linux/arch/arm/include/asm/elf.h
Kees Cook 6a9af90a3b arm: move ELF_ET_DYN_BASE to 4MB
Now that explicitly executed loaders are loaded in the mmap region, we
have more freedom to decide where we position PIE binaries in the
address space to avoid possible collisions with mmap or stack regions.

4MB is chosen here mainly to have parity with x86, where this is the
traditional minimum load location, likely to avoid historically
requiring a 4MB page table entry when only a portion of the first 4MB
would be used (since the NULL address is avoided).

For ARM the position could be 0x8000, the standard ET_EXEC load address,
but that is needlessly close to the NULL address, and anyone running PIE
on 32-bit ARM will have an MMU, so the tight mapping is not needed.

Link: http://lkml.kernel.org/r/1498154792-49952-2-git-send-email-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Qualys Security Advisory <qsa@qualys.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:36 -07:00

140 lines
4.1 KiB
C

#ifndef __ASMARM_ELF_H
#define __ASMARM_ELF_H
#include <asm/auxvec.h>
#include <asm/hwcap.h>
#include <asm/vdso_datapage.h>
/*
* ELF register definitions..
*/
#include <asm/ptrace.h>
#include <asm/user.h>
struct task_struct;
typedef unsigned long elf_greg_t;
typedef unsigned long elf_freg_t[3];
#define ELF_NGREG (sizeof (struct pt_regs) / sizeof(elf_greg_t))
typedef elf_greg_t elf_gregset_t[ELF_NGREG];
typedef struct user_fp elf_fpregset_t;
#define EF_ARM_EABI_MASK 0xff000000
#define EF_ARM_EABI_UNKNOWN 0x00000000
#define EF_ARM_EABI_VER1 0x01000000
#define EF_ARM_EABI_VER2 0x02000000
#define EF_ARM_EABI_VER3 0x03000000
#define EF_ARM_EABI_VER4 0x04000000
#define EF_ARM_EABI_VER5 0x05000000
#define EF_ARM_BE8 0x00800000 /* ABI 4,5 */
#define EF_ARM_LE8 0x00400000 /* ABI 4,5 */
#define EF_ARM_MAVERICK_FLOAT 0x00000800 /* ABI 0 */
#define EF_ARM_VFP_FLOAT 0x00000400 /* ABI 0 */
#define EF_ARM_SOFT_FLOAT 0x00000200 /* ABI 0 */
#define EF_ARM_OLD_ABI 0x00000100 /* ABI 0 */
#define EF_ARM_NEW_ABI 0x00000080 /* ABI 0 */
#define EF_ARM_ALIGN8 0x00000040 /* ABI 0 */
#define EF_ARM_PIC 0x00000020 /* ABI 0 */
#define EF_ARM_MAPSYMSFIRST 0x00000010 /* ABI 2 */
#define EF_ARM_APCS_FLOAT 0x00000010 /* ABI 0, floats in fp regs */
#define EF_ARM_DYNSYMSUSESEGIDX 0x00000008 /* ABI 2 */
#define EF_ARM_APCS_26 0x00000008 /* ABI 0 */
#define EF_ARM_SYMSARESORTED 0x00000004 /* ABI 1,2 */
#define EF_ARM_INTERWORK 0x00000004 /* ABI 0 */
#define EF_ARM_HASENTRY 0x00000002 /* All */
#define EF_ARM_RELEXEC 0x00000001 /* All */
#define R_ARM_NONE 0
#define R_ARM_PC24 1
#define R_ARM_ABS32 2
#define R_ARM_CALL 28
#define R_ARM_JUMP24 29
#define R_ARM_TARGET1 38
#define R_ARM_V4BX 40
#define R_ARM_PREL31 42
#define R_ARM_MOVW_ABS_NC 43
#define R_ARM_MOVT_ABS 44
#define R_ARM_THM_CALL 10
#define R_ARM_THM_JUMP24 30
#define R_ARM_THM_MOVW_ABS_NC 47
#define R_ARM_THM_MOVT_ABS 48
/*
* These are used to set parameters in the core dumps.
*/
#define ELF_CLASS ELFCLASS32
#ifdef __ARMEB__
#define ELF_DATA ELFDATA2MSB
#else
#define ELF_DATA ELFDATA2LSB
#endif
#define ELF_ARCH EM_ARM
/*
* This yields a string that ld.so will use to load implementation
* specific libraries for optimization. This is more specific in
* intent than poking at uname or /proc/cpuinfo.
*
* For now we just provide a fairly general string that describes the
* processor family. This could be made more specific later if someone
* implemented optimisations that require it. 26-bit CPUs give you
* "v1l" for ARM2 (no SWP) and "v2l" for anything else (ARM1 isn't
* supported). 32-bit CPUs give you "v3[lb]" for anything based on an
* ARM6 or ARM7 core and "armv4[lb]" for anything based on a StrongARM-1
* core.
*/
#define ELF_PLATFORM_SIZE 8
#define ELF_PLATFORM (elf_platform)
extern char elf_platform[];
struct elf32_hdr;
/*
* This is used to ensure we don't load something for the wrong architecture.
*/
extern int elf_check_arch(const struct elf32_hdr *);
#define elf_check_arch elf_check_arch
#define vmcore_elf64_check_arch(x) (0)
extern int arm_elf_read_implies_exec(const struct elf32_hdr *, int);
#define elf_read_implies_exec(ex,stk) arm_elf_read_implies_exec(&(ex), stk)
struct task_struct;
int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs);
#define ELF_CORE_COPY_TASK_REGS dump_task_regs
#define CORE_DUMP_USE_REGSET
#define ELF_EXEC_PAGESIZE 4096
/* This is the base location for PIE (ET_DYN with INTERP) loads. */
#define ELF_ET_DYN_BASE 0x400000UL
/* When the program starts, a1 contains a pointer to a function to be
registered with atexit, as per the SVR4 ABI. A value of 0 means we
have no such handler. */
#define ELF_PLAT_INIT(_r, load_addr) (_r)->ARM_r0 = 0
extern void elf_set_personality(const struct elf32_hdr *);
#define SET_PERSONALITY(ex) elf_set_personality(&(ex))
#ifdef CONFIG_MMU
#ifdef CONFIG_VDSO
#define ARCH_DLINFO \
do { \
NEW_AUX_ENT(AT_SYSINFO_EHDR, \
(elf_addr_t)current->mm->context.vdso); \
} while (0)
#endif
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
struct linux_binprm;
int arch_setup_additional_pages(struct linux_binprm *, int);
#endif
#endif