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 #include "helpers.h"
24
25 static int nerrs = 0;
26
27 static jmp_buf jmpbuf;
28
sigsegv(int sig,siginfo_t * si,void * ctx_void)29 static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
30 {
31 siglongjmp(jmpbuf, 1);
32 }
33
try_outb(unsigned short port)34 static bool try_outb(unsigned short port)
35 {
36 sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
37 if (sigsetjmp(jmpbuf, 1) != 0) {
38 return false;
39 } else {
40 asm volatile ("outb %%al, %w[port]"
41 : : [port] "Nd" (port), "a" (0));
42 return true;
43 }
44 clearhandler(SIGSEGV);
45 }
46
expect_ok(unsigned short port)47 static void expect_ok(unsigned short port)
48 {
49 if (!try_outb(port)) {
50 printf("[FAIL]\toutb to 0x%02hx failed\n", port);
51 exit(1);
52 }
53
54 printf("[OK]\toutb to 0x%02hx worked\n", port);
55 }
56
expect_gp(unsigned short port)57 static void expect_gp(unsigned short port)
58 {
59 if (try_outb(port)) {
60 printf("[FAIL]\toutb to 0x%02hx worked\n", port);
61 exit(1);
62 }
63
64 printf("[OK]\toutb to 0x%02hx failed\n", port);
65 }
66
main(void)67 int main(void)
68 {
69 cpu_set_t cpuset;
70 CPU_ZERO(&cpuset);
71 CPU_SET(0, &cpuset);
72 if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
73 err(1, "sched_setaffinity to CPU 0");
74
75 expect_gp(0x80);
76 expect_gp(0xed);
77
78 /*
79 * Probe for ioperm support. Note that clearing ioperm bits
80 * works even as nonroot.
81 */
82 printf("[RUN]\tenable 0x80\n");
83 if (ioperm(0x80, 1, 1) != 0) {
84 printf("[OK]\tioperm(0x80, 1, 1) failed (%d) -- try running as root\n",
85 errno);
86 return 0;
87 }
88 expect_ok(0x80);
89 expect_gp(0xed);
90
91 printf("[RUN]\tdisable 0x80\n");
92 if (ioperm(0x80, 1, 0) != 0) {
93 printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
94 return 1;
95 }
96 expect_gp(0x80);
97 expect_gp(0xed);
98
99 /* Make sure that fork() preserves ioperm. */
100 if (ioperm(0x80, 1, 1) != 0) {
101 printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
102 return 1;
103 }
104
105 pid_t child = fork();
106 if (child == -1)
107 err(1, "fork");
108
109 if (child == 0) {
110 printf("[RUN]\tchild: check that we inherited permissions\n");
111 expect_ok(0x80);
112 expect_gp(0xed);
113 printf("[RUN]\tchild: Extend permissions to 0x81\n");
114 if (ioperm(0x81, 1, 1) != 0) {
115 printf("[FAIL]\tioperm(0x81, 1, 1) failed (%d)", errno);
116 return 1;
117 }
118 printf("[RUN]\tchild: Drop permissions to 0x80\n");
119 if (ioperm(0x80, 1, 0) != 0) {
120 printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
121 return 1;
122 }
123 expect_gp(0x80);
124 return 0;
125 } else {
126 int status;
127 if (waitpid(child, &status, 0) != child ||
128 !WIFEXITED(status)) {
129 printf("[FAIL]\tChild died\n");
130 nerrs++;
131 } else if (WEXITSTATUS(status) != 0) {
132 printf("[FAIL]\tChild failed\n");
133 nerrs++;
134 } else {
135 printf("[OK]\tChild succeeded\n");
136 }
137 }
138
139 /* Verify that the child dropping 0x80 did not affect the parent */
140 printf("\tVerify that unsharing the bitmap worked\n");
141 expect_ok(0x80);
142
143 /* Test the capability checks. */
144 printf("\tDrop privileges\n");
145 if (setresuid(1, 1, 1) != 0) {
146 printf("[WARN]\tDropping privileges failed\n");
147 return 0;
148 }
149
150 printf("[RUN]\tdisable 0x80\n");
151 if (ioperm(0x80, 1, 0) != 0) {
152 printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
153 return 1;
154 }
155 printf("[OK]\tit worked\n");
156
157 printf("[RUN]\tenable 0x80 again\n");
158 if (ioperm(0x80, 1, 1) == 0) {
159 printf("[FAIL]\tit succeeded but should have failed.\n");
160 return 1;
161 }
162 printf("[OK]\tit failed\n");
163 return 0;
164 }
165