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![Herbert Xu](/assets/img/avatar_default.png)
Merging the crypto tree for 3.17 in order to resolve the conflict on the 32-bit DRBG overflow fix.
1991 lines
57 KiB
C
1991 lines
57 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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/***************************************************************
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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 = "ecb(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 = "ecb(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 = "ecb(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 = 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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.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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#endif /* CONFIG_CRYPTO_DRBG_HMAC */
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};
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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
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* The test is performed on the result of one round of the output
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* function. Thus, the function implicitly knows the size of the
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* buffer.
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*
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* The FIPS test can be called in an endless loop until it returns
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* true. Although the code looks like a potential for a deadlock, it
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* is not the case, because returning a false cannot mathematically
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* occur (except once when a reseed took place and the updated state
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* would is now set up such that the generation of new value returns
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* an identical one -- this is most unlikely and would happen only once).
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* Thus, if this function repeatedly returns false and thus would cause
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* a deadlock, the integrity of the entire kernel is lost.
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*
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* @drbg DRBG handle
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* @buf output buffer of random data to be checked
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*
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* return:
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* true on success
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* false on error
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*/
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static bool drbg_fips_continuous_test(struct drbg_state *drbg,
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const unsigned char *buf)
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{
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#ifdef CONFIG_CRYPTO_FIPS
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int ret = 0;
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/* skip test if we test the overall system */
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if (drbg->test_data)
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return true;
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/* only perform test in FIPS mode */
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if (0 == fips_enabled)
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return true;
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if (!drbg->fips_primed) {
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/* Priming of FIPS test */
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memcpy(drbg->prev, buf, drbg_blocklen(drbg));
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drbg->fips_primed = true;
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/* return false due to priming, i.e. another round is needed */
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return false;
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}
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ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg));
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memcpy(drbg->prev, buf, drbg_blocklen(drbg));
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/* the test shall pass when the two compared values are not equal */
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return ret != 0;
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#else
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return true;
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#endif /* CONFIG_CRYPTO_FIPS */
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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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/*
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* Increment buffer
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*
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* @dst buffer to increment
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* @add value to add
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*/
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static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
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const unsigned char *add, size_t addlen)
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{
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/* implied: dstlen > addlen */
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unsigned char *dstptr;
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const unsigned char *addptr;
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unsigned int remainder = 0;
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size_t len = addlen;
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dstptr = dst + (dstlen-1);
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addptr = add + (addlen-1);
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while (len) {
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remainder += *dstptr + *addptr;
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*dstptr = remainder & 0xff;
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remainder >>= 8;
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len--; dstptr--; addptr--;
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}
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len = dstlen - addlen;
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while (len && remainder > 0) {
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remainder = *dstptr + 1;
