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Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ioperm.c - Test case for ioperm(2)
4 * Copyright (c) 2015 Andrew Lutomirski
5 */
6
7#define _GNU_SOURCE
8#include <err.h>
9#include <stdio.h>
10#include <stdint.h>
11#include <signal.h>
12#include <setjmp.h>
13#include <stdlib.h>
14#include <string.h>
15#include <errno.h>
16#include <unistd.h>
17#include <sys/types.h>
18#include <sys/wait.h>
19#include <stdbool.h>
20#include <sched.h>
21#include <sys/io.h>
22
23static int nerrs = 0;
24
25static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
26 int flags)
27{
28 struct sigaction sa;
29 memset(&sa, 0, sizeof(sa));
30 sa.sa_sigaction = handler;
31 sa.sa_flags = SA_SIGINFO | flags;
32 sigemptyset(&sa.sa_mask);
33 if (sigaction(sig, &sa, 0))
34 err(1, "sigaction");
35
36}
37
38static void clearhandler(int sig)
39{
40 struct sigaction sa;
41 memset(&sa, 0, sizeof(sa));
42 sa.sa_handler = SIG_DFL;
43 sigemptyset(&sa.sa_mask);
44 if (sigaction(sig, &sa, 0))
45 err(1, "sigaction");
46}
47
48static jmp_buf jmpbuf;
49
50static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
51{
52 siglongjmp(jmpbuf, 1);
53}
54
55static bool try_outb(unsigned short port)
56{
57 sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
58 if (sigsetjmp(jmpbuf, 1) != 0) {
59 return false;
60 } else {
61 asm volatile ("outb %%al, %w[port]"
62 : : [port] "Nd" (port), "a" (0));
63 return true;
64 }
65 clearhandler(SIGSEGV);
66}
67
68static void expect_ok(unsigned short port)
69{
70 if (!try_outb(port)) {
71 printf("[FAIL]\toutb to 0x%02hx failed\n", port);
72 exit(1);
73 }
74
75 printf("[OK]\toutb to 0x%02hx worked\n", port);
76}
77
78static void expect_gp(unsigned short port)
79{
80 if (try_outb(port)) {
81 printf("[FAIL]\toutb to 0x%02hx worked\n", port);
82 exit(1);
83 }
84
85 printf("[OK]\toutb to 0x%02hx failed\n", port);
86}
87
88int main(void)
89{
90 cpu_set_t cpuset;
91 CPU_ZERO(&cpuset);
92 CPU_SET(0, &cpuset);
93 if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
94 err(1, "sched_setaffinity to CPU 0");
95
96 expect_gp(0x80);
97 expect_gp(0xed);
98
99 /*
100 * Probe for ioperm support. Note that clearing ioperm bits
101 * works even as nonroot.
102 */
103 printf("[RUN]\tenable 0x80\n");
104 if (ioperm(0x80, 1, 1) != 0) {
105 printf("[OK]\tioperm(0x80, 1, 1) failed (%d) -- try running as root\n",
106 errno);
107 return 0;
108 }
109 expect_ok(0x80);
110 expect_gp(0xed);
111
112 printf("[RUN]\tdisable 0x80\n");
113 if (ioperm(0x80, 1, 0) != 0) {
114 printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
115 return 1;
116 }
117 expect_gp(0x80);
118 expect_gp(0xed);
119
120 /* Make sure that fork() preserves ioperm. */
121 if (ioperm(0x80, 1, 1) != 0) {
122 printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
123 return 1;
124 }
125
126 pid_t child = fork();
127 if (child == -1)
128 err(1, "fork");
129
130 if (child == 0) {
131 printf("[RUN]\tchild: check that we inherited permissions\n");
132 expect_ok(0x80);
133 expect_gp(0xed);
134 return 0;
135 } else {
136 int status;
137 if (waitpid(child, &status, 0) != child ||
138 !WIFEXITED(status)) {
139 printf("[FAIL]\tChild died\n");
140 nerrs++;
141 } else if (WEXITSTATUS(status) != 0) {
142 printf("[FAIL]\tChild failed\n");
143 nerrs++;
144 } else {
145 printf("[OK]\tChild succeeded\n");
146 }
147 }
148
149 /* Test the capability checks. */
150
151 printf("\tDrop privileges\n");
152 if (setresuid(1, 1, 1) != 0) {
153 printf("[WARN]\tDropping privileges failed\n");
154 return 0;
155 }
156
157 printf("[RUN]\tdisable 0x80\n");
158 if (ioperm(0x80, 1, 0) != 0) {
159 printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
160 return 1;
161 }
162 printf("[OK]\tit worked\n");
163
164 printf("[RUN]\tenable 0x80 again\n");
165 if (ioperm(0x80, 1, 1) == 0) {
166 printf("[FAIL]\tit succeeded but should have failed.\n");
167 return 1;
168 }
169 printf("[OK]\tit failed\n");
170 return 0;
171}