crypto/secret_common.c - qemu - Git at Google

 /*
  * QEMU crypto secret support
  *
  * Copyright (c) 2015 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  *
  */

 #include "qemu/osdep.h"
 #include "crypto/secret_common.h"
 #include "crypto/cipher.h"
 #include "qapi/error.h"
 #include "qom/object_interfaces.h"
 #include "qemu/base64.h"
 #include "qemu/module.h"
 #include "trace.h"


 static void qcrypto_secret_decrypt(QCryptoSecretCommon *secret,
                                    const uint8_t *input,
                                    size_t inputlen,
                                    uint8_t **output,
                                    size_t *outputlen,
                                    Error **errp)
 {
     g_autofree uint8_t *iv = NULL;
     g_autofree uint8_t *key = NULL;
     g_autofree uint8_t *ciphertext = NULL;
     size_t keylen, ciphertextlen, ivlen;
     g_autoptr(QCryptoCipher) aes = NULL;
     g_autofree uint8_t *plaintext = NULL;

     *output = NULL;
     *outputlen = 0;

     if (qcrypto_secret_lookup(secret->keyid,
                               &key, &keylen,
                               errp) < 0) {
         return;
     }

     if (keylen != 32) {
         error_setg(errp, "Key should be 32 bytes in length");
         return;
     }

     if (!secret->iv) {
         error_setg(errp, "IV is required to decrypt secret");
         return;
     }

     iv = qbase64_decode(secret->iv, -1, &ivlen, errp);
     if (!iv) {
         return;
     }
     if (ivlen != 16) {
         error_setg(errp, "IV should be 16 bytes in length not %zu",
                    ivlen);
         return;
     }

     aes = qcrypto_cipher_new(QCRYPTO_CIPHER_ALGO_AES_256,
                              QCRYPTO_CIPHER_MODE_CBC,
                              key, keylen,
                              errp);
     if (!aes) {
         return;
     }

     if (qcrypto_cipher_setiv(aes, iv, ivlen, errp) < 0) {
         return;
     }

     if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
         ciphertext = qbase64_decode((const gchar *)input,
                                     inputlen,
                                     &ciphertextlen,
                                     errp);
         if (!ciphertext) {
             return;
         }
         plaintext = g_new0(uint8_t, ciphertextlen + 1);
     } else {
         ciphertextlen = inputlen;
         plaintext = g_new0(uint8_t, inputlen + 1);
     }
     if (qcrypto_cipher_decrypt(aes,
                                ciphertext ? ciphertext : input,
                                plaintext,
                                ciphertextlen,
                                errp) < 0) {
         return;
     }

     if (plaintext[ciphertextlen - 1] > 16 ||
         plaintext[ciphertextlen - 1] > ciphertextlen) {
         error_setg(errp, "Incorrect number of padding bytes (%d) "
                    "found on decrypted data",
                    (int)plaintext[ciphertextlen - 1]);
         return;
     }

     /*
      *  Even though plaintext may contain arbitrary NUL
      * ensure it is explicitly NUL terminated.
      */
     ciphertextlen -= plaintext[ciphertextlen - 1];
     plaintext[ciphertextlen] = '\0';

     *output = g_steal_pointer(&plaintext);
     *outputlen = ciphertextlen;
 }


 static void qcrypto_secret_decode(const uint8_t *input,
                                   size_t inputlen,
                                   uint8_t **output,
                                   size_t *outputlen,
                                   Error **errp)
 {
     *output = qbase64_decode((const gchar *)input,
                              inputlen,
                              outputlen,
                              errp);
 }


 static void
 qcrypto_secret_complete(UserCreatable *uc, Error **errp)
 {
     QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(uc);
     QCryptoSecretCommonClass *sec_class
                                 = QCRYPTO_SECRET_COMMON_GET_CLASS(uc);

