![Andy Lutomirski](/assets/img/avatar_default.png)
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 <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/ef54f8d066b30a3eb36bbf26300eebb242185700.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
110 lines
2.3 KiB
C
110 lines
2.3 KiB
C
/*
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* check_initial_reg_state.c - check that execve sets the correct state
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* Copyright (c) 2014-2016 Andrew Lutomirski
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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unsigned long ax, bx, cx, dx, si, di, bp, sp, flags;
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unsigned long r8, r9, r10, r11, r12, r13, r14, r15;
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asm (
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".pushsection .text\n\t"
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".type real_start, @function\n\t"
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".global real_start\n\t"
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"real_start:\n\t"
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#ifdef __x86_64__
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"mov %rax, ax\n\t"
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"mov %rbx, bx\n\t"
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"mov %rcx, cx\n\t"
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"mov %rdx, dx\n\t"
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"mov %rsi, si\n\t"
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"mov %rdi, di\n\t"
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"mov %rbp, bp\n\t"
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"mov %rsp, sp\n\t"
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"mov %r8, r8\n\t"
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"mov %r9, r9\n\t"
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"mov %r10, r10\n\t"
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"mov %r11, r11\n\t"
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"mov %r12, r12\n\t"
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"mov %r13, r13\n\t"
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"mov %r14, r14\n\t"
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"mov %r15, r15\n\t"
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"pushfq\n\t"
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"popq flags\n\t"
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#else
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"mov %eax, ax\n\t"
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"mov %ebx, bx\n\t"
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"mov %ecx, cx\n\t"
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"mov %edx, dx\n\t"
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"mov %esi, si\n\t"
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"mov %edi, di\n\t"
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"mov %ebp, bp\n\t"
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"mov %esp, sp\n\t"
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"pushfl\n\t"
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"popl flags\n\t"
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#endif
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"jmp _start\n\t"
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".size real_start, . - real_start\n\t"
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".popsection");
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int main()
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{
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int nerrs = 0;
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if (sp == 0) {
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printf("[FAIL]\tTest was built incorrectly\n");
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return 1;
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}
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if (ax || bx || cx || dx || si || di || bp
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#ifdef __x86_64__
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|| r8 || r9 || r10 || r11 || r12 || r13 || r14 || r15
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#endif
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) {
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printf("[FAIL]\tAll GPRs except SP should be 0\n");
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#define SHOW(x) printf("\t" #x " = 0x%lx\n", x);
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SHOW(ax);
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SHOW(bx);
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SHOW(cx);
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SHOW(dx);
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SHOW(si);
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SHOW(di);
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SHOW(bp);
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SHOW(sp);
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#ifdef __x86_64__
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SHOW(r8);
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SHOW(r9);
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SHOW(r10);
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SHOW(r11);
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SHOW(r12);
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SHOW(r13);
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SHOW(r14);
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SHOW(r15);
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#endif
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nerrs++;
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} else {
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printf("[OK]\tAll GPRs except SP are 0\n");
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}
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if (flags != 0x202) {
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printf("[FAIL]\tFLAGS is 0x%lx, but it should be 0x202\n", flags);
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nerrs++;
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} else {
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printf("[OK]\tFLAGS is 0x202\n");
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}
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return nerrs ? 1 : 0;
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}
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