QAPI's 'prefix' feature can make the connection between enumeration type and its constants less than obvious. It's best used with restraint. QCryptoHashAlgorithm has a 'prefix' that overrides the generated enumeration constants' prefix to QCRYPTO_HASH_ALG. We could simply drop 'prefix', but then the prefix becomes QCRYPTO_HASH_ALGORITHM, which is rather long. We could additionally rename the type to QCryptoHashAlg, but I think the abbreviation "alg" is less than clear. Rename the type to QCryptoHashAlgo instead. The prefix becomes to QCRYPTO_HASH_ALGO. Signed-off-by: Markus Armbruster <armbru@redhat.com> Acked-by: Daniel P. Berrangé <berrange@redhat.com> Message-ID: <20240904111836.3273842-12-armbru@redhat.com> [Conflicts with merge commit 7bbadc60b58b resolved]
		
			
				
	
	
		
			330 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			330 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * QEMU Crypto block device encryption
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 *
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 * Copyright (c) 2015-2016 Red Hat, Inc.
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 *
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 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
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 *
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 */
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#ifndef QCRYPTO_BLOCK_H
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#define QCRYPTO_BLOCK_H
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#include "crypto/cipher.h"
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#include "crypto/ivgen.h"
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typedef struct QCryptoBlock QCryptoBlock;
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/* See also QCryptoBlockFormat, QCryptoBlockCreateOptions
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 * and QCryptoBlockOpenOptions in qapi/crypto.json */
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typedef int (*QCryptoBlockReadFunc)(QCryptoBlock *block,
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                                    size_t offset,
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                                    uint8_t *buf,
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                                    size_t buflen,
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                                    void *opaque,
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                                    Error **errp);
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typedef int (*QCryptoBlockInitFunc)(QCryptoBlock *block,
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                                    size_t headerlen,
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                                    void *opaque,
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                                    Error **errp);
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typedef int (*QCryptoBlockWriteFunc)(QCryptoBlock *block,
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                                     size_t offset,
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                                     const uint8_t *buf,
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                                     size_t buflen,
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                                     void *opaque,
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                                     Error **errp);
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/**
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 * qcrypto_block_has_format:
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 * @format: the encryption format
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 * @buf: the data from head of the volume
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 * @len: the length of @buf in bytes
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 *
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 * Given @len bytes of data from the head of a storage volume
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 * in @buf, probe to determine if the volume has the encryption
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 * format specified in @format.
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 *
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 * Returns: true if the data in @buf matches @format
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 */
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bool qcrypto_block_has_format(QCryptoBlockFormat format,
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                              const uint8_t *buf,
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                              size_t buflen);
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typedef enum {
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    QCRYPTO_BLOCK_OPEN_NO_IO = (1 << 0),
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    QCRYPTO_BLOCK_OPEN_DETACHED = (1 << 1),
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} QCryptoBlockOpenFlags;
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/**
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 * qcrypto_block_open:
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 * @options: the encryption options
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 * @optprefix: name prefix for options
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 * @readfunc: callback for reading data from the volume
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 * @opaque: data to pass to @readfunc
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 * @flags: bitmask of QCryptoBlockOpenFlags values
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 * @errp: pointer to a NULL-initialized error object
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 *
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 * Create a new block encryption object for an existing
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 * storage volume encrypted with format identified by
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 * the parameters in @options.
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 *
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 * This will use @readfunc to initialize the encryption
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 * context based on the volume header(s), extracting the
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 * master key(s) as required.
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 *
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 * If @flags contains QCRYPTO_BLOCK_OPEN_NO_IO then
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 * the open process will be optimized to skip any parts
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 * that are only required to perform I/O. In particular
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 * this would usually avoid the need to decrypt any
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 * master keys. The only thing that can be done with
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 * the resulting QCryptoBlock object would be to query
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 * metadata such as the payload offset. There will be
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 * no cipher or ivgen objects available.