     Error *local_err = NULL;
     uint8_t *input = NULL;
     size_t inputlen = 0;
     uint8_t *output = NULL;
     size_t outputlen = 0;

     if (sec_class->load_data) {
         sec_class->load_data(secret, &input, &inputlen, &local_err);
         if (local_err) {
             error_propagate(errp, local_err);
             return;
         }
     } else {
         error_setg(errp, "%s provides no 'load_data' method'",
                          object_get_typename(OBJECT(uc)));
         return;
     }

     if (secret->keyid) {
         qcrypto_secret_decrypt(secret, input, inputlen,
                                &output, &outputlen, &local_err);
         g_free(input);
         if (local_err) {
             error_propagate(errp, local_err);
             return;
         }
         input = output;
         inputlen = outputlen;
     } else {
         if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
             qcrypto_secret_decode(input, inputlen,
                                   &output, &outputlen, &local_err);
             g_free(input);
             if (local_err) {
                 error_propagate(errp, local_err);
                 return;
             }
             input = output;
             inputlen = outputlen;
         }
     }

     secret->rawdata = input;
     secret->rawlen = inputlen;
 }


 static void
 qcrypto_secret_prop_set_format(Object *obj,
                                int value,
                                Error **errp G_GNUC_UNUSED)
 {
     QCryptoSecretCommon *creds = QCRYPTO_SECRET_COMMON(obj);
     creds->format = value;
 }


 static int
 qcrypto_secret_prop_get_format(Object *obj,
                                Error **errp G_GNUC_UNUSED)
 {
     QCryptoSecretCommon *creds = QCRYPTO_SECRET_COMMON(obj);
     return creds->format;
 }


 static void
 qcrypto_secret_prop_set_iv(Object *obj,
                            const char *value,
                            Error **errp)
 {
     QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);

     g_free(secret->iv);
     secret->iv = g_strdup(value);
 }


 static char *
 qcrypto_secret_prop_get_iv(Object *obj,
                            Error **errp)
 {
     QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
     return g_strdup(secret->iv);
 }


 static void
 qcrypto_secret_prop_set_keyid(Object *obj,
                               const char *value,
                               Error **errp)
 {
     QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);

     g_free(secret->keyid);
     secret->keyid = g_strdup(value);
 }


 static char *
 qcrypto_secret_prop_get_keyid(Object *obj,
                               Error **errp)
 {
     QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
     return g_strdup(secret->keyid);
 }


 static void
 qcrypto_secret_finalize(Object *obj)
 {
     QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);

     g_free(secret->iv);
     g_free(secret->keyid);
     g_free(secret->rawdata);
 }

 static void
 qcrypto_secret_class_init(ObjectClass *oc, void *data)
 {
     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);

     ucc->complete = qcrypto_secret_complete;

     object_class_property_add_enum(oc, "format",
                                    "QCryptoSecretFormat",
                                    &QCryptoSecretFormat_lookup,
                                    qcrypto_secret_prop_get_format,
                                    qcrypto_secret_prop_set_format);
     object_class_property_add_str(oc, "keyid",
                                   qcrypto_secret_prop_get_keyid,
                                   qcrypto_secret_prop_set_keyid);
     object_class_property_add_str(oc, "iv",
                                   qcrypto_secret_prop_get_iv,
                                   qcrypto_secret_prop_set_iv);
 }


 int qcrypto_secret_lookup(const char *secretid,
                           uint8_t **data,
                           size_t *datalen,
                           Error **errp)
 {
     Object *obj;
     QCryptoSecretCommon *secret;

     obj = object_resolve_path_component(
         object_get_objects_root(), secretid);
     if (!obj) {
         error_setg(errp, "No secret with id '%s'", secretid);
         return -1;
     }

     secret = (QCryptoSecretCommon *)
         object_dynamic_cast(obj,
                             TYPE_QCRYPTO_SECRET_COMMON);
     if (!secret) {
         error_setg(errp, "Object with id '%s' is not a secret",
                    secretid);
         return -1;
     }

     if (!secret->rawdata) {
         error_setg(errp, "Secret with id '%s' has no data",
                    secretid);
         return -1;
     }

