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![Nicolai Stange](/assets/img/avatar_default.png)
A subsequent patch will make the jitterentropy RNG to unconditionally report health test errors back to callers, independent of whether fips_enabled is set or not. The DRBG needs access to a functional jitterentropy instance only in FIPS mode (because it's the only SP800-90B compliant entropy source as it currently stands). Thus, it is perfectly fine for the DRBGs to obtain entropy from the jitterentropy source only on a best effort basis if fips_enabled is off. Make the DRBGs to ignore jitterentropy failures if fips_enabled is not set. Signed-off-by: Nicolai Stange <nstange@suse.de> Reviewed-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2169 lines
60 KiB
C
2169 lines
60 KiB
C
/*
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* DRBG: Deterministic Random Bits Generator
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* Based on NIST Recommended DRBG from NIST SP800-90A with the following
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* properties:
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* * CTR DRBG with DF with AES-128, AES-192, AES-256 cores
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* * Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
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* * HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
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* * with and without prediction resistance
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*
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* Copyright Stephan Mueller <smueller@chronox.de>, 2014
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, and the entire permission notice in its entirety,
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* including the disclaimer of warranties.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* ALTERNATIVELY, this product may be distributed under the terms of
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* the GNU General Public License, in which case the provisions of the GPL are
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* required INSTEAD OF the above restrictions. (This clause is
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* necessary due to a potential bad interaction between the GPL and
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* the restrictions contained in a BSD-style copyright.)
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
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* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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* USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* DRBG Usage
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* ==========
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* The SP 800-90A DRBG allows the user to specify a personalization string
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* for initialization as well as an additional information string for each
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* random number request. The following code fragments show how a caller
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* uses the kernel crypto API to use the full functionality of the DRBG.
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*
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* Usage without any additional data
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* ---------------------------------
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* struct crypto_rng *drng;
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* int err;
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* char data[DATALEN];
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*
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* drng = crypto_alloc_rng(drng_name, 0, 0);
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* err = crypto_rng_get_bytes(drng, &data, DATALEN);
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* crypto_free_rng(drng);
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*
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*
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* Usage with personalization string during initialization
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* -------------------------------------------------------
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* struct crypto_rng *drng;
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* int err;
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* char data[DATALEN];
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* struct drbg_string pers;
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* char personalization[11] = "some-string";
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*
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* drbg_string_fill(&pers, personalization, strlen(personalization));
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* drng = crypto_alloc_rng(drng_name, 0, 0);
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* // The reset completely re-initializes the DRBG with the provided
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* // personalization string
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* err = crypto_rng_reset(drng, &personalization, strlen(personalization));
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* err = crypto_rng_get_bytes(drng, &data, DATALEN);
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* crypto_free_rng(drng);
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*
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*
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* Usage with additional information string during random number request
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* ---------------------------------------------------------------------
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* struct crypto_rng *drng;
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* int err;
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* char data[DATALEN];
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* char addtl_string[11] = "some-string";
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* string drbg_string addtl;
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*
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* drbg_string_fill(&addtl, addtl_string, strlen(addtl_string));
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* drng = crypto_alloc_rng(drng_name, 0, 0);
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* // The following call is a wrapper to crypto_rng_get_bytes() and returns
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* // the same error codes.
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* err = crypto_drbg_get_bytes_addtl(drng, &data, DATALEN, &addtl);
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* crypto_free_rng(drng);
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*
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*
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* Usage with personalization and additional information strings
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* -------------------------------------------------------------
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* Just mix both scenarios above.
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*/
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#include <crypto/drbg.h>
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#include <crypto/internal/cipher.h>
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#include <linux/kernel.h>
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#include <linux/jiffies.h>
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/***************************************************************
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* Backend cipher definitions available to DRBG
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***************************************************************/
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/*
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* The order of the DRBG definitions here matter: every DRBG is registered
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* as stdrng. Each DRBG receives an increasing cra_priority values the later
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* they are defined in this array (see drbg_fill_array).
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*
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* HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
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* the SHA256 / AES 256 over other ciphers. Thus, the favored
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* DRBGs are the latest entries in this array.
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*/
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static const struct drbg_core drbg_cores[] = {
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#ifdef CONFIG_CRYPTO_DRBG_CTR
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{
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.flags = DRBG_CTR | DRBG_STRENGTH128,
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.statelen = 32, /* 256 bits as defined in 10.2.1 */
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.blocklen_bytes = 16,
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.cra_name = "ctr_aes128",
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.backend_cra_name = "aes",
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}, {
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.flags = DRBG_CTR | DRBG_STRENGTH192,
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.statelen = 40, /* 320 bits as defined in 10.2.1 */
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.blocklen_bytes = 16,
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.cra_name = "ctr_aes192",
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.backend_cra_name = "aes",
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}, {
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.flags = DRBG_CTR | DRBG_STRENGTH256,
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.statelen = 48, /* 384 bits as defined in 10.2.1 */
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.blocklen_bytes = 16,
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.cra_name = "ctr_aes256",
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.backend_cra_name = "aes",
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},
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#endif /* CONFIG_CRYPTO_DRBG_CTR */
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#ifdef CONFIG_CRYPTO_DRBG_HASH
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{
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.flags = DRBG_HASH | DRBG_STRENGTH128,
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.statelen = 55, /* 440 bits */
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.blocklen_bytes = 20,
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.cra_name = "sha1",
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.backend_cra_name = "sha1",
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}, {
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.flags = DRBG_HASH | DRBG_STRENGTH256,
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.statelen = 111, /* 888 bits */
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.blocklen_bytes = 48,
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.cra_name = "sha384",
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.backend_cra_name = "sha384",
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}, {
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.flags = DRBG_HASH | DRBG_STRENGTH256,
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.statelen = 111, /* 888 bits */
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.blocklen_bytes = 64,
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.cra_name = "sha512",
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.backend_cra_name = "sha512",
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}, {
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.flags = DRBG_HASH | DRBG_STRENGTH256,
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.statelen = 55, /* 440 bits */
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.blocklen_bytes = 32,
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.cra_name = "sha256",
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.backend_cra_name = "sha256",
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},
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#endif /* CONFIG_CRYPTO_DRBG_HASH */
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#ifdef CONFIG_CRYPTO_DRBG_HMAC
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{
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.flags = DRBG_HMAC | DRBG_STRENGTH128,
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.statelen = 20, /* block length of cipher */
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.blocklen_bytes = 20,
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.cra_name = "hmac_sha1",
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.backend_cra_name = "hmac(sha1)",
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}, {
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.flags = DRBG_HMAC | DRBG_STRENGTH256,
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.statelen = 48, /* block length of cipher */
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.blocklen_bytes = 48,
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.cra_name = "hmac_sha384",
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.backend_cra_name = "hmac(sha384)",
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}, {
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.flags = DRBG_HMAC | DRBG_STRENGTH256,
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.statelen = 32, /* block length of cipher */
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.blocklen_bytes = 32,
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.cra_name = "hmac_sha256",
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.backend_cra_name = "hmac(sha256)",
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}, {
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.flags = DRBG_HMAC | DRBG_STRENGTH256,
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.statelen = 64, /* block length of cipher */
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.blocklen_bytes = 64,
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.cra_name = "hmac_sha512",
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.backend_cra_name = "hmac(sha512)",
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},
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#endif /* CONFIG_CRYPTO_DRBG_HMAC */
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};
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static int drbg_uninstantiate(struct drbg_state *drbg);
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/******************************************************************
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* Generic helper functions
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******************************************************************/
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/*
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* Return strength of DRBG according to SP800-90A section 8.4
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*
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* @flags DRBG flags reference
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*
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* Return: normalized strength in *bytes* value or 32 as default
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* to counter programming errors
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*/
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static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
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{
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switch (flags & DRBG_STRENGTH_MASK) {
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case DRBG_STRENGTH128:
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return 16;
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case DRBG_STRENGTH192:
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return 24;
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case DRBG_STRENGTH256:
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return 32;
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default:
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return 32;
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}
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}
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/*
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* FIPS 140-2 continuous self test for the noise source
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* The test is performed on the noise source input data. Thus, the function
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* implicitly knows the size of the buffer to be equal to the security
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* strength.
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*
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* Note, this function disregards the nonce trailing the entropy data during
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* initial seeding.
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*
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* drbg->drbg_mutex must have been taken.
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*
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* @drbg DRBG handle
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* @entropy buffer of seed data to be checked
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*
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* return:
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* 0 on success
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* -EAGAIN on when the CTRNG is not yet primed
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* < 0 on error
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*/
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static int drbg_fips_continuous_test(struct drbg_state *drbg,
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const unsigned char *entropy)
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{
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unsigned short entropylen = drbg_sec_strength(drbg->core->flags);
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int ret = 0;
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if (!IS_ENABLED(CONFIG_CRYPTO_FIPS))
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return 0;
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/* skip test if we test the overall system */
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if (list_empty(&drbg->test_data.list))
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return 0;
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/* only perform test in FIPS mode */
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if (!fips_enabled)
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return 0;
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if (!drbg->fips_primed) {
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/* Priming of FIPS test */
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memcpy(drbg->prev, entropy, entropylen);
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drbg->fips_primed = true;
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/* priming: another round is needed */
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return -EAGAIN;
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}
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ret = memcmp(drbg->prev, entropy, entropylen);
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if (!ret)
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panic("DRBG continuous self test failed\n");
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memcpy(drbg->prev, entropy, entropylen);
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/* the test shall pass when the two values are not equal */
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return 0;
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}
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/*
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* Convert an integer into a byte representation of this integer.
