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2167 lines
60 KiB
2167 lines
60 KiB
/* |
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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 <[email protected]>, 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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|
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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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/*************************************************************** |
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* Backend cipher definitions available to DRBG |
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***************************************************************/ |
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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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|
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static int drbg_uninstantiate(struct drbg_state *drbg); |
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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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/* |
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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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/* |
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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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|
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if (!IS_ENABLED(CONFIG_CRYPTO_FIPS)) |
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return 0; |
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|
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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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|
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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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|
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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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/* |
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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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|
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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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/****************************************************************** |
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* CTR DRBG callback functions |
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******************************************************************/ |
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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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|
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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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|
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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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|
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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 |
|
* 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 |
|
* blocklen-wise. Now, when the statelen is not a multiple |
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* of blocklen, the generateion loop below "spills over" |
|
* by at most blocklen. Thus, we need to give sufficient |
|
* 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) |
|
* iv |
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* start: pad + drbg_blocklen(drbg) |
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* length: drbg_blocklen(drbg) |
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* temp |
|
* start: iv + drbg_blocklen(drbg) |
|
* length: drbg_satelen(drbg) + drbg_blocklen(drbg) |
|
* note: temp is the buffer that the BCC function operates |
|
* on. BCC operates blockwise. drbg_statelen(drbg) |
|
* is sufficient when the DRBG state length is a multiple |
|
* of the block size. For AES192 (and maybe other ciphers) |
|
* this is not correct and the length for temp is |
|
* insufficient (yes, that also means for such ciphers, |
|
* the final output of all BCC rounds are truncated). |
|
* Therefore, add drbg_blocklen(drbg) to cover all |
|
* possibilities. |
|
*/ |
|
|
|
/* Derivation Function for CTR DRBG as defined in 10.4.2 */ |
|
static int drbg_ctr_df(struct drbg_state *drbg, |
|
unsigned char *df_data, size_t bytes_to_return, |
|
struct list_head *seedlist) |
|
{ |
|
int ret = -EFAULT; |
|
unsigned char L_N[8]; |
|
/* S3 is input */ |
|
struct drbg_string S1, S2, S4, cipherin; |
|
LIST_HEAD(bcc_list); |
|
unsigned char *pad = df_data + drbg_statelen(drbg); |
|
unsigned char *iv = pad + drbg_blocklen(drbg); |
|
unsigned char *temp = iv + drbg_blocklen(drbg); |
|
size_t padlen = 0; |
|
unsigned int templen = 0; |
|
/* 10.4.2 step 7 */ |
|
unsigned int i = 0; |
|
/* 10.4.2 step 8 */ |
|
const unsigned char *K = (unsigned char *) |
|
"\x00\x01\x02\x03\x04\x05\x06\x07" |
|
"\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" |
|
"\x10\x11\x12\x13\x14\x15\x16\x17" |
|
"\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"; |
|
unsigned char *X; |
|
size_t generated_len = 0; |
|
size_t inputlen = 0; |
|
struct drbg_string *seed = NULL; |
|
|
|
memset(pad, 0, drbg_blocklen(drbg)); |
|
memset(iv, 0, drbg_blocklen(drbg)); |
|
|
|
/* 10.4.2 step 1 is implicit as we work byte-wise */ |
|
|
|
/* 10.4.2 step 2 */ |
|
if ((512/8) < bytes_to_return) |
|
return -EINVAL; |
|
|
|
/* 10.4.2 step 2 -- calculate the entire length of all input data */ |
|
list_for_each_entry(seed, seedlist, list) |
|
inputlen += seed->len; |
|
drbg_cpu_to_be32(inputlen, &L_N[0]); |
|
|
|
/* 10.4.2 step 3 */ |
|
drbg_cpu_to_be32(bytes_to_return, &L_N[4]); |
|
|
|
/* 10.4.2 step 5: length is L_N, input_string, one byte, padding */ |
|
padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg)); |
|
/* wrap the padlen appropriately */ |
|
if (padlen) |
|
padlen = drbg_blocklen(drbg) - padlen; |
|
/* |
|
* pad / padlen contains the 0x80 byte and the following zero bytes. |
|
* As the calculated padlen value only covers the number of zero |
|
* bytes, this value has to be incremented by one for the 0x80 byte. |
|
*/ |
|
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 = 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 = 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 = 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 = 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 = 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 <[email protected]>"); |
|
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);
|
|
|