r_info); - unsigned sym = ELFW(R_SYM)(rel->r_info); - ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rel->r_offset + si->load_bias); - ElfW(Addr) sym_addr = 0; - const char* sym_name = nullptr; - sym_name = reinterpret_cast<const char*>(si->strtab + si->symtab[sym].st_name); - s = soinfo_do_lookup(si, sym_name, &lsi); +static ElfW(Addr) call_ifunc_resolver(ElfW(Addr) resolver_addr) { + typedef ElfW(Addr) (*ifunc_resolver_t)(void); + ifunc_resolver_t ifunc_resolver = reinterpret_cast<ifunc_resolver_t>(resolver_addr); + ElfW(Addr) ifunc_addr = ifunc_resolver(); + TRACE_TYPE(RELO, "Called ifunc_resolver@%p. The result is %p", ifunc_resolver, reinterpret_cast<void*>(ifunc_addr)); - if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC && type == R_386_JMP_SLOT) { - TRACE("IFUNC RELOCATION, PASS 2: %p", (void*)(sym_addr)); - ElfW(Addr) (*ifunc_ptr)(); - ifunc_ptr = reinterpret_cast<ElfW(Addr)(*)()>(s->st_value + si->base); - *reinterpret_cast<ElfW(Addr)*>(reloc) = ifunc_ptr(); - } - } + return ifunc_addr; } -#endif - -#if defined(__x86_64__) -static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count) { - for (size_t idx = 0; idx < count; ++idx, ++rela) { - ElfW(Sym)* s; - soinfo* lsi; - unsigned type = ELFW(R_TYPE)(rela->r_info); - unsigned sym = ELFW(R_SYM)(rela->r_info); - ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rela->r_offset + si->load_bias); - ElfW(Addr) sym_addr = 0; - const char* sym_name = nullptr; - sym_name = reinterpret_cast<const char*>(si->strtab + si->symtab[sym].st_name); - s = soinfo_do_lookup(si, sym_name, &lsi); - - if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC && type == R_X86_64_JUMP_SLOT) { - TRACE("IFUNC RELOCATION, PASS 2: %p", (void*)(sym_addr + rela->r_addend)); - ElfW(Addr) (*ifunc_ptr)(); - ifunc_ptr = reinterpret_cast<ElfW(Addr)(*)()>(s->st_value + si->base); - *reinterpret_cast<ElfW(Addr)*>(reloc) = ifunc_ptr(); - } - } -} -#endif #if defined(USE_RELA) int soinfo::Relocate(ElfW(Rela)* rela, unsigned count) { @@ -1206,6 +1142,7 @@ int soinfo::Relocate(ElfW(Rela)* rela, unsigned count) { case R_AARCH64_ABS32: case R_AARCH64_ABS16: case R_AARCH64_RELATIVE: + case R_AARCH64_IRELATIVE: /* * The sym_addr was initialized to be zero above, or the relocation * code below does not care about value of sym_addr. @@ -1218,6 +1155,7 @@ int soinfo::Relocate(ElfW(Rela)* rela, unsigned count) { case R_X86_64_32: case R_X86_64_64: case R_X86_64_RELATIVE: + case R_X86_64_IRELATIVE: // No need to do anything. break; case R_X86_64_PC32: @@ -1230,7 +1168,7 @@ int soinfo::Relocate(ElfW(Rela)* rela, unsigned count) { } } else { // We got a definition. - sym_addr = static_cast<ElfW(Addr)>(s->st_value + lsi->load_bias); + sym_addr = lsi->resolve_symbol_address(s); } count_relocation(kRelocSymbol); } @@ -1342,6 +1280,13 @@ int soinfo::Relocate(ElfW(Rela)* rela, unsigned count) { *reinterpret_cast<ElfW(Addr)*>(reloc) = (base + rela->r_addend); break; + case R_AARCH64_IRELATIVE: + count_relocation(kRelocRelative); + MARK(rela->r_offset); + TRACE_TYPE(RELO, "RELO IRELATIVE %16llx <- %16llx\n", reloc, (base + rela->r_addend)); + *reinterpret_cast<ElfW(Addr)*>(reloc) = call_ifunc_resolver(base + rela->r_addend); + break; + case R_AARCH64_COPY: /* * ET_EXEC is not supported so this should not happen. @@ -1368,11 +1313,7 @@ int soinfo::Relocate(ElfW(Rela)* rela, unsigned count) { MARK(rela->r_offset); TRACE_TYPE(RELO, "RELO JMP_SLOT %08zx <- %08zx %s", static_cast<size_t>(reloc), static_cast<size_t>(sym_addr + rela->r_addend), sym_name); - if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC) { - set_has_ifuncs(true); - } else { - *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend; - } + *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend; break; case R_X86_64_GLOB_DAT: count_relocation(kRelocAbsolute); @@ -1392,6 +1333,12 @@ int soinfo::Relocate(ElfW(Rela)* rela, unsigned count) { static_cast<size_t>(base)); *reinterpret_cast<ElfW(Addr)*>(reloc) = base + rela->r_addend; break; + case R_X86_64_IRELATIVE: + count_relocation(kRelocRelative); + MARK(rela->r_offset); + TRACE_TYPE(RELO, "RELO IRELATIVE %16llx <- %16llx\n", reloc, (base + rela->r_addend)); + *reinterpret_cast<ElfW(Addr)*>(reloc) = call_ifunc_resolver(base + rela->r_addend); + break; case R_X86_64_32: count_relocation(kRelocRelative); MARK(rela->r_offset); @@ -1481,6 +1428,7 @@ int soinfo::Relocate(ElfW(Rel)* rel, unsigned count) { case R_386_GLOB_DAT: case R_386_32: case R_386_RELATIVE: /* Don't care. */ + case R_386_IRELATIVE: // sym_addr was initialized to be zero above or relocation // code below does not care about value of sym_addr. // No need to do anything. @@ -1500,7 +1448,7 @@ int soinfo::Relocate(ElfW(Rel)* rel, unsigned count) { } } else { // We got a definition. - sym_addr = static_cast<ElfW(Addr)>(s->st_value + lsi->load_bias); + sym_addr = lsi->resolve_symbol_address(s); } count_relocation(kRelocSymbol); } @@ -1549,11 +1497,7 @@ int soinfo::Relocate(ElfW(Rel)* rel, unsigned count) { count_relocation(kRelocAbsolute); MARK(rel->r_offset); TRACE_TYPE(RELO, "RELO JMP_SLOT %08x <- %08x %s", reloc, sym_addr, sym_name); - if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC) { - set_has_ifuncs(true); - } else { - *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr; - } + *reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr; break; case R_386_GLOB_DAT: count_relocation(kRelocAbsolute); @@ -1614,6 +1558,14 @@ int soinfo::Relocate(ElfW(Rel)* rel, unsigned count) { reinterpret_cast<void*>(reloc), reinterpret_cast<void*>(base)); *reinterpret_cast<ElfW(Addr)*>(reloc) += base; break; +#if defined(__i386__) + case R_386_IRELATIVE: + count_relocation(kRelocRelative); + MARK(rel->r_offset); + TRACE_TYPE(RELO, "RELO IRELATIVE %p <- %p", reinterpret_cast<void*>(reloc), reinterpret_cast<void*>(base)); + *reinterpret_cast<ElfW(Addr)*>(reloc) = call_ifunc_resolver(base + *reinterpret_cast<ElfW(Addr)*>(reloc)); + break; +#endif default: DL_ERR("unknown reloc type %d @ %p (%zu)", type, rel, idx); @@ -1671,7 +1623,7 @@ static bool mips_relocate_got(soinfo* si) { // FIXME: is this sufficient? // For reference see NetBSD link loader // http://cvsweb.netbsd.org/bsdweb.cgi/src/libexec/ld.elf_so/arch/mips/mips_reloc.c?rev=1.53&content-type=text/x-cvsweb-markup - *got = reinterpret_cast<ElfW(Addr)*>(lsi->load_bias + s->st_value); + *got = reinterpret_cast<ElfW(Addr)*>(lsi->resolve_symbol_address(s)); } } return true; @@ -1749,8 +1701,6 @@ void soinfo::CallConstructors() { // DT_INIT should be called before DT_INIT_ARRAY if both are present. CallFunction("DT_INIT", init_func); CallArray("DT_INIT_ARRAY", init_array, init_array_count, false); - - resolve_ifunc_symbols(); } void soinfo::CallDestructors() { @@ -1812,12 +1762,6 @@ void soinfo::set_st_ino(ino_t ino) { } } -void soinfo::set_has_ifuncs(bool ifuncs) { - if (has_min_version(1)) { - has_ifuncs = ifuncs; - } -} - dev_t soinfo::get_st_dev() { if (has_min_version(0)) { return