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 *
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 * If @flags contains QCRYPTO_BLOCK_OPEN_DETACHED then
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 * the open process will be optimized to skip the LUKS
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 * payload overlap check.
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 *
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 * If any part of initializing the encryption context
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 * fails an error will be returned. This could be due
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 * to the volume being in the wrong format, a cipher
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 * or IV generator algorithm that is not supported,
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 * or incorrect passphrases.
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 *
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 * Returns: a block encryption format, or NULL on error
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 */
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QCryptoBlock *qcrypto_block_open(QCryptoBlockOpenOptions *options,
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                                 const char *optprefix,
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                                 QCryptoBlockReadFunc readfunc,
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                                 void *opaque,
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                                 unsigned int flags,
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                                 Error **errp);
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typedef enum {
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    QCRYPTO_BLOCK_CREATE_DETACHED = (1 << 0),
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} QCryptoBlockCreateFlags;
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/**
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 * qcrypto_block_create:
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 * @options: the encryption options
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 * @optprefix: name prefix for options
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 * @initfunc: callback for initializing volume header
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 * @writefunc: callback for writing data to the volume header
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 * @opaque: data to pass to @initfunc and @writefunc
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 * @flags: bitmask of QCryptoBlockCreateFlags values
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 * @errp: pointer to a NULL-initialized error object
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 *
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 * Create a new block encryption object for initializing
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 * a storage volume to be encrypted with format identified
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 * by the parameters in @options.
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 *
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 * This method will allocate space for a new volume header
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 * using @initfunc and then write header data using @writefunc,
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 * generating new master keys, etc as required. Any existing
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 * data present on the volume will be irrevocably destroyed.
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 *
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 * If @flags contains QCRYPTO_BLOCK_CREATE_DETACHED then
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 * the open process will set the payload_offset_sector to 0
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 * to specify the starting point for the read/write of a
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 * detached LUKS header image.
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 *
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 * If any part of initializing the encryption context
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 * fails an error will be returned. This could be due
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 * to the volume being in the wrong format, a cipher
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 * or IV generator algorithm that is not supported,
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 * or incorrect passphrases.
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 *
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 * Returns: a block encryption format, or NULL on error
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 */
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QCryptoBlock *qcrypto_block_create(QCryptoBlockCreateOptions *options,
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                                   const char *optprefix,
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                                   QCryptoBlockInitFunc initfunc,
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                                   QCryptoBlockWriteFunc writefunc,
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                                   void *opaque,
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                                   unsigned int flags,
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                                   Error **errp);
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/**
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 * qcrypto_block_amend_options:
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 * @block: the block encryption object
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 *
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 * @readfunc: callback for reading data from the volume header
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 * @writefunc: callback for writing data to the volume header
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 * @opaque: data to pass to @readfunc and @writefunc
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 * @options: the new/amended encryption options
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 * @force: hint for the driver to allow unsafe operation
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 * @errp: error pointer
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 *
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 * Changes the crypto options of the encryption format
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 *
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 */
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int qcrypto_block_amend_options(QCryptoBlock *block,
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                                QCryptoBlockReadFunc readfunc,
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                                QCryptoBlockWriteFunc writefunc,
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                                void *opaque,
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                                QCryptoBlockAmendOptions *options,
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                                bool force,
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                                Error **errp);
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/**
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 * qcrypto_block_calculate_payload_offset:
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 * @create_opts: the encryption options
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 * @optprefix: name prefix for options
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 * @len: output for number of header bytes before payload
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 * @errp: pointer to a NULL-initialized error object
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 *
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 * Calculate the number of header bytes before the payload in an encrypted
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 * storage volume.  The header is an area before the payload that is reserved
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 * for encryption metadata.
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 *
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 * Returns: true on success, false on error
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 */
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bool
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qcrypto_block_calculate_payload_offset(QCryptoBlockCreateOptions *create_opts,
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                                       const char *optprefix,
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                                       size_t *len,
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                                       Error **errp);
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/**
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 * qcrypto_block_get_info:
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 * @block: the block encryption object
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 * @errp: pointer to a NULL-initialized error object
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 *
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 * Get information about the configuration options for the
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 * block encryption object. This includes details such as
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 * the cipher algorithms, modes, and initialization vector
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 * generators.
