102 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * check_initial_reg_state.c - check that execve sets the correct state4 * Copyright (c) 2014-2016 Andrew Lutomirski5 */6 7#define _GNU_SOURCE8 9#include <stdio.h>10 11unsigned long ax, bx, cx, dx, si, di, bp, sp, flags;12unsigned long r8, r9, r10, r11, r12, r13, r14, r15;13 14asm (15 ".pushsection .text\n\t"16 ".type real_start, @function\n\t"17 ".global real_start\n\t"18 "real_start:\n\t"19#ifdef __x86_64__20 "mov %rax, ax\n\t"21 "mov %rbx, bx\n\t"22 "mov %rcx, cx\n\t"23 "mov %rdx, dx\n\t"24 "mov %rsi, si\n\t"25 "mov %rdi, di\n\t"26 "mov %rbp, bp\n\t"27 "mov %rsp, sp\n\t"28 "mov %r8, r8\n\t"29 "mov %r9, r9\n\t"30 "mov %r10, r10\n\t"31 "mov %r11, r11\n\t"32 "mov %r12, r12\n\t"33 "mov %r13, r13\n\t"34 "mov %r14, r14\n\t"35 "mov %r15, r15\n\t"36 "pushfq\n\t"37 "popq flags\n\t"38#else39 "mov %eax, ax\n\t"40 "mov %ebx, bx\n\t"41 "mov %ecx, cx\n\t"42 "mov %edx, dx\n\t"43 "mov %esi, si\n\t"44 "mov %edi, di\n\t"45 "mov %ebp, bp\n\t"46 "mov %esp, sp\n\t"47 "pushfl\n\t"48 "popl flags\n\t"49#endif50 "jmp _start\n\t"51 ".size real_start, . - real_start\n\t"52 ".popsection");53 54int main()55{56 int nerrs = 0;57 58 if (sp == 0) {59 printf("[FAIL]\tTest was built incorrectly\n");60 return 1;61 }62 63 if (ax || bx || cx || dx || si || di || bp64#ifdef __x86_64__65 || r8 || r9 || r10 || r11 || r12 || r13 || r14 || r1566#endif67 ) {68 printf("[FAIL]\tAll GPRs except SP should be 0\n");69#define SHOW(x) printf("\t" #x " = 0x%lx\n", x);70 SHOW(ax);71 SHOW(bx);72 SHOW(cx);73 SHOW(dx);74 SHOW(si);75 SHOW(di);76 SHOW(bp);77 SHOW(sp);78#ifdef __x86_64__79 SHOW(r8);80 SHOW(r9);81 SHOW(r10);82 SHOW(r11);83 SHOW(r12);84 SHOW(r13);85 SHOW(r14);86 SHOW(r15);87#endif88 nerrs++;89 } else {90 printf("[OK]\tAll GPRs except SP are 0\n");91 }92 93 if (flags != 0x202) {94 printf("[FAIL]\tFLAGS is 0x%lx, but it should be 0x202\n", flags);95 nerrs++;96 } else {97 printf("[OK]\tFLAGS is 0x202\n");98 }99 100 return nerrs ? 1 : 0;101}102