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/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
#include <aws/cal/hmac.h>
#include <CommonCrypto/CommonHMAC.h>
static void s_destroy(struct aws_hmac *hmac);
static int s_update(struct aws_hmac *hmac, const struct aws_byte_cursor *to_hmac);
static int s_finalize(struct aws_hmac *hmac, struct aws_byte_buf *output);
static struct aws_hmac_vtable s_sha256_hmac_vtable = {
.destroy = s_destroy,
.update = s_update,
.finalize = s_finalize,
.alg_name = "SHA256 HMAC",
.provider = "CommonCrypto",
};
struct cc_hmac {
struct aws_hmac hmac;
CCHmacContext cc_hmac_ctx;
};
struct aws_hmac *aws_sha256_hmac_default_new(struct aws_allocator *allocator, const struct aws_byte_cursor *secret) {
AWS_ASSERT(secret->ptr);
struct cc_hmac *cc_hmac = aws_mem_acquire(allocator, sizeof(struct cc_hmac));
if (!cc_hmac) {
return NULL;
}
cc_hmac->hmac.allocator = allocator;
cc_hmac->hmac.vtable = &s_sha256_hmac_vtable;
cc_hmac->hmac.impl = cc_hmac;
cc_hmac->hmac.digest_size = AWS_SHA256_HMAC_LEN;
cc_hmac->hmac.good = true;
CCHmacInit(&cc_hmac->cc_hmac_ctx, kCCHmacAlgSHA256, secret->ptr, (CC_LONG)secret->len);
return &cc_hmac->hmac;
}
static void s_destroy(struct aws_hmac *hmac) {
struct cc_hmac *ctx = hmac->impl;
aws_mem_release(hmac->allocator, ctx);
}
static int s_update(struct aws_hmac *hmac, const struct aws_byte_cursor *to_hmac) {
if (!hmac->good) {
return aws_raise_error(AWS_ERROR_INVALID_STATE);
}
struct cc_hmac *ctx = hmac->impl;
CCHmacUpdate(&ctx->cc_hmac_ctx, to_hmac->ptr, (CC_LONG)to_hmac->len);
return AWS_OP_SUCCESS;
}
static int s_finalize(struct aws_hmac *hmac, struct aws_byte_buf *output) {
if (!hmac->good) {
return aws_raise_error(AWS_ERROR_INVALID_STATE);
}
struct cc_hmac *ctx = hmac->impl;
size_t buffer_len = output->capacity - output->len;
if (buffer_len < hmac->digest_size) {
return aws_raise_error(AWS_ERROR_SHORT_BUFFER);
}
CCHmacFinal(&ctx->cc_hmac_ctx, output->buffer + output->len);
hmac->good = false;
output->len += hmac->digest_size;
return AWS_OP_SUCCESS;
}
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