From 218314e712fdb44683fcb9f974b6cd071dcc4a32 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Sun, 29 Jul 2007 03:09:00 +0100 Subject: [PATCH] Added HMAC code from TLS project --- src/crypto/hmac.c | 120 ++++++++++++++++++++++++++++++++++++++++ src/include/gpxe/hmac.h | 30 ++++++++++ 2 files changed, 150 insertions(+) create mode 100644 src/crypto/hmac.c create mode 100644 src/include/gpxe/hmac.h diff --git a/src/crypto/hmac.c b/src/crypto/hmac.c new file mode 100644 index 00000000..6884bde9 --- /dev/null +++ b/src/crypto/hmac.c @@ -0,0 +1,120 @@ +/* + * Copyright (C) 2007 Michael Brown . + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +/** + * @file + * + * Keyed-Hashing for Message Authentication + */ + +#include +#include +#include +#include + +/** + * Reduce HMAC key length + * + * @v digest Digest algorithm to use + * @v digest_ctx Digest context + * @v key Key + * @v key_len Length of key + */ +static void hmac_reduce_key ( struct crypto_algorithm *digest, + void *key, size_t *key_len ) { + uint8_t digest_ctx[digest->ctxsize]; + + digest_init ( digest, digest_ctx ); + digest_update ( digest, digest_ctx, key, *key_len ); + digest_final ( digest, digest_ctx, key ); + *key_len = digest->digestsize; +} + +/** + * Initialise HMAC + * + * @v digest Digest algorithm to use + * @v digest_ctx Digest context + * @v key Key + * @v key_len Length of key + * + * The length of the key should be less than the block size of the + * digest algorithm being used. (If the key length is greater, it + * will be replaced with its own digest, and key_len will be updated + * accordingly). + */ +void hmac_init ( struct crypto_algorithm *digest, void *digest_ctx, + void *key, size_t *key_len ) { + unsigned char k_ipad[digest->blocksize]; + unsigned int i; + + /* Reduce key if necessary */ + if ( *key_len > sizeof ( k_ipad ) ) + hmac_reduce_key ( digest, key, key_len ); + + /* Construct input pad */ + memset ( k_ipad, 0, sizeof ( k_ipad ) ); + memcpy ( k_ipad, key, *key_len ); + for ( i = 0 ; i < sizeof ( k_ipad ) ; i++ ) { + k_ipad[i] ^= 0x36; + } + + /* Start inner hash */ + digest_init ( digest, digest_ctx ); + digest_update ( digest, digest_ctx, k_ipad, sizeof ( k_ipad ) ); +} + +/** + * Finalise HMAC + * + * @v digest Digest algorithm to use + * @v digest_ctx Digest context + * @v key Key + * @v key_len Length of key + * @v hmac HMAC digest to fill in + * + * The length of the key should be less than the block size of the + * digest algorithm being used. (If the key length is greater, it + * will be replaced with its own digest, and key_len will be updated + * accordingly). + */ +void hmac_final ( struct crypto_algorithm *digest, void *digest_ctx, + void *key, size_t *key_len, void *hmac ) { + unsigned char k_opad[digest->blocksize]; + unsigned int i; + + /* Reduce key if necessary */ + if ( *key_len > sizeof ( k_opad ) ) + hmac_reduce_key ( digest, key, key_len ); + + /* Construct output pad */ + memset ( k_opad, 0, sizeof ( k_opad ) ); + memcpy ( k_opad, key, *key_len ); + for ( i = 0 ; i < sizeof ( k_opad ) ; i++ ) { + k_opad[i] ^= 0x5c; + } + + /* Finish inner hash */ + digest_final ( digest, digest_ctx, hmac ); + + /* Perform outer hash */ + digest_init ( digest, digest_ctx ); + digest_update ( digest, digest_ctx, k_opad, sizeof ( k_opad ) ); + digest_update ( digest, digest_ctx, hmac, digest->digestsize ); + digest_final ( digest, digest_ctx, hmac ); +} diff --git a/src/include/gpxe/hmac.h b/src/include/gpxe/hmac.h new file mode 100644 index 00000000..fd34db04 --- /dev/null +++ b/src/include/gpxe/hmac.h @@ -0,0 +1,30 @@ +#ifndef _GPXE_HMAC_H +#define _GPXE_HMAC_H + +/** @file + * + * Keyed-Hashing for Message Authentication + */ + +#include + +/** + * Update HMAC + * + * @v digest Digest algorithm to use + * @v digest_ctx Digest context + * @v data Data + * @v len Length of data + */ +static inline void hmac_update ( struct crypto_algorithm *digest, + void *digest_ctx, const void *data, + size_t len ) { + digest_update ( digest, digest_ctx, data, len ); +} + +extern void hmac_init ( struct crypto_algorithm *digest, void *digest_ctx, + void *key, size_t *key_len ); +extern void hmac_final ( struct crypto_algorithm *digest, void *digest_ctx, + void *key, size_t *key_len, void *hmac ); + +#endif /* _GPXE_HMAC_H */