     *data = g_new0(uint8_t, secret->rawlen + 1);
     memcpy(*data, secret->rawdata, secret->rawlen);
     (*data)[secret->rawlen] = '\0';
     *datalen = secret->rawlen;

     return 0;
 }


 char *qcrypto_secret_lookup_as_utf8(const char *secretid,
                                     Error **errp)
 {
     uint8_t *data;
     size_t datalen;

     if (qcrypto_secret_lookup(secretid,
                               &data,
                               &datalen,
                               errp) < 0) {
         return NULL;
     }

     if (!g_utf8_validate((const gchar *)data, datalen, NULL)) {
         error_setg(errp,
                    "Data from secret %s is not valid UTF-8",
                    secretid);
         g_free(data);
         return NULL;
     }

     return (char *)data;
 }


 char *qcrypto_secret_lookup_as_base64(const char *secretid,
                                       Error **errp)
 {
     uint8_t *data;
     size_t datalen;
     char *ret;

     if (qcrypto_secret_lookup(secretid,
                               &data,
                               &datalen,
                               errp) < 0) {
         return NULL;
     }

     ret = g_base64_encode(data, datalen);
     g_free(data);
     return ret;
 }


 static const TypeInfo qcrypto_secret_info = {
     .parent = TYPE_OBJECT,
     .name = TYPE_QCRYPTO_SECRET_COMMON,
     .instance_size = sizeof(QCryptoSecretCommon),
     .instance_finalize = qcrypto_secret_finalize,
     .class_size = sizeof(QCryptoSecretCommonClass),
     .class_init = qcrypto_secret_class_init,
     .abstract = true,
     .interfaces = (InterfaceInfo[]) {
         { TYPE_USER_CREATABLE },
         { }
     }
 };


 static void
 qcrypto_secret_register_types(void)
 {
     type_register_static(&qcrypto_secret_info);
 }


 type_init(qcrypto_secret_register_types);
	/*
	* QEMU crypto secret support
	*
	* Copyright (c) 2015 Red Hat, Inc.
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, see <http://www.gnu.org/licenses/>.
	*
	*/

	#include "qemu/osdep.h"
	#include "crypto/secret_common.h"
	#include "crypto/cipher.h"
	#include "qapi/error.h"
	#include "qom/object_interfaces.h"
	#include "qemu/base64.h"
	#include "qemu/module.h"
	#include "trace.h"


	static void qcrypto_secret_decrypt(QCryptoSecretCommon *secret,
	const uint8_t *input,
	size_t inputlen,
	uint8_t **output,
	size_t *outputlen,
	Error **errp)
	{
	g_autofree uint8_t *iv = NULL;
	g_autofree uint8_t *key = NULL;
	g_autofree uint8_t *ciphertext = NULL;
	size_t keylen, ciphertextlen, ivlen;
	g_autoptr(QCryptoCipher) aes = NULL;
	g_autofree uint8_t *plaintext = NULL;

	*output = NULL;
	*outputlen = 0;

	if (qcrypto_secret_lookup(secret->keyid,
	&key, &keylen,
	errp) < 0) {
	return;
	}

	if (keylen != 32) {
	error_setg(errp, "Key should be 32 bytes in length");
	return;
	}

	if (!secret->iv) {
	error_setg(errp, "IV is required to decrypt secret");
	return;
	}

	iv = qbase64_decode(secret->iv, -1, &ivlen, errp);
	if (!iv) {
	return;
	}
	if (ivlen != 16) {
	error_setg(errp, "IV should be 16 bytes in length not %zu",
	ivlen);
	return;
	}

	aes = qcrypto_cipher_new(QCRYPTO_CIPHER_ALGO_AES_256,
	QCRYPTO_CIPHER_MODE_CBC,
	key, keylen,
	errp);
	if (!aes) {
	return;
	}

