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/*
* Copyright 2019-present MongoDB, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mongocrypt-ciphertext-private.h"
#include "mongocrypt-private.h"
void _mongocrypt_ciphertext_init(_mongocrypt_ciphertext_t *ciphertext) {
BSON_ASSERT_PARAM(ciphertext);
memset(ciphertext, 0, sizeof(*ciphertext));
}
void _mongocrypt_ciphertext_cleanup(_mongocrypt_ciphertext_t *ciphertext) {
if (!ciphertext) {
return;
}
_mongocrypt_buffer_cleanup(&ciphertext->key_id);
_mongocrypt_buffer_cleanup(&ciphertext->data);
}
bool _mongocrypt_ciphertext_parse_unowned(_mongocrypt_buffer_t *in,
_mongocrypt_ciphertext_t *ciphertext,
mongocrypt_status_t *status) {
uint32_t offset;
/* From BSON Binary subtype 6 specification:
struct fle_blob {
uint8 fle_blob_subtype = (1 or 2);
uint8 key_uuid[16];
uint8 original_bson_type;
uint8 ciphertext[ciphertext_length];
}
*/
if (!ciphertext) {
CLIENT_ERR("ciphertext cannot be null");
return false;
}
if (!in) {
CLIENT_ERR("in parameter cannot be null");
return false;
}
if (!status) {
CLIENT_ERR("status cannot be null");
return false;
}
offset = 0;
/* At a minimum, a ciphertext must be 19 bytes:
* fle_blob_subtype (1) +
* key_uuid (16) +
* original_bson_type (1) +
* ciphertext (> 0)
*/
if (in->len < 19) {
CLIENT_ERR("malformed ciphertext, too small");
return false;
}
ciphertext->blob_subtype = in->data[0];
offset += 1;
/* TODO: merge new changes. */
if (ciphertext->blob_subtype != 1 && ciphertext->blob_subtype != 2) {
CLIENT_ERR("malformed ciphertext, expected blob subtype of 1 or 2");
return false;
}
_mongocrypt_buffer_init(&ciphertext->key_id);
ciphertext->key_id.data = in->data + offset;
ciphertext->key_id.len = 16;
ciphertext->key_id.subtype = BSON_SUBTYPE_UUID;
offset += 16;
ciphertext->original_bson_type = in->data[offset];
offset += 1;
_mongocrypt_buffer_init(&ciphertext->data);
ciphertext->data.data = in->data + offset;
ciphertext->data.len = in->len - offset;
return true;
}
bool _mongocrypt_serialize_ciphertext(_mongocrypt_ciphertext_t *ciphertext, _mongocrypt_buffer_t *out) {
uint32_t offset;
/* From BSON Binary subtype 6 specification:
struct fle_blob {
uint8 fle_blob_subtype = (1 or 2);
uint8 key_uuid[16];
uint8 original_bson_type;
uint8 ciphertext[ciphertext_length];
}
*/
if (!ciphertext || !out) {
return false;
}
if (ciphertext->key_id.len != 16) {
return false;
}
if (ciphertext->key_id.len > (UINT32_MAX - ciphertext->data.len - 1)
|| ciphertext->key_id.len > (SIZE_MAX - ciphertext->data.len - 1)) {
return false;
}
_mongocrypt_buffer_init(out);
offset = 0;
out->len = 1 + ciphertext->key_id.len + 1 + ciphertext->data.len;
out->data = bson_malloc0(out->len);
BSON_ASSERT(out->data);
out->owned = true;
/* ciphertext->blob_subtype is an enum and easily fits in uint8_t */
out->data[offset] = (uint8_t)ciphertext->blob_subtype;
offset += 1;
memcpy(out->data + offset, ciphertext->key_id.data, ciphertext->key_id.len);
offset += ciphertext->key_id.len;
out->data[offset] = ciphertext->original_bson_type;
offset += 1;
memcpy(out->data + offset, ciphertext->data.data, ciphertext->data.len);
return true;
}
/*
From "FLE and AEAD" doc:
A = Associated Data = fle_blob_subtype + key_uuid[16] + original_bson_type
*/
bool _mongocrypt_ciphertext_serialize_associated_data(_mongocrypt_ciphertext_t *ciphertext, _mongocrypt_buffer_t *out) {
BSON_ASSERT_PARAM(ciphertext);
uint32_t bytes_written = 0;
if (!out) {
return false;
}
_mongocrypt_buffer_init(out);
if (!ciphertext->original_bson_type) {
return false;
}
if (!_mongocrypt_buffer_is_uuid(&ciphertext->key_id)) {
return false;
}
if ((ciphertext->blob_subtype != MC_SUBTYPE_FLE1DeterministicEncryptedValue)
&& (ciphertext->blob_subtype != MC_SUBTYPE_FLE1RandomEncryptedValue)) {
return false;
}
if (ciphertext->key_id.len > (UINT32_MAX - 2)) {
return false;
}
out->len = 1 + ciphertext->key_id.len + 1;
out->data = bson_malloc(out->len);
BSON_ASSERT(out->data);
out->owned = true;
out->data[bytes_written++] = (uint8_t)ciphertext->blob_subtype;
memcpy(out->data + bytes_written, ciphertext->key_id.data, ciphertext->key_id.len);
bytes_written += ciphertext->key_id.len;
out->data[bytes_written++] = (uint8_t)ciphertext->original_bson_type;
return true;
}
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