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 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 "qom/object.h"
  25
  26#define TYPE_QCRYPTO_SECRET "secret"
  27#define QCRYPTO_SECRET(obj)                  \
  28    OBJECT_CHECK(QCryptoSecret, (obj), TYPE_QCRYPTO_SECRET)
  29
  30typedef struct QCryptoSecret QCryptoSecret;
  31typedef struct QCryptoSecretClass QCryptoSecretClass;
  32
  33/**
  34 * QCryptoSecret:
  35 *
  36 * The QCryptoSecret object provides storage of secrets,
  37 * which may be user passwords, encryption keys or any
  38 * other kind of sensitive data that is represented as
  39 * a sequence of bytes.
  40 *
  41 * The sensitive data associated with the secret can
  42 * be provided directly via the 'data' property, or
  43 * indirectly via the 'file' property. In the latter
  44 * case there is support for file descriptor passing
  45 * via the usual /dev/fdset/NN syntax that QEMU uses.
  46 *
  47 * The data for a secret can be provided in two formats,
  48 * either as a UTF-8 string (the default), or as base64
  49 * encoded 8-bit binary data. The latter is appropriate
  50 * for raw encryption keys, while the former is appropriate
  51 * for user entered passwords.
  52 *
  53 * The data may be optionally encrypted with AES-256-CBC,
  54 * and the decryption key provided by another
  55 * QCryptoSecret instance identified by the 'keyid'
  56 * property. When passing sensitive data directly
  57 * via the 'data' property it is strongly recommended
  58 * to use the AES encryption facility to prevent the
  59 * sensitive data being exposed in the process listing
  60 * or system log files.
  61 *
  62 * Providing data directly, insecurely (suitable for
  63 * ad hoc developer testing only)
  64 *
  65 *  $QEMU -object secret,id=sec0,data=letmein
  66 *
  67 * Providing data indirectly:
  68 *
  69 *  # printf "letmein" > password.txt
  70 *  # $QEMU \
  71 *      -object secret,id=sec0,file=password.txt
  72 *
  73 * Using a master encryption key with data.
  74 *
  75 * The master key needs to be created as 32 secure
  76 * random bytes (optionally base64 encoded)
  77 *
  78 *  # openssl rand -base64 32 > key.b64
  79 *  # KEY=$(base64 -d key.b64 | hexdump  -v -e '/1 "%02X"')
  80 *
  81 * Each secret to be encrypted needs to have a random
  82 * initialization vector generated. These do not need
  83 * to be kept secret
  84 *
  85 *  # openssl rand -base64 16 > iv.b64
  86 *  # IV=$(base64 -d iv.b64 | hexdump  -v -e '/1 "%02X"')
  87 *
  88 * A secret to be defined can now be encrypted
  89 *
  90 *  # SECRET=$(printf "letmein" |
  91 *             openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
  92 *
  93 * When launching QEMU, create a master secret pointing
  94 * to key.b64 and specify that to be used to decrypt
  95 * the user password
  96 *
  97 *  # $QEMU \
  98 *      -object secret,id=secmaster0,format=base64,file=key.b64 \
  99 *      -object secret,id=sec0,keyid=secmaster0,format=base64,\
 100 *          data=$SECRET,iv=$(<iv.b64)
 101 *
 102 * When encrypting, the data can still be provided via an
 103 * external file, in which case it is possible to use either
 104 * raw binary data, or base64 encoded. This example uses
 105 * raw format
 106 *
 107 *  # printf "letmein" |
 108 *       openssl enc -aes-256-cbc -K $KEY -iv $IV -o pw.aes
 109 *  # $QEMU \
 110 *      -object secret,id=secmaster0,format=base64,file=key.b64 \
 111 *      -object secret,id=sec0,keyid=secmaster0,\
 112 *          file=pw.aes,iv=$(<iv.b64)
 113 *
 114 * Note that the ciphertext can be in either raw or base64
 115 * format, as indicated by the 'format' parameter, but the
 116 * plaintext resulting from decryption is expected to always
 117 * be in raw format.
 118 */
 119
 120struct QCryptoSecret {
 121    Object parent_obj;
 122    uint8_t *rawdata;
 123    size_t rawlen;
 124    QCryptoSecretFormat format;
 125    char *data;
 126    char *file;
 127    char *keyid;
 128    char *iv;
 129};
 130
 131
 132struct QCryptoSecretClass {
 133    ObjectClass parent_class;
 134};
 135
 136
 137extern int qcrypto_secret_lookup(const char *secretid,
 138                                 uint8_t **data,
 139                                 size_t *datalen,
 140                                 Error **errp);
 141extern char *qcrypto_secret_lookup_as_utf8(const char *secretid,
 142                                           Error **errp);
 143extern char *qcrypto_secret_lookup_as_base64(const char *secretid,
 144                                             Error **errp);
 145
 146#endif /* QCRYPTO_SECRET_H__ */
 147