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*dstptr = remainder & 0xff;
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remainder >>= 8;
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len--; dstptr--;
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}
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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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static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
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unsigned char *outval, 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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/* 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 1 */
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memset(out, 0, drbg_blocklen(drbg));
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/* 10.4.3 step 2 / 4 */
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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, key, 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, key, 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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memset(temp, 0, drbg_statelen(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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*/
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padlen++;
|
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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 */
|
|
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, temp, 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));
|
|
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);
|
|
unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */
|
|
unsigned int len = 0;
|
|
struct drbg_string cipherin;
|
|
unsigned char prefix = DRBG_PREFIX1;
|
|
|
|
memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
|
|
if (3 > reseed)
|
|
memset(df_data, 0, drbg_statelen(drbg));
|
|
|
|
/* 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;
|
|
}
|
|
|
|
drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg));
|
|
/*
|
|
* 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
|
|
* zeroizes all memory during initialization
|
|
*/
|
|
while (len < (drbg_statelen(drbg))) {
|
|
/* 10.2.1.2 step 2.1 */
|
|
drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
|
|
/*
|
|
* 10.2.1.2 step 2.2 */
|
|
ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin);
|
|
if (ret)
|
|
goto out;
|
|
/* 10.2.1.2 step 2.3 and 3 */
|
|
len += drbg_blocklen(drbg);
|
|
}
|
|
|
|
/* 10.2.1.2 step 4 */
|
|
temp_p = temp;
|
|
df_data_p = df_data;
|
|
for (len = 0; len < drbg_statelen(drbg); len++) {
|
|
*temp_p ^= *df_data_p;
|
|
df_data_p++; temp_p++;
|
|
}
|
|
|
|
/* 10.2.1.2 step 5 */
|
|
memcpy(drbg->C, temp, drbg_keylen(drbg));
|
|
/* 10.2.1.2 step 6 */
|
|
memcpy(drbg->V, temp + drbg_keylen(drbg), 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 len = 0;
|
|
int ret = 0;
|
|
struct drbg_string data;
|
|
unsigned char prefix = DRBG_PREFIX1;
|
|
|
|
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
|
|
|
|
/* 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 */
|
|
drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
|
|
drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg));
|
|
while (len < buflen) {
|
|
int outlen = 0;
|
|
/* 10.2.1.5.2 step 4.2 */
|
|
ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data);
|
|
if (ret) {
|
|
len = ret;
|
|
goto out;
|
|
}
|
|
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
|
|
drbg_blocklen(drbg) : (buflen - len);
|
|
if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {
|
|
/* 10.2.1.5.2 step 6 */
|
|
drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
|
|
continue;
|
|
}
|
|
/* 10.2.1.5.2 step 4.3 */
|
|
memcpy(buf + len, drbg->scratchpad, outlen);
|
|
len += outlen;
|
|
/* 10.2.1.5.2 step 6 */
|
|
if (len < buflen)
|
|
drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
|
|
}
|
|
|
|
/* 10.2.1.5.2 step 6 */
|
|
ret = drbg_ctr_update(drbg, NULL, 3);
|
|
if (ret)
|
|
len = ret;
|
|
|
|
out:
|
|
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
|
|
return len;
|
|
}
|
|
|
|
static 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, const unsigned char *key,
|
|
unsigned char *outval, const struct list_head *in);
|
|
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 "
|
|
/* 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_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, drbg->C, &seedlist);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* 10.1.2.2 step 2 and 5 -- HMAC for V */
|
|
ret = drbg_kcapi_hash(drbg, drbg->C, 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->C, drbg->V, &datalist);
|
|
if (ret)
|
|
return ret;
|
|
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
|
|
drbg_blocklen(drbg) : (buflen - len);
|
|
if (!drbg_fips_continuous_test(drbg, drbg->V))
|
|
continue;
|
|
|
|
/* 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 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 "
|
|
/*
|
|
* 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;
|
|
|
|
memset(tmp, 0, drbg_blocklen(drbg));
|
|
|
|
/* 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, NULL, 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;
|
|
|
|
memset(drbg->scratchpad, 0, drbg_statelen(drbg));
|
|
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;
|
|
|
|
/* this is value w as per documentation */
|
|
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
|
|
|
|
/* 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, NULL, 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);
|
|
unsigned char prefix = DRBG_PREFIX1;
|
|
|
|
memset(src, 0, drbg_statelen(drbg));
|
|
memset(dst, 0, drbg_blocklen(drbg));
|
|
|
|
/* 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, NULL, dst, &datalist);
|
|
if (ret) {
|
|
len = ret;
|
|
goto out;
|
|
}
|
|
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
|
|
drbg_blocklen(drbg) : (buflen - len);
|
|
if (!drbg_fips_continuous_test(drbg, dst)) {
|
|
drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
|
|
continue;
|
|
}
|
|
/* 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)
|
|
drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
|
|
}
|
|
|
|
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 */
|
|
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
|
|
/* 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, NULL, 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 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
|
|
******************************************************************/
|
|
|
|
/*
|
|
* 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 = 0;
|
|
unsigned char *entropy = NULL;
|
|
size_t entropylen = 0;
|
|
struct drbg_string data1;
|
|
LIST_HEAD(seedlist);
|
|
|
|
/* 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 (drbg->test_data && drbg->test_data->testentropy) {
|
|
drbg_string_fill(&data1, drbg->test_data->testentropy->buf,
|
|
drbg->test_data->testentropy->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.