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 *
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 * Returns: a block encryption info object, or NULL on error
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 */
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QCryptoBlockInfo *qcrypto_block_get_info(QCryptoBlock *block,
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                                         Error **errp);
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/**
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 * @qcrypto_block_decrypt:
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 * @block: the block encryption object
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 * @offset: the position at which @iov was read
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 * @buf: the buffer to decrypt
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 * @len: the length of @buf in bytes
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 * @errp: pointer to a NULL-initialized error object
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 *
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 * Decrypt @len bytes of cipher text in @buf, writing
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 * plain text back into @buf. @len and @offset must be
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 * a multiple of the encryption format sector size.
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 *
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 * Returns 0 on success, -1 on failure
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 */
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int qcrypto_block_decrypt(QCryptoBlock *block,
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                          uint64_t offset,
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                          uint8_t *buf,
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                          size_t len,
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                          Error **errp);
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/**
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 * @qcrypto_block_encrypt:
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 * @block: the block encryption object
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 * @offset: the position at which @iov will be written
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 * @buf: the buffer to decrypt
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 * @len: the length of @buf in bytes
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 * @errp: pointer to a NULL-initialized error object
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 *
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 * Encrypt @len bytes of plain text in @buf, writing
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 * cipher text back into @buf. @len and @offset must be
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 * a multiple of the encryption format sector size.
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 *
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 * Returns 0 on success, -1 on failure
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 */
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int qcrypto_block_encrypt(QCryptoBlock *block,
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                          uint64_t offset,
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                          uint8_t *buf,
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                          size_t len,
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                          Error **errp);
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/**
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 * qcrypto_block_get_cipher:
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 * @block: the block encryption object
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 *
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 * Get the cipher to use for payload encryption
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 *
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 * Returns: the cipher object
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 */
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QCryptoCipher *qcrypto_block_get_cipher(QCryptoBlock *block);
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/**
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 * qcrypto_block_get_ivgen:
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 * @block: the block encryption object
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 *
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 * Get the initialization vector generator to use for
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 * payload encryption
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 *
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 * Returns: the IV generator object
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 */
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QCryptoIVGen *qcrypto_block_get_ivgen(QCryptoBlock *block);
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/**
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 * qcrypto_block_get_kdf_hash:
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 * @block: the block encryption object
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 *
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 * Get the hash algorithm used with the key derivation
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 * function
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 *
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 * Returns: the hash algorithm
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 */
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QCryptoHashAlgo qcrypto_block_get_kdf_hash(QCryptoBlock *block);
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/**
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 * qcrypto_block_get_payload_offset:
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 * @block: the block encryption object
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 *
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 * Get the offset to the payload indicated by the
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 * encryption header, in bytes.
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 *
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 * Returns: the payload offset in bytes
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 */
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uint64_t qcrypto_block_get_payload_offset(QCryptoBlock *block);
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/**
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 * qcrypto_block_get_sector_size:
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 * @block: the block encryption object
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 *
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 * Get the size of sectors used for payload encryption. A new
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 * IV is used at the start of each sector. The encryption
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 * sector size is not required to match the sector size of the
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 * underlying storage. For example LUKS will always use a 512
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 * byte sector size, even if the volume is on a disk with 4k
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 * sectors.
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 *
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 * Returns: the sector in bytes
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 */
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uint64_t qcrypto_block_get_sector_size(QCryptoBlock *block);
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/**
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 * qcrypto_block_free:
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 * @block: the block encryption object
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 *
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 * Release all resources associated with the encryption
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 * object
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 */
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void qcrypto_block_free(QCryptoBlock *block);
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G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoBlock, qcrypto_block_free)
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#endif /* QCRYPTO_BLOCK_H */
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