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* The byte representation is big-endian
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*
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* @val value to be converted
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* @buf buffer holding the converted integer -- caller must ensure that
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* buffer size is at least 32 bit
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*/
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#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
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static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
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{
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struct s {
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__be32 conv;
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};
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struct s *conversion = (struct s *) buf;
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conversion->conv = cpu_to_be32(val);
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}
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#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
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/******************************************************************
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* CTR DRBG callback functions
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******************************************************************/
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#ifdef CONFIG_CRYPTO_DRBG_CTR
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#define CRYPTO_DRBG_CTR_STRING "CTR "
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MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
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MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
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MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
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MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
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MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
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MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
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static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
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const unsigned char *key);
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static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
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const struct drbg_string *in);
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static int drbg_init_sym_kernel(struct drbg_state *drbg);
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static int drbg_fini_sym_kernel(struct drbg_state *drbg);
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static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
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u8 *inbuf, u32 inbuflen,
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u8 *outbuf, u32 outlen);
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#define DRBG_OUTSCRATCHLEN 256
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/* BCC function for CTR DRBG as defined in 10.4.3 */
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static int drbg_ctr_bcc(struct drbg_state *drbg,
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unsigned char *out, const unsigned char *key,
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struct list_head *in)
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{
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int ret = 0;
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struct drbg_string *curr = NULL;
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struct drbg_string data;
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short cnt = 0;
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drbg_string_fill(&data, out, drbg_blocklen(drbg));
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/* 10.4.3 step 2 / 4 */
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drbg_kcapi_symsetkey(drbg, key);
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list_for_each_entry(curr, in, list) {
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const unsigned char *pos = curr->buf;
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size_t len = curr->len;
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/* 10.4.3 step 4.1 */
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while (len) {
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/* 10.4.3 step 4.2 */
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if (drbg_blocklen(drbg) == cnt) {
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cnt = 0;
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ret = drbg_kcapi_sym(drbg, out, &data);
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if (ret)
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return ret;
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}
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out[cnt] ^= *pos;
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pos++;
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cnt++;
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len--;
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}
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}
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/* 10.4.3 step 4.2 for last block */
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if (cnt)
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ret = drbg_kcapi_sym(drbg, out, &data);
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return ret;
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}
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/*
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* scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
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* (and drbg_ctr_bcc, but this function does not need any temporary buffers),
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* the scratchpad is used as follows:
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* drbg_ctr_update:
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* temp
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* start: drbg->scratchpad
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* length: drbg_statelen(drbg) + drbg_blocklen(drbg)
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* note: the cipher writing into this variable works
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* blocklen-wise. Now, when the statelen is not a multiple
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* of blocklen, the generateion loop below "spills over"
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* by at most blocklen. Thus, we need to give sufficient
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* memory.
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* df_data
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* start: drbg->scratchpad +
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* drbg_statelen(drbg) + drbg_blocklen(drbg)
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* length: drbg_statelen(drbg)
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*
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* drbg_ctr_df:
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* pad
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* start: df_data + drbg_statelen(drbg)
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* length: drbg_blocklen(drbg)
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* iv
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* start: pad + drbg_blocklen(drbg)
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* length: drbg_blocklen(drbg)
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* temp
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* start: iv + drbg_blocklen(drbg)
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* length: drbg_satelen(drbg) + drbg_blocklen(drbg)
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* note: temp is the buffer that the BCC function operates
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* on. BCC operates blockwise. drbg_statelen(drbg)
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* is sufficient when the DRBG state length is a multiple
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* of the block size. For AES192 (and maybe other ciphers)
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* this is not correct and the length for temp is
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* insufficient (yes, that also means for such ciphers,
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* the final output of all BCC rounds are truncated).
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* Therefore, add drbg_blocklen(drbg) to cover all
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* possibilities.
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*/
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/* Derivation Function for CTR DRBG as defined in 10.4.2 */
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static int drbg_ctr_df(struct drbg_state *drbg,
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unsigned char *df_data, size_t bytes_to_return,
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struct list_head *seedlist)
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{
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int ret = -EFAULT;
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unsigned char L_N[8];
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/* S3 is input */
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struct drbg_string S1, S2, S4, cipherin;
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LIST_HEAD(bcc_list);
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unsigned char *pad = df_data + drbg_statelen(drbg);
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unsigned char *iv = pad + drbg_blocklen(drbg);
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unsigned char *temp = iv + drbg_blocklen(drbg);
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size_t padlen = 0;
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unsigned int templen = 0;
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/* 10.4.2 step 7 */
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unsigned int i = 0;
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/* 10.4.2 step 8 */
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const unsigned char *K = (unsigned char *)
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"\x00\x01\x02\x03\x04\x05\x06\x07"
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"\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
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"\x10\x11\x12\x13\x14\x15\x16\x17"
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"\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
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unsigned char *X;
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size_t generated_len = 0;
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size_t inputlen = 0;
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struct drbg_string *seed = NULL;
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memset(pad, 0, drbg_blocklen(drbg));
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memset(iv, 0, drbg_blocklen(drbg));
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/* 10.4.2 step 1 is implicit as we work byte-wise */
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/* 10.4.2 step 2 */
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if ((512/8) < bytes_to_return)
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return -EINVAL;
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/* 10.4.2 step 2 -- calculate the entire length of all input data */
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list_for_each_entry(seed, seedlist, list)
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inputlen += seed->len;
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drbg_cpu_to_be32(inputlen, &L_N[0]);
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/* 10.4.2 step 3 */
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drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
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/* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
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padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
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/* wrap the padlen appropriately */
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if (padlen)
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padlen = drbg_blocklen(drbg) - padlen;
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/*
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* pad / padlen contains the 0x80 byte and the following zero bytes.
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* As the calculated padlen value only covers the number of zero
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* bytes, this value has to be incremented by one for the 0x80 byte.
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*/
|
|
padlen++;
|
|
pad[0] = 0x80;
|
|
|
|
/* 10.4.2 step 4 -- first fill the linked list and then order it */
|
|
drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
|
|
list_add_tail(&S1.list, &bcc_list);
|
|
drbg_string_fill(&S2, L_N, sizeof(L_N));
|
|
list_add_tail(&S2.list, &bcc_list);
|
|
list_splice_tail(seedlist, &bcc_list);
|
|
drbg_string_fill(&S4, pad, padlen);
|
|
list_add_tail(&S4.list, &bcc_list);
|
|
|
|
/* 10.4.2 step 9 */
|
|
while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
|
|
/*
|
|
* 10.4.2 step 9.1 - the padding is implicit as the buffer
|
|
* holds zeros after allocation -- even the increment of i
|
|
* is irrelevant as the increment remains within length of i
|
|
*/
|
|
drbg_cpu_to_be32(i, iv);
|
|
/* 10.4.2 step 9.2 -- BCC and concatenation with temp */
|
|
ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
|
|
if (ret)
|
|
goto out;
|
|
/* 10.4.2 step 9.3 */
|
|
i++;
|
|
templen += drbg_blocklen(drbg);
|
|
}
|
|
|
|
/* 10.4.2 step 11 */
|
|
X = temp + (drbg_keylen(drbg));
|
|
drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
|
|
|
|
/* 10.4.2 step 12: overwriting of outval is implemented in next step */
|
|
|
|
/* 10.4.2 step 13 */
|
|
drbg_kcapi_symsetkey(drbg, temp);
|
|
while (generated_len < bytes_to_return) {
|
|
short blocklen = 0;
|
|
/*
|
|
* 10.4.2 step 13.1: the truncation of the key length is
|
|
* implicit as the key is only drbg_blocklen in size based on
|
|
* the implementation of the cipher function callback
|
|
*/
|
|
ret = drbg_kcapi_sym(drbg, X, &cipherin);
|
|
if (ret)
|
|
goto out;
|
|
blocklen = (drbg_blocklen(drbg) <
|
|
(bytes_to_return - generated_len)) ?
|
|
drbg_blocklen(drbg) :
|
|
(bytes_to_return - generated_len);
|
|
/* 10.4.2 step 13.2 and 14 */
|
|
memcpy(df_data + generated_len, X, blocklen);
|
|
generated_len += blocklen;
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
out:
|
|
memset(iv, 0, drbg_blocklen(drbg));
|
|
memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
|
|
memset(pad, 0, drbg_blocklen(drbg));
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* update function of CTR DRBG as defined in 10.2.1.2
|
|
*
|
|
* The reseed variable has an enhanced meaning compared to the update
|
|
* functions of the other DRBGs as follows:
|
|
* 0 => initial seed from initialization
|
|
* 1 => reseed via drbg_seed
|
|
* 2 => first invocation from drbg_ctr_update when addtl is present. In
|
|
* this case, the df_data scratchpad is not deleted so that it is
|
|
* available for another calls to prevent calling the DF function
|
|
* again.
|
|
* 3 => second invocation from drbg_ctr_update. When the update function
|
|
* was called with addtl, the df_data memory already contains the
|
|
* DFed addtl information and we do not need to call DF again.
|
|
*/
|
|
static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
|
|
int reseed)
|
|
{
|
|
int ret = -EFAULT;
|
|
/* 10.2.1.2 step 1 */
|
|
unsigned char *temp = drbg->scratchpad;
|
|
unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
|
|
drbg_blocklen(drbg);
|
|
|
|
if (3 > reseed)
|
|
memset(df_data, 0, drbg_statelen(drbg));
|
|
|
|
if (!reseed) {
|
|
/*
|
|
* The DRBG uses the CTR mode of the underlying AES cipher. The
|
|
* CTR mode increments the counter value after the AES operation
|
|
* but SP800-90A requires that the counter is incremented before
|
|
* the AES operation. Hence, we increment it at the time we set
|
|
* it by one.