	if (qcrypto_cipher_setiv(aes, iv, ivlen, errp) < 0) {
	return;
	}

	if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
	ciphertext = qbase64_decode((const gchar *)input,
	inputlen,
	&ciphertextlen,
	errp);
	if (!ciphertext) {
	return;
	}
	plaintext = g_new0(uint8_t, ciphertextlen + 1);
	} else {
	ciphertextlen = inputlen;
	plaintext = g_new0(uint8_t, inputlen + 1);
	}
	if (qcrypto_cipher_decrypt(aes,
	ciphertext ? ciphertext : input,
	plaintext,
	ciphertextlen,
	errp) < 0) {
	return;
	}

	if (plaintext[ciphertextlen - 1] > 16 \|\|
	plaintext[ciphertextlen - 1] > ciphertextlen) {
	error_setg(errp, "Incorrect number of padding bytes (%d) "
	"found on decrypted data",
	(int)plaintext[ciphertextlen - 1]);
	return;
	}

	/*
	* Even though plaintext may contain arbitrary NUL
	* ensure it is explicitly NUL terminated.
	*/
	ciphertextlen -= plaintext[ciphertextlen - 1];
	plaintext[ciphertextlen] = '\0';

	*output = g_steal_pointer(&plaintext);
	*outputlen = ciphertextlen;
	}


	static void qcrypto_secret_decode(const uint8_t *input,
	size_t inputlen,
	uint8_t **output,
	size_t *outputlen,
	Error **errp)
	{
	output = qbase64_decode((const gchar )input,
	inputlen,
	outputlen,
	errp);
	}


	static void
	qcrypto_secret_complete(UserCreatable uc, Error *errp)
	{
	QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(uc);
	QCryptoSecretCommonClass *sec_class
	= QCRYPTO_SECRET_COMMON_GET_CLASS(uc);

	Error *local_err = NULL;
	uint8_t *input = NULL;
	size_t inputlen = 0;
	uint8_t *output = NULL;
	size_t outputlen = 0;

	if (sec_class->load_data) {
	sec_class->load_data(secret, &input, &inputlen, &local_err);
	if (local_err) {
	error_propagate(errp, local_err);
	return;
	}
	} else {
	error_setg(errp, "%s provides no 'load_data' method'",
	object_get_typename(OBJECT(uc)));
	return;
	}

	if (secret->keyid) {
	qcrypto_secret_decrypt(secret, input, inputlen,
	&output, &outputlen, &local_err);
	g_free(input);
	if (local_err) {
	error_propagate(errp, local_err);
	return;
	}
	input = output;
	inputlen = outputlen;
	} else {
	if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
	qcrypto_secret_decode(input, inputlen,
	&output, &outputlen, &local_err);
	g_free(input);
	if (local_err) {
	error_propagate(errp, local_err);
	return;
	}
	input = output;
	inputlen = outputlen;
	}
	}

	secret->rawdata = input;
	secret->rawlen = inputlen;
	}


	static void
	qcrypto_secret_prop_set_format(Object *obj,
	int value,
	Error **errp G_GNUC_UNUSED)
	{
	QCryptoSecretCommon *creds = QCRYPTO_SECRET_COMMON(obj);
	creds->format = value;
	}


	static int
	qcrypto_secret_prop_get_format(Object *obj,
	Error **errp G_GNUC_UNUSED)
	{
	QCryptoSecretCommon *creds = QCRYPTO_SECRET_COMMON(obj);
	return creds->format;
	}


	static void
	qcrypto_secret_prop_set_iv(Object *obj,
	const char *value,
	Error **errp)
	{
	QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);

	g_free(secret->iv);
	secret->iv = g_strdup(value);
	}


	static char *
	qcrypto_secret_prop_get_iv(Object *obj,
	Error **errp)
	{
	QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
	return g_strdup(secret->iv);
	}


