df64e52e41
Stack mapping entropy is currently hard-wired to 11 bits of entropy on 32-bit and 18 bits of entropy on 64-bit. The stack itself gains an extra 8 bits of entropy from lower bit randomization within 16 byte alignment constraints. The argument block could have all lower bits randomized but it currently only gets the mapping randomization. Rather than hard-wiring values this switches to using the mmap entropy configuration like the mmap base and executable base, resulting in a range of 8 to 16 bits on 32-bit and 18 to 24 bits on 64-bit (with 4k pages and 3 level page tables) depending on kernel configuration and overridable via the sysctl entries. It's worth noting that since these kernel configuration options default to the minimum supported entropy value, the entropy on 32-bit will drop from 11 to 8 bits for builds using the defaults. However, following the configuration seems like the right thing to do regardless. At the very least, changing the defaults for COMPAT (32-bit processes on 64-bit) should be considered due to the larger address space compared to real 32-bit. Signed-off-by: Daniel Micay <danielmicay@gmail.com> Signed-off-by: anupritaisno1 <www.anuprita804@gmail.com>
304 lines
8.2 KiB
C
Executable file
304 lines
8.2 KiB
C
Executable file
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2012 ARM Ltd.
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*/
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#ifndef __ASM_ELF_H
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#define __ASM_ELF_H
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#include <asm/hwcap.h>
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/*
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* ELF register definitions..
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*/
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#include <asm/ptrace.h>
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#include <asm/user.h>
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/*
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* AArch64 static relocation types.
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*/
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/* Miscellaneous. */
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#define R_ARM_NONE 0
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#define R_AARCH64_NONE 256
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/* Data. */
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#define R_AARCH64_ABS64 257
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#define R_AARCH64_ABS32 258
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#define R_AARCH64_ABS16 259
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#define R_AARCH64_PREL64 260
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#define R_AARCH64_PREL32 261
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#define R_AARCH64_PREL16 262
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/* Instructions. */
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#define R_AARCH64_MOVW_UABS_G0 263
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#define R_AARCH64_MOVW_UABS_G0_NC 264
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#define R_AARCH64_MOVW_UABS_G1 265
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#define R_AARCH64_MOVW_UABS_G1_NC 266
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#define R_AARCH64_MOVW_UABS_G2 267
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#define R_AARCH64_MOVW_UABS_G2_NC 268
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#define R_AARCH64_MOVW_UABS_G3 269
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#define R_AARCH64_MOVW_SABS_G0 270
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#define R_AARCH64_MOVW_SABS_G1 271
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#define R_AARCH64_MOVW_SABS_G2 272
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#define R_AARCH64_LD_PREL_LO19 273
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#define R_AARCH64_ADR_PREL_LO21 274
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#define R_AARCH64_ADR_PREL_PG_HI21 275
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#define R_AARCH64_ADR_PREL_PG_HI21_NC 276
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#define R_AARCH64_ADD_ABS_LO12_NC 277
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#define R_AARCH64_LDST8_ABS_LO12_NC 278
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#define R_AARCH64_TSTBR14 279
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#define R_AARCH64_CONDBR19 280
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#define R_AARCH64_JUMP26 282
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#define R_AARCH64_CALL26 283
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#define R_AARCH64_LDST16_ABS_LO12_NC 284
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#define R_AARCH64_LDST32_ABS_LO12_NC 285
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#define R_AARCH64_LDST64_ABS_LO12_NC 286
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#define R_AARCH64_LDST128_ABS_LO12_NC 299
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#define R_AARCH64_MOVW_PREL_G0 287
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#define R_AARCH64_MOVW_PREL_G0_NC 288
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#define R_AARCH64_MOVW_PREL_G1 289
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#define R_AARCH64_MOVW_PREL_G1_NC 290
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#define R_AARCH64_MOVW_PREL_G2 291
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#define R_AARCH64_MOVW_PREL_G2_NC 292
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#define R_AARCH64_MOVW_PREL_G3 293
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#define R_AARCH64_RELATIVE 1027
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#if IS_ENABLED(CONFIG_SEC_DEBUG_COREDUMP)
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#define ARCH_HAVE_EXTRA_ELF_NOTES
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#endif
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/*
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* These are used to set parameters in the core dumps.
