diff options
| -rw-r--r-- | arch/arm/crypto/ghash-ce-glue.c | 2 | ||||
| -rw-r--r-- | arch/s390/crypto/ghash_s390.c | 2 | ||||
| -rw-r--r-- | arch/x86/crypto/ghash-clmulni-intel_glue.c | 3 | ||||
| -rw-r--r-- | crypto/Kconfig | 11 | ||||
| -rw-r--r-- | crypto/ghash-generic.c | 31 | ||||
| -rw-r--r-- | drivers/crypto/Kconfig | 6 | ||||
| -rw-r--r-- | include/crypto/ghash.h | 2 |
7 files changed, 41 insertions, 16 deletions
diff --git a/arch/arm/crypto/ghash-ce-glue.c b/arch/arm/crypto/ghash-ce-glue.c index bb906b5f1eb3..c691077679a6 100644 --- a/arch/arm/crypto/ghash-ce-glue.c +++ b/arch/arm/crypto/ghash-ce-glue.c @@ -18,7 +18,7 @@ #include <linux/crypto.h> #include <linux/module.h> -MODULE_DESCRIPTION("GHASH secure hash using ARMv8 Crypto Extensions"); +MODULE_DESCRIPTION("GHASH hash function using ARMv8 Crypto Extensions"); MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS_CRYPTO("ghash"); diff --git a/arch/s390/crypto/ghash_s390.c b/arch/s390/crypto/ghash_s390.c index eeeb6a7737a4..a3e7400e031c 100644 --- a/arch/s390/crypto/ghash_s390.c +++ b/arch/s390/crypto/ghash_s390.c @@ -153,4 +153,4 @@ module_exit(ghash_mod_exit); MODULE_ALIAS_CRYPTO("ghash"); MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation"); +MODULE_DESCRIPTION("GHASH hash function, s390 implementation"); diff --git a/arch/x86/crypto/ghash-clmulni-intel_glue.c b/arch/x86/crypto/ghash-clmulni-intel_glue.c index ac76fe88ac4f..04d72a5a8ce9 100644 --- a/arch/x86/crypto/ghash-clmulni-intel_glue.c +++ b/arch/x86/crypto/ghash-clmulni-intel_glue.c @@ -357,6 +357,5 @@ module_init(ghash_pclmulqdqni_mod_init); module_exit(ghash_pclmulqdqni_mod_exit); MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("GHASH Message Digest Algorithm, " - "accelerated by PCLMULQDQ-NI"); +MODULE_DESCRIPTION("GHASH hash function, accelerated by PCLMULQDQ-NI"); MODULE_ALIAS_CRYPTO("ghash"); diff --git a/crypto/Kconfig b/crypto/Kconfig index 2e7f08ba0675..455a3354e291 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -647,11 +647,12 @@ config CRYPTO_VPMSUM_TESTER Unless you are testing these algorithms, you don't need this. config CRYPTO_GHASH - tristate "GHASH digest algorithm" + tristate "GHASH hash function" select CRYPTO_GF128MUL select CRYPTO_HASH help - GHASH is message digest algorithm for GCM (Galois/Counter Mode). + GHASH is the hash function used in GCM (Galois/Counter Mode). + It is not a general-purpose cryptographic hash function. config CRYPTO_POLY1305 tristate "Poly1305 authenticator algorithm" @@ -976,12 +977,12 @@ config CRYPTO_WP512 <http://www.larc.usp.br/~pbarreto/WhirlpoolPage.html> config CRYPTO_GHASH_CLMUL_NI_INTEL - tristate "GHASH digest algorithm (CLMUL-NI accelerated)" + tristate "GHASH hash function (CLMUL-NI accelerated)" depends on X86 && 64BIT select CRYPTO_CRYPTD help - GHASH is message digest algorithm for GCM (Galois/Counter Mode). - The implementation is accelerated by CLMUL-NI of Intel. + This is the x86_64 CLMUL-NI accelerated implementation of + GHASH, the hash function used in GCM (Galois/Counter mode). comment "Ciphers" diff --git a/crypto/ghash-generic.c b/crypto/ghash-generic.c index dad9e1f91a78..5027b3461c92 100644 --- a/crypto/ghash-generic.c +++ b/crypto/ghash-generic.c @@ -1,12 +1,37 @@ // SPDX-License-Identifier: GPL-2.0-only /* - * GHASH: digest algorithm for GCM (Galois/Counter Mode). + * GHASH: hash function for GCM (Galois/Counter Mode). * * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi> * Copyright (c) 2009 Intel Corp. * Author: Huang Ying <ying.huang@intel.com> + */ + +/* + * GHASH is a keyed hash function used in GCM authentication tag generation. + * + * The original GCM paper [1] presents GHASH as a function GHASH(H, A, C) which + * takes a 16-byte hash key H, additional authenticated data A, and a ciphertext + * C. It formats A and C into a single byte string X, interprets X as a + * polynomial over GF(2^128), and evaluates this polynomial at the point H. + * + * However, the NIST standard for GCM [2] presents GHASH as GHASH(H, X) where X + * is the already-formatted byte string containing both A and C. + * + * "ghash" in the Linux crypto API uses the 'X' (pre-formatted) convention, + * since the API supports only a single data stream per hash. Thus, the + * formatting of 'A' and 'C' is done in the "gcm" template, not in "ghash". + * + * The reason "ghash" is separate from "gcm" is to allow "gcm" to use an + * accelerated "ghash" when a standalone accelerated "gcm(aes)" is unavailable. + * It is generally inappropriate to use "ghash" for other purposes, since it is + * an "ε-almost-XOR-universal hash function", not a cryptographic hash function. + * It can only be used securely in crypto modes specially designed to use it. * - * The algorithm implementation is copied from gcm.c. + * [1] The Galois/Counter Mode of Operation (GCM) + * (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.694.695&rep=rep1&type=pdf) + * [2] Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC + * (https://csrc.nist.gov/publications/detail/sp/800-38d/final) */ #include <crypto/algapi.h> @@ -156,6 +181,6 @@ subsys_initcall(ghash_mod_init); module_exit(ghash_mod_exit); MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("GHASH Message Digest Algorithm"); +MODULE_DESCRIPTION("GHASH hash function"); MODULE_ALIAS_CRYPTO("ghash"); MODULE_ALIAS_CRYPTO("ghash-generic"); diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig index 69d1bbd5d9bf..b8c50871f11b 100644 --- a/drivers/crypto/Kconfig +++ b/drivers/crypto/Kconfig @@ -189,12 +189,12 @@ config S390_PRNG It is available as of z9. config CRYPTO_GHASH_S390 - tristate "GHASH digest algorithm" + tristate "GHASH hash function" depends on S390 select CRYPTO_HASH help - This is the s390 hardware accelerated implementation of the - GHASH message digest algorithm for GCM (Galois/Counter Mode). + This is the s390 hardware accelerated implementation of GHASH, + the hash function used in GCM (Galois/Counter mode). It is available as of z196. diff --git a/include/crypto/ghash.h b/include/crypto/ghash.h index 9136301062a5..f832c9f2aca3 100644 --- a/include/crypto/ghash.h +++ b/include/crypto/ghash.h @@ -1,6 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0 */ /* - * Common values for GHASH algorithms + * Common values for the GHASH hash function */ #ifndef __CRYPTO_GHASH_H__ |