st_dev; @@ -1834,14 +1778,6 @@ ino_t soinfo::get_st_ino() { return 0; } -bool soinfo::get_has_ifuncs() { - if (has_min_version(1)) { - return has_ifuncs; - } - - return false; -} - // This is a return on get_children()/get_parents() if // 'this->flags' does not have FLAG_NEW_SOINFO set. static soinfo::soinfo_list_t g_empty_list; @@ -1862,6 +1798,14 @@ soinfo::soinfo_list_t& soinfo::get_parents() { return this->parents; } +ElfW(Addr) soinfo::resolve_symbol_address(ElfW(Sym)* s) { + if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC) { + return call_ifunc_resolver(s->st_value + load_bias); + } + + return static_cast<ElfW(Addr)>(s->st_value + load_bias); +} + /* Force any of the closed stdin, stdout and stderr to be associated with /dev/null. */ static int nullify_closed_stdio() { @@ -2168,44 +2112,32 @@ bool soinfo::LinkImage(const android_dlextinfo* extinfo) { #endif #if defined(USE_RELA) - if (plt_rela != nullptr) { - DEBUG("[ relocating %s plt ]\n", name); - if (Relocate(plt_rela, plt_rela_count)) { - return false; - } - } if (rela != nullptr) { - DEBUG("[ relocating %s ]\n", name); + DEBUG("[ relocating %s ]", name); if (Relocate(rela, rela_count)) { return false; } } -#else - if (plt_rel != nullptr) { + if (plt_rela != nullptr) { DEBUG("[ relocating %s plt ]", name); - if (Relocate(plt_rel, plt_rel_count)) { + if (Relocate(plt_rela, plt_rela_count)) { return false; } } +#else if (rel != nullptr) { DEBUG("[ relocating %s ]", name); if (Relocate(rel, rel_count)) { return false; } } -#endif - - // if there are ifuncs, we need to do an additional relocation pass. - // they cannot be resolved until the rest of the relocations are done - // because we need to call the resolution function which may be waiting - // on relocations. - if(get_has_ifuncs()) { -#if defined(__i386__) - soinfo_ifunc_relocate(this, plt_rel, plt_rel_count); -#elif defined(__x86_64__) - soinfo_ifunc_relocate(this, plt_rela, plt_rela_count); -#endif + if (plt_rel != nullptr) { + DEBUG("[ relocating %s plt ]", name); + if (Relocate(plt_rel, plt_rel_count)) { + return false; + } } +#endif #if defined(__mips__) if (!mips_relocate_got(this)) { diff --git a/linker/linker.h b/linker/linker.h index 3024d3a..37d513e 100644 --- a/linker/linker.h +++ b/linker/linker.h @@ -197,6 +197,8 @@ struct soinfo { #if !defined(__LP64__) bool has_text_relocations; #endif + // TODO: remove this flag, dynamic linker + // should not use it in any way. bool has_DT_SYMBOLIC; soinfo(const char* name, const struct stat* file_stat); @@ -212,21 +214,20 @@ struct soinfo { void set_st_dev(dev_t st_dev); void set_st_ino(ino_t st_ino); - void set_has_ifuncs(bool ifunc); ino_t get_st_ino(); dev_t get_st_dev(); - bool get_has_ifuncs(); soinfo_list_t& get_children(); soinfo_list_t& get_parents(); + ElfW(Addr) resolve_symbol_address(ElfW(Sym)* s); + bool inline has_min_version(uint32_t min_version) { return (flags & FLAG_NEW_SOINFO) != 0 && version >= min_version; } private: void CallArray(const char* array_name, linker_function_t* functions, size_t count, bool reverse); void CallFunction(const char* function_name, linker_function_t function); - void resolve_ifunc_symbols(); #if defined(USE_RELA) int Relocate(ElfW(Rela)* rela, unsigned count); #else @@ -247,7 +248,6 @@ struct soinfo { soinfo_list_t parents; // version >= 1 - bool has_ifuncs; }; extern soinfo* get_libdl_info(); diff --git a/tests/Android.build.mk b/tests/Android.build.mk index d4b0396..d54c851 