|
|
*/
|
|
crypto_inc(drbg->V, drbg_blocklen(drbg));
|
|
|
|
ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
|
|
drbg_keylen(drbg));
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
|
|
/* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
|
|
if (seed) {
|
|
ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
|
|
ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),
|
|
temp, drbg_statelen(drbg));
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* 10.2.1.2 step 5 */
|
|
ret = crypto_skcipher_setkey(drbg->ctr_handle, temp,
|
|
drbg_keylen(drbg));
|
|
if (ret)
|
|
goto out;
|
|
/* 10.2.1.2 step 6 */
|
|
memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
|
|
/* See above: increment counter by one to compensate timing of CTR op */
|
|
crypto_inc(drbg->V, drbg_blocklen(drbg));
|
|
ret = 0;
|
|
|
|
out:
|
|
memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
|
|
if (2 != reseed)
|
|
memset(df_data, 0, drbg_statelen(drbg));
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* scratchpad use: drbg_ctr_update is called independently from
|
|
* drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
|
|
*/
|
|
/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
|
|
static int drbg_ctr_generate(struct drbg_state *drbg,
|
|
unsigned char *buf, unsigned int buflen,
|
|
struct list_head *addtl)
|
|
{
|
|
int ret;
|
|
int len = min_t(int, buflen, INT_MAX);
|
|
|
|
/* 10.2.1.5.2 step 2 */
|
|
if (addtl && !list_empty(addtl)) {
|
|
ret = drbg_ctr_update(drbg, addtl, 2);
|
|
if (ret)
|
|
return 0;
|
|
}
|
|
|
|
/* 10.2.1.5.2 step 4.1 */
|
|
ret = drbg_kcapi_sym_ctr(drbg, NULL, 0, buf, len);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* 10.2.1.5.2 step 6 */
|
|
ret = drbg_ctr_update(drbg, NULL, 3);
|
|
if (ret)
|
|
len = ret;
|
|
|
|
return len;
|
|
}
|
|
|
|
static const struct drbg_state_ops drbg_ctr_ops = {
|
|
.update = drbg_ctr_update,
|
|
.generate = drbg_ctr_generate,
|
|
.crypto_init = drbg_init_sym_kernel,
|
|
.crypto_fini = drbg_fini_sym_kernel,
|
|
};
|
|
#endif /* CONFIG_CRYPTO_DRBG_CTR */
|
|
|
|
/******************************************************************
|
|
* HMAC DRBG callback functions
|
|
******************************************************************/
|
|
|
|
#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
|
|
static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
|
|
const struct list_head *in);
|
|
static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
|
|
const unsigned char *key);
|
|
static int drbg_init_hash_kernel(struct drbg_state *drbg);
|
|
static int drbg_fini_hash_kernel(struct drbg_state *drbg);
|
|
#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
|
|
|
|
#ifdef CONFIG_CRYPTO_DRBG_HMAC
|
|
#define CRYPTO_DRBG_HMAC_STRING "HMAC "
|
|
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
|
|
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
|
|
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
|
|
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
|
|
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
|
|
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
|
|
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
|
|
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
|
|
|
|
/* update function of HMAC DRBG as defined in 10.1.2.2 */
|
|
static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
|
|
int reseed)
|
|
{
|
|
int ret = -EFAULT;
|
|
int i = 0;
|
|
struct drbg_string seed1, seed2, vdata;
|
|
LIST_HEAD(seedlist);
|
|
LIST_HEAD(vdatalist);
|
|
|
|
if (!reseed) {
|
|
/* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
|
|
memset(drbg->V, 1, drbg_statelen(drbg));
|
|
drbg_kcapi_hmacsetkey(drbg, drbg->C);
|
|
}
|
|
|
|
drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
|
|
list_add_tail(&seed1.list, &seedlist);
|
|
/* buffer of seed2 will be filled in for loop below with one byte */
|
|
drbg_string_fill(&seed2, NULL, 1);
|
|
list_add_tail(&seed2.list, &seedlist);
|
|
/* input data of seed is allowed to be NULL at this point */
|
|
if (seed)
|
|
list_splice_tail(seed, &seedlist);
|
|
|
|
drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
|
|
list_add_tail(&vdata.list, &vdatalist);
|
|
for (i = 2; 0 < i; i--) {
|
|
/* first round uses 0x0, second 0x1 */
|
|
unsigned char prefix = DRBG_PREFIX0;
|
|
if (1 == i)
|
|
prefix = DRBG_PREFIX1;
|
|
/* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
|
|
seed2.buf = &prefix;
|
|
ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist);
|
|
if (ret)
|
|
return ret;
|
|
drbg_kcapi_hmacsetkey(drbg, drbg->C);
|
|
|
|
/* 10.1.2.2 step 2 and 5 -- HMAC for V */
|
|
ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* 10.1.2.2 step 3 */
|
|
if (!seed)
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* generate function of HMAC DRBG as defined in 10.1.2.5 */
|
|
static int drbg_hmac_generate(struct drbg_state *drbg,
|
|
unsigned char *buf,
|
|
unsigned int buflen,
|
|
struct list_head *addtl)
|
|
{
|
|
int len = 0;
|
|
int ret = 0;
|
|
struct drbg_string data;
|
|
LIST_HEAD(datalist);
|
|
|
|
/* 10.1.2.5 step 2 */
|
|
if (addtl && !list_empty(addtl)) {
|
|
ret = drbg_hmac_update(drbg, addtl, 1);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
|
|
list_add_tail(&data.list, &datalist);
|
|
while (len < buflen) {
|
|
unsigned int outlen = 0;
|
|
/* 10.1.2.5 step 4.1 */
|
|
ret = drbg_kcapi_hash(drbg, drbg->V, &datalist);
|
|
if (ret)
|
|
return ret;
|
|
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
|
|
drbg_blocklen(drbg) : (buflen - len);
|
|
|
|
/* 10.1.2.5 step 4.2 */
|
|
memcpy(buf + len, drbg->V, outlen);
|
|
len += outlen;
|
|
}
|
|
|
|
/* 10.1.2.5 step 6 */
|
|
if (addtl && !list_empty(addtl))
|
|
ret = drbg_hmac_update(drbg, addtl, 1);
|
|
else
|
|
ret = drbg_hmac_update(drbg, NULL, 1);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return len;
|
|
}
|
|
|
|
static const struct drbg_state_ops drbg_hmac_ops = {
|
|
.update = drbg_hmac_update,
|
|
.generate = drbg_hmac_generate,
|
|
.crypto_init = drbg_init_hash_kernel,
|
|
.crypto_fini = drbg_fini_hash_kernel,
|
|
};
|
|
#endif /* CONFIG_CRYPTO_DRBG_HMAC */
|
|
|
|
/******************************************************************
|
|
* Hash DRBG callback functions
|
|
******************************************************************/
|
|
|
|
#ifdef CONFIG_CRYPTO_DRBG_HASH
|
|
#define CRYPTO_DRBG_HASH_STRING "HASH "
|
|
MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
|
|
MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
|
|
MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
|
|
MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
|
|
MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
|
|
MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
|
|
MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
|
|
MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
|
|
|
|
/*
|
|
* Increment buffer
|
|
*
|
|
* @dst buffer to increment
|
|
* @add value to add
|
|
*/
|
|
static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
|
|
const unsigned char *add, size_t addlen)
|
|
{
|
|
/* implied: dstlen > addlen */
|
|
unsigned char *dstptr;
|
|
const unsigned char *addptr;
|
|
unsigned int remainder = 0;
|
|
size_t len = addlen;
|
|
|
|
dstptr = dst + (dstlen-1);
|
|
addptr = add + (addlen-1);
|
|
while (len) {
|
|
remainder += *dstptr + *addptr;
|
|
*dstptr = remainder & 0xff;
|
|
remainder >>= 8;
|
|
len--; dstptr--; addptr--;
|
|
}
|
|
len = dstlen - addlen;
|
|
while (len && remainder > 0) {
|
|
remainder = *dstptr + 1;
|
|
*dstptr = remainder & 0xff;
|
|
remainder >>= 8;
|
|
len--; dstptr--;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* scratchpad usage: as drbg_hash_update and drbg_hash_df are used
|
|
* interlinked, the scratchpad is used as follows:
|
|
* drbg_hash_update
|
|
* start: drbg->scratchpad
|
|
* length: drbg_statelen(drbg)
|
|
* drbg_hash_df:
|
|
* start: drbg->scratchpad + drbg_statelen(drbg)
|
|
* length: drbg_blocklen(drbg)
|
|
*
|
|
* drbg_hash_process_addtl uses the scratchpad, but fully completes
|
|
* before either of the functions mentioned before are invoked. Therefore,
|
|
* drbg_hash_process_addtl does not need to be specifically considered.
