From: Aki Tuomi <aki.tuomi@dovecot.fi>
Date: Tue, 29 Nov 2016 21:18:56 +0000 (+0200)
Subject: lib: Add hmac helpers
X-Git-Tag: 2.2.27~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1163a576f2521ee913cf5ff967ea248b3ebe6487;p=thirdparty%2Fdovecot%2Fcore.git

lib: Add hmac helpers

These run hmac for given data with given parameters
and returns stack allocated buffer. They are helpful
when doing lots of HMACs, such as the AWS4 signing
protocol.
---

diff --git a/src/lib/hmac.c b/src/lib/hmac.c
index 52da3b442f..d3dc09f501 100644
--- a/src/lib/hmac.c
+++ b/src/lib/hmac.c
@@ -10,6 +10,7 @@
 #include "lib.h"
 #include "hmac.h"
 #include "safe-memset.h"
+#include "buffer.h"
 
 void hmac_init(struct hmac_context *_ctx, const unsigned char *key,
 		size_t key_len, const struct hash_method *meth)
@@ -59,3 +60,36 @@ void hmac_final(struct hmac_context *_ctx, unsigned char *digest)
 	ctx->hash->loop(ctx->ctxo, digest, ctx->hash->digest_size);
 	ctx->hash->result(ctx->ctxo, digest);
 }
+
+buffer_t *t_hmac_data(const struct hash_method *meth,
+		      const unsigned char *key, size_t key_len,
+		      const void *data, size_t data_len)
+{
+	struct hmac_context ctx;
+	i_assert(meth != NULL);
+	i_assert(key != NULL && key_len > 0);
+	i_assert(data != NULL || data_len == 0);
+
+	buffer_t *res = buffer_create_dynamic(pool_datastack_create(), meth->digest_size);
+	hmac_init(&ctx, key, key_len, meth);
+	if (data_len > 0)
+		hmac_update(&ctx, data, data_len);
+	unsigned char *buf = buffer_get_space_unsafe(res, 0, meth->digest_size);
+	hmac_final(&ctx, buf);
+	return res;
+}
+
+buffer_t *t_hmac_buffer(const struct hash_method *meth,
+			const unsigned char *key, size_t key_len,
+			const buffer_t *data)
+{
+	return t_hmac_data(meth, key, key_len, data->data, data->used);
+}
+
+buffer_t *t_hmac_str(const struct hash_method *meth,
+		     const unsigned char *key, size_t key_len,
+		     const char *data)
+{
+	return t_hmac_data(meth, key, key_len, data, strlen(data));
+}
+
diff --git a/src/lib/hmac.h b/src/lib/hmac.h
index 7e68cd0966..8b0a2806d1 100644
--- a/src/lib/hmac.h
+++ b/src/lib/hmac.h
@@ -32,4 +32,14 @@ hmac_update(struct hmac_context *_ctx, const void *data, size_t size)
 	ctx->hash->loop(ctx->ctx, data, size);
 }
 
+buffer_t *t_hmac_data(const struct hash_method *meth,
+		      const unsigned char *key, size_t key_len,
+		      const void *data, size_t data_len);
+buffer_t *t_hmac_buffer(const struct hash_method *meth,
+			const unsigned char *key, size_t key_len,
+			const buffer_t *data);
+buffer_t *t_hmac_str(const struct hash_method *meth,
+		     const unsigned char *key, size_t key_len,
+		     const char *data);
+
 #endif