static int default_cmm_decrypt_materials()

in source/default_cmm.c [100:150]

• 43 lines of code
• 9 McCabe index (conditional complexity)

static int default_cmm_decrypt_materials(
    struct aws_cryptosdk_cmm *cmm,
    struct aws_cryptosdk_dec_materials **output,
    struct aws_cryptosdk_dec_request *request) {
    struct aws_cryptosdk_dec_materials *dec_mat;
    struct default_cmm *self = (struct default_cmm *)cmm;

    dec_mat = aws_cryptosdk_dec_materials_new(request->alloc, request->alg);
    if (!dec_mat) goto err;

    if (aws_cryptosdk_keyring_on_decrypt(
            self->kr,
            request->alloc,
            &dec_mat->unencrypted_data_key,
            &dec_mat->keyring_trace,
            &request->encrypted_data_keys,
            request->enc_ctx,
            request->alg))
        goto err;

    if (!dec_mat->unencrypted_data_key.buffer) {
        aws_raise_error(AWS_CRYPTOSDK_ERR_CANNOT_DECRYPT);
        goto err;
    }

    const struct aws_cryptosdk_alg_properties *props = aws_cryptosdk_alg_props(request->alg);
    struct aws_hash_element *pElement                = NULL;
    aws_hash_table_find(request->enc_ctx, EC_PUBLIC_KEY_FIELD, &pElement);
    if (props->signature_len) {
        if (!pElement || !pElement->key) {
            aws_raise_error(AWS_CRYPTOSDK_ERR_BAD_CIPHERTEXT);
            goto err;
        }

        if (aws_cryptosdk_sig_verify_start(&dec_mat->signctx, request->alloc, pElement->value, props)) {
            goto err;
        }
    } else if (pElement) {
        // If alg suite is unsigned, enc_ctx must not contain EC_PUBLIC_KEY_FIELD
        aws_raise_error(AWS_CRYPTOSDK_ERR_BAD_CIPHERTEXT);
        goto err;
    }

    *output = dec_mat;
    return AWS_OP_SUCCESS;

err:
    *output = NULL;
    aws_cryptosdk_dec_materials_destroy(dec_mat);
    return AWS_OP_ERR;
}