|
|
*/
|
|
|
|
/* Derivation Function for Hash DRBG as defined in 10.4.1 */
|
|
static int drbg_hash_df(struct drbg_state *drbg,
|
|
unsigned char *outval, size_t outlen,
|
|
struct list_head *entropylist)
|
|
{
|
|
int ret = 0;
|
|
size_t len = 0;
|
|
unsigned char input[5];
|
|
unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
|
|
struct drbg_string data;
|
|
|
|
/* 10.4.1 step 3 */
|
|
input[0] = 1;
|
|
drbg_cpu_to_be32((outlen * 8), &input[1]);
|
|
|
|
/* 10.4.1 step 4.1 -- concatenation of data for input into hash */
|
|
drbg_string_fill(&data, input, 5);
|
|
list_add(&data.list, entropylist);
|
|
|
|
/* 10.4.1 step 4 */
|
|
while (len < outlen) {
|
|
short blocklen = 0;
|
|
/* 10.4.1 step 4.1 */
|
|
ret = drbg_kcapi_hash(drbg, tmp, entropylist);
|
|
if (ret)
|
|
goto out;
|
|
/* 10.4.1 step 4.2 */
|
|
input[0]++;
|
|
blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
|
|
drbg_blocklen(drbg) : (outlen - len);
|
|
memcpy(outval + len, tmp, blocklen);
|
|
len += blocklen;
|
|
}
|
|
|
|
out:
|
|
memset(tmp, 0, drbg_blocklen(drbg));
|
|
return ret;
|
|
}
|
|
|
|
/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
|
|
static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
|
|
int reseed)
|
|
{
|
|
int ret = 0;
|
|
struct drbg_string data1, data2;
|
|
LIST_HEAD(datalist);
|
|
LIST_HEAD(datalist2);
|
|
unsigned char *V = drbg->scratchpad;
|
|
unsigned char prefix = DRBG_PREFIX1;
|
|
|
|
if (!seed)
|
|
return -EINVAL;
|
|
|
|
if (reseed) {
|
|
/* 10.1.1.3 step 1 */
|
|
memcpy(V, drbg->V, drbg_statelen(drbg));
|
|
drbg_string_fill(&data1, &prefix, 1);
|
|
list_add_tail(&data1.list, &datalist);
|
|
drbg_string_fill(&data2, V, drbg_statelen(drbg));
|
|
list_add_tail(&data2.list, &datalist);
|
|
}
|
|
list_splice_tail(seed, &datalist);
|
|
|
|
/* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
|
|
ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
|
|
if (ret)
|
|
goto out;
|
|
|
|
/* 10.1.1.2 / 10.1.1.3 step 4 */
|
|
prefix = DRBG_PREFIX0;
|
|
drbg_string_fill(&data1, &prefix, 1);
|
|
list_add_tail(&data1.list, &datalist2);
|
|
drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
|
|
list_add_tail(&data2.list, &datalist2);
|
|
/* 10.1.1.2 / 10.1.1.3 step 4 */
|
|
ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
|
|
|
|
out:
|
|
memset(drbg->scratchpad, 0, drbg_statelen(drbg));
|
|
return ret;
|
|
}
|
|
|
|
/* processing of additional information string for Hash DRBG */
|
|
static int drbg_hash_process_addtl(struct drbg_state *drbg,
|
|
struct list_head *addtl)
|
|
{
|
|
int ret = 0;
|
|
struct drbg_string data1, data2;
|
|
LIST_HEAD(datalist);
|
|
unsigned char prefix = DRBG_PREFIX2;
|
|
|
|
/* 10.1.1.4 step 2 */
|
|
if (!addtl || list_empty(addtl))
|
|
return 0;
|
|
|
|
/* 10.1.1.4 step 2a */
|
|
drbg_string_fill(&data1, &prefix, 1);
|
|
drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
|
|
list_add_tail(&data1.list, &datalist);
|
|
list_add_tail(&data2.list, &datalist);
|
|
list_splice_tail(addtl, &datalist);
|
|
ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
|
|
if (ret)
|
|
goto out;
|
|
|
|
/* 10.1.1.4 step 2b */
|
|
drbg_add_buf(drbg->V, drbg_statelen(drbg),
|
|
drbg->scratchpad, drbg_blocklen(drbg));
|
|
|
|
out:
|
|
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
|
|
return ret;
|
|
}
|
|
|
|
/* Hashgen defined in 10.1.1.4 */
|
|
static int drbg_hash_hashgen(struct drbg_state *drbg,
|
|
unsigned char *buf,
|
|
unsigned int buflen)
|
|
{
|
|
int len = 0;
|
|
int ret = 0;
|
|
unsigned char *src = drbg->scratchpad;
|
|
unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
|
|
struct drbg_string data;
|
|
LIST_HEAD(datalist);
|
|
|
|
/* 10.1.1.4 step hashgen 2 */
|
|
memcpy(src, drbg->V, drbg_statelen(drbg));
|
|
|
|
drbg_string_fill(&data, src, drbg_statelen(drbg));
|
|
list_add_tail(&data.list, &datalist);
|
|
while (len < buflen) {
|
|
unsigned int outlen = 0;
|
|
/* 10.1.1.4 step hashgen 4.1 */
|
|
ret = drbg_kcapi_hash(drbg, dst, &datalist);
|
|
if (ret) {
|
|
len = ret;
|
|
goto out;
|
|
}
|
|
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
|
|
drbg_blocklen(drbg) : (buflen - len);
|
|
/* 10.1.1.4 step hashgen 4.2 */
|
|
memcpy(buf + len, dst, outlen);
|
|
len += outlen;
|
|
/* 10.1.1.4 hashgen step 4.3 */
|
|
if (len < buflen)
|
|
crypto_inc(src, drbg_statelen(drbg));
|
|
}
|
|
|
|
out:
|
|
memset(drbg->scratchpad, 0,
|
|
(drbg_statelen(drbg) + drbg_blocklen(drbg)));
|
|
return len;
|
|
}
|
|
|
|
/* generate function for Hash DRBG as defined in 10.1.1.4 */
|
|
static int drbg_hash_generate(struct drbg_state *drbg,
|
|
unsigned char *buf, unsigned int buflen,
|
|
struct list_head *addtl)
|
|
{
|
|
int len = 0;
|
|
int ret = 0;
|
|
union {
|
|
unsigned char req[8];
|
|
__be64 req_int;
|
|
} u;
|
|
unsigned char prefix = DRBG_PREFIX3;
|
|
struct drbg_string data1, data2;
|
|
LIST_HEAD(datalist);
|
|
|
|
/* 10.1.1.4 step 2 */
|
|
ret = drbg_hash_process_addtl(drbg, addtl);
|
|
if (ret)
|
|
return ret;
|
|
/* 10.1.1.4 step 3 */
|
|
len = drbg_hash_hashgen(drbg, buf, buflen);
|
|
|
|
/* this is the value H as documented in 10.1.1.4 */
|
|
/* 10.1.1.4 step 4 */
|
|
drbg_string_fill(&data1, &prefix, 1);
|
|
list_add_tail(&data1.list, &datalist);
|
|
drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
|
|
list_add_tail(&data2.list, &datalist);
|
|
ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
|
|
if (ret) {
|
|
len = ret;
|
|
goto out;
|
|
}
|
|
|
|
/* 10.1.1.4 step 5 */
|
|
drbg_add_buf(drbg->V, drbg_statelen(drbg),
|
|
drbg->scratchpad, drbg_blocklen(drbg));
|
|
drbg_add_buf(drbg->V, drbg_statelen(drbg),
|
|
drbg->C, drbg_statelen(drbg));
|
|
u.req_int = cpu_to_be64(drbg->reseed_ctr);
|
|
drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
|
|
|
|
out:
|
|
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
|
|
return len;
|
|
}
|
|
|
|
/*
|
|
* scratchpad usage: as update and generate are used isolated, both
|
|
* can use the scratchpad
|
|
*/
|
|
static const struct drbg_state_ops drbg_hash_ops = {
|
|
.update = drbg_hash_update,
|
|
.generate = drbg_hash_generate,
|
|
.crypto_init = drbg_init_hash_kernel,
|
|
.crypto_fini = drbg_fini_hash_kernel,
|
|
};
|
|
#endif /* CONFIG_CRYPTO_DRBG_HASH */
|
|
|
|
/******************************************************************
|
|
* Functions common for DRBG implementations
|
|
******************************************************************/
|
|
|
|
static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
|
|
int reseed, enum drbg_seed_state new_seed_state)
|
|
{
|
|
int ret = drbg->d_ops->update(drbg, seed, reseed);
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
drbg->seeded = new_seed_state;
|
|
drbg->last_seed_time = jiffies;
|
|
/* 10.1.1.2 / 10.1.1.3 step 5 */
|
|
drbg->reseed_ctr = 1;
|
|
|
|
switch (drbg->seeded) {
|
|
case DRBG_SEED_STATE_UNSEEDED:
|
|
/* Impossible, but handle it to silence compiler warnings. */
|
|
fallthrough;
|
|
case DRBG_SEED_STATE_PARTIAL:
|
|
/*
|
|
* Require frequent reseeds until the seed source is
|
|
* fully initialized.
|
|
*/
|
|
drbg->reseed_threshold = 50;
|
|
break;
|
|
|
|
case DRBG_SEED_STATE_FULL:
|
|
/*
|
|
* Seed source has become fully initialized, frequent
|
|
* reseeds no longer required.
