1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * syscall_arg_fault.c - tests faults 32-bit fast syscall stack args
4*4882a593Smuzhiyun * Copyright (c) 2018 Andrew Lutomirski
5*4882a593Smuzhiyun */
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun #define _GNU_SOURCE
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun #include <stdlib.h>
10*4882a593Smuzhiyun #include <stdio.h>
11*4882a593Smuzhiyun #include <stdbool.h>
12*4882a593Smuzhiyun #include <errno.h>
13*4882a593Smuzhiyun #include <unistd.h>
14*4882a593Smuzhiyun #include <syscall.h>
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun static int nerrs;
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun #define X32_BIT 0x40000000UL
19*4882a593Smuzhiyun
check_enosys(unsigned long nr,bool * ok)20*4882a593Smuzhiyun static void check_enosys(unsigned long nr, bool *ok)
21*4882a593Smuzhiyun {
22*4882a593Smuzhiyun /* If this fails, a segfault is reasonably likely. */
23*4882a593Smuzhiyun fflush(stdout);
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun long ret = syscall(nr, 0, 0, 0, 0, 0, 0);
26*4882a593Smuzhiyun if (ret == 0) {
27*4882a593Smuzhiyun printf("[FAIL]\tsyscall %lu succeeded, but it should have failed\n", nr);
28*4882a593Smuzhiyun *ok = false;
29*4882a593Smuzhiyun } else if (errno != ENOSYS) {
30*4882a593Smuzhiyun printf("[FAIL]\tsyscall %lu had error code %d, but it should have reported ENOSYS\n", nr, errno);
31*4882a593Smuzhiyun *ok = false;
32*4882a593Smuzhiyun }
33*4882a593Smuzhiyun }
34*4882a593Smuzhiyun
test_x32_without_x32_bit(void)35*4882a593Smuzhiyun static void test_x32_without_x32_bit(void)
36*4882a593Smuzhiyun {
37*4882a593Smuzhiyun bool ok = true;
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun /*
40*4882a593Smuzhiyun * Syscalls 512-547 are "x32" syscalls. They are intended to be
41*4882a593Smuzhiyun * called with the x32 (0x40000000) bit set. Calling them without
42*4882a593Smuzhiyun * the x32 bit set is nonsense and should not work.
43*4882a593Smuzhiyun */
44*4882a593Smuzhiyun printf("[RUN]\tChecking syscalls 512-547\n");
45*4882a593Smuzhiyun for (int i = 512; i <= 547; i++)
46*4882a593Smuzhiyun check_enosys(i, &ok);
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun /*
49*4882a593Smuzhiyun * Check that a handful of 64-bit-only syscalls are rejected if the x32
50*4882a593Smuzhiyun * bit is set.
51*4882a593Smuzhiyun */
52*4882a593Smuzhiyun printf("[RUN]\tChecking some 64-bit syscalls in x32 range\n");
53*4882a593Smuzhiyun check_enosys(16 | X32_BIT, &ok); /* ioctl */
54*4882a593Smuzhiyun check_enosys(19 | X32_BIT, &ok); /* readv */
55*4882a593Smuzhiyun check_enosys(20 | X32_BIT, &ok); /* writev */
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun /*
58*4882a593Smuzhiyun * Check some syscalls with high bits set.
59*4882a593Smuzhiyun */
60*4882a593Smuzhiyun printf("[RUN]\tChecking numbers above 2^32-1\n");
61*4882a593Smuzhiyun check_enosys((1UL << 32), &ok);
62*4882a593Smuzhiyun check_enosys(X32_BIT | (1UL << 32), &ok);
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun if (!ok)
65*4882a593Smuzhiyun nerrs++;
66*4882a593Smuzhiyun else
67*4882a593Smuzhiyun printf("[OK]\tThey all returned -ENOSYS\n");
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun
main()70*4882a593Smuzhiyun int main()
71*4882a593Smuzhiyun {
72*4882a593Smuzhiyun /*
73*4882a593Smuzhiyun * Anyone diagnosing a failure will want to know whether the kernel
74*4882a593Smuzhiyun * supports x32. Tell them.
75*4882a593Smuzhiyun */
76*4882a593Smuzhiyun printf("\tChecking for x32...");
77*4882a593Smuzhiyun fflush(stdout);
78*4882a593Smuzhiyun if (syscall(39 | X32_BIT, 0, 0, 0, 0, 0, 0) >= 0) {
79*4882a593Smuzhiyun printf(" supported\n");
80*4882a593Smuzhiyun } else if (errno == ENOSYS) {
81*4882a593Smuzhiyun printf(" not supported\n");
82*4882a593Smuzhiyun } else {
83*4882a593Smuzhiyun printf(" confused\n");
84*4882a593Smuzhiyun }
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun test_x32_without_x32_bit();
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun return nerrs ? 1 : 0;
89*4882a593Smuzhiyun }
90