1 /*
2 * check_initial_reg_state.c - check that execve sets the correct state
3 * Copyright (c) 2014-2016 Andrew Lutomirski
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 */
14
15 #define _GNU_SOURCE
16
17 #include <stdio.h>
18
19 unsigned long ax, bx, cx, dx, si, di, bp, sp, flags;
20 unsigned long r8, r9, r10, r11, r12, r13, r14, r15;
21
22 asm (
23 ".pushsection .text\n\t"
24 ".type real_start, @function\n\t"
25 ".global real_start\n\t"
26 "real_start:\n\t"
27 #ifdef __x86_64__
28 "mov %rax, ax\n\t"
29 "mov %rbx, bx\n\t"
30 "mov %rcx, cx\n\t"
31 "mov %rdx, dx\n\t"
32 "mov %rsi, si\n\t"
33 "mov %rdi, di\n\t"
34 "mov %rbp, bp\n\t"
35 "mov %rsp, sp\n\t"
36 "mov %r8, r8\n\t"
37 "mov %r9, r9\n\t"
38 "mov %r10, r10\n\t"
39 "mov %r11, r11\n\t"
40 "mov %r12, r12\n\t"
41 "mov %r13, r13\n\t"
42 "mov %r14, r14\n\t"
43 "mov %r15, r15\n\t"
44 "pushfq\n\t"
45 "popq flags\n\t"
46 #else
47 "mov %eax, ax\n\t"
48 "mov %ebx, bx\n\t"
49 "mov %ecx, cx\n\t"
50 "mov %edx, dx\n\t"
51 "mov %esi, si\n\t"
52 "mov %edi, di\n\t"
53 "mov %ebp, bp\n\t"
54 "mov %esp, sp\n\t"
55 "pushfl\n\t"
56 "popl flags\n\t"
57 #endif
58 "jmp _start\n\t"
59 ".size real_start, . - real_start\n\t"
60 ".popsection");
61
main()62 int main()
63 {
64 int nerrs = 0;
65
66 if (sp == 0) {
67 printf("[FAIL]\tTest was built incorrectly\n");
68 return 1;
69 }
70
71 if (ax || bx || cx || dx || si || di || bp
72 #ifdef __x86_64__
73 || r8 || r9 || r10 || r11 || r12 || r13 || r14 || r15
74 #endif
75 ) {
76 printf("[FAIL]\tAll GPRs except SP should be 0\n");
77 #define SHOW(x) printf("\t" #x " = 0x%lx\n", x);
78 SHOW(ax);
79 SHOW(bx);
80 SHOW(cx);
81 SHOW(dx);
82 SHOW(si);
83 SHOW(di);
84 SHOW(bp);
85 SHOW(sp);
86 #ifdef __x86_64__
87 SHOW(r8);
88 SHOW(r9);
89 SHOW(r10);
90 SHOW(r11);
91 SHOW(r12);
92 SHOW(r13);
93 SHOW(r14);
94 SHOW(r15);
95 #endif
96 nerrs++;
97 } else {
98 printf("[OK]\tAll GPRs except SP are 0\n");
99 }
100
101 if (flags != 0x202) {
102 printf("[FAIL]\tFLAGS is 0x%lx, but it should be 0x202\n", flags);
103 nerrs++;
104 } else {
105 printf("[OK]\tFLAGS is 0x202\n");
106 }
107
108 return nerrs ? 1 : 0;
109 }
110