/*
- * Non-physical true random number generator based on timing jitter.
+ * Non-physical true random number generator based on timing jitter --
+ * Jitter RNG standalone code.
*
- * Copyright Stephan Mueller <smueller@chronox.de>, 2014
+ * Copyright Stephan Mueller <smueller@chronox.de>, 2015
*
* Design
* ======
* version 1.1.0 provided at http://www.chronox.de/jent.html
*/
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/module.h>
-#include <linux/fips.h>
-#include <linux/time.h>
-#include <linux/crypto.h>
-#include <crypto/internal/rng.h>
+#ifdef __OPTIMIZE__
+ #error "The CPU Jitter random number generator must not be compiled with optimizations. See documentation. Use the compiler switch -O0 for compiling jitterentropy.c."
+#endif
+
+typedef unsigned long long __u64;
+typedef long long __s64;
+typedef unsigned int __u32;
+#define NULL ((void *) 0)
/* The entropy pool */
struct rand_data {
* entropy, saves MEMORY_SIZE RAM for
* entropy collector */
-#define DRIVER_NAME "jitterentropy"
-
/* -- error codes for init function -- */
#define JENT_ENOTIME 1 /* Timer service not available */
#define JENT_ECOARSETIME 2 /* Timer too coarse for RNG */
* Helper functions
***************************************************************************/
-static inline void jent_get_nstime(__u64 *out)
-{
- struct timespec ts;
- __u64 tmp = 0;
-
- tmp = random_get_entropy();
-
- /*
- * If random_get_entropy does not return a value (which is possible on,
- * for example, MIPS), invoke __getnstimeofday
- * hoping that there are timers we can work with.
- *
- * The list of available timers can be obtained from
- * /sys/devices/system/clocksource/clocksource0/available_clocksource
- * and are registered with clocksource_register()
- */
- if ((0 == tmp) &&
- (0 == __getnstimeofday(&ts))) {
- tmp = ts.tv_sec;
- tmp = tmp << 32;
- tmp = tmp | ts.tv_nsec;
- }
-
- *out = tmp;
-}
-
+void jent_get_nstime(__u64 *out);
+__u64 jent_rol64(__u64 word, unsigned int shift);
+void *jent_zalloc(unsigned int len);
+void jent_zfree(void *ptr);
+int jent_fips_enabled(void);
+void jent_panic(char *s);
+void jent_memcpy(void *dest, const void *src, unsigned int n);
/**
* Update of the loop count used for the next round of
* Noise sources
***************************************************************************/
-/*
- * The disabling of the optimizations is performed as documented and assessed
- * thoroughly in http://www.chronox.de/jent.html. However, instead of disabling
- * the optimization of the entire C file, only the main functions the jitter is
- * measured for are not optimized. These functions include the noise sources as
- * well as the main functions triggering the noise sources. As the time
- * measurement is done from one invocation of the jitter noise source to the
- * next, even the execution jitter of the code invoking the noise sources
- * contribute to the overall randomness as well. The behavior of the RNG and the
- * statistical characteristics when only the mentioned functions are not
- * optimized is almost equal to the a completely non-optimized RNG compilation
- * as tested with the test tools provided at the initially mentioned web site.
- */
-
/**
* CPU Jitter noise source -- this is the noise source based on the CPU
* execution time jitter
*
* @return Number of loops the folding operation is performed
*/
-#pragma GCC push_options
-#pragma GCC optimize ("-O0")
static __u64 jent_fold_time(struct rand_data *ec, __u64 time,
__u64 *folded, __u64 loop_cnt)
{
*folded = new;
return fold_loop_cnt;
}
-#pragma GCC pop_options
/**
* Memory Access noise source -- this is a noise source based on variations in
*
* @return Number of memory access operations
*/
-#pragma GCC push_options
-#pragma GCC optimize ("-O0")
static unsigned int jent_memaccess(struct rand_data *ec, __u64 loop_cnt)
{
unsigned char *tmpval = NULL;
}
return i;
}
-#pragma GCC pop_options
/***************************************************************************
* Start of entropy processing logic
*
* @return One random bit
*/
-#pragma GCC push_options
-#pragma GCC optimize ("-O0")
static __u64 jent_measure_jitter(struct rand_data *ec)
{
__u64 time = 0;
return data;
}
-#pragma GCC pop_options
/**
* Von Neuman unbias as explained in RFC 4086 section 4.2. As shown in the
*/
if ((entropy_collector->data >> i) & 1)
mixer.u64 ^= constant.u64;
- mixer.u64 = rol64(mixer.u64, 1);
+ mixer.u64 = jent_rol64(mixer.u64, 1);
}
entropy_collector->data ^= mixer.u64;
}
* Input:
* @ec Reference to entropy collector
*/
-#pragma GCC push_options
-#pragma GCC optimize ("-O0")
static void jent_gen_entropy(struct rand_data *ec)
{
unsigned int k = 0;
ec->data ^= ((ec->data >> 30) & 1);
ec->data ^= ((ec->data >> 27) & 1);
ec->data ^= ((ec->data >> 22) & 1);
- ec->data = rol64(ec->data, 1);
+ ec->data = jent_rol64(ec->data, 1);
/*
* We multiply the loop value with ->osr to obtain the
if (ec->stir)
jent_stir_pool(ec);
}
-#pragma GCC pop_options
/**
* The continuous test required by FIPS 140-2 -- the function automatically
*/
static void jent_fips_test(struct rand_data *ec)
{
- if (!fips_enabled)
+ if (!jent_fips_enabled())
return;
/* prime the FIPS test */
}
if (ec->data == ec->old_data)
- panic(DRIVER_NAME ": Duplicate output detected\n");
+ jent_panic("jitterentropy: Duplicate output detected\n");
ec->old_data = ec->data;
}
-
/**
* Entry function: Obtain entropy for the caller.
