From 20ded8660f1a6eb4dd13002c54ead53e6ff58e88 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 24 May 2021 16:11:04 -0700 Subject: [PATCH v3] x86: Propery check PC16 reloc overflow in 16-bit mode instructions commit a7664973b24a242cd9ea17deb5eaf503065fc0bd Author: Jan Beulich Date: Mon Apr 26 10:41:35 2021 +0200 x86: correct overflow checking for 16-bit PC-relative relocs caused linker failure when building 16-bit program in a 32-bit ELF container. Update GNU_PROPERTY_X86_FEATURE_2_USED with #define GNU_PROPERTY_X86_FEATURE_2_CODE16 (1U << 12) to indicate that 16-bit mode instructions are used in the input object: https://groups.google.com/g/x86-64-abi/c/UvvXWeHIGMA to indicate that 16-bit mode instructions are used in the object to allow linker to properly perform relocation overflow check for 16-bit PC-relative relocations in 16-bit mode instructions. 1. Update x86 assembler to always generate the GNU property note with GNU_PROPERTY_X86_FEATURE_2_CODE16 for .code16 in ELF object. 2. Update i386 and x86-64 linkers to use 16-bit PC16 relocations if input object is marked with GNU_PROPERTY_X86_FEATURE_2_CODE16. bfd/ PR ld/27905 * elf32-i386.c: Include "libiberty.h". (elf_howto_table): Add 16-bit R_386_PC16 entry. (elf_i386_rtype_to_howto): Add a BFD argument. Use 16-bit R_386_PC16 if input has 16-bit mode instructions. (elf_i386_info_to_howto_rel): Update elf_i386_rtype_to_howto call. (elf_i386_tls_transition): Likewise. (elf_i386_relocate_section): Likewise. * elf64-x86-64.c (x86_64_elf_howto_table): Add 16-bit R_X86_64_PC16 entry. (elf_x86_64_rtype_to_howto): Use 16-bit R_X86_64_PC16 if input has 16-bit mode instructions. * elfxx-x86.c (_bfd_x86_elf_parse_gnu_properties): Set elf_x86_has_code16 if relocatable input is marked with GNU_PROPERTY_X86_FEATURE_2_CODE16. * elfxx-x86.h (elf_x86_obj_tdata): Add has_code16. (elf_x86_has_code16): New. binutils/ PR ld/27905 * readelf.c (decode_x86_feature_2): Support GNU_PROPERTY_X86_FEATURE_2_CODE16. gas/ PR ld/27905 * config/tc-i386.c (set_code_flag): Update x86_feature_2_used with GNU_PROPERTY_X86_FEATURE_2_CODE16 for .code16 in ELF object. (set_16bit_gcc_code_flag): Likewise. (x86_cleanup): Always generate the GNU property note if x86_feature_2_used isn't 0. * testsuite/gas/i386/code16-2.d: New file. * testsuite/gas/i386/code16-2.s: Likewise. * testsuite/gas/i386/x86-64-code16-2.d: Likewise. * testsuite/gas/i386/i386.exp: Run code16-2 and x86-64-code16-2. include/ PR ld/27905 * elf/common.h (GNU_PROPERTY_X86_FEATURE_2_CODE16): New. ld/ PR ld/27905 * testsuite/ld-i386/code16.d: New file. * testsuite/ld-i386/code16.t: Likewise. * testsuite/ld-x86-64/code16.d: Likewise. * testsuite/ld-x86-64/code16.t: Likewise. * testsuite/ld-i386/i386.exp: Run code16. * testsuite/ld-x86-64/x86-64.exp: Likewise. --- bfd/elf32-i386.c | 23 +++++++--- bfd/elf64-x86-64.c | 12 ++++++ bfd/elfxx-x86.c | 9 +++- bfd/elfxx-x86.h | 6 +++ binutils/readelf.c | 3 ++ gas/config/tc-i386.c | 55 ++++++++++++++++-------- gas/testsuite/gas/i386/code16-2.d | 8 ++++ gas/testsuite/gas/i386/code16-2.s | 10 +++++ gas/testsuite/gas/i386/i386.exp | 2 + gas/testsuite/gas/i386/x86-64-code16-2.d | 9 ++++ include/elf/common.h | 1 + ld/testsuite/ld-i386/code16.d | 19 ++++++++ ld/testsuite/ld-i386/code16.t | 7 +++ ld/testsuite/ld-i386/i386.exp | 1 + ld/testsuite/ld-x86-64/code16.d | 19 ++++++++ ld/testsuite/ld-x86-64/code16.t | 7 +++ ld/testsuite/ld-x86-64/x86-64.exp | 1 + 17 files changed, 167 insertions(+), 25 deletions(-) create mode 100644 gas/testsuite/gas/i386/code16-2.d create mode 100644 gas/testsuite/gas/i386/code16-2.s create mode 100644 gas/testsuite/gas/i386/x86-64-code16-2.d create mode 100644 ld/testsuite/ld-i386/code16.d create mode 100644 ld/testsuite/ld-i386/code16.t create mode 100644 ld/testsuite/ld-x86-64/code16.d create mode 100644 ld/testsuite/ld-x86-64/code16.t diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c index 4451f9b451c..c68741af02c 100644 --- a/bfd/elf32-i386.c +++ b/bfd/elf32-i386.c @@ -22,6 +22,7 @@ #include "elf-vxworks.h" #include "dwarf2.h" #include "opcode/i386.h" +#include "libiberty.h" /* 386 uses REL relocations instead of RELA. */ #define USE_REL 1 @@ -175,10 +176,14 @@ static reloc_howto_type elf_howto_table[]= false, /* partial_inplace */ 0, /* src_mask */ 0, /* dst_mask */ - false) /* pcrel_offset */ + false), /* pcrel_offset */ #define R_386_vt (R_386_GNU_VTENTRY + 1 - R_386_vt_offset) +/* Use complain_overflow_bitfield on R_386_PC16 for code16. */ + HOWTO(R_386_PC16, 0, 1, 16, true, 0, complain_overflow_bitfield, + bfd_elf_generic_reloc, "R_386_PC16", + true, 0xffff, 0xffff, true) }; #define X86_PCREL_TYPE_P(TYPE) ((TYPE) == R_386_PC32) @@ -369,7 +374,7 @@ elf_i386_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED, } static reloc_howto_type * -elf_i386_rtype_to_howto (unsigned r_type) +elf_i386_rtype_to_howto (bfd *abfd, unsigned r_type) { unsigned int indx; @@ -384,6 +389,11 @@ elf_i386_rtype_to_howto (unsigned r_type) /* PR 17512: file: 0f67f69d. */ if (elf_howto_table [indx].type != r_type) return NULL; + + /* Use complain_overflow_bitfield on R_386_PC16 for code16. */ + if (r_type == (unsigned int) R_386_PC16 && elf_x86_has_code16 (abfd)) + indx = ARRAY_SIZE (elf_howto_table) - 1; + return &elf_howto_table[indx]; } @@ -394,7 +404,8 @@ elf_i386_info_to_howto_rel (bfd *abfd, { unsigned int r_type = ELF32_R_TYPE (dst->r_info); - if ((cache_ptr->howto = elf_i386_rtype_to_howto (r_type)) == NULL) + if ((cache_ptr->howto = elf_i386_rtype_to_howto (abfd, r_type)) + == NULL) { /* xgettext:c-format */ _bfd_error_handler (_("%pB: unsupported relocation type %#x"), @@ -1142,8 +1153,8 @@ elf_i386_tls_transition (struct bfd_link_info *info, bfd *abfd, reloc_howto_type *from, *to; const char *name; - from = elf_i386_rtype_to_howto (from_type); - to = elf_i386_rtype_to_howto (to_type); + from = elf_i386_rtype_to_howto (abfd, from_type); + to = elf_i386_rtype_to_howto (abfd, to_type); if (h) name = h->root.root.string; @@ -2074,7 +2085,7 @@ elf_i386_relocate_section (bfd *output_bfd, continue; } - howto = elf_i386_rtype_to_howto (r_type); + howto = elf_i386_rtype_to_howto (input_bfd, r_type); if (howto == NULL) return _bfd_unrecognized_reloc (input_bfd, input_section, r_type); diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c index d0c994e570a..d420561c156 100644 --- a/bfd/elf64-x86-64.c +++ b/bfd/elf64-x86-64.c @@ -187,6 +187,10 @@ static reloc_howto_type x86_64_elf_howto_table[] = _bfd_elf_rel_vtable_reloc_fn, "R_X86_64_GNU_VTENTRY", false, 0, 0, false), +/* Use complain_overflow_bitfield on R_X86_64_PC16 for code16. */ + HOWTO(R_X86_64_PC16, 0, 1, 16, true, 0, complain_overflow_bitfield, + bfd_elf_generic_reloc, "R_X86_64_PC16", false, 0, 0xffff, true), + /* Use complain_overflow_bitfield on R_X86_64_32 for x32. */ HOWTO(R_X86_64_32, 0, 2, 32, false, 0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_X86_64_32", false, 0, 0xffffffff, @@ -270,6 +274,14 @@ elf_x86_64_rtype_to_howto (bfd *abfd, unsigned r_type) else i = ARRAY_SIZE (x86_64_elf_howto_table) - 1; } + else if (r_type == (unsigned int) R_X86_64_PC16) + { + /* Use complain_overflow_bitfield on R_X86_64_PC16 for code16. */ + if (elf_x86_has_code16 (abfd)) + i = ARRAY_SIZE (x86_64_elf_howto_table) - 2; + else + i = r_type; + } else if (r_type < (unsigned int) R_X86_64_GNU_VTINHERIT || r_type >= (unsigned int) R_X86_64_max) { diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c index 62d516aab8d..29dc7f04b4d 100644 --- a/bfd/elfxx-x86.c +++ b/bfd/elfxx-x86.c @@ -2353,6 +2353,7 @@ _bfd_x86_elf_parse_gnu_properties (bfd *abfd, unsigned int type, || (type >= GNU_PROPERTY_X86_UINT32_OR_AND_LO && type <= GNU_PROPERTY_X86_UINT32_OR_AND_HI)) { + unsigned int number; if (datasz != 4) { _bfd_error_handler @@ -2361,7 +2362,13 @@ _bfd_x86_elf_parse_gnu_properties (bfd *abfd, unsigned int type, return property_corrupt; } prop = _bfd_elf_get_property (abfd, type, datasz); - prop->u.number |= bfd_h_get_32 (abfd, ptr); + number = bfd_h_get_32 (abfd, ptr); + if ((abfd->flags + & (DYNAMIC | BFD_LINKER_CREATED | BFD_PLUGIN)) == 0 + && type == GNU_PROPERTY_X86_FEATURE_2_USED + && (number & GNU_PROPERTY_X86_FEATURE_2_CODE16) != 0) + elf_x86_has_code16 (abfd) = 1; + prop->u.number |= number; prop->pr_kind = property_number; return property_number; } diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h index db11327e96f..e8344305492 100644 --- a/bfd/elfxx-x86.h +++ b/bfd/elfxx-x86.h @@ -549,6 +549,9 @@ struct elf_x86_obj_tdata /* GOTPLT entries for TLS descriptors. */ bfd_vma *local_tlsdesc_gotent; + + /* Set if the objec file has 16-bit code. */ + unsigned int has_code16 : 1; }; enum elf_x86_plt_type @@ -584,6 +587,9 @@ struct elf_x86_plt #define elf_x86_local_tlsdesc_gotent(abfd) \ (elf_x86_tdata (abfd)->local_tlsdesc_gotent) +#define elf_x86_has_code16(abfd) \ + (elf_x86_tdata (abfd)->has_code16) + #define elf_x86_compute_jump_table_size(htab) \ ((htab)->elf.srelplt->reloc_count * (htab)->got_entry_size) diff --git a/binutils/readelf.c b/binutils/readelf.c index 2989adf31b6..8f24cc4071b 100644 --- a/binutils/readelf.c +++ b/binutils/readelf.c @@ -19140,6 +19140,9 @@ decode_x86_feature_2 (unsigned int bitmask) case GNU_PROPERTY_X86_FEATURE_2_XSAVEC: printf ("XSAVEC"); break; + case GNU_PROPERTY_X86_FEATURE_2_CODE16: + printf ("CODE16"); + break; default: printf (_(""), bit); break; diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c index d3441988e34..c17f4da16fe 100644 --- a/gas/config/tc-i386.c +++ b/gas/config/tc-i386.c @@ -2695,6 +2695,10 @@ static void set_code_flag (int value) { update_code_flag (value, 0); +#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF) + if (value == CODE_16BIT) + x86_feature_2_used |= GNU_PROPERTY_X86_FEATURE_2_CODE16; +#endif } static void @@ -2706,6 +2710,10 @@ set_16bit_gcc_code_flag (int new_code_flag) cpu_arch_flags.bitfield.cpu64 = 0; cpu_arch_flags.bitfield.cpuno64 = 1; stackop_size = LONG_MNEM_SUFFIX; +#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF) + if (new_code_flag == CODE_16BIT) + x86_feature_2_used |= GNU_PROPERTY_X86_FEATURE_2_CODE16; +#endif } static void @@ -9032,7 +9040,7 @@ x86_cleanup (void) unsigned int isa_1_descsz_raw, feature_2_descsz_raw; unsigned int padding; - if (!IS_ELF || !x86_used_note) + if (!IS_ELF || (!x86_used_note && !x86_feature_2_used)) return; x86_feature_2_used |= GNU_PROPERTY_X86_FEATURE_2_X86; @@ -9072,15 +9080,23 @@ x86_cleanup (void) bfd_set_section_alignment (sec, alignment); elf_section_type (sec) = SHT_NOTE; - /* GNU_PROPERTY_X86_ISA_1_USED: 4-byte type + 4-byte data size - + 4-byte data */ - isa_1_descsz_raw = 4 + 4 + 4; - /* Align GNU_PROPERTY_X86_ISA_1_USED. */ - isa_1_descsz = (isa_1_descsz_raw + align_size_1) & ~align_size_1; + if (x86_used_note) + { + /* GNU_PROPERTY_X86_ISA_1_USED: 4-byte type + 4-byte data size + + 4-byte data */ + isa_1_descsz_raw = 4 + 4 + 4; + /* Align GNU_PROPERTY_X86_ISA_1_USED. */ + isa_1_descsz = (isa_1_descsz_raw + align_size_1) & ~align_size_1; + } + else + { + isa_1_descsz_raw = 0; + isa_1_descsz = 0; + } feature_2_descsz_raw = isa_1_descsz; /* GNU_PROPERTY_X86_FEATURE_2_USED: 4-byte type + 4-byte data size - + 4-byte data */ + + 4-byte data */ feature_2_descsz_raw += 4 + 4 + 4; /* Align GNU_PROPERTY_X86_FEATURE_2_USED. */ feature_2_descsz = ((feature_2_descsz_raw + align_size_1) @@ -9102,20 +9118,23 @@ x86_cleanup (void) /* Write n_name. */ memcpy (p + 4 * 3, "GNU", 4); - /* Write 4-byte type. */ - md_number_to_chars (p + 4 * 4, - (valueT) GNU_PROPERTY_X86_ISA_1_USED, 4); + if (isa_1_descsz != 0) + { + /* Write 4-byte type. */ + md_number_to_chars (p + 4 * 4, + (valueT) GNU_PROPERTY_X86_ISA_1_USED, 4); - /* Write 4-byte data size. */ - md_number_to_chars (p + 4 * 5, (valueT) 4, 4); + /* Write 4-byte data size. */ + md_number_to_chars (p + 4 * 5, (valueT) 4, 4); - /* Write 4-byte data. */ - md_number_to_chars (p + 4 * 6, (valueT) x86_isa_1_used, 4); + /* Write 4-byte data. */ + md_number_to_chars (p + 4 * 6, (valueT) x86_isa_1_used, 4); - /* Zero out paddings. */ - padding = isa_1_descsz - isa_1_descsz_raw; - if (padding) - memset (p + 4 * 7, 0, padding); + /* Zero out paddings. */ + padding = isa_1_descsz - isa_1_descsz_raw; + if (padding) + memset (p + 4 * 7, 0, padding); + } /* Write 4-byte type. */ md_number_to_chars (p + isa_1_descsz + 4 * 4, diff --git a/gas/testsuite/gas/i386/code16-2.d b/gas/testsuite/gas/i386/code16-2.d new file mode 100644 index 00000000000..37b66c85f4e --- /dev/null +++ b/gas/testsuite/gas/i386/code16-2.d @@ -0,0 +1,8 @@ +#name: i386 code16 2 +#as: -mx86-used-note=no --generate-missing-build-notes=no +#readelf: -n + +Displaying notes found in: .note.gnu.property +[ ]+Owner[ ]+Data size[ ]+Description + GNU 0x[0-9a-f]+ NT_GNU_PROPERTY_TYPE_0 + Properties: x86 feature used: x86, CODE16 diff --git a/gas/testsuite/gas/i386/code16-2.s b/gas/testsuite/gas/i386/code16-2.s new file mode 100644 index 00000000000..66e5d558791 --- /dev/null +++ b/gas/testsuite/gas/i386/code16-2.s @@ -0,0 +1,10 @@ + .code16gcc + .text + .section .text.default_process_op.isra.0,"ax",@progbits + .type default_process_op.isra.0, @function +default_process_op.isra.0: + ret + .section .text.mpt_scsi_process_op,"ax",@progbits + .type mpt_scsi_process_op, @function +mpt_scsi_process_op: + jmp default_process_op.isra.0 diff --git a/gas/testsuite/gas/i386/i386.exp b/gas/testsuite/gas/i386/i386.exp index 39010bdd500..a459c6fe392 100644 --- a/gas/testsuite/gas/i386/i386.exp +++ b/gas/testsuite/gas/i386/i386.exp @@ -734,6 +734,7 @@ if {[is_elf_format] || [istarget "*-*-vxworks*"]} then { run_dump_test "property-ldmxcsr" run_dump_test "property-vldmxcsr" run_dump_test "property-vzeroall" + run_dump_test "code16-2" if {![istarget "*-*-dragonfly*"] && ![istarget "*-*-gnu*"] @@ -1298,6 +1299,7 @@ if [gas_64_check] then { run_dump_test "x86-64-property-8" run_dump_test "x86-64-property-9" run_dump_test "x86-64-property-14" + run_dump_test "x86-64-code16-2" if {[istarget "*-*-linux*"]} then { run_dump_test "x86-64-align-branch-3" diff --git a/gas/testsuite/gas/i386/x86-64-code16-2.d b/gas/testsuite/gas/i386/x86-64-code16-2.d new file mode 100644 index 00000000000..dbabd67e888 --- /dev/null +++ b/gas/testsuite/gas/i386/x86-64-code16-2.d @@ -0,0 +1,9 @@ +#source: code16-2.s +#name: x86-64 code16 2 +#as: -mx86-used-note=no --generate-missing-build-notes=no +#readelf: -n + +Displaying notes found in: .note.gnu.property +[ ]+Owner[ ]+Data size[ ]+Description + GNU 0x[0-9a-f]+ NT_GNU_PROPERTY_TYPE_0 + Properties: x86 feature used: x86, CODE16 diff --git a/include/elf/common.h b/include/elf/common.h index 24d0a09b7c8..564ab711a20 100644 --- a/include/elf/common.h +++ b/include/elf/common.h @@ -872,6 +872,7 @@ #define GNU_PROPERTY_X86_FEATURE_2_XSAVEC (1U << 9) #define GNU_PROPERTY_X86_FEATURE_2_TMM (1U << 10) #define GNU_PROPERTY_X86_FEATURE_2_MASK (1U << 11) +#define GNU_PROPERTY_X86_FEATURE_2_CODE16 (1U << 12) #define