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
23 static int nerrs = 0;
24
25 static 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
38 static 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
48 static jmp_buf jmpbuf;
49
50 static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
51 {
52 siglongjmp(jmpbuf, 1);
53 }
54
55 static 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
68 static 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
78 static 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
88 int 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 printf("[RUN]\tchild: Extend permissions to 0x81\n");
135 if (ioperm(0x81, 1, 1) != 0) {
136 printf("[FAIL]\tioperm(0x81, 1, 1) failed (%d)", errno);
137 return 1;
138 }
139 printf("[RUN]\tchild: Drop permissions to 0x80\n");
140 if (ioperm(0x80, 1, 0) != 0) {
141 printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
142 return 1;
143 }
144 expect_gp(0x80);
145 return 0;
146 } else {
147 int status;
148 if (waitpid(child, &status, 0) != child ||
149 !WIFEXITED(status)) {
150 printf("[FAIL]\tChild died\n");
151 nerrs++;
152 } else if (WEXITSTATUS(status) != 0) {
153 printf("[FAIL]\tChild failed\n");
154 nerrs++;
155 } else {
156 printf("[OK]\tChild succeeded\n");
157 }
158 }
159
160 /* Verify that the child dropping 0x80 did not affect the parent */
161 printf("\tVerify that unsharing the bitmap worked\n");
162 expect_ok(0x80);
163
164 /* Test the capability checks. */
165 printf("\tDrop privileges\n");
166 if (setresuid(1, 1, 1) != 0) {
167 printf("[WARN]\tDropping privileges failed\n");
168 return 0;
169 }
170
171 printf("[RUN]\tdisable 0x80\n");
172 if (ioperm(0x80, 1, 0) != 0) {
173 printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
174 return 1;
175 }
176 printf("[OK]\tit worked\n");
177
178 printf("[RUN]\tenable 0x80 again\n");
179 if (ioperm(0x80, 1, 1) == 0) {
180 printf("[FAIL]\tit succeeded but should have failed.\n");
181 return 1;
182 }
183 printf("[OK]\tit failed\n");
184 return 0;
185 }
186
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