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