GNU_PROPERTY_X86_COMPAT_2_ISA_1_NEEDED \ (GNU_PROPERTY_X86_UINT32_OR_LO + 0) diff --git a/ld/testsuite/ld-i386/code16.d b/ld/testsuite/ld-i386/code16.d new file mode 100644 index 00000000000..8b67861db91 --- /dev/null +++ b/ld/testsuite/ld-i386/code16.d @@ -0,0 +1,19 @@ +#name: i386 R_386_PC16 reloc in 16-bit mode +#as: --32 -mx86-used-note=no --generate-missing-build-notes=no +#source: ${srcdir}/../../../gas/testsuite/gas/i386/code16-2.s +#ld: -T code16.t +#objdump: -dw -Mi8086 + +.*: +file format .* + + +Disassembly of section .text.default_process_op.isra.0: + +0+737c : + +[a-f0-9]+: 66 c3 retl + +Disassembly of section .text.mpt_scsi_process_op: + +0+f869 : + +[a-f0-9]+: e9 10 7b jmp 737c +#pass diff --git a/ld/testsuite/ld-i386/code16.t b/ld/testsuite/ld-i386/code16.t new file mode 100644 index 00000000000..0cf99042e40 --- /dev/null +++ b/ld/testsuite/ld-i386/code16.t @@ -0,0 +1,7 @@ +OUTPUT_FORMAT("elf32-i386") +OUTPUT_ARCH("i386") +SECTIONS +{ +.text.default_process_op.isra.0 0x737c : { *(.text.default_process_op.isra.0) } +.text.mpt_scsi_process_op 0xf869 : { *(.text.mpt_scsi_process_op) } +} diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp index d0b3f69fb8d..3d6047b790d 100644 --- a/ld/testsuite/ld-i386/i386.exp +++ b/ld/testsuite/ld-i386/i386.exp @@ -492,6 +492,7 @@ run_dump_test "property-x86-isa2" run_dump_test "property-x86-isa3" run_dump_test "property-x86-isa4" run_dump_test "pr26869" +run_dump_test "code16" if { !([istarget "i?86-*-linux*"] || [istarget "i?86-*-gnu*"] diff --git a/ld/testsuite/ld-x86-64/code16.d b/ld/testsuite/ld-x86-64/code16.d new file mode 100644 index 00000000000..20096ab6abf --- /dev/null +++ b/ld/testsuite/ld-x86-64/code16.d @@ -0,0 +1,19 @@ +#name: x86-64 R_X86_64_PC16 reloc in 16-bit mode +#as: --64 -mx86-used-note=no --generate-missing-build-notes=no +#source: ${srcdir}/../../../gas/testsuite/gas/i386/code16-2.s +#ld: -T code16.t +#objdump: -dw -Mi8086 + +.*: +file format .* + + +Disassembly of section .text.default_process_op.isra.0: + +0+737c : + +[a-f0-9]+: 66 c3 retl + +Disassembly of section .text.mpt_scsi_process_op: + +0+f869 : + +[a-f0-9]+: e9 10 7b jmp 737c +#pass diff --git a/ld/testsuite/ld-x86-64/code16.t b/ld/testsuite/ld-x86-64/code16.t new file mode 100644 index 00000000000..9ef00a3404d --- /dev/null +++ b/ld/testsuite/ld-x86-64/code16.t @@ -0,0 +1,7 @@ +OUTPUT_FORMAT("elf64-x86-64") +OUTPUT_ARCH("i386:x86-64") +SECTIONS +{ +.text.default_process_op.isra.0 0x737c : { *(.text.default_process_op.isra.0) } +.text.mpt_scsi_process_op 0xf869 : { *(.text.mpt_scsi_process_op) } +} diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp index 37cf998252c..80716668df6 100644 --- a/ld/testsuite/ld-x86-64/x86-64.exp +++ b/ld/testsuite/ld-x86-64/x86-64.exp @@ -474,6 +474,7 @@ run_dump_test "property-x86-isa3" run_dump_test "property-x86-isa3-x32" run_dump_test "property-x86-isa4" run_dump_test "property-x86-isa4-x32" +run_dump_test "code16" if ![istarget "x86_64-*-linux*"] { return -- 2.31.1