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-rw-r--r--source4/lib/crypto/hmacsha256.c91
1 files changed, 91 insertions, 0 deletions
diff --git a/source4/lib/crypto/hmacsha256.c b/source4/lib/crypto/hmacsha256.c
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+++ b/source4/lib/crypto/hmacsha256.c
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+/*
+ Unix SMB/CIFS implementation.
+
+ Interface header: HMAC SHA-256 code
+
+ Copyright (C) Andrew Tridgell 2008
+
+ based in hmacsha1.c which is:
+ Copyright (C) Stefan Metzmacher
+
+ 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 3 of the License, or
+ (at your option) 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, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+ taken direct from rfc2202 implementation and modified for suitable use
+ */
+
+#include "includes.h"
+#include "lib/crypto/crypto.h"
+
+/***********************************************************************
+ the rfc 2104/2202 version of hmac_sha256 initialisation.
+***********************************************************************/
+_PUBLIC_ void hmac_sha256_init(const uint8_t *key, size_t key_len, struct HMACSHA256Context *ctx)
+{
+ int i;
+ uint8_t tk[SHA256_DIGEST_LENGTH];
+
+ /* if key is longer than 64 bytes reset it to key=HASH(key) */
+ if (key_len > 64)
+ {
+ SHA256_CTX tctx;
+
+ SHA256_Init(&tctx);
+ SHA256_Update(&tctx, key, key_len);
+ SHA256_Final(tk, &tctx);
+
+ key = tk;
+ key_len = SHA256_DIGEST_LENGTH;
+ }
+
+ /* start out by storing key in pads */
+ ZERO_STRUCT(ctx->k_ipad);
+ ZERO_STRUCT(ctx->k_opad);
+ memcpy( ctx->k_ipad, key, key_len);
+ memcpy( ctx->k_opad, key, key_len);
+
+ /* XOR key with ipad and opad values */
+ for (i=0; i<64; i++)
+ {
+ ctx->k_ipad[i] ^= 0x36;
+ ctx->k_opad[i] ^= 0x5c;
+ }
+
+ SHA256_Init(&ctx->ctx);
+ SHA256_Update(&ctx->ctx, ctx->k_ipad, 64);
+}
+
+/***********************************************************************
+ update hmac_sha256 "inner" buffer
+***********************************************************************/
+_PUBLIC_ void hmac_sha256_update(const uint8_t *data, size_t data_len, struct HMACSHA256Context *ctx)
+{
+ SHA256_Update(&ctx->ctx, data, data_len); /* then text of datagram */
+}
+
+/***********************************************************************
+ finish off hmac_sha256 "inner" buffer and generate outer one.
+***********************************************************************/
+_PUBLIC_ void hmac_sha256_final(uint8_t digest[SHA256_DIGEST_LENGTH], struct HMACSHA256Context *ctx)
+{
+ SHA256_CTX ctx_o;
+
+ SHA256_Final(digest, &ctx->ctx);
+
+ SHA256_Init(&ctx_o);
+ SHA256_Update(&ctx_o, ctx->k_opad, 64);
+ SHA256_Update(&ctx_o, digest, SHA256_DIGEST_LENGTH);
+ SHA256_Final(digest, &ctx_o);
+}