1 /* $NetBSD: auth.h,v 1.24 2024/07/08 22:33:43 christos Exp $ */ 2 /* $OpenBSD: auth.h,v 1.108 2024/05/17 06:42:04 jsg Exp $ */ 3 4 /* 5 * Copyright (c) 2000 Markus Friedl. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 */ 28 29 #ifndef AUTH_H 30 #define AUTH_H 31 32 #include <signal.h> 33 #include <stdio.h> 34 35 #include <openssl/rsa.h> 36 37 #ifdef HAVE_LOGIN_CAP 38 #include <login_cap.h> 39 #endif 40 #ifdef BSD_AUTH 41 #include <bsd_auth.h> 42 #endif 43 #ifdef KRB5 44 #include <krb5.h> 45 #endif 46 47 struct passwd; 48 struct ssh; 49 struct sshbuf; 50 struct sshkey; 51 struct sshkey_cert; 52 struct sshauthopt; 53 54 typedef struct Authctxt Authctxt; 55 typedef struct Authmethod Authmethod; 56 typedef struct KbdintDevice KbdintDevice; 57 58 struct Authctxt { 59 sig_atomic_t success; 60 int authenticated; /* authenticated and alarms cancelled */ 61 int postponed; /* authentication needs another step */ 62 int valid; /* user exists and is allowed to login */ 63 int attempt; 64 int failures; 65 int server_caused_failure; 66 int force_pwchange; 67 char *user; /* username sent by the client */ 68 char *service; 69 struct passwd *pw; /* set if 'valid' */ 70 char *style; 71 72 /* Method lists for multiple authentication */ 73 char **auth_methods; /* modified from server config */ 74 u_int num_auth_methods; 75 76 /* Authentication method-specific data */ 77 void *methoddata; 78 void *kbdintctxt; 79 #ifdef BSD_AUTH 80 auth_session_t *as; 81 #endif 82 #ifdef KRB5 83 krb5_context krb5_ctx; 84 krb5_auth_context krb5_auth_ctx; 85 krb5_ccache krb5_fwd_ccache; 86 krb5_principal krb5_user; 87 char *krb5_ticket_file; 88 #endif 89 90 /* Authentication keys already used; these will be refused henceforth */ 91 struct sshkey **prev_keys; 92 u_int nprev_keys; 93 94 /* Last used key and ancillary information from active auth method */ 95 struct sshkey *auth_method_key; 96 char *auth_method_info; 97 98 /* Information exposed to session */ 99 struct sshbuf *session_info; /* Auth info for environment */ 100 }; 101 102 /* 103 * Every authentication method has to handle authentication requests for 104 * non-existing users, or for users that are not allowed to login. In this 105 * case 'valid' is set to 0, but 'user' points to the username requested by 106 * the client. 107 */ 108 109 #ifdef USE_PAM 110 #include "auth-pam.h" 111 #endif 112 113 struct authmethod_cfg { 114 const char *name; 115 const char *synonym; 116 int *enabled; 117 }; 118 119 struct Authmethod { 120 struct authmethod_cfg *cfg; 121 int (*userauth)(struct ssh *, const char *); 122 }; 123 124 /* 125 * Keyboard interactive device: 126 * init_ctx returns: non NULL upon success 127 * query returns: 0 - success, otherwise failure 128 * respond returns: 0 - success, 1 - need further interaction, 129 * otherwise - failure 130 */ 131 struct KbdintDevice 132 { 133 const char *name; 134 void* (*init_ctx)(Authctxt*); 135 int (*query)(void *ctx, char **name, char **infotxt, 136 u_int *numprompts, char ***prompts, u_int **echo_on); 137 int (*respond)(void *ctx, u_int numresp, char **responses); 138 void (*free_ctx)(void *ctx); 139 }; 140 141 int 142 auth_rhosts2(struct passwd *, const char *, const char *, const char *); 143 144 int auth_password(struct ssh *, const char *); 145 146 int hostbased_key_allowed(struct ssh *, struct passwd *, 147 const char *, char *, struct sshkey *); 148 int user_key_allowed(struct ssh *ssh, struct passwd *, struct sshkey *, 149 int, struct sshauthopt **); 150 int auth2_key_already_used(Authctxt *, const struct sshkey *); 151 152 /* 153 * Handling auth method-specific information for logging and prevention 154 * of key reuse during multiple authentication. 155 */ 156 void auth2_authctxt_reset_info(Authctxt *); 157 void auth2_record_key(Authctxt *, int, const struct sshkey *); 158 void auth2_record_info(Authctxt *authctxt, const char *, ...) 159 __attribute__((__format__ (printf, 2, 3))) 160 __attribute__((__nonnull__ (2))); 161 void auth2_update_session_info(Authctxt *, const char *, const char *); 162 163 #ifdef KRB5 164 int auth_krb5(struct ssh *, krb5_data *auth, char **client, krb5_data *); 165 int auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt); 166 int auth_krb5_password(Authctxt *authctxt, const char *password); 167 void krb5_cleanup_proc(Authctxt *authctxt); 168 #endif /* KRB5 */ 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 int auth_activate_options(struct ssh *, struct sshauthopt *); 215 void auth_restrict_session(struct ssh *); 216 void auth_log_authopts(const char *, const struct sshauthopt *, int); 217 218 /* debug messages during authentication */ 219 void auth_debug_add(const char *fmt,...) 220 __attribute__((format(printf, 1, 2))); 221 void auth_debug_send(struct ssh *); 222 void auth_debug_reset(void); 223 224 void disable_forwarding(void); 225 226 struct passwd *fakepw(void); 227 228 /* auth2-pubkeyfile.c */ 229 int auth_authorise_keyopts(struct passwd *, struct sshauthopt *, int, 230 const char *, const char *, const char *); 231 int auth_check_principals_line(char *, const struct sshkey_cert *, 232 const char *, struct sshauthopt **); 233 int auth_process_principals(FILE *, const char *, 234 const struct sshkey_cert *, struct sshauthopt **); 235 int auth_check_authkey_line(struct passwd *, struct sshkey *, 236 char *, const char *, const char *, const char *, struct sshauthopt **); 237 int auth_check_authkeys_file(struct passwd *, FILE *, char *, 238 struct sshkey *, const char *, const char *, struct sshauthopt **); 239 FILE *auth_openkeyfile(const char *, struct passwd *, int); 240 FILE *auth_openprincipals(const char *, struct passwd *, int); 241 242 #endif 243