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hwaccess_x86_io: refactor rget_io_perms()

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Abstract the different I/O Port permission methods in own functions.

Change-Id: If4b2f8c2532f3732086ee1d479da6ae6693f9a42
Signed-off-by: Thomas Heijligen <thomas.heijligen@secunet.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/61275
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
This commit is contained in:
Thomas Heijligen 2022-01-20 14:33:56 +01:00 committed by Nico Huber
parent 6f63f20b33
commit a2aa33e24c
1 changed files with 98 additions and 50 deletions
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148
hwaccess_x86_io.c
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@ -2,6 +2,8 @@
* This file is part of the flashrom project.
*
* Copyright (C) 2009,2010 Carl-Daniel Hailfinger
* Copyright (C) 2022 secunet Security Networks AG
* (Written by Thomas Heijligen <thomas.heijligen@secunet.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@ -14,70 +16,116 @@
* GNU General Public License for more details.
*/
/*
* This file implements x86 I/O port permission handling.
*
* For this purpose the platform specific code is encapsuled in two functions
* and compiled only on the respective platform. `platform_get_io_perms()` is
* called to get the permissions and `platform_release_io_perms()` is called for
* releasing those.
*/
#include <errno.h>
#include <string.h>
#if !defined (__DJGPP__) && !defined(__LIBPAYLOAD__)
/* No file access needed/possible to get hardware access permissions. */
#include <unistd.h>
#include <fcntl.h>
#endif
#include "hwaccess_x86_io.h"
#include "flash.h"
#include "hwaccess_x86_io.h"
#if USE_IOPERM
#include <sys/io.h>
#endif
#if USE_DEV_IO
int io_fd;
#endif
#if !(defined(__DJGPP__) || defined(__LIBPAYLOAD__))
static int release_io_perms(void *p)
#if defined(__DJGPP__) || defined(__LIBPAYLOAD) /* DJGPP, libpayload */
static int platform_get_io_perms(void)
{
return 0;
}
static int platform_release_io_perms(void *p)
{
return 0;
}
#endif
#if defined(__sun) /* SunOS */
#include <sys/sysi86.h>
static int platform_get_io_perms(void)
{
return sysi86(SI86V86, V86SC_IOPL, PS_IOPL);
}
static int platform_release_io_perms(void *p)
{
#if defined (__sun)
sysi86(SI86V86, V86SC_IOPL, 0);
#elif USE_DEV_IO
return 0;
}
#endif
#if USE_DEV_IO /* FreeBSD, DragonFlyBSD */
#include <fcntl.h>
#include <unistd.h>
int io_fd;
static int platform_get_io_perms(void)
{
io_fd = open("/dev/io", O_RDWR);
return (io_fd >= 0 ? 0 : -1);
}
static int platform_release_io_perms(void *p)
{
close(io_fd);
#elif USE_IOPERM
return 0;
}
#endif
#if USE_IOPERM /* GNU Hurd */
#include <sys/io.h>
static int platform_get_io_perms(void)
{
return ioperm(0, 65536, 1);
}
static int platform_release_io_perms(void *p)
{
ioperm(0, 65536, 0);
#elif USE_IOPL
return 0;
}
#endif
#if USE_IOPL /* Linux, Darwin, NetBSD, OpenBSD */
static int platform_get_io_perms(void)
{
return iopl(3);
}
static int platform_release_io_perms(void *p)
{
iopl(0);
#endif
return 0;
}
#endif
/* Get I/O permissions with automatic permission release on shutdown. */
/**
* @brief Get access to the x86 I/O ports
*
* This function abstracts the platform dependent function to get access to the
* x86 I/O ports and musst be called before using IN[B/W/L] or OUT[B/W/L].
* It registers a shutdown function to release those privileges.
*
* @return 0 on success, platform specific number on failure
*/
int rget_io_perms(void)
{
#if defined (__sun)
if (sysi86(SI86V86, V86SC_IOPL, PS_IOPL) != 0) {
#elif USE_DEV_IO
if ((io_fd = open("/dev/io", O_RDWR)) < 0) {
#elif USE_IOPERM
if (ioperm(0, 65536, 1) != 0) {
#elif USE_IOPL
if (iopl(3) != 0) {
#endif
msg_perr("ERROR: Could not get I/O privileges (%s).\n", strerror(errno));
msg_perr("You need to be root.\n");
msg_perr("On OpenBSD set securelevel=-1 in /etc/rc.securelevel and\n"
"reboot, or reboot into single user mode.\n");
msg_perr("On NetBSD reboot into single user mode or make sure\n"
"that your kernel configuration has the option INSECURE enabled.\n");
return 1;
} else {
register_shutdown(release_io_perms, NULL);
if (platform_get_io_perms() == 0) {
register_shutdown(platform_release_io_perms, NULL);
return 0;
}
return 0;
msg_perr("ERROR: Could not get I/O privileges (%s).\n", strerror(errno));
msg_perr("Make sure you are root. If you are root, your kernel may still\n"
"prevent access based on security policies.\n");
msg_perr("On OpenBSD set securelevel=-1 in /etc/rc.securelevel and\n"
"reboot, or reboot into single user mode.\n");
msg_perr("On NetBSD reboot into single user mode or make sure\n"
"that your kernel configuration has the option INSECURE enabled.\n");
return 1;
}
#else
/* DJGPP and libpayload environments have full PCI port I/O permissions by default. */
int rget_io_perms(void)
{
return 0;
}
#endif