1 /* $NetBSD: auth.h,v 1.21 2021/03/05 17:47:15 christos Exp $ */ 2 /* $OpenBSD: auth.h,v 1.101 2020/12/22 00:12:22 djm 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 34 #include <openssl/rsa.h> 35 36 #ifdef HAVE_LOGIN_CAP 37 #include <login_cap.h> 38 #endif 39 #ifdef BSD_AUTH 40 #include <bsd_auth.h> 41 #endif 42 #ifdef KRB5 43 #include <krb5.h> 44 #endif 45 46 struct passwd; 47 struct ssh; 48 struct sshbuf; 49 struct sshkey; 50 struct sshauthopt; 51 52 typedef struct Authctxt Authctxt; 53 typedef struct Authmethod Authmethod; 54 typedef struct KbdintDevice KbdintDevice; 55 56 struct Authctxt { 57 sig_atomic_t success; 58 int authenticated; /* authenticated and alarms cancelled */ 59 int postponed; /* authentication needs another step */ 60 int valid; /* user exists and is allowed to login */ 61 int attempt; 62 int failures; 63 int server_caused_failure; 64 int force_pwchange; 65 char *user; /* username sent by the client */ 66 char *service; 67 struct passwd *pw; /* set if 'valid' */ 68 char *style; 69 70 /* Method lists for multiple authentication */ 71 char **auth_methods; /* modified from server config */ 72 u_int num_auth_methods; 73 74 /* Authentication method-specific data */ 75 void *methoddata; 76 void *kbdintctxt; 77 #ifdef BSD_AUTH 78 auth_session_t *as; 79 #endif 80 #ifdef KRB5 81 krb5_context krb5_ctx; 82 krb5_auth_context krb5_auth_ctx; 83 krb5_ccache krb5_fwd_ccache; 84 krb5_principal krb5_user; 85 char *krb5_ticket_file; 86 #endif 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 #ifdef USE_PAM 108 #include "auth-pam.h" 109 #endif 110 111 struct Authmethod { 112 const char *name; 113 int (*userauth)(struct ssh *); 114 int *enabled; 115 }; 116 117 /* 118 * Keyboard interactive device: 119 * init_ctx returns: non NULL upon success 120 * query returns: 0 - success, otherwise failure 121 * respond returns: 0 - success, 1 - need further interaction, 122 * otherwise - failure 123 */ 124 struct KbdintDevice 125 { 126 const char *name; 127 void* (*init_ctx)(Authctxt*); 128 int (*query)(void *ctx, char **name, char **infotxt, 129 u_int *numprompts, char ***prompts, u_int **echo_on); 130 int (*respond)(void *ctx, u_int numresp, char **responses); 131 void (*free_ctx)(void *ctx); 132 }; 133 134 int 135 auth_rhosts2(struct passwd *, const char *, const char *, const char *); 136 137 int auth_password(struct ssh *, const char *); 138 139 int hostbased_key_allowed(struct ssh *, struct passwd *, 140 const char *, char *, struct sshkey *); 141 int user_key_allowed(struct ssh *, struct passwd *, struct sshkey *, int, 142 struct sshauthopt **); 143 int auth2_key_already_used(Authctxt *, const struct sshkey *); 144 145 /* 146 * Handling auth method-specific information for logging and prevention 147 * of key reuse during multiple authentication. 148 */ 149 void auth2_authctxt_reset_info(Authctxt *); 150 void auth2_record_key(Authctxt *, int, const struct sshkey *); 151 void auth2_record_info(Authctxt *authctxt, const char *, ...) 152 __attribute__((__format__ (printf, 2, 3))) 153 __attribute__((__nonnull__ (2))); 154 void auth2_update_session_info(Authctxt *, const char *, const char *); 155 156 #ifdef KRB5 157 int auth_krb5(struct ssh *, krb5_data *auth, char **client, krb5_data *); 158 int auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt); 159 int auth_krb5_password(Authctxt *authctxt, const char *password); 160 void krb5_cleanup_proc(Authctxt *authctxt); 161 #endif /* KRB5 */ 162 163 void do_authentication2(struct ssh *); 164 165 void auth_log(struct ssh *, int, int, const char *, const char *); 166 void auth_maxtries_exceeded(struct ssh *) __attribute__((noreturn)); 167 void userauth_finish(struct ssh *, int, const char *, const char *); 168 int auth_root_allowed(struct ssh *, const char *); 169 170 char *auth2_read_banner(void); 171 int auth2_methods_valid(const char *, int); 172 int auth2_update_methods_lists(Authctxt *, const char *, const char *); 173 int auth2_setup_methods_lists(Authctxt *); 174 int auth2_method_allowed(Authctxt *, const char *, const char *); 175 176 void privsep_challenge_enable(void); 177 178 int auth2_challenge(struct ssh *, char *); 179 void auth2_challenge_stop(struct ssh *); 180 int bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **); 181 int bsdauth_respond(void *, u_int, char **); 182 183 int allowed_user(struct ssh *, struct passwd *); 184 struct passwd * getpwnamallow(struct ssh *, const char *user); 185 186 char *expand_authorized_keys(const char *, struct passwd *pw); 187 char *authorized_principals_file(struct passwd *); 188 189 FILE *auth_openkeyfile(const char *, struct passwd *, int); 190 FILE *auth_openprincipals(const char *, struct passwd *, int); 191 int auth_key_is_revoked(struct sshkey *); 192 193 const char *auth_get_canonical_hostname(struct ssh *, int); 194 195 HostStatus 196 check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *, 197 const char *, const char *); 198 199 /* hostkey handling */ 200 struct sshkey *get_hostkey_by_index(int); 201 struct sshkey *get_hostkey_public_by_index(int, struct ssh *); 202 struct sshkey *get_hostkey_public_by_type(int, int, struct ssh *); 203 struct sshkey *get_hostkey_private_by_type(int, int, struct ssh *); 204 int get_hostkey_index(struct sshkey *, int, struct ssh *); 205 int sshd_hostkey_sign(struct ssh *, struct sshkey *, struct sshkey *, 206 u_char **, size_t *, const u_char *, size_t, const char *); 207 208 /* Key / cert options linkage to auth layer */ 209 const struct sshauthopt *auth_options(struct ssh *); 210 int auth_activate_options(struct ssh *, struct sshauthopt *); 211 void auth_restrict_session(struct ssh *); 212 int auth_authorise_keyopts(struct ssh *, struct passwd *pw, 213 struct sshauthopt *, int, const char *); 214 void auth_log_authopts(const char *, const struct sshauthopt *, int); 215 216 /* debug messages during authentication */ 217 void auth_debug_add(const char *fmt,...) 218 __attribute__((format(printf, 1, 2))); 219 void auth_debug_send(struct ssh *); 220 void auth_debug_reset(void); 221 222 void disable_forwarding(void); 223 224 struct passwd *fakepw(void); 225 226 #endif 227