|
|
*/
|
|
entropylen = drbg_sec_strength(drbg->core->flags);
|
|
if (!entropylen)
|
|
return -EFAULT;
|
|
if (!reseed)
|
|
entropylen = ((entropylen + 1) / 2) * 3;
|
|
pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n",
|
|
entropylen);
|
|
entropy = kzalloc(entropylen, GFP_KERNEL);
|
|
if (!entropy)
|
|
return -ENOMEM;
|
|
get_random_bytes(entropy, entropylen);
|
|
drbg_string_fill(&data1, entropy, entropylen);
|
|
}
|
|
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->d_ops->update(drbg, &seedlist, reseed);
|
|
if (ret)
|
|
goto out;
|
|
|
|
drbg->seeded = true;
|
|
/* 10.1.1.2 / 10.1.1.3 step 5 */
|
|
drbg->reseed_ctr = 1;
|
|
|
|
out:
|
|
kzfree(entropy);
|
|
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;
|
|
kzfree(drbg->V);
|
|
drbg->V = NULL;
|
|
kzfree(drbg->C);
|
|
drbg->C = NULL;
|
|
kzfree(drbg->scratchpad);
|
|
drbg->scratchpad = NULL;
|
|
drbg->reseed_ctr = 0;
|
|
#ifdef CONFIG_CRYPTO_FIPS
|
|
kzfree(drbg->prev);
|
|
drbg->prev = NULL;
|
|
drbg->fips_primed = false;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
drbg->V = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
|
|
if (!drbg->V)
|
|
goto err;
|
|
drbg->C = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
|
|
if (!drbg->C)
|
|
goto err;
|
|
#ifdef CONFIG_CRYPTO_FIPS
|
|
drbg->prev = kmalloc(drbg_blocklen(drbg), GFP_KERNEL);
|
|
if (!drbg->prev)
|
|
goto err;
|
|
drbg->fips_primed = false;
|
|
#endif
|
|
/* 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->scratchpad = kzalloc(sb_size, GFP_KERNEL);
|
|
if (!drbg->scratchpad)
|
|
goto err;
|
|
}
|
|
spin_lock_init(&drbg->drbg_lock);
|
|
return 0;
|
|
|
|
err:
|
|
drbg_dealloc_state(drbg);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Strategy to avoid holding long term locks: generate a shadow copy of DRBG
|
|
* and perform all operations on this shadow copy. After finishing, restore
|
|
* the updated state of the shadow copy into original drbg state. This way,
|
|
* only the read and write operations of the original drbg state must be
|
|
* locked
|
|
*/
|
|
static inline void drbg_copy_drbg(struct drbg_state *src,
|
|
struct drbg_state *dst)
|
|
{
|
|
if (!src || !dst)
|
|
return;
|
|
memcpy(dst->V, src->V, drbg_statelen(src));
|
|
memcpy(dst->C, src->C, drbg_statelen(src));
|
|
dst->reseed_ctr = src->reseed_ctr;
|
|
dst->seeded = src->seeded;
|
|
dst->pr = src->pr;
|
|
#ifdef CONFIG_CRYPTO_FIPS
|
|
dst->fips_primed = src->fips_primed;
|
|
memcpy(dst->prev, src->prev, drbg_blocklen(src));
|
|
#endif
|
|
/*
|
|
* Not copied:
|
|
* scratchpad is initialized drbg_alloc_state;
|
|
* priv_data is initialized with call to crypto_init;
|
|
* d_ops and core are set outside, as these parameters are const;
|
|
* test_data is set outside to prevent it being copied back.
