1 /* $OpenBSD: auth.h,v 1.106 2022/06/15 16:08:25 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 #include <stdio.h> 33 34 #ifdef HAVE_LOGIN_CAP 35 #include <login_cap.h> 36 #endif 37 #ifdef BSD_AUTH 38 #include <bsd_auth.h> 39 #endif 40 #ifdef KRB5 41 #include <krb5.h> 42 #endif 43 44 struct passwd; 45 struct ssh; 46 struct sshbuf; 47 struct sshkey; 48 struct sshkey_cert; 49 struct sshauthopt; 50 51 typedef struct Authctxt Authctxt; 52 typedef struct Authmethod Authmethod; 53 typedef struct KbdintDevice KbdintDevice; 54 55 struct Authctxt { 56 sig_atomic_t success; 57 int authenticated; /* authenticated and alarms cancelled */ 58 int postponed; /* authentication needs another step */ 59 int valid; /* user exists and is allowed to login */ 60 int attempt; 61 int failures; 62 int server_caused_failure; 63 int force_pwchange; 64 char *user; /* username sent by the client */ 65 char *service; 66 struct passwd *pw; /* set if 'valid' */ 67 char *style; 68 69 /* Method lists for multiple authentication */ 70 char **auth_methods; /* modified from server config */ 71 u_int num_auth_methods; 72 73 /* Authentication method-specific data */ 74 void *methoddata; 75 void *kbdintctxt; 76 #ifdef BSD_AUTH 77 auth_session_t *as; 78 #endif 79 #ifdef KRB5 80 krb5_context krb5_ctx; 81 krb5_ccache krb5_fwd_ccache; 82 krb5_principal krb5_user; 83 char *krb5_ticket_file; 84 char *krb5_ccname; 85 #endif 86 struct sshbuf *loginmsg; 87 88 /* Authentication keys already used; these will be refused henceforth */ 89 struct sshkey **prev_keys; 90 u_int nprev_keys; 91 92 /* Last used key and ancillary information from active auth method */ 93 struct sshkey *auth_method_key; 94 char *auth_method_info; 95 96 /* Information exposed to session */ 97 struct sshbuf *session_info; /* Auth info for environment */ 98 }; 99 100 /* 101 * Every authentication method has to handle authentication requests for 102 * non-existing users, or for users that are not allowed to login. In this 103 * case 'valid' is set to 0, but 'user' points to the username requested by 104 * the client. 105 */ 106 107 struct Authmethod { 108 char *name; 109 char *synonym; 110 int (*userauth)(struct ssh *, const char *); 111 int *enabled; 112 }; 113 114 /* 115 * Keyboard interactive device: 116 * init_ctx returns: non NULL upon success 117 * query returns: 0 - success, otherwise failure 118 * respond returns: 0 - success, 1 - need further interaction, 119 * otherwise - failure 120 */ 121 struct KbdintDevice 122 { 123 const char *name; 124 void* (*init_ctx)(Authctxt*); 125 int (*query)(void *ctx, char **name, char **infotxt, 126 u_int *numprompts, char ***prompts, u_int **echo_on); 127 int (*respond)(void *ctx, u_int numresp, char **responses); 128 void (*free_ctx)(void *ctx); 129 }; 130 131 int 132 auth_rhosts2(struct passwd *, const char *, const char *, const char *); 133 134 int auth_password(struct ssh *, const char *); 135 136 int hostbased_key_allowed(struct ssh *, struct passwd *, 137 const char *, char *, struct sshkey *); 138 int user_key_allowed(struct ssh *ssh, struct passwd *, struct sshkey *, 139 int, struct sshauthopt **); 140 int auth2_key_already_used(Authctxt *, const struct sshkey *); 141 142 /* 143 * Handling auth method-specific information for logging and prevention 144 * of key reuse during multiple authentication. 145 */ 146 void auth2_authctxt_reset_info(Authctxt *); 147 void auth2_record_key(Authctxt *, int, const struct sshkey *); 148 void auth2_record_info(Authctxt *authctxt, const char *, ...) 