/*
* Copyright (c) 1999-2009 Apple, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <string.h>
#include <miscfs/devfs/devfs.h>
#include <kern/locks.h>
#include <kern/clock.h>
#include <sys/time.h>
#include <sys/malloc.h>
#include <sys/sysproto.h>
#include <sys/uio_internal.h>
#include <dev/random/randomdev.h>
#include <libkern/OSByteOrder.h>
#include <libkern/OSAtomic.h>
#include <mach/mach_time.h>
#define RANDOM_MAJOR -1 /* let the kernel pick the device number */
#define RANDOM_MINOR 0
#define URANDOM_MINOR 1
d_ioctl_t random_ioctl;
static int
random_stop(__unused struct tty *tp, __unused int rw)
{
return 0;
}
static int
random_reset(__unused int uban)
{
return 0;
}
static int
random_select(__unused dev_t dev, __unused int which, __unused void *wql,
__unused struct proc *p)
{
return ENODEV;
}
static const struct cdevsw random_cdevsw =
{
.d_open = random_open,
.d_close = random_close,
.d_read = random_read,
.d_write = random_write,
.d_ioctl = random_ioctl,
.d_stop = random_stop,
.d_reset = random_reset,
.d_select = random_select,
.d_mmap = eno_mmap,
.d_strategy = eno_strat,
.d_reserved_1 = eno_getc,
.d_reserved_2 = eno_putc,
};
/*
* Called to initialize our device,
* and to register ourselves with devfs
*/
void
random_init(void)
{
int ret;
ret = cdevsw_add(RANDOM_MAJOR, &random_cdevsw);
if (ret < 0) {
panic("random_init: failed to allocate a major number!");
}
devfs_make_node(makedev(ret, RANDOM_MINOR), DEVFS_CHAR,
UID_ROOT, GID_WHEEL, 0666, "random");
/*
* also make urandom
* (which is exactly the same thing in our context)
*/
devfs_make_node(makedev(ret, URANDOM_MINOR), DEVFS_CHAR,
UID_ROOT, GID_WHEEL, 0666, "urandom");
}
int
random_ioctl( __unused dev_t dev, u_long cmd, __unused caddr_t data,
__unused int flag, __unused struct proc *p )
{
switch (cmd) {
case FIONBIO:
case FIOASYNC:
break;
default:
return ENODEV;
}
return 0;
}
/*
* Open the device. Make sure init happened, and make sure the caller is
* authorized.
*/
int
random_open(__unused dev_t dev, int flags, __unused int devtype, __unused struct proc *p)
{
/*
* if we are being opened for write,
* make sure that we have privledges do so
*/
if (flags & FWRITE) {
if (securelevel >= 2) {
return EPERM;
}
#ifndef __APPLE__
if ((securelevel >= 1) && proc_suser(p)) {
return EPERM;
}
#endif /* !__APPLE__ */
}
return 0;
}
/*
* close the device.
*/
int
random_close(__unused dev_t dev, __unused int flags, __unused int mode, __unused struct proc *p)
{
return 0;
}
/*
* Get entropic data from the Security Server, and use it to reseed the
* prng.
*/
int
random_write(dev_t dev, struct uio *uio, __unused int ioflag)
{
int retCode = 0;
char rdBuffer[256];
if (minor(dev) != RANDOM_MINOR) {
return EPERM;
}
/* Security server is sending us entropy */
while ((size_t)uio_resid(uio) > 0 && retCode == 0) {
/* get the user's data */
size_t bytesToInput = MIN((size_t)uio_resid(uio), sizeof(rdBuffer));
retCode = uiomove(rdBuffer, (int)bytesToInput, uio);
if (retCode != 0) {
break;
}
retCode = write_random(rdBuffer, (u_int)bytesToInput);
if (retCode != 0) {
break;
}
}
return retCode;
}
/*
* return data to the caller. Results unpredictable.
*/
int
random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
{
int retCode = 0;
char buffer[512];
size_t bytes_remaining = (size_t)uio_resid(uio);
while (bytes_remaining > 0 && retCode == 0) {
size_t bytesToRead = MIN(bytes_remaining, sizeof(buffer));
read_random(buffer, (u_int)bytesToRead);
retCode = uiomove(buffer, (int)bytesToRead, uio);
if (retCode != 0) {
break;
}
bytes_remaining = (size_t)uio_resid(uio);
}
return retCode;
}
/*
* Return an u_int32_t pseudo-random number.
*/
u_int32_t
RandomULong(void)
{
u_int32_t buf;
read_random(&buf, sizeof(buf));
return buf;
}
int
getentropy(__unused struct proc * p, struct getentropy_args *gap, __unused int * ret)
{
user_addr_t user_addr;
user_size_t user_size;
char buffer[256];
user_addr = (user_addr_t)gap->buffer;
user_size = gap->size;
/* Can't request more than 256 random bytes
* at once. Complying with openbsd getentropy()
*/
if (user_size > sizeof(buffer)) {
return EINVAL;
}
read_random(buffer, (u_int)user_size);
return copyout(buffer, user_addr, user_size);
}