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/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2021 OpenVPN Inc <sales@openvpn.net>
* Copyright (C) 2010-2021 Fox Crypto B.V. <openvpn@foxcrypto.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/**
* @file Control Channel Verification Module
*/
#ifndef SSL_VERIFY_H_
#define SSL_VERIFY_H_
#include "syshead.h"
#include "misc.h"
#include "ssl_common.h"
/* Include OpenSSL-specific code */
#ifdef ENABLE_CRYPTO_OPENSSL
#include "ssl_verify_openssl.h"
#endif
#ifdef ENABLE_CRYPTO_MBEDTLS
#include "ssl_verify_mbedtls.h"
#endif
#include "ssl_verify_backend.h"
/*
* Keep track of certificate hashes at various depths
*/
/** Maximum certificate depth we will allow */
#define MAX_CERT_DEPTH 16
/** Structure containing the hash for a single certificate */
struct cert_hash {
unsigned char sha256_hash[256/8];
};
/** Structure containing the hashes for a full certificate chain */
struct cert_hash_set {
struct cert_hash *ch[MAX_CERT_DEPTH]; /**< Array of certificate hashes */
};
#define VERIFY_X509_NONE 0
#define VERIFY_X509_SUBJECT_DN 1
#define VERIFY_X509_SUBJECT_RDN 2
#define VERIFY_X509_SUBJECT_RDN_PREFIX 3
#define TLS_AUTHENTICATION_SUCCEEDED 0
#define TLS_AUTHENTICATION_FAILED 1
#define TLS_AUTHENTICATION_DEFERRED 2
#define TLS_AUTHENTICATION_UNDEFINED 3
/*
* Return current session authentication state. Return
* value is TLS_AUTHENTICATION_x.
*
* TODO: document this function
*/
int tls_authentication_status(struct tls_multi *multi, const int latency);
/** Check whether the \a ks \c key_state is ready to receive data channel
* packets.
* @ingroup data_crypto
*
* If true, it is safe to assume that this session has been authenticated
* by TLS.
*
* @note This macro only works if S_SENT_KEY + 1 == S_GOT_KEY. */
#define DECRYPT_KEY_ENABLED(multi, ks) ((ks)->state >= (S_GOT_KEY - (multi)->opt.server))
/**
* Remove the given key state's auth control file, if it exists.
*
* @param ks The key state the remove the file for
*/
void key_state_rm_auth_control_file(struct key_state *ks);
/**
* Frees the given set of certificate hashes.
*
* @param chs The certificate hash set to free.
*/
void cert_hash_free(struct cert_hash_set *chs);
/**
* Locks the certificate hash set used in the given tunnel
*
* @param multi The tunnel to lock
*/
void tls_lock_cert_hash_set(struct tls_multi *multi);
/**
* Locks the common name field for the given tunnel
*
* @param multi The tunnel to lock
*/
void tls_lock_common_name(struct tls_multi *multi);
/**
* Returns the common name field for the given tunnel
*
* @param multi The tunnel to return the common name for
* @param null Whether null may be returned. If not, "UNDEF" will be returned.
*/
const char *tls_common_name(const struct tls_multi *multi, const bool null);
/**
* Returns the username field for the given tunnel
*
* @param multi The tunnel to return the username for
* @param null Whether null may be returned. If not, "UNDEF" will be returned.
*/
const char *tls_username(const struct tls_multi *multi, const bool null);
/**
* Compares certificates hashes, returns true if hashes are equal.
*
* @param chs1 cert 1 hash set
* @param chs2 cert 2 hash set
*/
bool cert_hash_compare(const struct cert_hash_set *chs1, const struct cert_hash_set *chs2);
#ifdef ENABLE_PF
/**
* Retrieve the given tunnel's common name and its hash value.
*
* @param multi The tunnel to use
* @param cn Common name's string
* @param cn_hash Common name's hash value
*
* @return true if the common name was set, false otherwise.
*/
static inline bool
tls_common_name_hash(const struct tls_multi *multi, const char **cn, uint32_t *cn_hash)
{
if (multi)
{
const struct tls_session *s = &multi->session[TM_ACTIVE];
if (s->common_name && s->common_name[0] != '\0')
{
*cn = s->common_name;
*cn_hash = s->common_name_hashval;
return true;
}
}
return false;
}
#endif
/**
* Verify the given username and password, using either an external script, a
* plugin, or the management interface.
*
* If authentication succeeds, the appropriate state is filled into the
* session's primary key state's authenticated field. Authentication may also
* be deferred, in which case the key state's auth_deferred field is filled in.
*
* @param up The username and password to verify.
* @param multi The TLS multi structure to verify usernames against.
* @param session The current TLS session
*
*/
void verify_user_pass(struct user_pass *up, struct tls_multi *multi,
struct tls_session *session);
/**
* Perform final authentication checks, including locking of the cn, the allowed
* certificate hashes, and whether a client config entry exists in the
* client config directory.
*
* @param multi The TLS multi structure to verify locked structures.
* @param session The current TLS session
*
*/
void verify_final_auth_checks(struct tls_multi *multi, struct tls_session *session);
struct x509_track
{
const struct x509_track *next;
const char *name;
#define XT_FULL_CHAIN (1<<0)
unsigned int flags;
int nid;
};
/*
* Certificate checking for verify_nsCertType
*/
/** Do not perform Netscape certificate type verification */
#define NS_CERT_CHECK_NONE (0)
/** Do not perform Netscape certificate type verification */
#define NS_CERT_CHECK_SERVER (1<<0)
/** Do not perform Netscape certificate type verification */
#define NS_CERT_CHECK_CLIENT (1<<1)
/** Require keyUsage to be present in cert (0xFFFF is an invalid KU value) */
#define OPENVPN_KU_REQUIRED (0xFFFF)
/*
* TODO: document
*/
#ifdef MANAGEMENT_DEF_AUTH
bool tls_authenticate_key(struct tls_multi *multi, const unsigned int mda_key_id, const bool auth, const char *client_reason);
#endif
/**
* Sets the reason why authentication of a client failed. This be will send to the client
* when the AUTH_FAILED message is sent
* An example would be "SESSION: Token expired"
* @param multi The multi tls struct
* @param client_reason The string to send to the client as part of AUTH_FAILED
*/
void auth_set_client_reason(struct tls_multi *multi, const char *client_reason);
static inline const char *
tls_client_reason(struct tls_multi *multi)
{
return multi->client_reason;
}
/** Remove any X509_ env variables from env_set es */
void tls_x509_clear_env(struct env_set *es);
#endif /* SSL_VERIFY_H_ */
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