Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
crypto: ghash - add comment and improve help text
To help avoid confusion, add a comment to ghash-generic.c which explains
the convention that the kernel's implementation of GHASH uses.
Also update the Kconfig help text and module descriptions to call GHASH
a "hash function" rather than a "message digest", since the latter
normally means a real cryptographic hash function, which GHASH is not.
Cc: Pascal Van Leeuwen <pvanleeuwen@verimatrix.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Pascal Van Leeuwen <pvanleeuwen@verimatrix.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
authored by
Eric Biggers
and committed by
Herbert Xu
8dfa20fc
065cf577
+41
-16
+1
-1
arch/arm/crypto/ghash-ce-glue.c
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arch/arm/crypto/ghash-ce-glue.c
···
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#include <linux/crypto.h>
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#include <linux/module.h>
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MODULE_DESCRIPTION("GHASH secure hash using ARMv8 Crypto Extensions");
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MODULE_DESCRIPTION("GHASH hash function using ARMv8 Crypto Extensions");
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS_CRYPTO("ghash");
+1
-1
arch/s390/crypto/ghash_s390.c
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arch/s390/crypto/ghash_s390.c
+1
-2
arch/x86/crypto/ghash-clmulni-intel_glue.c
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arch/x86/crypto/ghash-clmulni-intel_glue.c
···
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module_exit(ghash_pclmulqdqni_mod_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("GHASH Message Digest Algorithm, "
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"accelerated by PCLMULQDQ-NI");
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MODULE_DESCRIPTION("GHASH hash function, accelerated by PCLMULQDQ-NI");
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MODULE_ALIAS_CRYPTO("ghash");
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-5
crypto/Kconfig
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crypto/Kconfig
···
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Unless you are testing these algorithms, you don't need this.
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config CRYPTO_GHASH
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tristate "GHASH digest algorithm"
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tristate "GHASH hash function"
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select CRYPTO_GF128MUL
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select CRYPTO_HASH
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help
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GHASH is message digest algorithm for GCM (Galois/Counter Mode).
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GHASH is the hash function used in GCM (Galois/Counter Mode).
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It is not a general-purpose cryptographic hash function.
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config CRYPTO_POLY1305
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tristate "Poly1305 authenticator algorithm"
···
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<http://www.larc.usp.br/~pbarreto/WhirlpoolPage.html>
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config CRYPTO_GHASH_CLMUL_NI_INTEL
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tristate "GHASH digest algorithm (CLMUL-NI accelerated)"
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tristate "GHASH hash function (CLMUL-NI accelerated)"
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depends on X86 && 64BIT
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select CRYPTO_CRYPTD
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help
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GHASH is message digest algorithm for GCM (Galois/Counter Mode).
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The implementation is accelerated by CLMUL-NI of Intel.
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This is the x86_64 CLMUL-NI accelerated implementation of
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GHASH, the hash function used in GCM (Galois/Counter mode).
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comment "Ciphers"
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+28
-3
crypto/ghash-generic.c
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crypto/ghash-generic.c
···
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* GHASH: digest algorithm for GCM (Galois/Counter Mode).
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* GHASH: hash function for GCM (Galois/Counter Mode).
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*
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* Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
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* Copyright (c) 2009 Intel Corp.
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* Author: Huang Ying <ying.huang@intel.com>
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*/
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/*
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* GHASH is a keyed hash function used in GCM authentication tag generation.
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*
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* The algorithm implementation is copied from gcm.c.
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* The original GCM paper [1] presents GHASH as a function GHASH(H, A, C) which
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* takes a 16-byte hash key H, additional authenticated data A, and a ciphertext
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* C. It formats A and C into a single byte string X, interprets X as a
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* polynomial over GF(2^128), and evaluates this polynomial at the point H.
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*
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* However, the NIST standard for GCM [2] presents GHASH as GHASH(H, X) where X
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* is the already-formatted byte string containing both A and C.
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*
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* "ghash" in the Linux crypto API uses the 'X' (pre-formatted) convention,
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* since the API supports only a single data stream per hash. Thus, the
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* formatting of 'A' and 'C' is done in the "gcm" template, not in "ghash".
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*
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* The reason "ghash" is separate from "gcm" is to allow "gcm" to use an
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* accelerated "ghash" when a standalone accelerated "gcm(aes)" is unavailable.
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* It is generally inappropriate to use "ghash" for other purposes, since it is
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* an "ε-almost-XOR-universal hash function", not a cryptographic hash function.
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* It can only be used securely in crypto modes specially designed to use it.
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*
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* [1] The Galois/Counter Mode of Operation (GCM)
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* (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.694.695&rep=rep1&type=pdf)
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* [2] Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC
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* (https://csrc.nist.gov/publications/detail/sp/800-38d/final)
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*/
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#include <crypto/algapi.h>
···
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module_exit(ghash_mod_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
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MODULE_DESCRIPTION("GHASH hash function");
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MODULE_ALIAS_CRYPTO("ghash");
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MODULE_ALIAS_CRYPTO("ghash-generic");
+3
-3
drivers/crypto/Kconfig
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-3
drivers/crypto/Kconfig
···
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It is available as of z9.
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config CRYPTO_GHASH_S390
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tristate "GHASH digest algorithm"
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tristate "GHASH hash function"
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depends on S390
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select CRYPTO_HASH
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help
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This is the s390 hardware accelerated implementation of the
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GHASH message digest algorithm for GCM (Galois/Counter Mode).
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This is the s390 hardware accelerated implementation of GHASH,
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the hash function used in GCM (Galois/Counter mode).
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It is available as of z196.
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