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 "qapi/qapi-types-crypto.h" 25 #include "qom/object.h" 26 27 #define TYPE_QCRYPTO_SECRET "secret" 28 #define QCRYPTO_SECRET(obj) \ 29 OBJECT_CHECK(QCryptoSecret, (obj), TYPE_QCRYPTO_SECRET) 30 31 typedef struct QCryptoSecret QCryptoSecret; 32 typedef struct QCryptoSecretClass QCryptoSecretClass; 33 34 /** 35 * QCryptoSecret: 36 * 37 * The QCryptoSecret object provides storage of secrets, 38 * which may be user passwords, encryption keys or any 39 * other kind of sensitive data that is represented as 40 * a sequence of bytes. 41 * 42 * The sensitive data associated with the secret can 43 * be provided directly via the 'data' property, or 44 * indirectly via the 'file' property. In the latter 45 * case there is support for file descriptor passing 46 * via the usual /dev/fdset/NN syntax that QEMU uses. 47 * 48 * The data for a secret can be provided in two formats, 49 * either as a UTF-8 string (the default), or as base64 50 * encoded 8-bit binary data. The latter is appropriate 51 * for raw encryption keys, while the former is appropriate 52 * for user entered passwords. 53 * 54 * The data may be optionally encrypted with AES-256-CBC, 55 * and the decryption key provided by another 56 * QCryptoSecret instance identified by the 'keyid' 57 * property. When passing sensitive data directly 58 * via the 'data' property it is strongly recommended 59 * to use the AES encryption facility to prevent the 60 * sensitive data being exposed in the process listing 61 * or system log files. 62 * 63 * Providing data directly, insecurely (suitable for 64 * ad hoc developer testing only) 65 * 66 * $QEMU -object secret,id=sec0,data=letmein 67 * 68 * Providing data indirectly: 69 * 70 * # printf "letmein" > password.txt 71 * # $QEMU \ 72 * -object secret,id=sec0,file=password.txt 73 * 74 * Using a master encryption key with data. 75 * 76 * The master key needs to be created as 32 secure 77 * random bytes (optionally base64 encoded) 78 * 79 * # openssl rand -base64 32 > key.b64 80 * # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 81 * 82 * Each secret to be encrypted needs to have a random 83 * initialization vector generated. These do not need 84 * to be kept secret 85 * 86 * # openssl rand -base64 16 > iv.b64 87 * # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 88 * 89 * A secret to be defined can now be encrypted 90 * 91 * # SECRET=$(printf "letmein" | 92 * openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 93 * 94 * When launching QEMU, create a master secret pointing 95 * to key.b64 and specify that to be used to decrypt 96 * the user password 97 * 98 * # $QEMU \ 99 * -object secret,id=secmaster0,format=base64,file=key.b64 \ 100 * -object secret,id=sec0,keyid=secmaster0,format=base64,\ 101 * data=$SECRET,iv=$(<iv.b64) 102 * 103 * When encrypting, the data can still be provided via an 104 * external file, in which case it is possible to use either 105 * raw binary data, or base64 encoded. This example uses 106 * raw format 107 * 108 * # printf "letmein" | 109 * openssl enc -aes-256-cbc -K $KEY -iv $IV -o pw.aes 110 * # $QEMU \ 111 * -object secret,id=secmaster0,format=base64,file=key.b64 \ 112 * -object secret,id=sec0,keyid=secmaster0,\ 113 * file=pw.aes,iv=$(<iv.b64) 114 * 115 * Note that the ciphertext can be in either raw or base64 116 * format, as indicated by the 'format' parameter, but the 117 * plaintext resulting from decryption is expected to always 118 * be in raw format. 119 */ 120 121 struct QCryptoSecret { 122 Object parent_obj; 123 uint8_t *rawdata; 124 size_t rawlen; 125 QCryptoSecretFormat format; 126 char *data; 127 char *file; 128 char *keyid; 129 char *iv; 130 }; 131 132 133 struct QCryptoSecretClass { 134 ObjectClass parent_class; 135 }; 136 137 138 extern int qcrypto_secret_lookup(const char *secretid, 139 uint8_t **data, 140 size_t *datalen, 141 Error **errp); 142 extern char *qcrypto_secret_lookup_as_utf8(const char *secretid, 143 Error **errp); 144 extern char *qcrypto_secret_lookup_as_base64(const char *secretid, 145 Error **errp); 146 147 #endif /* QCRYPTO_SECRET_H */ 148