100644 --- a/tests/Android.build.mk +++ b/tests/Android.build.mk @@ -37,6 +37,10 @@ LOCAL_CLANG := $($(module)_clang_$(build_type)) LOCAL_FORCE_STATIC_EXECUTABLE := $($(module)_force_static_executable) +ifneq ($($(module)_multilib),) + LOCAL_MULTILIB := $($(module)_multilib) +endif + LOCAL_CFLAGS := \ $(common_cflags) \ $($(module)_cflags) \ diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp index bb9d8c0..ea02c1a 100644 --- a/tests/dlfcn_test.cpp +++ b/tests/dlfcn_test.cpp @@ -89,8 +89,8 @@ TEST(dlfcn, dlopen_noload) { ASSERT_EQ(0, dlclose(handle2)); } -// ifuncs are only supported on intel for now -#if defined(__i386__) || defined(__x86_64__) +// ifuncs are only supported on intel and arm64 for now +#if defined (__aarch64__) || defined(__i386__) || defined(__x86_64__) TEST(dlfcn, ifunc) { typedef const char* (*fn_ptr)(); @@ -124,9 +124,13 @@ TEST(dlfcn, ifunc_ctor_call) { typedef const char* (*fn_ptr)(); void* handle = dlopen("libtest_ifunc.so", RTLD_NOW); - ASSERT_TRUE(handle != NULL) << dlerror(); - fn_ptr is_ctor_called = reinterpret_cast<fn_ptr>(dlsym(handle, "is_ctor_called")); - ASSERT_TRUE(is_ctor_called != NULL) << dlerror(); + ASSERT_TRUE(handle != nullptr) << dlerror(); + fn_ptr is_ctor_called = reinterpret_cast<fn_ptr>(dlsym(handle, "is_ctor_called_irelative")); + ASSERT_TRUE(is_ctor_called != nullptr) << dlerror(); + ASSERT_STREQ("false", is_ctor_called()); + + is_ctor_called = reinterpret_cast<fn_ptr>(dlsym(handle, "is_ctor_called_jump_slot")); + ASSERT_TRUE(is_ctor_called != nullptr) << dlerror(); ASSERT_STREQ("true", is_ctor_called()); dlclose(handle); } diff --git a/tests/libs/Android.mk b/tests/libs/Android.mk index 21681ee..1004b74 100644 --- a/tests/libs/Android.mk +++ b/tests/libs/Android.mk @@ -294,7 +294,7 @@ include $(TEST_PATH)/Android.build.mk # ----------------------------------------------------------------------------- # Library used by ifunc tests # ----------------------------------------------------------------------------- -ifeq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),x86 x86_64)) +ifeq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),arm64 x86 x86_64)) libtest_ifunc_src_files := \ dlopen_testlib_ifunc.c @@ -302,6 +302,14 @@ ifeq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),x86 x86_64)) module := libtest_ifunc build_type := target build_target := SHARED_LIBRARY + + ifeq ($(TARGET_ARCH),arm64) + libtest_ifunc_multilib := 64 + # TODO: This is a workaround - remove it once gcc + # removes its Android ifunc checks + libtest_ifunc_cflags := -mglibc + endif + include $(TEST_PATH)/Android.build.mk endif diff --git a/tests/libs/dlopen_testlib_ifunc.c b/tests/libs/dlopen_testlib_ifunc.c index 4874841..b68a3dd 100644 --- a/tests/libs/dlopen_testlib_ifunc.c +++ b/tests/libs/dlopen_testlib_ifunc.c @@ -23,8 +23,17 @@ static void __attribute__((constructor)) init_flag() { g_flag = 1; } +static const char* is_ctor_called() __attribute__ ((ifunc("is_ctor_called_ifun"))); + const char* foo() __attribute__ ((ifunc ("foo_ifunc"))); -const char* is_ctor_called() __attribute__ ((ifunc("is_ctor_called_ifun"))); + +// Static linker creates GLOBAL/IFUNC symbol and JUMP_SLOT relocation type for plt segment +const char* is_ctor_called_jump_slot() __attribute__ ((ifunc("is_ctor_called_ifun"))); + +const char* is_ctor_called_irelative() { + // Call internal ifunc-resolved function with IRELATIVE reloc + return is_ctor_called(); +} const char* return_true() { return "true"; |