|
|
*/
|
|
}
|
|
|
|
static int drbg_make_shadow(struct drbg_state *drbg, struct drbg_state **shadow)
|
|
{
|
|
int ret = -ENOMEM;
|
|
struct drbg_state *tmp = NULL;
|
|
|
|
tmp = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
|
|
if (!tmp)
|
|
return -ENOMEM;
|
|
|
|
/* read-only data as they are defined as const, no lock needed */
|
|
tmp->core = drbg->core;
|
|
tmp->d_ops = drbg->d_ops;
|
|
|
|
ret = drbg_alloc_state(tmp);
|
|
if (ret)
|
|
goto err;
|
|
|
|
spin_lock_bh(&drbg->drbg_lock);
|
|
drbg_copy_drbg(drbg, tmp);
|
|
/* only make a link to the test buffer, as we only read that data */
|
|
tmp->test_data = drbg->test_data;
|
|
spin_unlock_bh(&drbg->drbg_lock);
|
|
*shadow = tmp;
|
|
return 0;
|
|
|
|
err:
|
|
kzfree(tmp);
|
|
return ret;
|
|
}
|
|
|
|
static void drbg_restore_shadow(struct drbg_state *drbg,
|
|
struct drbg_state **shadow)
|
|
{
|
|
struct drbg_state *tmp = *shadow;
|
|
|
|
spin_lock_bh(&drbg->drbg_lock);
|
|
drbg_copy_drbg(tmp, drbg);
|
|
spin_unlock_bh(&drbg->drbg_lock);
|
|
drbg_dealloc_state(tmp);
|
|
kzfree(tmp);
|
|
*shadow = NULL;
|
|
}
|
|
|
|
/*************************************************************************
|
|
* 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: generated number of bytes
|
|
*/
|
|
static int drbg_generate(struct drbg_state *drbg,
|
|
unsigned char *buf, unsigned int buflen,
|
|
struct drbg_string *addtl)
|
|
{
|
|
int len = 0;
|
|
struct drbg_state *shadow = NULL;
|
|
LIST_HEAD(addtllist);
|
|
struct drbg_string timestamp;
|
|
union {
|
|
cycles_t cycles;
|
|
unsigned char char_cycles[sizeof(cycles_t)];
|
|
} now;
|
|
|
|
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;
|
|
}
|
|
|
|
len = drbg_make_shadow(drbg, &shadow);
|
|
if (len) {
|
|
pr_devel("DRBG: shadow copy cannot be generated\n");
|
|
return len;
|
|
}
|
|
|
|
/* 9.3.1 step 2 */
|
|
len = -EINVAL;
|
|
if (buflen > (drbg_max_request_bytes(shadow))) {
|
|
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(shadow))) {
|
|
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_max_requests(shadow)) < shadow->reseed_ctr)
|
|
shadow->seeded = false;
|
|
|
|
/* allocate cipher handle */
|
|
len = shadow->d_ops->crypto_init(shadow);
|
|
if (len)
|
|
goto err;
|
|
|
|
if (shadow->pr || !shadow->seeded) {
|
|
pr_devel("DRBG: reseeding before generation (prediction "
|
|
"resistance: %s, state %s)\n",
|
|
drbg->pr ? "true" : "false",
|
|
drbg->seeded ? "seeded" : "unseeded");
|
|
/* 9.3.1 steps 7.1 through 7.3 */
|
|
len = drbg_seed(shadow, addtl, true);
|
|
if (len)
|
|
goto err;
|
|
/* 9.3.1 step 7.4 */
|
|
addtl = NULL;
|
|
}
|
|
|
|
/*
|
|
* Mix the time stamp into the DRBG state if the DRBG is not in
|
|
* test mode. If there are two callers invoking the DRBG at the same
|
|
* time, i.e. before the first caller merges its shadow state back,
|
|
* both callers would obtain the same random number stream without
|
|
* changing the state here.
