On Wed, Aug 14, 2019 at 11:22:16PM +0300, Maxim Levitsky wrote: > This implements the encryption key management > using the generic code in qcrypto layer > > 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 <mlevi...@redhat.com> > --- > block/crypto.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 93 insertions(+), 3 deletions(-) > > diff --git a/block/crypto.c b/block/crypto.c > index 42a3f0898b..415b6db041 100644 > --- a/block/crypto.c > +++ b/block/crypto.c > @@ -36,6 +36,7 @@ typedef struct BlockCrypto BlockCrypto; > > struct BlockCrypto { > QCryptoBlock *block; > + bool updating_keys; > }; > > > @@ -69,6 +70,24 @@ 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) > +{ > + 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; > @@ -622,6 +641,78 @@ block_crypto_get_specific_info_luks(BlockDriverState > *bs, Error **errp) > return spec_info; > } > > + > +static int > +block_crypto_setup_encryption(BlockDriverState *bs, > + enum BlkSetupEncryptionAction action, > + QCryptoEncryptionSetupOptions *options, > + bool force, > + Error **errp) > +{ > + BlockCrypto *crypto = bs->opaque; > + int ret; > + > + assert(crypto); > + assert(crypto->block); > + > + crypto->updating_keys = true; > + > + ret = bdrv_child_refresh_perms(bs, bs->file, errp); > + > + if (ret) { > + crypto->updating_keys = false; > + return ret; > + } > + > + ret = qcrypto_block_setup_encryption(crypto->block, > + block_crypto_read_func, > + block_crypto_write_func, > + bs, > + action, > + options, > + force, > + errp); > + > + crypto->updating_keys = false; > + bdrv_child_refresh_perms(bs, bs->file, errp); > + > + > + 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; > + }
So if 2 QEMU's have the same LUKS image open, this means that if one tries to update the header, it will fail to upgrade its lock & thus be blocked from updating header ? > + > + bdrv_filter_default_perms(bs, c, role, reopen_queue, > + perm, shared, nperm, nshared); > +} Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|