crypto/openssh/auth.h

   1 /* $OpenBSD: auth.h,v 1.93 2017/08/18 05:36:45 djm Exp $ */
   2
   3 /*
   4  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  *
  26  */
  27
  28 #ifndef AUTH_H
  29 #define AUTH_H
  30
  31 #include <signal.h>
  32
  33 #include <openssl/rsa.h>
  34
  35 #ifdef HAVE_LOGIN_CAP
  36 #include <login_cap.h>
  37 #endif
  38 #ifdef BSD_AUTH
  39 #include <bsd_auth.h>
  40 #endif
  41 #ifdef KRB5
  42 #include <krb5.h>
  43 #endif
  44
  45 struct ssh;
  46 struct sshkey;
  47 struct sshbuf;
  48
  49 typedef struct Authctxt Authctxt;
  50 typedef struct Authmethod Authmethod;
  51 typedef struct KbdintDevice KbdintDevice;
  52
  53 struct Authctxt {
  54         sig_atomic_t     success;
  55         int              authenticated; /* authenticated and alarms cancelled */
  56         int              postponed;     /* authentication needs another step */
  57         int              valid;         /* user exists and is allowed to login */
  58         int              attempt;
  59         int              failures;
  60         int              server_caused_failure;
  61         int              force_pwchange;
  62         char            *user;          /* username sent by the client */
  63         char            *service;
  64         struct passwd   *pw;            /* set if 'valid' */
  65         char            *style;
  66
  67         /* Method lists for multiple authentication */
  68         char            **auth_methods; /* modified from server config */
  69         u_int            num_auth_methods;
  70
  71         /* Authentication method-specific data */
  72         void            *methoddata;
  73         void            *kbdintctxt;
  74 #ifdef BSD_AUTH
  75         auth_session_t  *as;
  76 #endif
  77 #ifdef KRB5
  78         krb5_context     krb5_ctx;
  79         krb5_ccache      krb5_fwd_ccache;
  80         krb5_principal   krb5_user;
  81         char            *krb5_ticket_file;
  82         char            *krb5_ccname;
  83 #endif
  84         struct sshbuf   *loginmsg;
  85
  86         /* Authentication keys already used; these will be refused henceforth */
  87         struct sshkey   **prev_keys;
  88         u_int            nprev_keys;
  89
  90         /* Last used key and ancilliary information from active auth method */
  91         struct sshkey   *auth_method_key;
  92         char            *auth_method_info;
  93
  94         /* Information exposed to session */
  95         struct sshbuf   *session_info;  /* Auth info for environment */
  96 };
  97
  98 /*
  99  * Every authentication method has to handle authentication requests for
 100  * non-existing users, or for users that are not allowed to login. In this
 101  * case 'valid' is set to 0, but 'user' points to the username requested by
 102  * the client.
 103  */
 104
 105 struct Authmethod {
 106         char    *name;
 107         int     (*userauth)(struct ssh *);
 108         int     *enabled;
 109 };
 110
 111 /*
 112  * Keyboard interactive device:
 113  * init_ctx     returns: non NULL upon success
 114  * query        returns: 0 - success, otherwise failure
 115  * respond      returns: 0 - success, 1 - need further interaction,
 116  *              otherwise - failure
 117  */
 118 struct KbdintDevice
 119 {
 120         const char *name;
 121         void*   (*init_ctx)(Authctxt*);
 122         int     (*query)(void *ctx, char **name, char **infotxt,
 123                     u_int *numprompts, char ***prompts, u_int **echo_on);
 124         int     (*respond)(void *ctx, u_int numresp, char **responses);
 125         void    (*free_ctx)(void *ctx);
 126 };
 127
 128 int
 129 auth_rhosts2(struct passwd *, const char *, const char *, const char *);
 130
 131 int      auth_password(Authctxt *, const char *);
 132
 133 int      hostbased_key_allowed(struct passwd *, const char *, char *,
 134             struct sshkey *);
 135 int      user_key_allowed(struct passwd *, struct sshkey *, int);
 136 int      auth2_key_already_used(Authctxt *, const struct sshkey *);
 137
 138 /*
 139  * Handling auth method-specific information for logging and prevention
 140  * of key reuse during multiple authentication.