|
|
*/
|
|
if (!drbg->test_data) {
|
|
now.cycles = random_get_entropy();
|
|
drbg_string_fill(×tamp, now.char_cycles, sizeof(cycles_t));
|
|
list_add_tail(×tamp.list, &addtllist);
|
|
}
|
|
if (addtl && 0 < addtl->len)
|
|
list_add_tail(&addtl->list, &addtllist);
|
|
/* 9.3.1 step 8 and 10 */
|
|
len = shadow->d_ops->generate(shadow, buf, buflen, &addtllist);
|
|
|
|
/* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
|
|
shadow->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 (shadow->reseed_ctr && !(shadow->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);
|
|
drbg_dealloc_state(shadow);
|
|
kzfree(shadow);
|
|
return 0;
|
|
} else {
|
|
pr_devel("DRBG: self test successful\n");
|
|
}
|
|
}
|
|
#endif
|
|
|
|
err:
|
|
shadow->d_ops->crypto_fini(shadow);
|
|
drbg_restore_shadow(drbg, &shadow);
|
|
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)
|
|
{
|
|
int len = 0;
|
|
unsigned int slice = 0;
|
|
do {
|
|
int tmplen = 0;
|
|
unsigned int chunk = 0;
|
|
slice = ((buflen - len) / drbg_max_request_bytes(drbg));
|
|
chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
|
|
tmplen = drbg_generate(drbg, buf + len, chunk, addtl);
|
|
if (0 >= tmplen)
|
|
return tmplen;
|
|
len += tmplen;
|
|
} while (slice > 0 && (len < buflen));
|
|
return len;
|
|
}
|
|
|
|
/*
|
|
* 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 = -ENOMEM;
|
|
|
|
pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
|
|
"%s\n", coreref, pr ? "enabled" : "disabled");
|
|
drbg->core = &drbg_cores[coreref];
|
|
drbg->pr = pr;
|
|
drbg->seeded = false;
|
|
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:
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
/* 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 */
|
|
|
|
ret = drbg_alloc_state(drbg);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = -EFAULT;
|
|
if (drbg->d_ops->crypto_init(drbg))
|
|
goto err;
|
|
ret = drbg_seed(drbg, pers, false);
|
|
drbg->d_ops->crypto_fini(drbg);
|
|
if (ret)
|
|
goto err;
|
|
|
|
return 0;
|
|
|
|
err:
|
|
drbg_dealloc_state(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)
|
|
{
|
|
spin_lock_bh(&drbg->drbg_lock);
|
|
drbg_dealloc_state(drbg);
|
|
/* no scrubbing of test_data -- this shall survive an uninstantiate */
|
|
spin_unlock_bh(&drbg->drbg_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Helper function for setting the test data in the DRBG
|
|
*
|
|
* @drbg DRBG state handle
|
|
* @test_data test data to sets
|
|
*/
|
|
static inline void drbg_set_testdata(struct drbg_state *drbg,
|
|
struct drbg_test_data *test_data)
|
|
{
|
|
if (!test_data || !test_data->testentropy)
|
|
return;
|
|
spin_lock_bh(&drbg->drbg_lock);
|
|
drbg->test_data = test_data;
|
|
spin_unlock_bh(&drbg->drbg_lock);
|
|
}
|
|
|
|
/***************************************************************
|
|
* 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\n");
|
|
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;
|
|
sdesc->shash.flags = 0;
|
|
drbg->priv_data = sdesc;
|
|
return 0;
|
|
}
|
|
|
|
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);
|
|
kzfree(sdesc);
|
|
}
|
|
drbg->priv_data = NULL;
|
|
return 0;
|
|
}
|
|
|
|
static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
|
|
unsigned char *outval, const struct list_head *in)
