On Mon, Dec 07, 2015 at 01:51:27PM -0800, Andy Lutomirski wrote:
> This checks that ELF binaries are started with an appropriately
> blank register state.
>
> (There's currently a nasty special case in the entry asm to arrange
> for this. I'm planning on removing the special case, and this will
> help make sure I don't break it.)
>
> Signed-off-by: Andy Lutomirski <l...@kernel.org>
> ---
> tools/testing/selftests/x86/Makefile | 8 +-
> .../selftests/x86/check_initial_reg_state.c | 108
> +++++++++++++++++++++
> 2 files changed, 115 insertions(+), 1 deletion(-)
> create mode 100644 tools/testing/selftests/x86/check_initial_reg_state.c
>
> diff --git a/tools/testing/selftests/x86/Makefile
> b/tools/testing/selftests/x86/Makefile
> index a460fe7c5365..b82409421fa6 100644
> --- a/tools/testing/selftests/x86/Makefile
> +++ b/tools/testing/selftests/x86/Makefile
> @@ -4,7 +4,7 @@ include ../lib.mk
>
> .PHONY: all all_32 all_64 warn_32bit_failure clean
>
> -TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs ldt_gdt syscall_nt
> ptrace_syscall
> +TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs ldt_gdt syscall_nt
> ptrace_syscall check_initial_reg_state
> TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault sigreturn
> test_syscall_vdso unwind_vdso
>
> TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY)
> @@ -63,3 +63,9 @@ endif
> sysret_ss_attrs_64: thunks.S
> ptrace_syscall_32: raw_syscall_helper_32.S
> test_syscall_vdso_32: thunks_32.S
> +
> +# check_initial_reg_state is special: it needs a custom entry, and it
> +# needs to be static so that its interpreter doesn't destroy its initial
> +# state.
> +check_initial_reg_state_32: CFLAGS += -Wl,-ereal_start -static
> +check_initial_reg_state_64: CFLAGS += -Wl,-ereal_start -static
> diff --git a/tools/testing/selftests/x86/check_initial_reg_state.c
> b/tools/testing/selftests/x86/check_initial_reg_state.c
> new file mode 100644
> index 000000000000..0cb565f7786d
> --- /dev/null
> +++ b/tools/testing/selftests/x86/check_initial_reg_state.c
> @@ -0,0 +1,108 @@
> +/*
> + * check_initial_reg_state.c - check that execve sets the correct state
> + * Copyright (c) 2014-2015 Andrew Lutomirski
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + */
> +
> +#define _GNU_SOURCE
> +
> +#include <stdio.h>
> +
> +unsigned long ax, bx, cx, dx, si, di, bp, sp, flags;
> +unsigned long r8, r9, r10, r11, r12, r13, r14, r15;
> +
> +asm (".pushsection .text\n\t"
WARNING: please, no spaces at the start of a line
#82: FILE: tools/testing/selftests/x86/check_initial_reg_state.c:23:
+ ".type real_start, @function\n\t"$
Something trampled over the preceding tabs in that whole asm().
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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