cregit-Linux how code gets into the kernel

Release 4.11 crypto/jitterentropy-kcapi.c

Directory: crypto
/*
 * Non-physical true random number generator based on timing jitter --
 * Linux Kernel Crypto API specific code
 *
 * Copyright Stephan Mueller <smueller@chronox.de>, 2015
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, and the entire permission notice in its entirety,
 *    including the disclaimer of warranties.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.
 *
 * ALTERNATIVELY, this product may be distributed under the terms of
 * the GNU General Public License, in which case the provisions of the GPL2 are
 * required INSTEAD OF the above restrictions.  (This clause is
 * necessary due to a potential bad interaction between the GPL and
 * the restrictions contained in a BSD-style copyright.)
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/fips.h>
#include <linux/time.h>
#include <linux/crypto.h>
#include <crypto/internal/rng.h>

struct rand_data;
int jent_read_entropy(struct rand_data *ec, unsigned char *data,
		      unsigned int len);
int jent_entropy_init(void);
struct rand_data *jent_entropy_collector_alloc(unsigned int osr,
					       unsigned int flags);
void jent_entropy_collector_free(struct rand_data *entropy_collector);

/***************************************************************************
 * Helper function
 ***************************************************************************/


__u64 jent_rol64(__u64 word, unsigned int shift) { return rol64(word, shift); }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller20100.00%1100.00%
Total20100.00%1100.00%


void *jent_zalloc(unsigned int len) { return kzalloc(len, GFP_KERNEL); }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller18100.00%1100.00%
Total18100.00%1100.00%


void jent_zfree(void *ptr) { kzfree(ptr); }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller14100.00%1100.00%
Total14100.00%1100.00%


int jent_fips_enabled(void) { return fips_enabled; }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller10100.00%1100.00%
Total10100.00%1100.00%


void jent_panic(char *s) { panic("%s", s); }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller1487.50%150.00%
Kees Cook212.50%150.00%
Total16100.00%2100.00%


void jent_memcpy(void *dest, const void *src, unsigned int n) { memcpy(dest, src, n); }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller27100.00%1100.00%
Total27100.00%1100.00%

/* * Obtain a high-resolution time stamp value. The time stamp is used to measure * the execution time of a given code path and its variations. Hence, the time * stamp must have a sufficiently high resolution. * * Note, if the function returns zero because a given architecture does not * implement a high-resolution time stamp, the RNG code's runtime test * will detect it and will not produce output. */
void jent_get_nstime(__u64 *out) { __u64 tmp = 0; tmp = random_get_entropy(); /* * If random_get_entropy does not return a value, i.e. it is not * implemented for a given architecture, use a clock source. * hoping that there are timers we can work with. */ if (tmp == 0) tmp = ktime_get_ns(); *out = tmp; }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller36100.00%2100.00%
Total36100.00%2100.00%

/*************************************************************************** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller60100.00%1100.00%
Total60100.00%1100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller56100.00%1100.00%
Total56100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller75100.00%1100.00%
Total75100.00%1100.00%


static int jent_kcapi_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen) { return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller23100.00%1100.00%
Total23100.00%1100.00%

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("jitterentropy: Initialization failed with host not compliant with requirements: %d\n", ret); return -EFAULT; } return crypto_register_rng(&jent_alg); }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller43100.00%1100.00%
Total43100.00%1100.00%


static void __exit jent_mod_exit(void) { crypto_unregister_rng(&jent_alg); }

Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller15100.00%1100.00%
Total15100.00%1100.00%

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");

Overall Contributors

PersonTokensPropCommitsCommitProp
Stephan Mueller59299.66%266.67%
Kees Cook20.34%133.33%
Total594100.00%3100.00%
Directory: crypto
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