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Re: [Qemu-block] [PATCH 05/10] block/crypto: implement the encryption ke
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-block] [PATCH 05/10] block/crypto: implement the encryption key management |
Date: |
Fri, 6 Sep 2019 15:04:23 +0100 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
On Fri, Aug 30, 2019 at 11:56:03PM +0300, Maxim Levitsky wrote:
> This implements the encryption key management
> using the generic code in qcrypto layer
> (currently only for qemu-img amend)
>
> This code adds another 'write_func' because the initialization
> write_func works directly on the underlying file,
> because during the creation, there is no open instance
> of the luks driver, but during regular use, we have it,
> and should use it instead.
>
> Signed-off-by: Maxim Levitsky <address@hidden>
> ---
> block/crypto.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 103 insertions(+), 3 deletions(-)
>
> diff --git a/block/crypto.c b/block/crypto.c
> index a6a3e1f1d8..dbd95a99ba 100644
> --- a/block/crypto.c
> +++ b/block/crypto.c
> @@ -36,6 +36,7 @@ typedef struct BlockCrypto BlockCrypto;
>
> struct BlockCrypto {
> QCryptoBlock *block;
> + bool updating_keys;
> };
>
>
> @@ -70,6 +71,24 @@ static ssize_t block_crypto_read_func(QCryptoBlock *block,
> return ret;
> }
>
> +static ssize_t block_crypto_write_func(QCryptoBlock *block,
> + size_t offset,
> + const uint8_t *buf,
> + size_t buflen,
> + void *opaque,
> + Error **errp)
Indent off-by-1 - align with param on the first line
> +{
> + BlockDriverState *bs = opaque;
> + ssize_t ret;
> +
> + ret = bdrv_pwrite(bs->file, offset, buf, buflen);
> + if (ret < 0) {
> + error_setg_errno(errp, -ret, "Could not write encryption header");
> + return ret;
> + }
> + return ret;
> +}
> +
>
> struct BlockCryptoCreateData {
> BlockBackend *blk;
> @@ -647,6 +666,88 @@ block_crypto_get_specific_info_luks(BlockDriverState
> *bs, Error **errp)
> return spec_info;
> }
>
> +
> +static int
> +block_crypto_amend_options(BlockDriverState *bs,
> + QemuOpts *opts,
> + BlockDriverAmendStatusCB *status_cb,
> + void *cb_opaque,
> + bool force,
> + Error **errp)
> +{
> + BlockCrypto *crypto = bs->opaque;
> + QDict *cryptoopts = NULL;
> + QCryptoBlockCreateOptions *amend_options = NULL;
> + int ret;
> +
> + assert(crypto);
> + assert(crypto->block);
> +
> + crypto->updating_keys = true;
> +
> + ret = bdrv_child_refresh_perms(bs, bs->file, errp);
> + if (ret) {
I can;'t remember - does this need to be "ret < 0" or
does refresh_perms return positive errnos ?
> + goto cleanup;
> + }
> +
> + cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL,
> + &block_crypto_create_opts_luks,
> + true);
> +
> + qdict_put_str(cryptoopts, "format", "luks");
> + amend_options = block_crypto_create_opts_init(cryptoopts, errp);
> + if (!amend_options) {
> + ret = -EINVAL;
> + goto cleanup;
> + }
> +
> + ret = qcrypto_block_amend_options(crypto->block,
> + block_crypto_read_func,
> + block_crypto_write_func,
> + bs,
> + amend_options,
> + force,
> + errp);
> +cleanup:
> + crypto->updating_keys = false;
> + bdrv_child_refresh_perms(bs, bs->file, errp);
> + qapi_free_QCryptoBlockCreateOptions(amend_options);
> + qobject_unref(cryptoopts);
> + return ret;
> +}
> +
> +
> +static void
> +block_crypto_child_perms(BlockDriverState *bs, BdrvChild *c,
> + const BdrvChildRole *role,
> + BlockReopenQueue *reopen_queue,
> + uint64_t perm, uint64_t shared,
> + uint64_t *nperm, uint64_t *nshared)
> +{
> +
> + BlockCrypto *crypto = bs->opaque;
> +
> + /*
> + * This driver doesn't modify LUKS metadata except
> + * when updating the encryption slots.
> + * Allow share-rw=on as a special case.
> + *
> + * Encryption update will set the crypto->updating_keys
> + * during that period and refresh permissions
> + *
> + * */
> +
> + if (crypto->updating_keys) {
> + /*need exclusive write access for header update */
> + perm |= BLK_PERM_WRITE;
> + shared &= ~BLK_PERM_WRITE;
> + }
> +
> + bdrv_filter_default_perms(bs, c, role, reopen_queue,
> + perm, shared, nperm, nshared);
> +}
> +
> +
> static const char *const block_crypto_strong_runtime_opts[] = {
> BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET,
>
> @@ -659,9 +760,7 @@ static BlockDriver bdrv_crypto_luks = {
> .bdrv_probe = block_crypto_probe_luks,
> .bdrv_open = block_crypto_open_luks,
> .bdrv_close = block_crypto_close,
> - /* This driver doesn't modify LUKS metadata except when creating image.
> - * Allow share-rw=on as a special case. */
> - .bdrv_child_perm = bdrv_filter_default_perms,
> + .bdrv_child_perm = block_crypto_child_perms,
> .bdrv_co_create = block_crypto_co_create_luks,
> .bdrv_co_create_opts = block_crypto_co_create_opts_luks,
> .bdrv_co_truncate = block_crypto_co_truncate,
> @@ -674,6 +773,7 @@ static BlockDriver bdrv_crypto_luks = {
> .bdrv_getlength = block_crypto_getlength,
> .bdrv_get_info = block_crypto_get_info_luks,
> .bdrv_get_specific_info = block_crypto_get_specific_info_luks,
> + .bdrv_amend_options = block_crypto_amend_options,
>
> .strong_runtime_opts = block_crypto_strong_runtime_opts,
> };
> --
> 2.17.2
>
Regards,
Daniel
--
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- Re: [Qemu-block] [PATCH 05/10] block/crypto: implement the encryption key management,
Daniel P . Berrangé <=