1/* $NetBSD: auth.h,v 1.23 2022/10/05 22:39:36 christos Exp $ */ 2/* $OpenBSD: auth.h,v 1.106 2022/06/15 16:08:25 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#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 47struct passwd; 48struct ssh; 49struct sshbuf; 50struct sshkey; 51struct sshkey_cert; 52struct sshauthopt; 53 54typedef struct Authctxt Authctxt; 55typedef struct Authmethod Authmethod; 56typedef struct KbdintDevice KbdintDevice; 57 58struct 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 113struct Authmethod { 114 const char *name; 115 const char *synonym; 116 int (*userauth)(struct ssh *, const char *); 117 int *enabled; 118}; 119 120/* 121 * Keyboard interactive device: 122 * init_ctx returns: non NULL upon success 123 * query returns: 0 - success, otherwise failure 124 * respond returns: 0 - success, 1 - need further interaction, 125 * otherwise - failure 126 */ 127struct KbdintDevice 128{ 129 const char *name; 130 void* (*init_ctx)(Authctxt*); 131 int (*query)(void *ctx, char **name, char **infotxt, 132 u_int *numprompts, char ***prompts, u_int **echo_on); 133 int (*respond)(void *ctx, u_int numresp, char **responses); 134 void (*free_ctx)(void *ctx); 135}; 136 137int 138auth_rhosts2(struct passwd *, const char *, const char *, const char *); 139 140int auth_password(struct ssh *, const char *); 141 142int hostbased_key_allowed(struct ssh *, struct passwd *, 143 const char *, char *, struct sshkey *); 144int user_key_allowed(struct ssh *ssh, struct passwd *, struct sshkey *, 145 int, struct sshauthopt **); 146int auth2_key_already_used(Authctxt *, const struct sshkey *); 147 148/* 149 * Handling auth method-specific information for logging and prevention 150 * of key reuse during multiple authentication. 151 */ 152void auth2_authctxt_reset_info(Authctxt *); 153void auth2_record_key(Authctxt *, int, const struct sshkey *); 154void auth2_record_info(Authctxt *authctxt, const char *, ...) 155 __attribute__((__format__ (printf, 2, 3))) 156 __attribute__((__nonnull__ (2))); 157void auth2_update_session_info(Authctxt *, const char *, const char *); 158 159#ifdef KRB5 160int auth_krb5(struct ssh *, krb5_data *auth, char **client, krb5_data *); 161int auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt); 162int auth_krb5_password(Authctxt *authctxt, const char *password); 163void krb5_cleanup_proc(Authctxt *authctxt); 164#endif /* KRB5 */ 165 166void do_authentication2(struct ssh *); 167 168void auth_log(struct ssh *, int, int, const char *, const char *); 169void auth_maxtries_exceeded(struct ssh *) __attribute__((noreturn)); 170void userauth_finish(struct ssh *, int, const char *, const char *); 171int auth_root_allowed(struct ssh *, const char *); 172 173char *auth2_read_banner(void); 174int auth2_methods_valid(const char *, int); 175int auth2_update_methods_lists(Authctxt *, const char *, const char *); 176int auth2_setup_methods_lists(Authctxt *); 177int auth2_method_allowed(Authctxt *, const char *, const char *); 178 179void privsep_challenge_enable(void); 180 181int auth2_challenge(struct ssh *, char *); 182void auth2_challenge_stop(struct ssh *); 183int bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **); 184int bsdauth_respond(void *, u_int, char **); 185 186int allowed_user(struct ssh *, struct passwd *); 187struct passwd * getpwnamallow(struct ssh *, const char *user); 188 189char *expand_authorized_keys(const char *, struct passwd *pw); 190char *authorized_principals_file(struct passwd *); 191 192int auth_key_is_revoked(struct sshkey *); 193 194const char *auth_get_canonical_hostname(struct ssh *, int); 195 196HostStatus 197check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *, 198 const char *, const char *); 199 200/* hostkey handling */ 201struct sshkey *get_hostkey_by_index(int); 202struct sshkey *get_hostkey_public_by_index(int, struct ssh *); 203struct sshkey *get_hostkey_public_by_type(int, int, struct ssh *); 204struct sshkey *get_hostkey_private_by_type(int, int, struct ssh *); 205int get_hostkey_index(struct sshkey *, int, struct ssh *); 206int sshd_hostkey_sign(struct ssh *, struct sshkey *, struct sshkey *, 207 u_char **, size_t *, const u_char *, size_t, const char *); 208 209/* Key / cert options linkage to auth layer */ 210const struct sshauthopt *auth_options(struct ssh *); 211int auth_activate_options(struct ssh *, struct sshauthopt *); 212void auth_restrict_session(struct ssh *); 213void auth_log_authopts(const char *, const struct sshauthopt *, int); 214 215/* debug messages during authentication */ 216void auth_debug_add(const char *fmt,...) 217 __attribute__((format(printf, 1, 2))); 218void auth_debug_send(struct ssh *); 219void auth_debug_reset(void); 220 221void disable_forwarding(void); 222 223struct passwd *fakepw(void); 224 225/* auth2-pubkeyfile.c */ 226int auth_authorise_keyopts(struct passwd *, struct sshauthopt *, int, 227 const char *, const char *, const char *); 228int auth_check_principals_line(char *, const struct sshkey_cert *, 229 const char *, struct sshauthopt **); 230int auth_process_principals(FILE *, const char *, 231 const struct sshkey_cert *, struct sshauthopt **); 232int auth_check_authkey_line(struct passwd *, struct sshkey *, 233 char *, const char *, const char *, const char *, struct sshauthopt **); 234int auth_check_authkeys_file(struct passwd *, FILE *, char *, 235 struct sshkey *, const char *, const char *, struct sshauthopt **); 236FILE *auth_openkeyfile(const char *, struct passwd *, int); 237FILE *auth_openprincipals(const char *, struct passwd *, int); 238 239#endif 240