|
|
*/
|
|
drbg->reseed_threshold = drbg_max_requests(drbg);
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static inline int drbg_get_random_bytes(struct drbg_state *drbg,
|
|
unsigned char *entropy,
|
|
unsigned int entropylen)
|
|
{
|
|
int ret;
|
|
|
|
do {
|
|
get_random_bytes(entropy, entropylen);
|
|
ret = drbg_fips_continuous_test(drbg, entropy);
|
|
if (ret && ret != -EAGAIN)
|
|
return ret;
|
|
} while (ret);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int drbg_seed_from_random(struct drbg_state *drbg)
|
|
{
|
|
struct drbg_string data;
|
|
LIST_HEAD(seedlist);
|
|
unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
|
|
unsigned char entropy[32];
|
|
int ret;
|
|
|
|
BUG_ON(!entropylen);
|
|
BUG_ON(entropylen > sizeof(entropy));
|
|
|
|
drbg_string_fill(&data, entropy, entropylen);
|
|
list_add_tail(&data.list, &seedlist);
|
|
|
|
ret = drbg_get_random_bytes(drbg, entropy, entropylen);
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = __drbg_seed(drbg, &seedlist, true, DRBG_SEED_STATE_FULL);
|
|
|
|
out:
|
|
memzero_explicit(entropy, entropylen);
|
|
return ret;
|
|
}
|
|
|
|
static bool drbg_nopr_reseed_interval_elapsed(struct drbg_state *drbg)
|
|
{
|
|
unsigned long next_reseed;
|
|
|
|
/* Don't ever reseed from get_random_bytes() in test mode. */
|
|
if (list_empty(&drbg->test_data.list))
|
|
return false;
|
|
|
|
/*
|
|
* Obtain fresh entropy for the nopr DRBGs after 300s have
|
|
* elapsed in order to still achieve sort of partial
|
|
* prediction resistance over the time domain at least. Note
|
|
* that the period of 300s has been chosen to match the
|
|
* CRNG_RESEED_INTERVAL of the get_random_bytes()' chacha
|
|
* rngs.
|
|
*/
|
|
next_reseed = drbg->last_seed_time + 300 * HZ;
|
|
return time_after(jiffies, next_reseed);
|
|
}
|
|
|
|
/*
|
|
* Seeding or reseeding of the DRBG
|
|
*
|
|
* @drbg: DRBG state struct
|
|
* @pers: personalization / additional information buffer
|
|
* @reseed: 0 for initial seed process, 1 for reseeding
|
|
*
|
|
* return:
|
|
* 0 on success
|
|
* error value otherwise
|
|
*/
|
|
static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
|
|
bool reseed)
|
|
{
|
|
int ret;
|
|
unsigned char entropy[((32 + 16) * 2)];
|
|
unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
|
|
struct drbg_string data1;
|
|
LIST_HEAD(seedlist);
|
|
enum drbg_seed_state new_seed_state = DRBG_SEED_STATE_FULL;
|
|
|
|
/* 9.1 / 9.2 / 9.3.1 step 3 */
|
|
if (pers && pers->len > (drbg_max_addtl(drbg))) {
|
|
pr_devel("DRBG: personalization string too long %zu\n",
|
|
pers->len);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (list_empty(&drbg->test_data.list)) {
|
|
drbg_string_fill(&data1, drbg->test_data.buf,
|
|
drbg->test_data.len);
|
|
pr_devel("DRBG: using test entropy\n");
|
|
} else {
|
|
/*
|
|
* Gather entropy equal to the security strength of the DRBG.
|
|
* With a derivation function, a nonce is required in addition
|
|
* to the entropy. A nonce must be at least 1/2 of the security
|
|
* strength of the DRBG in size. Thus, entropy + nonce is 3/2
|
|
* of the strength. The consideration of a nonce is only
|
|
* applicable during initial seeding.
|
|
*/
|
|
BUG_ON(!entropylen);
|
|
if (!reseed)
|
|
entropylen = ((entropylen + 1) / 2) * 3;
|
|
BUG_ON((entropylen * 2) > sizeof(entropy));
|
|
|
|
/* Get seed from in-kernel /dev/urandom */
|
|
if (!rng_is_initialized())
|
|
new_seed_state = DRBG_SEED_STATE_PARTIAL;
|
|
|
|
ret = drbg_get_random_bytes(drbg, entropy, entropylen);
|
|
if (ret)
|
|
goto out;
|
|
|
|
if (!drbg->jent) {
|
|
drbg_string_fill(&data1, entropy, entropylen);
|
|
pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
|
|
entropylen);
|
|
} else {
|
|
/*
|
|
* Get seed from Jitter RNG, failures are
|
|
* fatal only in FIPS mode.
|
|
*/
|
|
ret = crypto_rng_get_bytes(drbg->jent,
|
|
entropy + entropylen,
|
|
entropylen);
|
|
if (fips_enabled && ret) {
|
|
pr_devel("DRBG: jent failed with %d\n", ret);
|
|
|
|
/*
|
|
* Do not treat the transient failure of the
|
|
* Jitter RNG as an error that needs to be
|
|
* reported. The combined number of the
|
|
* maximum reseed threshold times the maximum
|
|
* number of Jitter RNG transient errors is
|
|
* less than the reseed threshold required by
|
|
* SP800-90A allowing us to treat the
|
|
* transient errors as such.
|
|
*
|
|
* However, we mandate that at least the first
|
|
* seeding operation must succeed with the
|
|
* Jitter RNG.
|
|
*/
|
|
if (!reseed || ret != -EAGAIN)
|
|
goto out;
|
|
}
|
|
|
|
drbg_string_fill(&data1, entropy, entropylen * 2);
|
|
pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
|
|
entropylen * 2);
|
|
}
|
|
}
|
|
list_add_tail(&data1.list, &seedlist);
|
|
|
|
/*
|
|
* concatenation of entropy with personalization str / addtl input)
|
|
* the variable pers is directly handed in by the caller, so check its
|
|
* contents whether it is appropriate
|
|
*/
|
|
if (pers && pers->buf && 0 < pers->len) {
|
|
list_add_tail(&pers->list, &seedlist);
|
|
pr_devel("DRBG: using personalization string\n");
|
|
}
|
|
|
|
if (!reseed) {
|
|
memset(drbg->V, 0, drbg_statelen(drbg));
|
|
memset(drbg->C, 0, drbg_statelen(drbg));
|
|
}
|
|
|
|
ret = __drbg_seed(drbg, &seedlist, reseed, new_seed_state);
|
|
|
|
out:
|
|
memzero_explicit(entropy, entropylen * 2);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Free all substructures in a DRBG state without the DRBG state structure */
|
|
static inline void drbg_dealloc_state(struct drbg_state *drbg)
|
|
{
|
|
if (!drbg)
|
|
return;
|
|
kfree_sensitive(drbg->Vbuf);
|
|
drbg->Vbuf = NULL;
|
|
drbg->V = NULL;
|
|
kfree_sensitive(drbg->Cbuf);
|
|
drbg->Cbuf = NULL;
|
|
drbg->C = NULL;
|
|
kfree_sensitive(drbg->scratchpadbuf);
|
|
drbg->scratchpadbuf = NULL;
|
|
drbg->reseed_ctr = 0;
|
|
drbg->d_ops = NULL;
|
|
drbg->core = NULL;
|
|
if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
|
|
kfree_sensitive(drbg->prev);
|
|
drbg->prev = NULL;
|
|
drbg->fips_primed = false;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Allocate all sub-structures for a DRBG state.
|
|
* The DRBG state structure must already be allocated.
|
|
*/
|
|
static inline int drbg_alloc_state(struct drbg_state *drbg)
|
|
{
|
|
int ret = -ENOMEM;
|
|
unsigned int sb_size = 0;
|
|
|
|
switch (drbg->core->flags & DRBG_TYPE_MASK) {
|
|
#ifdef CONFIG_CRYPTO_DRBG_HMAC
|
|
case DRBG_HMAC:
|
|
drbg->d_ops = &drbg_hmac_ops;
|
|
break;
|
|
#endif /* CONFIG_CRYPTO_DRBG_HMAC */
|
|
#ifdef CONFIG_CRYPTO_DRBG_HASH
|
|
case DRBG_HASH:
|
|
drbg->d_ops = &drbg_hash_ops;
|
|
break;
|
|
#endif /* CONFIG_CRYPTO_DRBG_HASH */
|
|
#ifdef CONFIG_CRYPTO_DRBG_CTR
|
|
case DRBG_CTR:
|
|
drbg->d_ops = &drbg_ctr_ops;
|
|
break;
|
|
#endif /* CONFIG_CRYPTO_DRBG_CTR */
|
|
default:
|
|
ret = -EOPNOTSUPP;
|
|
goto err;
|
|
}
|
|
|
|
ret = drbg->d_ops->crypto_init(drbg);
|
|
if (ret < 0)
|
|
goto err;
|
|
|
|
drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
|
|
if (!drbg->Vbuf) {
|
|
ret = -ENOMEM;
|
|
goto fini;
|
|
}
|
|
drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1);
|
|
drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
|
|
if (!drbg->Cbuf) {
|
|
ret = -ENOMEM;
|
|
goto fini;
|
|
}
|
|
drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1);
|
|
/* scratchpad is only generated for CTR and Hash */
|
|
if (drbg->core->flags & DRBG_HMAC)
|
|
sb_size = 0;
|
|
else if (drbg->core->flags & DRBG_CTR)
|
|
sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
|
|
drbg_statelen(drbg) + /* df_data */
|
|
drbg_blocklen(drbg) + /* pad */
|
|
drbg_blocklen(drbg) + /* iv */
|
|
drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
|
|
else
|
|
sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
|
|
|
|
if (0 < sb_size) {
|
|
drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL);
|
|
if (!drbg->scratchpadbuf) {
|
|
ret = -ENOMEM;
|
|
goto fini;
|
|
}
|
|
drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1);
|
|
}
|
|
|
|
if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
|
|
drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
|
|
GFP_KERNEL);
|
|
if (!drbg->prev) {
|
|
ret = -ENOMEM;
|
|
goto fini;
|
|
}
|
|
drbg->fips_primed = false;
|
|
}
|
|
|
|
return 0;
|
|
|
|
fini:
|
|
drbg->d_ops->crypto_fini(drbg);
|
|
err:
|
|
drbg_dealloc_state(drbg);
|
|
return ret;
|
|
}
|
|
|
|
/*************************************************************************
|
|
* DRBG interface functions
|
|
*************************************************************************/
|
|
|
|
/*
|
|
* DRBG generate function as required by SP800-90A - this function
|
|
* generates random numbers
|
|
*
|
|
* @drbg DRBG state handle
|
|
* @buf Buffer where to store the random numbers -- the buffer must already
|
|
* be pre-allocated by caller
|
|
* @buflen Length of output buffer - this value defines the number of random
|
|
* bytes pulled from DRBG
|
|
* @addtl Additional input that is mixed into state, may be NULL -- note
|
|
* the entropy is pulled by the DRBG internally unconditionally
|
|
* as defined in SP800-90A. The additional input is mixed into
|
|
* the state in addition to the pulled entropy.