*
* The following error codes can occur:
* -1 entropy_collector is NULL
*/
-static ssize_t jent_read_entropy(struct rand_data *ec, u8 *data, size_t len)
+int jent_read_entropy(struct rand_data *ec, unsigned char *data,
+ unsigned int len)
{
- u8 *p = data;
+ unsigned char *p = data;
if (!ec)
- return -EINVAL;
+ return -1;
while (0 < len) {
- size_t tocopy;
+ unsigned int tocopy;
jent_gen_entropy(ec);
jent_fips_test(ec);
tocopy = (DATA_SIZE_BITS / 8);
else
tocopy = len;
- memcpy(p, &ec->data, tocopy);
+ jent_memcpy(p, &ec->data, tocopy);
len -= tocopy;
p += tocopy;
* Initialization logic
***************************************************************************/
-static struct rand_data *jent_entropy_collector_alloc(unsigned int osr,
- unsigned int flags)
+struct rand_data *jent_entropy_collector_alloc(unsigned int osr,
+ unsigned int flags)
{
struct rand_data *entropy_collector;
- entropy_collector = kzalloc(sizeof(struct rand_data), GFP_KERNEL);
+ entropy_collector = jent_zalloc(sizeof(struct rand_data));
if (!entropy_collector)
return NULL;
/* Allocate memory for adding variations based on memory
* access
*/
- entropy_collector->mem = kzalloc(JENT_MEMORY_SIZE, GFP_KERNEL);
+ entropy_collector->mem = jent_zalloc(JENT_MEMORY_SIZE);
if (!entropy_collector->mem) {
- kfree(entropy_collector);
+ jent_zfree(entropy_collector);
return NULL;
}
entropy_collector->memblocksize = JENT_MEMORY_BLOCKSIZE;
return entropy_collector;
}
-static void jent_entropy_collector_free(struct rand_data *entropy_collector)
+void jent_entropy_collector_free(struct rand_data *entropy_collector)
{
- if (entropy_collector->mem)
- kzfree(entropy_collector->mem);
+ jent_zfree(entropy_collector->mem);
entropy_collector->mem = NULL;
- if (entropy_collector)
- kzfree(entropy_collector);
+ jent_zfree(entropy_collector);
entropy_collector = NULL;
}
-static int jent_entropy_init(void)
+int jent_entropy_init(void)
{
int i;
__u64 delta_sum = 0;
return 0;
}
-
-/***************************************************************************
- * Kernel crypto API interface
- ***************************************************************************/
-
-struct jitterentropy {
- spinlock_t jent_lock;
- struct rand_data *entropy_collector;
-};
-
-static int jent_kcapi_init(struct crypto_tfm *tfm)
-{
- struct jitterentropy *rng = crypto_tfm_ctx(tfm);
- int ret = 0;
-
- rng->entropy_collector = jent_entropy_collector_alloc(1, 0);
- if (!rng->entropy_collector)
- ret = -ENOMEM;
-
- spin_lock_init(&rng->jent_lock);
- return ret;
-}
-
-static void jent_kcapi_cleanup(struct crypto_tfm *tfm)
-{
- struct jitterentropy *rng = crypto_tfm_ctx(tfm);
-
- spin_lock(&rng->jent_lock);
- if (rng->entropy_collector)
- jent_entropy_collector_free(rng->entropy_collector);
- rng->entropy_collector = NULL;
- spin_unlock(&rng->jent_lock);
-}
-
-static int jent_kcapi_random(struct crypto_rng *tfm,
- const u8 *src, unsigned int slen,
- u8 *rdata, unsigned int dlen)
-{
- struct jitterentropy *rng = crypto_rng_ctx(tfm);
- int ret = 0;
-
- spin_lock(&rng->jent_lock);
- ret = jent_read_entropy(rng->entropy_collector, rdata, dlen);
- spin_unlock(&rng->jent_lock);
-
- return ret;
-}
-
-static int jent_kcapi_reset(struct crypto_rng *tfm,
- const u8 *seed, unsigned int slen)
-{
- return 0;
-}
-
-static struct rng_alg jent_alg = {
- .generate = jent_kcapi_random,
- .seed = jent_kcapi_reset,
- .seedsize = 0,
- .base = {
- .cra_name = "jitterentropy_rng",
- .cra_driver_name = "jitterentropy_rng",
- .cra_priority = 100,
- .cra_ctxsize = sizeof(struct jitterentropy),
- .cra_module = THIS_MODULE,
- .cra_init = jent_kcapi_init,
- .cra_exit = jent_kcapi_cleanup,
-
- }
-};
-
-static int __init jent_mod_init(void)
-{
- int ret = 0;
-
- ret = jent_entropy_init();
- if (ret) {
- pr_info(DRIVER_NAME ": Initialization failed with host not compliant with requirements: %d\n", ret);
- return -EFAULT;
- }
- return crypto_register_rng(&jent_alg);
-}
-
-static void __exit jent_mod_exit(void)
-{
- crypto_unregister_rng(&jent_alg);
-}
-
-module_init(jent_mod_init);
-module_exit(jent_mod_exit);
-
-MODULE_LICENSE("Dual BSD/GPL");
-MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
-MODULE_DESCRIPTION("Non-physical True Random Number Generator based on CPU Jitter");
-MODULE_ALIAS_CRYPTO("jitterentropy_rng");
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