linux/tools/testing/selftests/x86/ioperm.c
Thomas Gleixner 0907a09c2e selftests/x86/ioperm: Extend testing so the shared bitmap is exercised
Add code to the fork path which forces the shared bitmap to be duplicated
and the reference count to be dropped. Verify that the child modifications
did not affect the parent.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2019-11-16 11:24:04 +01:00

186 lines
4.0 KiB
C

// 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);
printf("[RUN]\tchild: Extend permissions to 0x81\n");
if (ioperm(0x81, 1, 1) != 0) {
printf("[FAIL]\tioperm(0x81, 1, 1) failed (%d)", errno);
return 1;
}
printf("[RUN]\tchild: Drop permissions to 0x80\n");
if (ioperm(0x80, 1, 0) != 0) {
printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
return 1;
}
expect_gp(0x80);
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");
}
}
/* Verify that the child dropping 0x80 did not affect the parent */
printf("\tVerify that unsharing the bitmap worked\n");
expect_ok(0x80);
/* 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;
}