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/*
* 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;
}
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