|
|
*
|
|
* return: 0 when all bytes are generated; < 0 in case of an error
|
|
*/
|
|
static int drbg_generate(struct drbg_state *drbg,
|
|
unsigned char *buf, unsigned int buflen,
|
|
struct drbg_string *addtl)
|
|
{
|
|
int len = 0;
|
|
LIST_HEAD(addtllist);
|
|
|
|
if (!drbg->core) {
|
|
pr_devel("DRBG: not yet seeded\n");
|
|
return -EINVAL;
|
|
}
|
|
if (0 == buflen || !buf) {
|
|
pr_devel("DRBG: no output buffer provided\n");
|
|
return -EINVAL;
|
|
}
|
|
if (addtl && NULL == addtl->buf && 0 < addtl->len) {
|
|
pr_devel("DRBG: wrong format of additional information\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* 9.3.1 step 2 */
|
|
len = -EINVAL;
|
|
if (buflen > (drbg_max_request_bytes(drbg))) {
|
|
pr_devel("DRBG: requested random numbers too large %u\n",
|
|
buflen);
|
|
goto err;
|
|
}
|
|
|
|
/* 9.3.1 step 3 is implicit with the chosen DRBG */
|
|
|
|
/* 9.3.1 step 4 */
|
|
if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
|
|
pr_devel("DRBG: additional information string too long %zu\n",
|
|
addtl->len);
|
|
goto err;
|
|
}
|
|
/* 9.3.1 step 5 is implicit with the chosen DRBG */
|
|
|
|
/*
|
|
* 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
|
|
* here. The spec is a bit convoluted here, we make it simpler.
|
|
*/
|
|
if (drbg->reseed_threshold < drbg->reseed_ctr)
|
|
drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
|
|
|
|
if (drbg->pr || drbg->seeded == DRBG_SEED_STATE_UNSEEDED) {
|
|
pr_devel("DRBG: reseeding before generation (prediction "
|
|
"resistance: %s, state %s)\n",
|
|
drbg->pr ? "true" : "false",
|
|
(drbg->seeded == DRBG_SEED_STATE_FULL ?
|
|
"seeded" : "unseeded"));
|
|
/* 9.3.1 steps 7.1 through 7.3 */
|
|
len = drbg_seed(drbg, addtl, true);
|
|
if (len)
|
|
goto err;
|
|
/* 9.3.1 step 7.4 */
|
|
addtl = NULL;
|
|
} else if (rng_is_initialized() &&
|
|
(drbg->seeded == DRBG_SEED_STATE_PARTIAL ||
|
|
drbg_nopr_reseed_interval_elapsed(drbg))) {
|
|
len = drbg_seed_from_random(drbg);
|
|
if (len)
|
|
goto err;
|
|
}
|
|
|
|
if (addtl && 0 < addtl->len)
|
|
list_add_tail(&addtl->list, &addtllist);
|
|
/* 9.3.1 step 8 and 10 */
|
|
len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
|
|
|
|
/* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
|
|
drbg->reseed_ctr++;
|
|
if (0 >= len)
|
|
goto err;
|
|
|
|
/*
|
|
* Section 11.3.3 requires to re-perform self tests after some
|
|
* generated random numbers. The chosen value after which self
|
|
* test is performed is arbitrary, but it should be reasonable.
|
|
* However, we do not perform the self tests because of the following
|
|
* reasons: it is mathematically impossible that the initial self tests
|
|
* were successfully and the following are not. If the initial would
|
|
* pass and the following would not, the kernel integrity is violated.
|
|
* In this case, the entire kernel operation is questionable and it
|
|
* is unlikely that the integrity violation only affects the
|
|
* correct operation of the DRBG.
|
|
*
|
|
* Albeit the following code is commented out, it is provided in
|
|
* case somebody has a need to implement the test of 11.3.3.
|
|
*/
|
|
#if 0
|
|
if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
|
|
int err = 0;
|
|
pr_devel("DRBG: start to perform self test\n");
|
|
if (drbg->core->flags & DRBG_HMAC)
|
|
err = alg_test("drbg_pr_hmac_sha256",
|
|
"drbg_pr_hmac_sha256", 0, 0);
|
|
else if (drbg->core->flags & DRBG_CTR)
|
|
err = alg_test("drbg_pr_ctr_aes128",
|
|
"drbg_pr_ctr_aes128", 0, 0);
|
|
else
|
|
err = alg_test("drbg_pr_sha256",
|
|
"drbg_pr_sha256", 0, 0);
|
|
if (err) {
|
|
pr_err("DRBG: periodical self test failed\n");
|
|
/*
|
|
* uninstantiate implies that from now on, only errors
|
|
* are returned when reusing this DRBG cipher handle
|
|
*/
|
|
drbg_uninstantiate(drbg);
|
|
return 0;
|
|
} else {
|
|
pr_devel("DRBG: self test successful\n");
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* All operations were successful, return 0 as mandated by
|
|
* the kernel crypto API interface.
|
|
*/
|
|
len = 0;
|
|
err:
|
|
return len;
|
|
}
|
|
|
|
/*
|
|
* Wrapper around drbg_generate which can pull arbitrary long strings
|
|
* from the DRBG without hitting the maximum request limitation.
|
|
*
|
|
* Parameters: see drbg_generate
|
|
* Return codes: see drbg_generate -- if one drbg_generate request fails,
|
|
* the entire drbg_generate_long request fails
|
|
*/
|
|
static int drbg_generate_long(struct drbg_state *drbg,
|
|
unsigned char *buf, unsigned int buflen,
|
|
struct drbg_string *addtl)
|
|
{
|
|
unsigned int len = 0;
|
|
unsigned int slice = 0;
|
|
do {
|
|
int err = 0;
|
|
unsigned int chunk = 0;
|
|
slice = ((buflen - len) / drbg_max_request_bytes(drbg));
|
|
chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
|
|
mutex_lock(&drbg->drbg_mutex);
|
|
err = drbg_generate(drbg, buf + len, chunk, addtl);
|
|
mutex_unlock(&drbg->drbg_mutex);
|
|
if (0 > err)
|
|
return err;
|
|
len += chunk;
|
|
} while (slice > 0 && (len < buflen));
|
|
return 0;
|
|
}
|
|
|
|
static int drbg_prepare_hrng(struct drbg_state *drbg)
|
|
{
|
|
/* We do not need an HRNG in test mode. */
|
|
if (list_empty(&drbg->test_data.list))
|
|
return 0;
|
|
|
|
drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
|
|
if (IS_ERR(drbg->jent)) {
|
|
const int err = PTR_ERR(drbg->jent);
|
|
|
|
drbg->jent = NULL;
|
|
if (fips_enabled || err != -ENOENT)
|
|
return err;
|
|
pr_info("DRBG: Continuing without Jitter RNG\n");
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* DRBG instantiation function as required by SP800-90A - this function
|
|
* sets up the DRBG handle, performs the initial seeding and all sanity
|
|
* checks required by SP800-90A
|
|
*
|
|
* @drbg memory of state -- if NULL, new memory is allocated
|
|
* @pers Personalization string that is mixed into state, may be NULL -- note
|
|
* the entropy is pulled by the DRBG internally unconditionally
|
|
* as defined in SP800-90A. The additional input is mixed into
|
|
* the state in addition to the pulled entropy.
