linux/fs/compat_binfmt_elf.c
Linus Torvalds ac7b34218a Split the old READ_IMPLIES_EXEC workaround from executable PT_GNU_STACK
now that toolchains long support PT_GNU_STACK marking and there's no
 need anymore to force modern programs into having all its user mappings
 executable instead of only the stack and the PROT_EXEC ones. Disable
 that automatic READ_IMPLIES_EXEC forcing on x86-64 and arm64. Add tables
 documenting how READ_IMPLIES_EXEC is handled on x86-64, arm and arm64.
 By Kees Cook.
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Merge tag 'core_core_updates_for_5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull READ_IMPLIES_EXEC changes from Borislav Petkov:
 "Split the old READ_IMPLIES_EXEC workaround from executable
  PT_GNU_STACK now that toolchains long support PT_GNU_STACK marking and
  there's no need anymore to force modern programs into having all its
  user mappings executable instead of only the stack and the PROT_EXEC
  ones.

  Disable that automatic READ_IMPLIES_EXEC forcing on x86-64 and
  arm64.

  Add tables documenting how READ_IMPLIES_EXEC is handled on x86-64, arm
  and arm64.

  By Kees Cook"

* tag 'core_core_updates_for_5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm64/elf: Disable automatic READ_IMPLIES_EXEC for 64-bit address spaces
  arm32/64/elf: Split READ_IMPLIES_EXEC from executable PT_GNU_STACK
  arm32/64/elf: Add tables to document READ_IMPLIES_EXEC
  x86/elf: Disable automatic READ_IMPLIES_EXEC on 64-bit
  x86/elf: Split READ_IMPLIES_EXEC from executable PT_GNU_STACK
  x86/elf: Add table to document READ_IMPLIES_EXEC
2020-06-05 13:45:21 -07:00

138 lines
3.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* 32-bit compatibility support for ELF format executables and core dumps.
*
* Copyright (C) 2007 Red Hat, Inc. All rights reserved.
*
* Red Hat Author: Roland McGrath.
*
* This file is used in a 64-bit kernel that wants to support 32-bit ELF.
* asm/elf.h is responsible for defining the compat_* and COMPAT_* macros
* used below, with definitions appropriate for 32-bit ABI compatibility.
*
* We use macros to rename the ABI types and machine-dependent
* functions used in binfmt_elf.c to compat versions.
*/
#include <linux/elfcore-compat.h>
#include <linux/time.h>
#define ELF_COMPAT 1
/*
* Rename the basic ELF layout types to refer to the 32-bit class of files.
*/
#undef ELF_CLASS
#define ELF_CLASS ELFCLASS32
#undef elfhdr
#undef elf_phdr
#undef elf_shdr
#undef elf_note
#undef elf_addr_t
#undef ELF_GNU_PROPERTY_ALIGN
#define elfhdr elf32_hdr
#define elf_phdr elf32_phdr
#define elf_shdr elf32_shdr
#define elf_note elf32_note
#define elf_addr_t Elf32_Addr
#define ELF_GNU_PROPERTY_ALIGN ELF32_GNU_PROPERTY_ALIGN
/*
* Some data types as stored in coredump.
*/
#define user_long_t compat_long_t
#define user_siginfo_t compat_siginfo_t
#define copy_siginfo_to_external copy_siginfo_to_external32
/*
* The machine-dependent core note format types are defined in elfcore-compat.h,
* which requires asm/elf.h to define compat_elf_gregset_t et al.
*/
#define elf_prstatus compat_elf_prstatus
#define elf_prpsinfo compat_elf_prpsinfo
#undef ns_to_kernel_old_timeval
#define ns_to_kernel_old_timeval ns_to_old_timeval32
/*
* To use this file, asm/elf.h must define compat_elf_check_arch.
* The other following macros can be defined if the compat versions
* differ from the native ones, or omitted when they match.
*/
#undef ELF_ARCH
#undef elf_check_arch
#define elf_check_arch compat_elf_check_arch
#ifdef COMPAT_ELF_PLATFORM
#undef ELF_PLATFORM
#define ELF_PLATFORM COMPAT_ELF_PLATFORM
#endif
#ifdef COMPAT_ELF_HWCAP
#undef ELF_HWCAP
#define ELF_HWCAP COMPAT_ELF_HWCAP
#endif
#ifdef COMPAT_ELF_HWCAP2
#undef ELF_HWCAP2
#define ELF_HWCAP2 COMPAT_ELF_HWCAP2
#endif
#ifdef COMPAT_ARCH_DLINFO
#undef ARCH_DLINFO
#define ARCH_DLINFO COMPAT_ARCH_DLINFO
#endif
#ifdef COMPAT_ELF_ET_DYN_BASE
#undef ELF_ET_DYN_BASE
#define ELF_ET_DYN_BASE COMPAT_ELF_ET_DYN_BASE
#endif
#ifdef COMPAT_ELF_EXEC_PAGESIZE
#undef ELF_EXEC_PAGESIZE
#define ELF_EXEC_PAGESIZE COMPAT_ELF_EXEC_PAGESIZE
#endif
#ifdef COMPAT_ELF_PLAT_INIT
#undef ELF_PLAT_INIT
#define ELF_PLAT_INIT COMPAT_ELF_PLAT_INIT
#endif
#ifdef COMPAT_SET_PERSONALITY
#undef SET_PERSONALITY
#define SET_PERSONALITY COMPAT_SET_PERSONALITY
#endif
#ifdef compat_start_thread
#undef start_thread
#define start_thread compat_start_thread
#endif
#ifdef compat_arch_setup_additional_pages
#undef ARCH_HAS_SETUP_ADDITIONAL_PAGES
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
#undef arch_setup_additional_pages
#define arch_setup_additional_pages compat_arch_setup_additional_pages
#endif
#ifdef compat_elf_read_implies_exec
#undef elf_read_implies_exec
#define elf_read_implies_exec compat_elf_read_implies_exec
#endif
/*
* Rename a few of the symbols that binfmt_elf.c will define.
* These are all local so the names don't really matter, but it
* might make some debugging less confusing not to duplicate them.
*/
#define elf_format compat_elf_format
#define init_elf_binfmt init_compat_elf_binfmt
#define exit_elf_binfmt exit_compat_elf_binfmt
/*
* We share all the actual code with the native (64-bit) version.
*/
#include "binfmt_elf.c"