Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 364 insertions, 0 deletions

diff --git a/crypto/jitterentropy-kcapi.c b/crypto/jitterentropy-kcapi.c
new file mode 100644
index 0000000000..7d1463a156
--- /dev/null
+++ b/crypto/jitterentropy-kcapi.c
@@ -0,0 +1,364 @@
+/*
+ * Non-physical true random number generator based on timing jitter --
+ * Linux Kernel Crypto API specific code
+ *
+ * Copyright Stephan Mueller <smueller@chronox.de>, 2015 - 2023
+ *
+ * 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 <crypto/hash.h>
+#include <crypto/sha3.h>
+#include <linux/fips.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <crypto/internal/rng.h>
+
+#include "jitterentropy.h"
+
+#define JENT_CONDITIONING_HASH	"sha3-256-generic"
+
+/***************************************************************************
+ * Helper function
+ ***************************************************************************/
+
+void *jent_zalloc(unsigned int len)
+{
+	return kzalloc(len, GFP_KERNEL);
+}
+
+void jent_zfree(void *ptr)
+{
+	kfree_sensitive(ptr);
+}
+
+/*
+ * 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;
+	jent_raw_hires_entropy_store(tmp);
+}
+
+int jent_hash_time(void *hash_state, __u64 time, u8 *addtl,
+		   unsigned int addtl_len, __u64 hash_loop_cnt,
+		   unsigned int stuck)
+{
+	struct shash_desc *hash_state_desc = (struct shash_desc *)hash_state;
+	SHASH_DESC_ON_STACK(desc, hash_state_desc->tfm);
+	u8 intermediary[SHA3_256_DIGEST_SIZE];
+	__u64 j = 0;
+	int ret;
+
+	desc->tfm = hash_state_desc->tfm;
+
+	if (sizeof(intermediary) != crypto_shash_digestsize(desc->tfm)) {
+		pr_warn_ratelimited("Unexpected digest size\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * This loop fills a buffer which is injected into the entropy pool.
+	 * The main reason for this loop is to execute something over which we
+	 * can perform a timing measurement. The injection of the resulting
+	 * data into the pool is performed to ensure the result is used and
+	 * the compiler cannot optimize the loop away in case the result is not
+	 * used at all. Yet that data is considered "additional information"
+	 * considering the terminology from SP800-90A without any entropy.
+	 *
+	 * Note, it does not matter which or how much data you inject, we are
+	 * interested in one Keccack1600 compression operation performed with
+	 * the crypto_shash_final.
+	 */
+	for (j = 0; j < hash_loop_cnt; j++) {
+		ret = crypto_shash_init(desc) ?:
+		      crypto_shash_update(desc, intermediary,
+					  sizeof(intermediary)) ?:
+		      crypto_shash_finup(desc, addtl, addtl_len, intermediary);
+		if (ret)
+			goto err;
+	}
+
+	/*
+	 * Inject the data from the previous loop into the pool. This data is
+	 * not considered to contain any entropy, but it stirs the pool a bit.
+	 */
+	ret = crypto_shash_update(desc, intermediary, sizeof(intermediary));
+	if (ret)
+		goto err;
+
+	/*
+	 * Insert the time stamp into the hash context representing the pool.
+	 *
+	 * If the time stamp is stuck, do not finally insert the value into the
+	 * entropy pool. Although this operation should not do any harm even
+	 * when the time stamp has no entropy, SP800-90B requires that any
+	 * conditioning operation to have an identical amount of input data
+	 * according to section 3.1.5.