|
|
* @coreref reference to core
|
|
* @pr prediction resistance enabled
|
|
*
|
|
* return
|
|
* 0 on success
|
|
* error value otherwise
|
|
*/
|
|
static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
|
|
int coreref, bool pr)
|
|
{
|
|
int ret;
|
|
bool reseed = true;
|
|
|
|
pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
|
|
"%s\n", coreref, pr ? "enabled" : "disabled");
|
|
mutex_lock(&drbg->drbg_mutex);
|
|
|
|
/* 9.1 step 1 is implicit with the selected DRBG type */
|
|
|
|
/*
|
|
* 9.1 step 2 is implicit as caller can select prediction resistance
|
|
* and the flag is copied into drbg->flags --
|
|
* all DRBG types support prediction resistance
|
|
*/
|
|
|
|
/* 9.1 step 4 is implicit in drbg_sec_strength */
|
|
|
|
if (!drbg->core) {
|
|
drbg->core = &drbg_cores[coreref];
|
|
drbg->pr = pr;
|
|
drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
|
|
drbg->last_seed_time = 0;
|
|
drbg->reseed_threshold = drbg_max_requests(drbg);
|
|
|
|
ret = drbg_alloc_state(drbg);
|
|
if (ret)
|
|
goto unlock;
|
|
|
|
ret = drbg_prepare_hrng(drbg);
|
|
if (ret)
|
|
goto free_everything;
|
|
|
|
reseed = false;
|
|
}
|
|
|
|
ret = drbg_seed(drbg, pers, reseed);
|
|
|
|
if (ret && !reseed)
|
|
goto free_everything;
|
|
|
|
mutex_unlock(&drbg->drbg_mutex);
|
|
return ret;
|
|
|
|
unlock:
|
|
mutex_unlock(&drbg->drbg_mutex);
|
|
return ret;
|
|
|
|
free_everything:
|
|
mutex_unlock(&drbg->drbg_mutex);
|
|
drbg_uninstantiate(drbg);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* DRBG uninstantiate function as required by SP800-90A - this function
|
|
* frees all buffers and the DRBG handle
|
|
*
|
|
* @drbg DRBG state handle
|
|
*
|
|
* return
|
|
* 0 on success
|
|
*/
|
|
static int drbg_uninstantiate(struct drbg_state *drbg)
|
|
{
|
|
if (!IS_ERR_OR_NULL(drbg->jent))
|
|
crypto_free_rng(drbg->jent);
|
|
drbg->jent = NULL;
|
|
|
|
if (drbg->d_ops)
|
|
drbg->d_ops->crypto_fini(drbg);
|
|
drbg_dealloc_state(drbg);
|
|
/* no scrubbing of test_data -- this shall survive an uninstantiate */
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Helper function for setting the test data in the DRBG
|
|
*
|
|
* @drbg DRBG state handle
|
|
* @data test data
|
|
* @len test data length
|
|
*/
|
|
static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
|
|
const u8 *data, unsigned int len)
|
|
{
|
|
struct drbg_state *drbg = crypto_rng_ctx(tfm);
|
|
|
|
mutex_lock(&drbg->drbg_mutex);
|
|
drbg_string_fill(&drbg->test_data, data, len);
|
|
mutex_unlock(&drbg->drbg_mutex);
|
|
}
|
|
|
|
/***************************************************************
|
|
* Kernel crypto API cipher invocations requested by DRBG
|
|
***************************************************************/
|
|
|
|
#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
|
|
struct sdesc {
|
|
struct shash_desc shash;
|
|
char ctx[];
|
|
};
|
|
|
|
static int drbg_init_hash_kernel(struct drbg_state *drbg)
|
|
{
|
|
struct sdesc *sdesc;
|
|
struct crypto_shash *tfm;
|
|
|
|
tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
|
|
if (IS_ERR(tfm)) {
|
|
pr_info("DRBG: could not allocate digest TFM handle: %s\n",
|
|
drbg->core->backend_cra_name);
|
|
return PTR_ERR(tfm);
|
|
}
|
|
BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
|
|
sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
|
|
GFP_KERNEL);
|
|
if (!sdesc) {
|
|
crypto_free_shash(tfm);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
sdesc->shash.tfm = tfm;
|
|
drbg->priv_data = sdesc;
|
|
|
|
return crypto_shash_alignmask(tfm);
|
|
}
|
|
|
|
static int drbg_fini_hash_kernel(struct drbg_state *drbg)
|
|
{
|
|
struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
|
|
if (sdesc) {
|
|
crypto_free_shash(sdesc->shash.tfm);
|
|
kfree_sensitive(sdesc);
|
|
}
|
|
drbg->priv_data = NULL;
|
|
return 0;
|
|
}
|
|
|
|
static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
|
|
const unsigned char *key)
|
|
{
|
|
struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
|
|
|
|
crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
|
|
}
|
|
|
|
static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
|
|
const struct list_head *in)
|
|
{
|
|
struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
|
|
struct drbg_string *input = NULL;
|
|
|
|
crypto_shash_init(&sdesc->shash);
|
|
list_for_each_entry(input, in, list)
|
|
crypto_shash_update(&sdesc->shash, input->buf, input->len);
|
|
return crypto_shash_final(&sdesc->shash, outval);
|
|
}
|
|
#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
|
|
|
|
#ifdef CONFIG_CRYPTO_DRBG_CTR
|
|
static int drbg_fini_sym_kernel(struct drbg_state *drbg)
|
|
{
|
|
struct crypto_cipher *tfm =
|
|
(struct crypto_cipher *)drbg->priv_data;
|
|
if (tfm)
|
|
crypto_free_cipher(tfm);
|
|
drbg->priv_data = NULL;
|
|
|
|
if (drbg->ctr_handle)
|
|
crypto_free_skcipher(drbg->ctr_handle);
|
|
drbg->ctr_handle = NULL;
|
|
|
|
if (drbg->ctr_req)
|
|
skcipher_request_free(drbg->ctr_req);
|
|
drbg->ctr_req = NULL;
|
|
|
|
kfree(drbg->outscratchpadbuf);
|
|
drbg->outscratchpadbuf = NULL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int drbg_init_sym_kernel(struct drbg_state *drbg)
|
|
{
|
|
struct crypto_cipher *tfm;
|
|
struct crypto_skcipher *sk_tfm;
|
|
struct skcipher_request *req;
|
|
unsigned int alignmask;
|
|
char ctr_name[CRYPTO_MAX_ALG_NAME];
|
|
|
|
tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
|
|
if (IS_ERR(tfm)) {
|
|
pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
|
|
drbg->core->backend_cra_name);
|
|
return PTR_ERR(tfm);
|
|
}
|
|
BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
|
|
drbg->priv_data = tfm;
|
|
|
|
if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
|
|
drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) {
|
|
drbg_fini_sym_kernel(drbg);
|
|
return -EINVAL;
|
|
}
|
|
sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0);
|
|
if (IS_ERR(sk_tfm)) {
|
|
pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
|
|
ctr_name);
|
|
drbg_fini_sym_kernel(drbg);
|
|
return PTR_ERR(sk_tfm);
|
|
}
|
|
drbg->ctr_handle = sk_tfm;
|
|
crypto_init_wait(&drbg->ctr_wait);
|
|
|
|
req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
|
|
if (!req) {
|
|
pr_info("DRBG: could not allocate request queue\n");
|
|
drbg_fini_sym_kernel(drbg);
|
|
return -ENOMEM;
|
|
}
|
|
drbg->ctr_req = req;
|
|
skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
|
|
CRYPTO_TFM_REQ_MAY_SLEEP,
|
|
crypto_req_done, &drbg->ctr_wait);
|
|
|
|
alignmask = crypto_skcipher_alignmask(sk_tfm);
|
|
drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask,
|
|
GFP_KERNEL);
|
|
if (!drbg->outscratchpadbuf) {
|
|
drbg_fini_sym_kernel(drbg);
|
|
return -ENOMEM;
|
|
}
|
|
drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf,
|
|
alignmask + 1);
|
|
|
|
sg_init_table(&drbg->sg_in, 1);
|
|
sg_init_one(&drbg->sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
|
|
|
|
return alignmask;
|
|
}
|
|
|
|
static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
|
|
const unsigned char *key)
|
|
{
|
|
struct crypto_cipher *tfm =
|
|
(struct crypto_cipher *)drbg->priv_data;
|
|
|
|
crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
|
|
}
|
|
|
|
static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
|
|
const struct drbg_string *in)
|
|
{
|
|
struct crypto_cipher *tfm =
|
|
(struct crypto_cipher *)drbg->priv_data;
|
|
|
|
/* there is only component in *in */
|
|
BUG_ON(in->len < drbg_blocklen(drbg));
|
|
crypto_cipher_encrypt_one(tfm, outval, in->buf);
|
|
return 0;
|
|
}
|
|
|
|
static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
|
|
u8 *inbuf, u32 inlen,
|
|
u8 *outbuf, u32 outlen)
|
|
{
|
|
struct scatterlist *sg_in = &drbg->sg_in, *sg_out = &drbg->sg_out;
|
|
u32 scratchpad_use = min_t(u32, outlen, DRBG_OUTSCRATCHLEN);
|
|
int ret;
|
|
|
|
if (inbuf) {
|
|
/* Use caller-provided input buffer */
|
|
sg_set_buf(sg_in, inbuf, inlen);
|
|
} else {
|
|
/* Use scratchpad for in-place operation */
|
|
inlen = scratchpad_use;
|
|
memset(drbg->outscratchpad, 0, scratchpad_use);
|
|
sg_set_buf(sg_in, drbg->outscratchpad, scratchpad_use);
|
|
}
|
|
|
|
while (outlen) {
|
|
u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);
|
|
|
|
/* Output buffer may not be valid for SGL, use scratchpad */
|
|
skcipher_request_set_crypt(drbg->ctr_req, sg_in, sg_out,
|
|
cryptlen, drbg->V);
|
|
ret = crypto_wait_req(crypto_skcipher_encrypt(drbg->ctr_req),
|
|
&drbg->ctr_wait);
|
|
if (ret)
|
|
goto out;
|
|
|
|
crypto_init_wait(&drbg->ctr_wait);
|
|
|
|
memcpy(outbuf, drbg->outscratchpad, cryptlen);
|
|
memzero_explicit(drbg->outscratchpad, cryptlen);
|
|
|
|
outlen -= cryptlen;
|
|
outbuf += cryptlen;
|
|
}
|
|
ret = 0;
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_CRYPTO_DRBG_CTR */
|
|
|
|
/***************************************************************
|
|
* Kernel crypto API interface to register DRBG
|
|
***************************************************************/
|
|
|
|
/*
|
|
* Look up the DRBG flags by given kernel crypto API cra_name
|
|
* The code uses the drbg_cores definition to do this
|
|
*
|
|
* @cra_name kernel crypto API cra_name
|
|
* @coreref reference to integer which is filled with the pointer to
|
|
* the applicable core
|
|
* @pr reference for setting prediction resistance
|
|
*
|
|
* return: flags
|
|
*/
|
|
static inline void drbg_convert_tfm_core(const char *cra_driver_name,
|
|
int *coreref, bool *pr)
|
|
{
|
|
int i = 0;
|
|
size_t start = 0;
|
|
int len = 0;
|
|
|
|
*pr = true;
|
|
/* disassemble the names */
|
|
if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
|
|
start = 10;
|
|
*pr = false;
|
|
} else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
|
|
start = 8;
|
|
} else {
|
|
return;
|
|
}
|
|
|
|
/* remove the first part */
|
|
len = strlen(cra_driver_name) - start;
|
|
for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
|
|
if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
|
|
len)) {
|
|
*coreref = i;
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
static int drbg_kcapi_init(struct crypto_tfm *tfm)
|
|
{
|
|
struct drbg_state *drbg = crypto_tfm_ctx(tfm);
|
|
|
|
mutex_init(&drbg->drbg_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
|
|
{
|
|
drbg_uninstantiate(crypto_tfm_ctx(tfm));
|
|
}
|
|
|
|
/*
|
|
* Generate random numbers invoked by the kernel crypto API:
|
|
* The API of the kernel crypto API is extended as follows:
|
|
*
|
|
* src is additional input supplied to the RNG.