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*/
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#define ELF_CLASS ELFCLASS64
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#ifdef __AARCH64EB__
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#define ELF_DATA ELFDATA2MSB
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#else
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#define ELF_DATA ELFDATA2LSB
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#endif
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#define ELF_ARCH EM_AARCH64
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/*
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* This yields a string that ld.so will use to load implementation
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* specific libraries for optimization. This is more specific in
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* intent than poking at uname or /proc/cpuinfo.
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*/
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#define ELF_PLATFORM_SIZE 16
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#ifdef __AARCH64EB__
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#define ELF_PLATFORM ("aarch64_be")
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#else
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#define ELF_PLATFORM ("aarch64")
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#endif
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/*
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* This is used to ensure we don't load something for the wrong architecture.
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*/
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#define elf_check_arch(x) ((x)->e_machine == EM_AARCH64)
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/*
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* An executable for which elf_read_implies_exec() returns TRUE will
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* have the READ_IMPLIES_EXEC personality flag set automatically.
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*
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* The decision process for determining the results are:
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*
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* CPU*: | arm32 | arm64 |
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* ELF: | | |
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* ---------------------|------------|------------|
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* missing PT_GNU_STACK | exec-all | exec-none |
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* PT_GNU_STACK == RWX | exec-stack | exec-stack |
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* PT_GNU_STACK == RW | exec-none | exec-none |
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*
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* exec-all : all PROT_READ user mappings are executable, except when
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* backed by files on a noexec-filesystem.
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* exec-none : only PROT_EXEC user mappings are executable.
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* exec-stack: only the stack and PROT_EXEC user mappings are executable.
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*
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* *all arm64 CPUs support NX, so there is no "lacks NX" column.
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*
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*/
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#define compat_elf_read_implies_exec(ex, stk) (stk == EXSTACK_DEFAULT)
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#define CORE_DUMP_USE_REGSET
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#define ELF_EXEC_PAGESIZE PAGE_SIZE
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/*
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* This is the base location for PIE (ET_DYN with INTERP) loads. On
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* 64-bit, this is above 4GB to leave the entire 32-bit address
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* space open for things that want to use the area for 32-bit pointers.
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*/
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#ifdef CONFIG_ARM64_FORCE_52BIT
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#define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3)
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#else
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#define ELF_ET_DYN_BASE (2 * DEFAULT_MAP_WINDOW_64 / 3)
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#endif /* CONFIG_ARM64_FORCE_52BIT */
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#ifndef __ASSEMBLY__
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#include <uapi/linux/elf.h>
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#include <linux/bug.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/types.h>
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#include <asm/processor.h> /* for signal_minsigstksz, used by ARCH_DLINFO */
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typedef unsigned long elf_greg_t;
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#define ELF_NGREG (sizeof(struct user_pt_regs) / sizeof(elf_greg_t))
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#define ELF_CORE_COPY_REGS(dest, regs) \
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*(struct user_pt_regs *)&(dest) = (regs)->user_regs;
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typedef elf_greg_t elf_gregset_t[ELF_NGREG];
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typedef struct user_fpsimd_state elf_fpregset_t;
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/*
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* When the program starts, a1 contains a pointer to a function to be
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* registered with atexit, as per the SVR4 ABI. A value of 0 means we have no
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* such handler.