+	 */
+	if (!stuck) {
+		ret = crypto_shash_update(hash_state_desc, (u8 *)&time,
+					  sizeof(__u64));
+	}
+
+err:
+	shash_desc_zero(desc);
+	memzero_explicit(intermediary, sizeof(intermediary));
+
+	return ret;
+}
+
+int jent_read_random_block(void *hash_state, char *dst, unsigned int dst_len)
+{
+	struct shash_desc *hash_state_desc = (struct shash_desc *)hash_state;
+	u8 jent_block[SHA3_256_DIGEST_SIZE];
+	/* Obtain data from entropy pool and re-initialize it */
+	int ret = crypto_shash_final(hash_state_desc, jent_block) ?:
+		  crypto_shash_init(hash_state_desc) ?:
+		  crypto_shash_update(hash_state_desc, jent_block,
+				      sizeof(jent_block));
+
+	if (!ret && dst_len)
+		memcpy(dst, jent_block, dst_len);
+
+	memzero_explicit(jent_block, sizeof(jent_block));
+	return ret;
+}
+
+/***************************************************************************
+ * Kernel crypto API interface
+ ***************************************************************************/
+
+struct jitterentropy {
+	spinlock_t jent_lock;
+	struct rand_data *entropy_collector;
+	struct crypto_shash *tfm;
+	struct shash_desc *sdesc;
+};
+
+static void jent_kcapi_cleanup(struct crypto_tfm *tfm)
+{
+	struct jitterentropy *rng = crypto_tfm_ctx(tfm);
+
+	spin_lock(&rng->jent_lock);
+
+	if (rng->sdesc) {
+		shash_desc_zero(rng->sdesc);
+		kfree(rng->sdesc);
+	}
+	rng->sdesc = NULL;
+
+	if (rng->tfm)
+		crypto_free_shash(rng->tfm);
+	rng->tfm = NULL;
+
+	if (rng->entropy_collector)
+		jent_entropy_collector_free(rng->entropy_collector);
+	rng->entropy_collector = NULL;
+	spin_unlock(&rng->jent_lock);
+}
+
+static int jent_kcapi_init(struct crypto_tfm *tfm)
+{
+	struct jitterentropy *rng = crypto_tfm_ctx(tfm);
+	struct crypto_shash *hash;
+	struct shash_desc *sdesc;
+	int size, ret = 0;
+
+	spin_lock_init(&rng->jent_lock);
+
+	/*
+	 * Use SHA3-256 as conditioner. We allocate only the generic
+	 * implementation as we are not interested in high-performance. The
+	 * execution time of the SHA3 operation is measured and adds to the
+	 * Jitter RNG's unpredictable behavior. If we have a slower hash
+	 * implementation, the execution timing variations are larger. When
+	 * using a fast implementation, we would need to call it more often
+	 * as its variations are lower.
+	 */
+	hash = crypto_alloc_shash(JENT_CONDITIONING_HASH, 0, 0);
+	if (IS_ERR(hash)) {
+		pr_err("Cannot allocate conditioning digest\n");
+		return PTR_ERR(hash);
+	}
+	rng->tfm = hash;
+
+	size = sizeof(struct shash_desc) + crypto_shash_descsize(hash);
+	sdesc = kmalloc(size, GFP_KERNEL);
+	if (!sdesc) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	sdesc->tfm = hash;
+	crypto_shash_init(sdesc);
+	rng->sdesc = sdesc;
+
+	rng->entropy_collector = jent_entropy_collector_alloc(1, 0, sdesc);
+	if (!rng->entropy_collector) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	spin_lock_init(&rng->jent_lock);
+	return 0;
+
+err:
+	jent_kcapi_cleanup(tfm);
+	return ret;
+}
+
+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);
+
+	if (ret == -3) {
+		/* Handle permanent health test error */
+		/*
+		 * If the kernel was booted with fips=1, it implies that
+		 * the entire kernel acts as a FIPS 140 module. In this case
+		 * an SP800-90B permanent health test error is treated as
+		 * a FIPS module error.
+		 */
+		if (fips_enabled)
+			panic("Jitter RNG permanent health test failure\n");
+
+		pr_err("Jitter RNG permanent health test failure\n");
+		ret = -EFAULT;
+	} else if (ret == -2) {
+		/* Handle intermittent health test error */
+		pr_warn_ratelimited("Reset Jitter RNG due to intermittent health test failure\n");
+		ret = -EAGAIN;
+	} else if (ret == -1) {
+		/* Handle other errors */
+		ret = -EINVAL;
+	}
+
+	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)
+{
+	SHASH_DESC_ON_STACK(desc, tfm);
+	struct crypto_shash *tfm;
+	int ret = 0;
+
+	jent_testing_init();
+
+	tfm = crypto_alloc_shash(JENT_CONDITIONING_HASH, 0, 0);
+	if (IS_ERR(tfm)) {
+		jent_testing_exit();
+		return PTR_ERR(tfm);
+	}
+
+	desc->tfm = tfm;
+	crypto_shash_init(desc);
+	ret = jent_entropy_init(desc);
+	shash_desc_zero(desc);
+	crypto_free_shash(tfm);
+	if (ret) {
+		/* Handle permanent health test error */
+		if (fips_enabled)
+			panic("jitterentropy: Initialization failed with host not compliant with requirements: %d\n", ret);
+
+		jent_testing_exit();
+		pr_info("jitterentropy: 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)
+{
+	jent_testing_exit();
+	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");