|
|
* slen is the length of src.
|
|
* dst is the output buffer where random data is to be stored.
|
|
* dlen is the length of dst.
|
|
*/
|
|
static int drbg_kcapi_random(struct crypto_rng *tfm,
|
|
const u8 *src, unsigned int slen,
|
|
u8 *dst, unsigned int dlen)
|
|
{
|
|
struct drbg_state *drbg = crypto_rng_ctx(tfm);
|
|
struct drbg_string *addtl = NULL;
|
|
struct drbg_string string;
|
|
|
|
if (slen) {
|
|
/* linked list variable is now local to allow modification */
|
|
drbg_string_fill(&string, src, slen);
|
|
addtl = &string;
|
|
}
|
|
|
|
return drbg_generate_long(drbg, dst, dlen, addtl);
|
|
}
|
|
|
|
/*
|
|
* Seed the DRBG invoked by the kernel crypto API
|
|
*/
|
|
static int drbg_kcapi_seed(struct crypto_rng *tfm,
|
|
const u8 *seed, unsigned int slen)
|
|
{
|
|
struct drbg_state *drbg = crypto_rng_ctx(tfm);
|
|
struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
|
|
bool pr = false;
|
|
struct drbg_string string;
|
|
struct drbg_string *seed_string = NULL;
|
|
int coreref = 0;
|
|
|
|
drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
|
|
&pr);
|
|
if (0 < slen) {
|
|
drbg_string_fill(&string, seed, slen);
|
|
seed_string = &string;
|
|
}
|
|
|
|
return drbg_instantiate(drbg, seed_string, coreref, pr);
|
|
}
|
|
|
|
/***************************************************************
|
|
* Kernel module: code to load the module
|
|
***************************************************************/
|
|
|
|
/*
|
|
* Tests as defined in 11.3.2 in addition to the cipher tests: testing
|
|
* of the error handling.
|
|
*
|
|
* Note: testing of failing seed source as defined in 11.3.2 is not applicable
|
|
* as seed source of get_random_bytes does not fail.
|
|
*
|
|
* Note 2: There is no sensible way of testing the reseed counter
|
|
* enforcement, so skip it.
|
|
*/
|
|
static inline int __init drbg_healthcheck_sanity(void)
|
|
{
|
|
int len = 0;
|
|
#define OUTBUFLEN 16
|
|
unsigned char buf[OUTBUFLEN];
|
|
struct drbg_state *drbg = NULL;
|
|
int ret;
|
|
int rc = -EFAULT;
|
|
bool pr = false;
|
|
int coreref = 0;
|
|
struct drbg_string addtl;
|
|
size_t max_addtllen, max_request_bytes;
|
|
|
|
/* only perform test in FIPS mode */
|
|
if (!fips_enabled)
|
|
return 0;
|
|
|
|
#ifdef CONFIG_CRYPTO_DRBG_CTR
|
|
drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
|
|
#elif defined CONFIG_CRYPTO_DRBG_HASH
|
|
drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
|
|
#else
|
|
drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
|
|
#endif
|
|
|
|
drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
|
|
if (!drbg)
|
|
return -ENOMEM;
|
|
|
|
mutex_init(&drbg->drbg_mutex);
|
|
drbg->core = &drbg_cores[coreref];
|
|
drbg->reseed_threshold = drbg_max_requests(drbg);
|
|
|
|
/*
|
|
* if the following tests fail, it is likely that there is a buffer
|
|
* overflow as buf is much smaller than the requested or provided
|
|
* string lengths -- in case the error handling does not succeed
|
|
* we may get an OOPS. And we want to get an OOPS as this is a
|
|
* grave bug.
|
|
*/
|
|
|
|
max_addtllen = drbg_max_addtl(drbg);
|
|
max_request_bytes = drbg_max_request_bytes(drbg);
|
|
drbg_string_fill(&addtl, buf, max_addtllen + 1);
|
|
/* overflow addtllen with additonal info string */
|
|
len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
|
|
BUG_ON(0 < len);
|
|
/* overflow max_bits */
|
|
len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
|
|
BUG_ON(0 < len);
|
|
|
|
/* overflow max addtllen with personalization string */
|
|
ret = drbg_seed(drbg, &addtl, false);
|
|
BUG_ON(0 == ret);
|
|
/* all tests passed */
|
|
rc = 0;
|
|
|
|
pr_devel("DRBG: Sanity tests for failure code paths successfully "
|
|
"completed\n");
|
|
|
|
kfree(drbg);
|
|
return rc;
|
|
}
|
|
|
|
static struct rng_alg drbg_algs[22];
|
|
|
|
/*
|
|
* Fill the array drbg_algs used to register the different DRBGs
|
|
* with the kernel crypto API. To fill the array, the information
|
|
* from drbg_cores[] is used.
|
|
*/
|
|
static inline void __init drbg_fill_array(struct rng_alg *alg,
|
|
const struct drbg_core *core, int pr)
|
|
{
|
|
int pos = 0;
|
|
static int priority = 200;
|
|
|
|
memcpy(alg->base.cra_name, "stdrng", 6);
|
|
if (pr) {
|
|
memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
|
|
pos = 8;
|
|
} else {
|
|
memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
|
|
pos = 10;
|
|
}
|
|
memcpy(alg->base.cra_driver_name + pos, core->cra_name,
|
|
strlen(core->cra_name));
|
|
|
|
alg->base.cra_priority = priority;
|
|
priority++;
|
|
/*
|
|
* If FIPS mode enabled, the selected DRBG shall have the
|
|
* highest cra_priority over other stdrng instances to ensure
|
|
* it is selected.
|
|
*/
|
|
if (fips_enabled)
|
|
alg->base.cra_priority += 200;
|
|
|
|
alg->base.cra_ctxsize = sizeof(struct drbg_state);
|
|
alg->base.cra_module = THIS_MODULE;
|
|
alg->base.cra_init = drbg_kcapi_init;
|
|
alg->base.cra_exit = drbg_kcapi_cleanup;
|
|
alg->generate = drbg_kcapi_random;
|
|
alg->seed = drbg_kcapi_seed;
|
|
alg->set_ent = drbg_kcapi_set_entropy;
|
|
alg->seedsize = 0;
|
|
}
|
|
|
|
static int __init drbg_init(void)
|
|
{
|
|
unsigned int i = 0; /* pointer to drbg_algs */
|
|
unsigned int j = 0; /* pointer to drbg_cores */
|
|
int ret;
|
|
|
|
ret = drbg_healthcheck_sanity();
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
|
|
pr_info("DRBG: Cannot register all DRBG types"
|
|
"(slots needed: %zu, slots available: %zu)\n",
|
|
ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
|
|
return -EFAULT;
|
|
}
|
|
|
|
/*
|
|
* each DRBG definition can be used with PR and without PR, thus
|
|
* we instantiate each DRBG in drbg_cores[] twice.
|
|
*
|
|
* As the order of placing them into the drbg_algs array matters
|
|
* (the later DRBGs receive a higher cra_priority) we register the
|
|
* prediction resistance DRBGs first as the should not be too
|
|
* interesting.
|
|
*/
|
|
for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
|
|
drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
|
|
for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
|
|
drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
|
|
return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
|
|
}
|
|
|
|
static void __exit drbg_exit(void)
|
|
{
|
|
crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
|
|
}
|
|
|
|
subsys_initcall(drbg_init);
|
|
module_exit(drbg_exit);
|
|
#ifndef CRYPTO_DRBG_HASH_STRING
|
|
#define CRYPTO_DRBG_HASH_STRING ""
|
|
#endif
|
|
#ifndef CRYPTO_DRBG_HMAC_STRING
|
|
#define CRYPTO_DRBG_HMAC_STRING ""
|
|
#endif
|
|
#ifndef CRYPTO_DRBG_CTR_STRING
|
|
#define CRYPTO_DRBG_CTR_STRING ""
|
|
#endif
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
|
|
MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
|
|
"using following cores: "
|
|
CRYPTO_DRBG_HASH_STRING
|
|
CRYPTO_DRBG_HMAC_STRING
|
|
CRYPTO_DRBG_CTR_STRING);
|
|
MODULE_ALIAS_CRYPTO("stdrng");
|
|
MODULE_IMPORT_NS(CRYPTO_INTERNAL);
|