1/* $OpenBSD: auth.h,v 1.108 2024/05/17 06:42:04 jsg 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#include <bsd_auth.h> 35#ifdef KRB5 36#include <krb5.h> 37#endif 38 39struct passwd; 40struct ssh; 41struct sshbuf; 42struct sshkey; 43struct sshkey_cert; 44struct sshauthopt; 45 46typedef struct Authctxt Authctxt; 47typedef struct Authmethod Authmethod; 48typedef struct KbdintDevice KbdintDevice; 49 50struct Authctxt { 51 sig_atomic_t success; 52 int authenticated; /* authenticated and alarms cancelled */ 53 int postponed; /* authentication needs another step */ 54 int valid; /* user exists and is allowed to login */ 55 int attempt; 56 int failures; 57 int server_caused_failure; 58 int force_pwchange; 59 char *user; /* username sent by the client */ 60 char *service; 61 struct passwd *pw; /* set if 'valid' */ 62 char *style; 63 64 /* Method lists for multiple authentication */ 65 char **auth_methods; /* modified from server config */ 66 u_int num_auth_methods; 67 68 /* Authentication method-specific data */ 69 void *methoddata; 70 void *kbdintctxt; 71 auth_session_t *as; 72#ifdef KRB5 73 krb5_context krb5_ctx; 74 krb5_ccache krb5_fwd_ccache; 75 krb5_principal krb5_user; 76 char *krb5_ticket_file; 77#endif 78 79 /* Authentication keys already used; these will be refused henceforth */ 80 struct sshkey **prev_keys; 81 u_int nprev_keys; 82 83 /* Last used key and ancillary information from active auth method */ 84 struct sshkey *auth_method_key; 85 char *auth_method_info; 86 87 /* Information exposed to session */ 88 struct sshbuf *session_info; /* Auth info for environment */ 89}; 90 91/* 92 * Every authentication method has to handle authentication requests for 93 * non-existing users, or for users that are not allowed to login. In this 94 * case 'valid' is set to 0, but 'user' points to the username requested by 95 * the client. 96 */ 97 98struct authmethod_cfg { 99 const char *name; 100 const char *synonym; 101 int *enabled; 102}; 103 104struct Authmethod { 105 struct authmethod_cfg *cfg; 106 int (*userauth)(struct ssh *, const char *); 107}; 108 109/* 110 * Keyboard interactive device: 111 * init_ctx returns: non NULL upon success 112 * query returns: 0 - success, otherwise failure 113 * respond returns: 0 - success, 1 - need further interaction, 114 * otherwise - failure 115 */ 116struct KbdintDevice 117{ 118 const char *name; 119 void* (*init_ctx)(Authctxt*); 120 int (*query)(void *ctx, char **name, char **infotxt, 121 u_int *numprompts, char ***prompts, u_int **echo_on); 122 int (*respond)(void *ctx, u_int numresp, char **responses); 123 void (*free_ctx)(void *ctx); 124}; 125 126int 127auth_rhosts2(struct passwd *, const char *, const char *, const char *); 128 129int auth_password(struct ssh *, const char *); 130 131int hostbased_key_allowed(struct ssh *, struct passwd *, 132 const char *, char *, struct sshkey *); 133int user_key_allowed(struct ssh *ssh, struct passwd *, struct sshkey *, 134 int, struct sshauthopt **); 135int auth2_key_already_used(Authctxt *, const struct sshkey *); 136 137/* 138 * Handling auth method-specific information for logging and prevention 139 * of key reuse during multiple authentication. 140 */ 141void auth2_authctxt_reset_info(Authctxt *); 142void auth2_record_key(Authctxt *, int, const struct sshkey *); 143void auth2_record_info(Authctxt *authctxt, const char *, ...) 144 __attribute__((__format__ (printf, 2, 3))) 145 __attribute__((__nonnull__ (2))); 146void auth2_update_session_info(Authctxt *, const char *, const char *); 147 148#ifdef KRB5 149int auth_krb5_password(Authctxt *authctxt, const char *password); 150void krb5_cleanup_proc(Authctxt *authctxt); 151#endif /* KRB5 */ 152 153void do_authentication2(struct ssh *); 154 155void auth_log(struct ssh *, int, int, const char *, const char *); 156void auth_maxtries_exceeded(struct ssh *) __attribute__((noreturn)); 157void userauth_finish(struct ssh *, int, const char *, const char *); 158int auth_root_allowed(struct ssh *, const char *); 159 160char *auth2_read_banner(void); 161int auth2_methods_valid(const char *, int); 162int auth2_update_methods_lists(Authctxt *, const char *, const char *); 163int auth2_setup_methods_lists(Authctxt *); 164int auth2_method_allowed(Authctxt *, const char *, const char *); 165 166void privsep_challenge_enable(void); 167 168int auth2_challenge(struct ssh *, char *); 169void auth2_challenge_stop(struct ssh *); 170int bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **); 171int bsdauth_respond(void *, u_int, char **); 172 173int allowed_user(struct ssh *, struct passwd *); 174struct passwd * getpwnamallow(struct ssh *, const char *user); 175 176char *expand_authorized_keys(const char *, struct passwd *pw); 177char *authorized_principals_file(struct passwd *); 178 179int auth_key_is_revoked(struct sshkey *); 180 181const char *auth_get_canonical_hostname(struct ssh *, int); 182 183HostStatus 184check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *, 185 const char *, const char *); 186 187/* hostkey handling */ 188struct sshkey *get_hostkey_by_index(int); 189struct sshkey *get_hostkey_public_by_index(int, struct ssh *); 190struct sshkey *get_hostkey_public_by_type(int, int, struct ssh *); 191struct sshkey *get_hostkey_private_by_type(int, int, struct ssh *); 192int get_hostkey_index(struct sshkey *, int, struct ssh *); 193int sshd_hostkey_sign(struct ssh *, struct sshkey *, struct sshkey *, 194 u_char **, size_t *, const u_char *, size_t, const char *); 195 196/* Key / cert options linkage to auth layer */ 197int auth_activate_options(struct ssh *, struct sshauthopt *); 198void auth_restrict_session(struct ssh *); 199void auth_log_authopts(const char *, const struct sshauthopt *, int); 200 201/* debug messages during authentication */ 202void auth_debug_add(const char *fmt,...) 203 __attribute__((format(printf, 1, 2))); 204void auth_debug_send(struct ssh *); 205void auth_debug_reset(void); 206 207struct passwd *fakepw(void); 208 209/* auth2-pubkeyfile.c */ 210int auth_authorise_keyopts(struct passwd *, struct sshauthopt *, int, 211 const char *, const char *, const char *); 212int auth_check_principals_line(char *, const struct sshkey_cert *, 213 const char *, struct sshauthopt **); 214int auth_process_principals(FILE *, const char *, 215 const struct sshkey_cert *, struct sshauthopt **); 216int auth_check_authkey_line(struct passwd *, struct sshkey *, 217 char *, const char *, const char *, const char *, struct sshauthopt **); 218int auth_check_authkeys_file(struct passwd *, FILE *, char *, 219 struct sshkey *, const char *, const char *, struct sshauthopt **); 220FILE *auth_openkeyfile(const char *, struct passwd *, int); 221FILE *auth_openprincipals(const char *, struct passwd *, int); 222 223#endif 224