|
|
{
|
|
struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
|
|
struct drbg_string *input = NULL;
|
|
|
|
if (key)
|
|
crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
|
|
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_init_sym_kernel(struct drbg_state *drbg)
|
|
{
|
|
int ret = 0;
|
|
struct crypto_blkcipher *tfm;
|
|
|
|
tfm = crypto_alloc_blkcipher(drbg->core->backend_cra_name, 0, 0);
|
|
if (IS_ERR(tfm)) {
|
|
pr_info("DRBG: could not allocate cipher TFM handle\n");
|
|
return PTR_ERR(tfm);
|
|
}
|
|
BUG_ON(drbg_blocklen(drbg) != crypto_blkcipher_blocksize(tfm));
|
|
drbg->priv_data = tfm;
|
|
return ret;
|
|
}
|
|
|
|
static int drbg_fini_sym_kernel(struct drbg_state *drbg)
|
|
{
|
|
struct crypto_blkcipher *tfm =
|
|
(struct crypto_blkcipher *)drbg->priv_data;
|
|
if (tfm)
|
|
crypto_free_blkcipher(tfm);
|
|
drbg->priv_data = NULL;
|
|
return 0;
|
|
}
|
|
|
|
static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
|
|
unsigned char *outval, const struct drbg_string *in)
|
|
{
|
|
int ret = 0;
|
|
struct scatterlist sg_in, sg_out;
|
|
struct blkcipher_desc desc;
|
|
struct crypto_blkcipher *tfm =
|
|
(struct crypto_blkcipher *)drbg->priv_data;
|
|
|
|
desc.tfm = tfm;
|
|
desc.flags = 0;
|
|
crypto_blkcipher_setkey(tfm, key, (drbg_keylen(drbg)));
|
|
/* there is only component in *in */
|
|
sg_init_one(&sg_in, in->buf, in->len);
|
|
sg_init_one(&sg_out, outval, drbg_blocklen(drbg));
|
|
ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in, in->len);
|
|
|
|
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);
|
|
bool pr = false;
|
|
int coreref = 0;
|
|
|
|
drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm), &coreref, &pr);
|
|
/*
|
|
* when personalization string is needed, the caller must call reset
|
|
* and provide the personalization string as seed information
|
|
*/
|
|
return drbg_instantiate(drbg, NULL, coreref, pr);
|
|
}
|
|
|
|
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:
|
|
*
|
|
* If dlen is larger than zero, rdata is interpreted as the output buffer
|
|
* where random data is to be stored.
|
|
*
|
|
* If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
|
|
* which holds the additional information string that is used for the
|
|
* DRBG generation process. The output buffer that is to be used to store
|
|
* data is also pointed to by struct drbg_gen.
|
|
*/
|
|
static int drbg_kcapi_random(struct crypto_rng *tfm, u8 *rdata,
|
|
unsigned int dlen)
|
|
{
|
|
struct drbg_state *drbg = crypto_rng_ctx(tfm);
|
|
if (0 < dlen) {
|
|
return drbg_generate_long(drbg, rdata, dlen, NULL);
|
|
} else {
|
|
struct drbg_gen *data = (struct drbg_gen *)rdata;
|
|
struct drbg_string addtl;
|
|
/* catch NULL pointer */
|
|
if (!data)
|
|
return 0;
|
|
drbg_set_testdata(drbg, data->test_data);
|
|
/* linked list variable is now local to allow modification */
|
|
drbg_string_fill(&addtl, data->addtl->buf, data->addtl->len);
|
|
return drbg_generate_long(drbg, data->outbuf, data->outlen,
|
|
&addtl);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Reset the DRBG invoked by the kernel crypto API
|
|
* The reset implies a full re-initialization of the DRBG. Similar to the
|
|
* generate function of drbg_kcapi_random, this function extends the
|
|
* kernel crypto API interface with struct drbg_gen
