crypto/secret_keyring.c

   1 /*
   2  * QEMU crypto secret support
   3  *
   4  * Copyright 2020 Yandex N.V.
   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 #include "qemu/osdep.h"
  22 #include <asm/unistd.h>
  23 #include <linux/keyctl.h>
  24 #include "qapi/error.h"
  25 #include "qom/object_interfaces.h"
  26 #include "trace.h"
  27 #include "crypto/secret_keyring.h"
  28
  29
  30 static inline
  31 long keyctl_read(int32_t key, uint8_t *buffer, size_t buflen)
  32 {
  33     return syscall(__NR_keyctl, KEYCTL_READ, key, buffer, buflen, 0);
  34 }
  35
  36
  37 static void
  38 qcrypto_secret_keyring_load_data(QCryptoSecretCommon *sec_common,
  39                                  uint8_t **output,
  40                                  size_t *outputlen,
  41                                  Error **errp)
  42 {
  43     QCryptoSecretKeyring *secret = QCRYPTO_SECRET_KEYRING(sec_common);
  44     uint8_t *buffer = NULL;
  45     long retcode;
  46
  47     *output = NULL;
  48     *outputlen = 0;
  49
  50     if (!secret->serial) {
  51         error_setg(errp, "'serial' parameter must be provided");
  52         return;
  53     }
  54
  55     retcode = keyctl_read(secret->serial, NULL, 0);
  56     if (retcode <= 0) {
  57         goto keyctl_error;
  58     }
  59
  60     buffer = g_new0(uint8_t, retcode);
  61
  62     retcode = keyctl_read(secret->serial, buffer, retcode);
  63     if (retcode < 0) {
  64         g_free(buffer);
  65         goto keyctl_error;
  66     }
  67
  68     *outputlen = retcode;
  69     *output = buffer;
  70     return;
  71
  72 keyctl_error:
  73     error_setg_errno(errp, errno,
  74                      "Unable to read serial key %08x",
  75                      secret->serial);
  76 }
  77
  78
  79 static void
  80 qcrypto_secret_prop_set_key(Object *obj, Visitor *v,
  81                             const char *name, void *opaque,
  82                             Error **errp)
  83 {
  84     QCryptoSecretKeyring *secret = QCRYPTO_SECRET_KEYRING(obj);
  85     int32_t value;
  86     visit_type_int32(v, name, &value, errp);
  87     if (!value) {
  88         error_setg(errp, "'serial' should not be equal to 0");
  89     }
  90     secret->serial = value;
  91 }
  92
  93
  94 static void
  95 qcrypto_secret_prop_get_key(Object *obj, Visitor *v,
  96                             const char *name, void *opaque,
  97                             Error **errp)
  98 {
  99     QCryptoSecretKeyring *secret = QCRYPTO_SECRET_KEYRING(obj);
 100     int32_t value = secret->serial;
 101     visit_type_int32(v, name, &value, errp);
 102 }
 103
 104
 105 static void
 106 qcrypto_secret_keyring_class_init(ObjectClass *oc, void *data)
 107 {
 108     QCryptoSecretCommonClass *sic = QCRYPTO_SECRET_COMMON_CLASS(oc);
 109     sic->load_data = qcrypto_secret_keyring_load_data;
 110
 111     object_class_property_add(oc, "serial", "int32_t",
 112                                   qcrypto_secret_prop_get_key,
 113                                   qcrypto_secret_prop_set_key,
 114                                   NULL, NULL);
 115 }
 116
 117
 118 static const TypeInfo qcrypto_secret_info = {
 119     .parent = TYPE_QCRYPTO_SECRET_COMMON,
 120     .name = TYPE_QCRYPTO_SECRET_KEYRING,
 121     .instance_size = sizeof(QCryptoSecretKeyring),
 122     .class_init = qcrypto_secret_keyring_class_init,
 123 };
 124
 125
 126 static void
 127 qcrypto_secret_register_types(void)
 128 {
 129     type_register_static(&qcrypto_secret_info);
 130 }
 131
 132
 133 type_init(qcrypto_secret_register_types);