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 52da3b442f8d2b2f95367d7889231bb998495c5a..d3dc09f50190e8f2efd93879e872a9b3dda18663 100644 (file)
--- 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 7e68cd0966199b43767816215f334d2665374132..8b0a2806d1577b1f7bb6ee0e36c87242b5530299 100644 (file)
--- 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