blob: 20888226465531dbc3ed9bd2edc84532216976c0 [file] [log] [blame] [edit]
/*
* A system independant way of adding entropy to the kernels pool
* this way the drivers can focus on the real work and we can take
* care of pushing it to the appropriate place in the kernel.
*
* This should be fast and callable from timers/interrupts
*
* Written by David McCullough <david_mccullough@mcafee.com>
* Copyright (C) 2006-2010 David McCullough
* Copyright (C) 2004-2005 Intel Corporation.
*
* LICENSE TERMS
*
* The free distribution and use of this software in both source and binary
* form is allowed (with or without changes) provided that:
*
* 1. distributions of this source code include the above copyright
* notice, this list of conditions and the following disclaimer;
*
* 2. distributions in binary form include the above copyright
* notice, this list of conditions and the following disclaimer
* in the documentation and/or other associated materials;
*
* 3. the copyright holder's name is not used to endorse products
* built using this software without specific written permission.
*
* ALTERNATIVELY, provided that this notice is retained in full, this product
* may be distributed under the terms of the GNU General Public License (GPL),
* in which case the provisions of the GPL apply INSTEAD OF those given above.
*
* DISCLAIMER
*
* This software is provided 'as is' with no explicit or implied warranties
* in respect of its properties, including, but not limited to, correctness
* and/or fitness for purpose.
*/
#ifndef AUTOCONF_INCLUDED
#include <linux/config.h>
#endif
#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/version.h>
#include <linux/unistd.h>
#include <linux/poll.h>
#include <linux/random.h>
#include <crypto/cryptodev.h>
#ifdef CONFIG_OCF_FIPS
#include "rndtest.h"
#endif
#ifndef HAS_RANDOM_INPUT_WAIT
#error "Please do not enable OCF_RANDOMHARVEST unless you have applied patches"
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
#include <linux/sched.h>
#define kill_proc(p,s,v) send_sig(s,find_task_by_vpid(p),0)
#endif
/*
* a hack to access the debug levels from the crypto driver
*/
extern int crypto_debug;
#define debug crypto_debug
/*
* a list of all registered random providers
*/
static LIST_HEAD(random_ops);
static int started = 0;
static int initted = 0;
struct random_op {
struct list_head random_list;
u_int32_t driverid;
int (*read_random)(void *arg, u_int32_t *buf, int len);
void *arg;
};
static int random_proc(void *arg);
static pid_t randomproc = (pid_t) -1;
static spinlock_t random_lock;
/*
* just init the spin locks
*/
static int
crypto_random_init(void)
{
spin_lock_init(&random_lock);
initted = 1;
return(0);
}
/*
* Add the given random reader to our list (if not present)
* and start the thread (if not already started)
*
* we have to assume that driver id is ok for now
*/
int
crypto_rregister(
u_int32_t driverid,
int (*read_random)(void *arg, u_int32_t *buf, int len),
void *arg)
{
unsigned long flags;
int ret = 0;
struct random_op *rops, *tmp;
dprintk("%s,%d: %s(0x%x, %p, %p)\n", __FILE__, __LINE__,
__FUNCTION__, driverid, read_random, arg);
if (!initted)
crypto_random_init();
#if 0
struct cryptocap *cap;
cap = crypto_checkdriver(driverid);
if (!cap)
return EINVAL;
#endif
list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
if (rops->driverid == driverid && rops->read_random == read_random)
return EEXIST;
}
rops = (struct random_op *) kmalloc(sizeof(*rops), GFP_KERNEL);
if (!rops)
return ENOMEM;
rops->driverid = driverid;
rops->read_random = read_random;
rops->arg = arg;
spin_lock_irqsave(&random_lock, flags);
list_add_tail(&rops->random_list, &random_ops);
if (!started) {
randomproc = kernel_thread(random_proc, NULL, CLONE_FS|CLONE_FILES);
if (randomproc < 0) {
ret = randomproc;
printk("crypto: crypto_rregister cannot start random thread; "
"error %d", ret);
} else
started = 1;
}
spin_unlock_irqrestore(&random_lock, flags);
return ret;
}
EXPORT_SYMBOL(crypto_rregister);
int
crypto_runregister_all(u_int32_t driverid)
{
struct random_op *rops, *tmp;
unsigned long flags;
dprintk("%s,%d: %s(0x%x)\n", __FILE__, __LINE__, __FUNCTION__, driverid);
list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
if (rops->driverid == driverid) {
list_del(&rops->random_list);
kfree(rops);
}
}
spin_lock_irqsave(&random_lock, flags);
if (list_empty(&random_ops) && started)
kill_proc(randomproc, SIGKILL, 1);
spin_unlock_irqrestore(&random_lock, flags);
return(0);
}
EXPORT_SYMBOL(crypto_runregister_all);
/*
* while we can add entropy to random.c continue to read random data from
* the drivers and push it to random.
