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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
#include "FormatRequest.h"
#include <stdlib.h>
#include <openssl/rand.h>
#include "common/dout.h"
#include "common/errno.h"
#include "include/compat.h"
#include "librbd/Utils.h"
#include "librbd/crypto/Utils.h"
#include "librbd/crypto/luks/Header.h"
#include "librbd/crypto/luks/Magic.h"
#include "librbd/io/AioCompletion.h"
#include "librbd/io/ImageDispatchSpec.h"
#define dout_subsys ceph_subsys_rbd
#undef dout_prefix
#define dout_prefix *_dout << "librbd::crypto::luks::FormatRequest: " << this \
<< " " << __func__ << ": "
namespace librbd {
namespace crypto {
namespace luks {
using librbd::util::create_context_callback;
template <typename I>
FormatRequest<I>::FormatRequest(
I* image_ctx, encryption_format_t format, encryption_algorithm_t alg,
std::string_view passphrase,
std::unique_ptr<CryptoInterface>* result_crypto, Context* on_finish,
bool insecure_fast_mode) : m_image_ctx(image_ctx), m_format(format),
m_alg(alg),
m_passphrase(passphrase),
m_result_crypto(result_crypto),
m_on_finish(on_finish),
m_insecure_fast_mode(insecure_fast_mode),
m_header(image_ctx->cct) {
}
template <typename I>
void FormatRequest<I>::send() {
const char* type;
size_t sector_size;
switch (m_format) {
case RBD_ENCRYPTION_FORMAT_LUKS1:
type = CRYPT_LUKS1;
sector_size = 512;
break;
case RBD_ENCRYPTION_FORMAT_LUKS2:
type = CRYPT_LUKS2;
sector_size = 4096;
break;
default:
lderr(m_image_ctx->cct) << "unsupported format type: " << m_format
<< dendl;
finish(-EINVAL);
return;
}
const char* cipher;
size_t key_size;
switch (m_alg) {
case RBD_ENCRYPTION_ALGORITHM_AES128:
cipher = "aes";
key_size = 32;
break;
case RBD_ENCRYPTION_ALGORITHM_AES256:
cipher = "aes";
key_size = 64;
break;
default:
lderr(m_image_ctx->cct) << "unsupported cipher algorithm: " << m_alg
<< dendl;
finish(-EINVAL);
return;
}
// generate encryption key
unsigned char* key = (unsigned char*)alloca(key_size);
if (RAND_bytes((unsigned char *)key, key_size) != 1) {
lderr(m_image_ctx->cct) << "cannot generate random encryption key"
<< dendl;
finish(-EAGAIN);
return;
}
// setup interface with libcryptsetup
auto r = m_header.init();
if (r < 0) {
finish(r);
return;
}
// format (create LUKS header)
auto stripe_period = m_image_ctx->get_stripe_period();
r = m_header.format(type, cipher, reinterpret_cast<char*>(key), key_size,
"xts-plain64", sector_size, stripe_period,
m_insecure_fast_mode);
if (r != 0) {
finish(r);
return;
}
m_image_ctx->image_lock.lock_shared();
uint64_t image_size = m_image_ctx->get_image_size(CEPH_NOSNAP);
m_image_ctx->image_lock.unlock_shared();
if (m_header.get_data_offset() > image_size) {
lderr(m_image_ctx->cct) << "image is too small, format requires "
<< m_header.get_data_offset() << " bytes" << dendl;
finish(-ENOSPC);
return;
}
// add keyslot (volume key encrypted with passphrase)
r = m_header.add_keyslot(m_passphrase.data(), m_passphrase.size());
if (r != 0) {
finish(r);
return;
}
r = util::build_crypto(m_image_ctx->cct, key, key_size,
m_header.get_sector_size(),
m_header.get_data_offset(), m_result_crypto);
ceph_memzero_s(key, key_size, key_size);
if (r != 0) {
finish(r);
return;
}
// read header from libcryptsetup interface
ceph::bufferlist bl;
r = m_header.read(&bl);
if (r < 0) {
finish(r);
return;
}
if (m_image_ctx->parent != nullptr) {
// parent is not encrypted with same key
// change LUKS magic to prevent decryption by other LUKS implementations
r = Magic::replace_magic(m_image_ctx->cct, bl);
if (r < 0) {
lderr(m_image_ctx->cct) << "error replacing LUKS magic: "
<< cpp_strerror(r) << dendl;
finish(r);
return;
}
}
// pad header to stripe period alignment to prevent copyup of parent data
// when writing encryption header to the child image
auto alignment = bl.length() % stripe_period;
if (alignment > 0) {
bl.append_zero(stripe_period - alignment);
}
// write header to offset 0 of the image
auto ctx = create_context_callback<
FormatRequest<I>, &FormatRequest<I>::handle_write_header>(this);
auto aio_comp = io::AioCompletion::create_and_start(
ctx, librbd::util::get_image_ctx(m_image_ctx), io::AIO_TYPE_WRITE);
ZTracer::Trace trace;
auto req = io::ImageDispatchSpec::create_write(
*m_image_ctx, io::IMAGE_DISPATCH_LAYER_API_START, aio_comp,
{{0, bl.length()}}, io::ImageArea::DATA, std::move(bl), 0, trace);
req->send();
}
template <typename I>
void FormatRequest<I>::handle_write_header(int r) {
ldout(m_image_ctx->cct, 20) << "r=" << r << dendl;
if (r < 0) {
lderr(m_image_ctx->cct) << "error writing header to image: "
<< cpp_strerror(r) << dendl;
finish(r);
return;
}
finish(0);
}
template <typename I>
void FormatRequest<I>::finish(int r) {
ldout(m_image_ctx->cct, 20) << "r=" << r << dendl;
m_on_finish->complete(r);
delete this;
}
} // namespace luks
} // namespace crypto
} // namespace librbd
template class librbd::crypto::luks::FormatRequest<librbd::ImageCtx>;
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