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amlutorkrcmar
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selftests/x86: Add a basic selftest for ioperm
This doesn't fully exercise the interaction between KVM and ioperm(), but it does test basic functionality. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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‎tools/testing/selftests/x86/Makefile

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@@ -5,7 +5,7 @@ include ../lib.mk
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.PHONY: all all_32 all_64 warn_32bit_failure clean
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TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall test_mremap_vdso \
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check_initial_reg_state sigreturn ldt_gdt iopl mpx-mini-test \
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check_initial_reg_state sigreturn ldt_gdt iopl mpx-mini-test ioperm \
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protection_keys test_vdso
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TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \
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test_FCMOV test_FCOMI test_FISTTP \

‎tools/testing/selftests/x86/ioperm.c

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/*
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* ioperm.c - Test case for ioperm(2)
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* Copyright (c) 2015 Andrew Lutomirski
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*/
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#define _GNU_SOURCE
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#include <err.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <signal.h>
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#include <setjmp.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <stdbool.h>
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#include <sched.h>
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#include <sys/io.h>
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static int nerrs = 0;
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static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
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int flags)
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{
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struct sigaction sa;
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memset(&sa, 0, sizeof(sa));
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sa.sa_sigaction = handler;
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sa.sa_flags = SA_SIGINFO | flags;
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sigemptyset(&sa.sa_mask);
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if (sigaction(sig, &sa, 0))
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err(1, "sigaction");
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}
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static void clearhandler(int sig)
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{
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struct sigaction sa;
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memset(&sa, 0, sizeof(sa));
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sa.sa_handler = SIG_DFL;
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sigemptyset(&sa.sa_mask);
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if (sigaction(sig, &sa, 0))
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err(1, "sigaction");
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}
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static jmp_buf jmpbuf;
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static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
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{
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siglongjmp(jmpbuf, 1);
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}
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static bool try_outb(unsigned short port)
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{
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sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
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if (sigsetjmp(jmpbuf, 1) != 0) {
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return false;
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} else {
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asm volatile ("outb %%al, %w[port]"
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: : [port] "Nd" (port), "a" (0));
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return true;
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}
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clearhandler(SIGSEGV);
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}
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static void expect_ok(unsigned short port)
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{
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if (!try_outb(port)) {
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printf("[FAIL]\toutb to 0x%02hx failed\n", port);
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exit(1);
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}
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printf("[OK]\toutb to 0x%02hx worked\n", port);
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}
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static void expect_gp(unsigned short port)
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{
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if (try_outb(port)) {
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printf("[FAIL]\toutb to 0x%02hx worked\n", port);
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exit(1);
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}
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printf("[OK]\toutb to 0x%02hx failed\n", port);
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}
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int main(void)
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{
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cpu_set_t cpuset;
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CPU_ZERO(&cpuset);
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CPU_SET(0, &cpuset);
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if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
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err(1, "sched_setaffinity to CPU 0");
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expect_gp(0x80);
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expect_gp(0xed);
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/*
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* Probe for ioperm support. Note that clearing ioperm bits
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* works even as nonroot.
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*/
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printf("[RUN]\tenable 0x80\n");
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if (ioperm(0x80, 1, 1) != 0) {
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printf("[OK]\tioperm(0x80, 1, 1) failed (%d) -- try running as root\n",
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errno);
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return 0;
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}
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expect_ok(0x80);
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expect_gp(0xed);
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printf("[RUN]\tdisable 0x80\n");
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if (ioperm(0x80, 1, 0) != 0) {
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printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
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return 1;
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}
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expect_gp(0x80);
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expect_gp(0xed);
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/* Make sure that fork() preserves ioperm. */
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if (ioperm(0x80, 1, 1) != 0) {
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printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
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return 1;
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}
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pid_t child = fork();
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if (child == -1)
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err(1, "fork");
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if (child == 0) {
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printf("[RUN]\tchild: check that we inherited permissions\n");
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expect_ok(0x80);
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expect_gp(0xed);
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return 0;
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} else {
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int status;
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if (waitpid(child, &status, 0) != child ||
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!WIFEXITED(status)) {
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printf("[FAIL]\tChild died\n");
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nerrs++;
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} else if (WEXITSTATUS(status) != 0) {
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printf("[FAIL]\tChild failed\n");
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nerrs++;
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} else {
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printf("[OK]\tChild succeeded\n");
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}
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}
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/* Test the capability checks. */
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printf("\tDrop privileges\n");
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if (setresuid(1, 1, 1) != 0) {
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printf("[WARN]\tDropping privileges failed\n");
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return 0;
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}
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printf("[RUN]\tdisable 0x80\n");
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if (ioperm(0x80, 1, 0) != 0) {
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printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
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return 1;
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}
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printf("[OK]\tit worked\n");
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printf("[RUN]\tenable 0x80 again\n");
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if (ioperm(0x80, 1, 1) == 0) {
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printf("[FAIL]\tit succeeded but should have failed.\n");
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return 1;
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}
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printf("[OK]\tit failed\n");
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return 0;
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}

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