The qcow2 .bdrv_measure() code calculates the crypto payload offset. This logic really belongs in crypto/block.c where it can be reused by other image formats.
The "luks" block driver will need this same logic in order to implement .bdrv_measure(), so extract the qcrypto_block_calculate_payload_offset() function now. Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> --- block/qcow2.c | 74 +++++++++++------------------------------- crypto/block.c | 40 +++++++++++++++++++++++ include/crypto/block.h | 22 +++++++++++++ 3 files changed, 81 insertions(+), 55 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index ef96606f8d..aca2c78fd9 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -4603,60 +4603,6 @@ static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) return ret; } -static ssize_t qcow2_measure_crypto_hdr_init_func(QCryptoBlock *block, - size_t headerlen, void *opaque, Error **errp) -{ - size_t *headerlenp = opaque; - - /* Stash away the payload size */ - *headerlenp = headerlen; - return 0; -} - -static ssize_t qcow2_measure_crypto_hdr_write_func(QCryptoBlock *block, - size_t offset, const uint8_t *buf, size_t buflen, - void *opaque, Error **errp) -{ - /* Discard the bytes, we're not actually writing to an image */ - return buflen; -} - -/* Determine the number of bytes for the LUKS payload */ -static bool qcow2_measure_luks_headerlen(QemuOpts *opts, size_t *len, - Error **errp) -{ - QDict *opts_qdict; - QDict *cryptoopts_qdict; - QCryptoBlockCreateOptions *cryptoopts; - QCryptoBlock *crypto; - - /* Extract "encrypt." options into a qdict */ - opts_qdict = qemu_opts_to_qdict(opts, NULL); - qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt."); - qobject_unref(opts_qdict); - - /* Build QCryptoBlockCreateOptions object from qdict */ - qdict_put_str(cryptoopts_qdict, "format", "luks"); - cryptoopts = block_crypto_create_opts_init(cryptoopts_qdict, errp); - qobject_unref(cryptoopts_qdict); - if (!cryptoopts) { - return false; - } - - /* Fake LUKS creation in order to determine the payload size */ - crypto = qcrypto_block_create(cryptoopts, "encrypt.", - qcow2_measure_crypto_hdr_init_func, - qcow2_measure_crypto_hdr_write_func, - len, errp); - qapi_free_QCryptoBlockCreateOptions(cryptoopts); - if (!crypto) { - return false; - } - - qcrypto_block_free(crypto); - return true; -} - static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, Error **errp) { @@ -4707,9 +4653,27 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, g_free(optstr); if (has_luks) { + g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL; + QDict *opts_qdict; + QDict *cryptoopts; size_t headerlen; - if (!qcow2_measure_luks_headerlen(opts, &headerlen, &local_err)) { + opts_qdict = qemu_opts_to_qdict(opts, NULL); + qdict_extract_subqdict(opts_qdict, &cryptoopts, "encrypt."); + qobject_unref(opts_qdict); + + qdict_put_str(cryptoopts, "format", "luks"); + + create_opts = block_crypto_create_opts_init(cryptoopts, errp); + qobject_unref(cryptoopts); + if (!create_opts) { + goto err; + } + + if (!qcrypto_block_calculate_payload_offset(create_opts, + "encrypt.", + &headerlen, + &local_err)) { goto err; } diff --git a/crypto/block.c b/crypto/block.c index 325752871c..a9e1b8cc36 100644 --- a/crypto/block.c +++ b/crypto/block.c @@ -115,6 +115,46 @@ QCryptoBlock *qcrypto_block_create(QCryptoBlockCreateOptions *options, } +static ssize_t qcrypto_block_headerlen_hdr_init_func(QCryptoBlock *block, + size_t headerlen, void *opaque, Error **errp) +{ + size_t *headerlenp = opaque; + + /* Stash away the payload size */ + *headerlenp = headerlen; + return 0; +} + + +static ssize_t qcrypto_block_headerlen_hdr_write_func(QCryptoBlock *block, + size_t offset, const uint8_t *buf, size_t buflen, + void *opaque, Error **errp) +{ + /* Discard the bytes, we're not actually writing to an image */ + return buflen; +} + + +bool +qcrypto_block_calculate_payload_offset(QCryptoBlockCreateOptions *create_opts, + const char *optprefix, + size_t *len, + Error **errp) +{ + QCryptoBlock *crypto; + bool ok; + + /* Fake LUKS creation in order to determine the payload size */ + crypto = qcrypto_block_create(create_opts, optprefix, + qcrypto_block_headerlen_hdr_init_func, + qcrypto_block_headerlen_hdr_write_func, + len, errp); + ok = crypto != NULL; + qcrypto_block_free(crypto); + return ok; +} + + QCryptoBlockInfo *qcrypto_block_get_info(QCryptoBlock *block, Error **errp) { diff --git a/include/crypto/block.h b/include/crypto/block.h index d49d2c2da9..c77ccaf9c0 100644 --- a/include/crypto/block.h +++ b/include/crypto/block.h @@ -145,6 +145,26 @@ QCryptoBlock *qcrypto_block_create(QCryptoBlockCreateOptions *options, Error **errp); +/** + * qcrypto_block_calculate_payload_offset: + * @create_opts: the encryption options + * @optprefix: name prefix for options + * @len: output for number of header bytes before payload + * @errp: pointer to a NULL-initialized error object + * + * Calculate the number of header bytes before the payload in an encrypted + * storage volume. The header is an area before the payload that is reserved + * for encryption metadata. + * + * Returns: true on success, false on error + */ +bool +qcrypto_block_calculate_payload_offset(QCryptoBlockCreateOptions *create_opts, + const char *optprefix, + size_t *len, + Error **errp); + + /** * qcrypto_block_get_info: * @block: the block encryption object @@ -269,5 +289,7 @@ uint64_t qcrypto_block_get_sector_size(QCryptoBlock *block); void qcrypto_block_free(QCryptoBlock *block); G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoBlock, qcrypto_block_free) +G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoBlockCreateOptions, + qapi_free_QCryptoBlockCreateOptions) #endif /* QCRYPTO_BLOCK_H */ -- 2.24.1