|
|
*/
|
|
static int drbg_kcapi_reset(struct crypto_rng *tfm, 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 seed_string;
|
|
int coreref = 0;
|
|
|
|
drbg_uninstantiate(drbg);
|
|
drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
|
|
&pr);
|
|
if (0 < slen) {
|
|
drbg_string_fill(&seed_string, seed, slen);
|
|
return drbg_instantiate(drbg, &seed_string, coreref, pr);
|
|
} else {
|
|
struct drbg_gen *data = (struct drbg_gen *)seed;
|
|
/* allow invocation of API call with NULL, 0 */
|
|
if (!data)
|
|
return drbg_instantiate(drbg, NULL, coreref, pr);
|
|
drbg_set_testdata(drbg, data->test_data);
|
|
/* linked list variable is now local to allow modification */
|
|
drbg_string_fill(&seed_string, data->addtl->buf,
|
|
data->addtl->len);
|
|
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)
|
|
{
|
|
#ifdef CONFIG_CRYPTO_FIPS
|
|
int len = 0;
|
|
#define OUTBUFLEN 16
|
|
unsigned char buf[OUTBUFLEN];
|
|
struct drbg_state *drbg = NULL;
|
|
int ret = -EFAULT;
|
|
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;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
/* get a valid instance of DRBG for following tests */
|
|
ret = drbg_instantiate(drbg, NULL, coreref, pr);
|
|
if (ret) {
|
|
rc = ret;
|
|
goto outbuf;
|
|
}
|
|
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);
|
|
drbg_uninstantiate(drbg);
|
|
|
|
/* overflow max addtllen with personalization string */
|
|
ret = drbg_instantiate(drbg, &addtl, coreref, pr);
|
|
BUG_ON(0 == ret);
|
|
/* all tests passed */
|
|
rc = 0;
|
|
|
|
pr_devel("DRBG: Sanity tests for failure code paths successfully "
|
|
"completed\n");
|
|
|
|
drbg_uninstantiate(drbg);
|
|
outbuf:
|
|
kzfree(drbg);
|
|
return rc;
|
|
#else /* CONFIG_CRYPTO_FIPS */
|
|
return 0;
|
|
#endif /* CONFIG_CRYPTO_FIPS */
|
|
}
|
|
|
|
static struct crypto_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 crypto_alg *alg,
|
|
const struct drbg_core *core, int pr)
|
|
{
|
|
int pos = 0;
|
|
static int priority = 100;
|
|
|
|
memset(alg, 0, sizeof(struct crypto_alg));
|
|
memcpy(alg->cra_name, "stdrng", 6);
|
|
if (pr) {
|
|
memcpy(alg->cra_driver_name, "drbg_pr_", 8);
|
|
pos = 8;
|
|
} else {
|
|
memcpy(alg->cra_driver_name, "drbg_nopr_", 10);
|
|
pos = 10;
|
|
}
|
|
memcpy(alg->cra_driver_name + pos, core->cra_name,
|
|
strlen(core->cra_name));
|
|
|
|
alg->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->cra_priority += 200;
|
|
|
|
alg->cra_flags = CRYPTO_ALG_TYPE_RNG;
|
|
alg->cra_ctxsize = sizeof(struct drbg_state);
|
|
alg->cra_type = &crypto_rng_type;
|
|
alg->cra_module = THIS_MODULE;
|
|
alg->cra_init = drbg_kcapi_init;
|
|
alg->cra_exit = drbg_kcapi_cleanup;
|
|
alg->cra_u.rng.rng_make_random = drbg_kcapi_random;
|
|
alg->cra_u.rng.rng_reset = drbg_kcapi_reset;
|
|
alg->cra_u.rng.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 = -EFAULT;
|
|
|
|
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 ret;
|
|
}
|
|
|
|
/*
|
|
* 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_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
|
|
}
|
|
|
|
static void __exit drbg_exit(void)
|
|
{
|
|
crypto_unregister_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
|
|
}
|
|
|
|
module_init(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);
|