149 __attribute__((__format__ (printf, 2, 3))) 150 __attribute__((__nonnull__ (2))); 151 void auth2_update_session_info(Authctxt *, const char *, const char *); 152 153 #ifdef KRB5 154 int auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *); 155 int auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt); 156 int auth_krb5_password(Authctxt *authctxt, const char *password); 157 void krb5_cleanup_proc(Authctxt *authctxt); 158 #endif /* KRB5 */ 159 160 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) 161 #include <shadow.h> 162 int auth_shadow_acctexpired(struct spwd *); 163 int auth_shadow_pwexpired(Authctxt *); 164 #endif 165 166 #include "auth-pam.h" 167 #include "audit.h" 168 void remove_kbdint_device(const char *); 169 170 void do_authentication2(struct ssh *); 171 172 void auth_log(struct ssh *, int, int, const char *, const char *); 173 void auth_maxtries_exceeded(struct ssh *) __attribute__((noreturn)); 174 void userauth_finish(struct ssh *, int, const char *, const char *); 175 int auth_root_allowed(struct ssh *, 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 **); 189 190 int allowed_user(struct ssh *, struct passwd *); 191 struct passwd * getpwnamallow(struct ssh *, const char *user); 192 193 char *expand_authorized_keys(const char *, struct passwd *pw); 194 char *authorized_principals_file(struct passwd *); 195 196 int auth_key_is_revoked(struct sshkey *); 197 198 const char *auth_get_canonical_hostname(struct ssh *, int); 199 200 HostStatus 201 check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *, 202 const char *, const char *); 203 204 /* hostkey handling */ 205 struct sshkey *get_hostkey_by_index(int); 206 struct sshkey *get_hostkey_public_by_index(int, struct ssh *); 207 struct sshkey *get_hostkey_public_by_type(int, int, struct ssh *); 208 struct sshkey *get_hostkey_private_by_type(int, int, struct ssh *); 209 int get_hostkey_index(struct sshkey *, int, struct ssh *); 210 int sshd_hostkey_sign(struct ssh *, struct sshkey *, struct sshkey *, 211 u_char **, size_t *, const u_char *, size_t, const char *); 212 213 /* Key / cert options linkage to auth layer */ 214 const struct sshauthopt *auth_options(struct ssh *); 215 int auth_activate_options(struct ssh *, struct sshauthopt *); 216 void auth_restrict_session(struct ssh *); 217 void auth_log_authopts(const char *, const struct sshauthopt *, int); 218 219 /* debug messages during authentication */ 220 void auth_debug_add(const char *fmt,...) 221 __attribute__((format(printf, 1, 2))); 222 void auth_debug_send(struct ssh *); 223 void auth_debug_reset(void); 224 225 struct passwd *fakepw(void); 226 227 /* auth2-pubkeyfile.c */ 228 int auth_authorise_keyopts(struct passwd *, struct sshauthopt *, int, 229 const char *, const char *, const char *); 230 int auth_check_principals_line(char *, const struct sshkey_cert *, 231 const char *, struct sshauthopt **); 232 int auth_process_principals(FILE *, const char *, 233 const struct sshkey_cert *, struct sshauthopt **); 234 int auth_check_authkey_line(struct passwd *, struct sshkey *, 235 char *, const char *, const char *, const char *, struct sshauthopt **); 236 int auth_check_authkeys_file(struct passwd *, FILE *, char *, 237 struct sshkey *, const char *, const char *, struct sshauthopt **); 238 FILE *auth_openkeyfile(const char *, struct passwd *, int); 239 FILE *auth_openprincipals(const char *, struct passwd *, int); 240 241 int sys_auth_passwd(struct ssh *, const char *); 242 243 #if defined(KRB5) && !defined(HEIMDAL) 244 krb5_error_code ssh_krb5_cc_gen(krb5_context, krb5_ccache *); 245 #endif 246 247 #endif /* AUTH_H */ 248