	static void
	qcrypto_secret_prop_set_keyid(Object *obj,
	const char *value,
	Error **errp)
	{
	QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);

	g_free(secret->keyid);
	secret->keyid = g_strdup(value);
	}


	static char *
	qcrypto_secret_prop_get_keyid(Object *obj,
	Error **errp)
	{
	QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
	return g_strdup(secret->keyid);
	}


	static void
	qcrypto_secret_finalize(Object *obj)
	{
	QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);

	g_free(secret->iv);
	g_free(secret->keyid);
	g_free(secret->rawdata);
	}

	static void
	qcrypto_secret_class_init(ObjectClass oc, void data)
	{
	UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);

	ucc->complete = qcrypto_secret_complete;

	object_class_property_add_enum(oc, "format",
	"QCryptoSecretFormat",
	&QCryptoSecretFormat_lookup,
	qcrypto_secret_prop_get_format,
	qcrypto_secret_prop_set_format);
	object_class_property_add_str(oc, "keyid",
	qcrypto_secret_prop_get_keyid,
	qcrypto_secret_prop_set_keyid);
	object_class_property_add_str(oc, "iv",
	qcrypto_secret_prop_get_iv,
	qcrypto_secret_prop_set_iv);
	}


	int qcrypto_secret_lookup(const char *secretid,
	uint8_t **data,
	size_t *datalen,
	Error **errp)
	{
	Object *obj;
	QCryptoSecretCommon *secret;

	obj = object_resolve_path_component(
	object_get_objects_root(), secretid);
	if (!obj) {
	error_setg(errp, "No secret with id '%s'", secretid);
	return -1;
	}

	secret = (QCryptoSecretCommon *)
	object_dynamic_cast(obj,
	TYPE_QCRYPTO_SECRET_COMMON);
	if (!secret) {
	error_setg(errp, "Object with id '%s' is not a secret",
	secretid);
	return -1;
	}

	if (!secret->rawdata) {
	error_setg(errp, "Secret with id '%s' has no data",
	secretid);
	return -1;
	}

	*data = g_new0(uint8_t, secret->rawlen + 1);
	memcpy(*data, secret->rawdata, secret->rawlen);
	(*data)[secret->rawlen] = '\0';
	*datalen = secret->rawlen;

	return 0;
	}


	char qcrypto_secret_lookup_as_utf8(const char secretid,
	Error **errp)
	{
	uint8_t *data;
	size_t datalen;

	if (qcrypto_secret_lookup(secretid,
	&data,
	&datalen,
	errp) < 0) {
	return NULL;
	}

	if (!g_utf8_validate((const gchar *)data, datalen, NULL)) {
	error_setg(errp,
	"Data from secret %s is not valid UTF-8",
	secretid);
	g_free(data);
	return NULL;
	}

	return (char *)data;
	}


	char qcrypto_secret_lookup_as_base64(const char secretid,
	Error **errp)
	{
	uint8_t *data;
	size_t datalen;
	char *ret;

	if (qcrypto_secret_lookup(secretid,
	&data,
	&datalen,
	errp) < 0) {
	return NULL;
	}

	ret = g_base64_encode(data, datalen);
	g_free(data);
	return ret;
	}


	static const TypeInfo qcrypto_secret_info = {
	.parent = TYPE_OBJECT,
	.name = TYPE_QCRYPTO_SECRET_COMMON,
	.instance_size = sizeof(QCryptoSecretCommon),
	.instance_finalize = qcrypto_secret_finalize,
	.class_size = sizeof(QCryptoSecretCommonClass),
	.class_init = qcrypto_secret_class_init,
	.abstract = true,
	.interfaces = (InterfaceInfo[]) {
	{ TYPE_USER_CREATABLE },
	{ }
	}
	};


	static void
	qcrypto_secret_register_types(void)
	{
	type_register_static(&qcrypto_secret_info);
	}


	type_init(qcrypto_secret_register_types);