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*/
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#define ELF_PLAT_INIT(_r, load_addr) (_r)->regs[0] = 0
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#define SET_PERSONALITY(ex) \
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({ \
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clear_thread_flag(TIF_32BIT); \
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current->personality &= ~READ_IMPLIES_EXEC; \
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})
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/* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
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#define ARCH_DLINFO \
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do { \
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NEW_AUX_ENT(AT_SYSINFO_EHDR, \
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(elf_addr_t)current->mm->context.vdso); \
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\
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/* \
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* Should always be nonzero unless there's a kernel bug. \
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* If we haven't determined a sensible value to give to \
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* userspace, omit the entry: \
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*/ \
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if (likely(signal_minsigstksz)) \
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NEW_AUX_ENT(AT_MINSIGSTKSZ, signal_minsigstksz); \
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else \
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NEW_AUX_ENT(AT_IGNORE, 0); \
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} while (0)
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#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
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struct linux_binprm;
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extern int arch_setup_additional_pages(struct linux_binprm *bprm,
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int uses_interp);
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/* 1GB of VA */
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#ifdef CONFIG_COMPAT
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#define STACK_RND_MASK (test_thread_flag(TIF_32BIT) ? \
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((1UL << mmap_rnd_compat_bits) - 1) >> (PAGE_SHIFT - 12) : \
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((1UL << mmap_rnd_bits) - 1) >> (PAGE_SHIFT - 12))
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#else
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#define STACK_RND_MASK (((1UL << mmap_rnd_bits) - 1) >> (PAGE_SHIFT - 12))
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#endif
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#ifdef __AARCH64EB__
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#define COMPAT_ELF_PLATFORM ("v8b")
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#else
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#define COMPAT_ELF_PLATFORM ("v8l")
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#endif
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#ifdef CONFIG_COMPAT
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/* PIE load location for compat arm. Must match ARM ELF_ET_DYN_BASE. */
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#define COMPAT_ELF_ET_DYN_BASE 0x000400000UL
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/* AArch32 registers. */
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#define COMPAT_ELF_NGREG 18
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typedef unsigned int compat_elf_greg_t;
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typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG];
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/* AArch32 EABI. */
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#define EF_ARM_EABI_MASK 0xff000000
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#define compat_elf_check_arch(x) (system_supports_32bit_el0() && \
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((x)->e_machine == EM_ARM) && \
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((x)->e_flags & EF_ARM_EABI_MASK))
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#define compat_start_thread compat_start_thread
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/*
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* Unlike the native SET_PERSONALITY macro, the compat version maintains
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* READ_IMPLIES_EXEC across an execve() since this is the behaviour on
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* arch/arm/.
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*/
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#define COMPAT_SET_PERSONALITY(ex) \
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({ \
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set_thread_flag(TIF_32BIT); \
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})
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#ifdef CONFIG_COMPAT_VDSO
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#define COMPAT_ARCH_DLINFO \
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do { \
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/* \
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* Note that we use Elf64_Off instead of elf_addr_t because \
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* elf_addr_t in compat is defined as Elf32_Addr and casting \
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* current->mm->context.vdso to it triggers a cast warning of \
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* cast from pointer to integer of different size. \
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*/ \
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NEW_AUX_ENT(AT_SYSINFO_EHDR, \
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(Elf64_Off)current->mm->context.vdso); \
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} while (0)
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#else
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#define COMPAT_ARCH_DLINFO
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#endif
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extern int aarch32_setup_additional_pages(struct linux_binprm *bprm,
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int uses_interp);
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#define compat_arch_setup_additional_pages \
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aarch32_setup_additional_pages
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#endif /* CONFIG_COMPAT */
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struct arch_elf_state {
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int flags;
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};
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#define ARM64_ELF_BTI (1 << 0)
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#define INIT_ARCH_ELF_STATE { \
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.flags = 0, \
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}
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static inline int arch_parse_elf_property(u32 type, const void *data,
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size_t datasz, bool compat,
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struct arch_elf_state *arch)
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{
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/* No known properties for AArch32 yet */
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if (IS_ENABLED(CONFIG_COMPAT) && compat)
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return 0;
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if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND) {
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const u32 *p = data;
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if (datasz != sizeof(*p))
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return -ENOEXEC;
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if (system_supports_bti() &&
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(*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
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arch->flags |= ARM64_ELF_BTI;
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}
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return 0;
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}
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static inline int arch_elf_pt_proc(void *ehdr, void *phdr,
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struct file *f, bool is_interp,
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struct arch_elf_state *state)
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{
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return 0;
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}
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static inline int arch_check_elf(void *ehdr, bool has_interp,
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void *interp_ehdr,
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struct arch_elf_state *state)
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{
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return 0;
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}
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#endif /* !__ASSEMBLY__ */
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#endif
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