LXR qemu/include/crypto/secret.h

   1/*
   2 * QEMU crypto secret support
   3 *
   4 * Copyright (c) 2015 Red Hat, Inc.
   5 *
   6 * This library is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU Lesser General Public
   8 * License as published by the Free Software Foundation; either
   9 * version 2.1 of the License, or (at your option) any later version.
  10 *
  11 * This library is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 * Lesser General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU Lesser General Public
  17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18 *
  19 */
  20
  21#ifndef QCRYPTO_SECRET_H
  22#define QCRYPTO_SECRET_H
  23
  24#include "qapi/qapi-types-crypto.h"
  25#include "qom/object.h"
  26#include "crypto/secret_common.h"
  27
  28#define TYPE_QCRYPTO_SECRET "secret"
  29typedef struct QCryptoSecret QCryptoSecret;
  30DECLARE_INSTANCE_CHECKER(QCryptoSecret, QCRYPTO_SECRET,
  31                         TYPE_QCRYPTO_SECRET)
  32
  33typedef struct QCryptoSecretClass QCryptoSecretClass;
  34
  35/**
  36 * QCryptoSecret:
  37 *
  38 * The QCryptoSecret object provides storage of secrets,
  39 * which may be user passwords, encryption keys or any
  40 * other kind of sensitive data that is represented as
  41 * a sequence of bytes.
  42 *
  43 * The sensitive data associated with the secret can
  44 * be provided directly via the 'data' property, or
  45 * indirectly via the 'file' property. In the latter
  46 * case there is support for file descriptor passing
  47 * via the usual /dev/fdset/NN syntax that QEMU uses.
  48 *
  49 * The data for a secret can be provided in two formats,
  50 * either as a UTF-8 string (the default), or as base64
  51 * encoded 8-bit binary data. The latter is appropriate
  52 * for raw encryption keys, while the former is appropriate
  53 * for user entered passwords.
  54 *
  55 * The data may be optionally encrypted with AES-256-CBC,
  56 * and the decryption key provided by another
  57 * QCryptoSecret instance identified by the 'keyid'
  58 * property. When passing sensitive data directly
  59 * via the 'data' property it is strongly recommended
  60 * to use the AES encryption facility to prevent the
  61 * sensitive data being exposed in the process listing
  62 * or system log files.
  63 *
  64 * Providing data directly, insecurely (suitable for
  65 * ad hoc developer testing only)
  66 *
  67 *  $QEMU -object secret,id=sec0,data=letmein
  68 *
  69 * Providing data indirectly:
  70 *
  71 *  # printf "letmein" > password.txt
  72 *  # $QEMU \
  73 *      -object secret,id=sec0,file=password.txt
  74 *
  75 * Using a master encryption key with data.
  76 *
  77 * The master key needs to be created as 32 secure
  78 * random bytes (optionally base64 encoded)
  79 *
  80 *  # openssl rand -base64 32 > key.b64
  81 *  # KEY=$(base64 -d key.b64 | hexdump  -v -e '/1 "%02X"')
  82 *
  83 * Each secret to be encrypted needs to have a random
  84 * initialization vector generated. These do not need
  85 * to be kept secret
  86 *
  87 *  # openssl rand -base64 16 > iv.b64
  88 *  # IV=$(base64 -d iv.b64 | hexdump  -v -e '/1 "%02X"')
  89 *
  90 * A secret to be defined can now be encrypted
  91 *
  92 *  # SECRET=$(printf "letmein" |
  93 *             openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
  94 *
  95 * When launching QEMU, create a master secret pointing
  96 * to key.b64 and specify that to be used to decrypt
  97 * the user password
  98 *
  99 *  # $QEMU \
 100 *      -object secret,id=secmaster0,format=base64,file=key.b64 \
 101 *      -object secret,id=sec0,keyid=secmaster0,format=base64,\
 102 *          data=$SECRET,iv=$(<iv.b64)
 103 *
 104 * When encrypting, the data can still be provided via an
 105 * external file, in which case it is possible to use either
 106 * raw binary data, or base64 encoded. This example uses
 107 * raw format
 108 *
 109 *  # printf "letmein" |
 110 *       openssl enc -aes-256-cbc -K $KEY -iv $IV -o pw.aes
 111 *  # $QEMU \
 112 *      -object secret,id=secmaster0,format=base64,file=key.b64 \
 113 *      -object secret,id=sec0,keyid=secmaster0,\
 114 *          file=pw.aes,iv=$(<iv.b64)
 115 *
 116 * Note that the ciphertext can be in either raw or base64
 117 * format, as indicated by the 'format' parameter, but the
 118 * plaintext resulting from decryption is expected to always
 119 * be in raw format.
 120 */
 121
 122struct QCryptoSecret {
 123    QCryptoSecretCommon parent_obj;
 124    char *data;
 125    char *file;
 126};
 127
 128
 129struct QCryptoSecretClass {
 130    QCryptoSecretCommonClass parent_class;
 131};
 132
 133#endif /* QCRYPTO_SECRET_H */
 134