 141  */
 142 void     auth2_authctxt_reset_info(Authctxt *);
 143 void     auth2_record_key(Authctxt *, int, const struct sshkey *);
 144 void     auth2_record_info(Authctxt *authctxt, const char *, ...)
 145             __attribute__((__format__ (printf, 2, 3)))
 146             __attribute__((__nonnull__ (2)));
 147 void     auth2_update_session_info(Authctxt *, const char *, const char *);
 148
 149 #ifdef KRB5
 150 int     auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *);
 151 int     auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt);
 152 int     auth_krb5_password(Authctxt *authctxt, const char *password);
 153 void    krb5_cleanup_proc(Authctxt *authctxt);
 154 #endif /* KRB5 */
 155
 156 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
 157 #include <shadow.h>
 158 int auth_shadow_acctexpired(struct spwd *);
 159 int auth_shadow_pwexpired(Authctxt *);
 160 #endif
 161
 162 #include "auth-pam.h"
 163 #include "audit.h"
 164 void remove_kbdint_device(const char *);
 165
 166 void disable_forwarding(void);
 167
 168 void    do_authentication2(Authctxt *);
 169
 170 void    auth_log(Authctxt *, int, int, const char *, const char *);
 171 void    auth_maxtries_exceeded(Authctxt *) __attribute__((noreturn));
 172 void    userauth_finish(struct ssh *, int, const char *, const char *);
 173 int     auth_root_allowed(const char *);
 174
 175 void    userauth_send_banner(const char *);
 176
 177 char    *auth2_read_banner(void);
 178 int      auth2_methods_valid(const char *, int);
 179 int      auth2_update_methods_lists(Authctxt *, const char *, const char *);
 180 int      auth2_setup_methods_lists(Authctxt *);
 181 int      auth2_method_allowed(Authctxt *, const char *, const char *);
 182
 183 void    privsep_challenge_enable(void);
 184
 185 int     auth2_challenge(struct ssh *, char *);
 186 void    auth2_challenge_stop(struct ssh *);
 187 int     bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **);
 188 int     bsdauth_respond(void *, u_int, char **);
 189 int     skey_query(void *, char **, char **, u_int *, char ***, u_int **);
 190 int     skey_respond(void *, u_int, char **);
 191
 192 int     allowed_user(struct passwd *);
 193 struct passwd * getpwnamallow(const char *user);
 194
 195 char    *expand_authorized_keys(const char *, struct passwd *pw);
 196 char    *authorized_principals_file(struct passwd *);
 197
 198 FILE    *auth_openkeyfile(const char *, struct passwd *, int);
 199 FILE    *auth_openprincipals(const char *, struct passwd *, int);
 200 int      auth_key_is_revoked(struct sshkey *);
 201
 202 const char      *auth_get_canonical_hostname(struct ssh *, int);
 203
 204 HostStatus
 205 check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *,
 206     const char *, const char *);
 207
 208 /* hostkey handling */
 209 struct sshkey   *get_hostkey_by_index(int);
 210 struct sshkey   *get_hostkey_public_by_index(int, struct ssh *);
 211 struct sshkey   *get_hostkey_public_by_type(int, int, struct ssh *);
 212 struct sshkey   *get_hostkey_private_by_type(int, int, struct ssh *);
 213 int      get_hostkey_index(struct sshkey *, int, struct ssh *);
 214 int      sshd_hostkey_sign(struct sshkey *, struct sshkey *, u_char **,
 215              size_t *, const u_char *, size_t, const char *, u_int);
 216
 217 /* debug messages during authentication */
 218 void     auth_debug_add(const char *fmt,...) __attribute__((format(printf, 1, 2)));
 219 void     auth_debug_send(void);
 220 void     auth_debug_reset(void);
 221
 222 struct passwd *fakepw(void);
 223
 224 int      sys_auth_passwd(Authctxt *, const char *);
 225
 226 #define SKEY_PROMPT "\nS/Key Password: "
 227
 228 #if defined(KRB5) && !defined(HEIMDAL)
 229 #include <krb5.h>
 230 krb5_error_code ssh_krb5_cc_gen(krb5_context, krb5_ccache *);
 231 #endif
 232 #endif