*/
static int
random_proc(void *arg)
{
int n;
int wantcnt;
int bufcnt = 0;
int retval = 0;
int *buf = NULL;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
daemonize();
spin_lock_irq(&current->sigmask_lock);
sigemptyset(&current->blocked);
recalc_sigpending(current);
spin_unlock_irq(&current->sigmask_lock);
sprintf(current->comm, "ocf-random");
#else
daemonize("ocf-random");
allow_signal(SIGKILL);
#endif
(void) get_fs();
set_fs(get_ds());
#ifdef CONFIG_OCF_FIPS
#define NUM_INT (RNDTEST_NBYTES/sizeof(int))
#else
#define NUM_INT 32
#endif
/*
* some devices can transferr their RNG data direct into memory,
* so make sure it is device friendly
*/
buf = kmalloc(NUM_INT * sizeof(int), GFP_DMA);
if (NULL == buf) {
printk("crypto: RNG could not allocate memory\n");
retval = -ENOMEM;
goto bad_alloc;
}
wantcnt = NUM_INT; /* start by adding some entropy */
/*
* its possible due to errors or driver removal that we no longer
* have anything to do, if so exit or we will consume all the CPU
* doing nothing
*/
while (!list_empty(&random_ops)) {
struct random_op *rops, *tmp;
#ifdef CONFIG_OCF_FIPS
if (wantcnt)
wantcnt = NUM_INT; /* FIPs mode can do 20000 bits or none */
#endif
/* see if we can get enough entropy to make the world
* a better place.
*/
while (bufcnt < wantcnt && bufcnt < NUM_INT) {
list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
n = (*rops->read_random)(rops->arg, &buf[bufcnt],
NUM_INT - bufcnt);
/* on failure remove the random number generator */
if (n == -1) {
list_del(&rops->random_list);
printk("crypto: RNG (driverid=0x%x) failed, disabling\n",
rops->driverid);
kfree(rops);
} else if (n > 0)
bufcnt += n;
}
/* give up CPU for a bit, just in case as this is a loop */
schedule();
}
#ifdef CONFIG_OCF_FIPS
if (bufcnt > 0 && rndtest_buf((unsigned char *) &buf[0])) {
dprintk("crypto: buffer had fips errors, discarding\n");
bufcnt = 0;
}
#endif
/*
* if we have a certified buffer, we can send some data
* to /dev/random and move along
*/
if (bufcnt > 0) {
/* add what we have */
random_input_words(buf, bufcnt, bufcnt*sizeof(int)*8);
bufcnt = 0;
}
/* give up CPU for a bit so we don't hog while filling */
schedule();
/* wait for needing more */
wantcnt = random_input_wait();
if (wantcnt <= 0)
wantcnt = 0; /* try to get some info again */
else
/* round up to one word or we can loop forever */
wantcnt = (wantcnt + (sizeof(int)*8)) / (sizeof(int)*8);
if (wantcnt > NUM_INT) {
wantcnt = NUM_INT;
}
if (signal_pending(current)) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
spin_lock_irq(&current->sigmask_lock);
#endif
flush_signals(current);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
spin_unlock_irq(&current->sigmask_lock);
#endif
}
}
kfree(buf);
bad_alloc:
spin_lock_irq(&random_lock);
randomproc = (pid_t) -1;
started = 0;
spin_unlock_irq(&random_lock);
return retval;
}