1 /* $OpenBSD: auth.h,v 1.93 2017/08/18 05:36:45 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 33 #include <openssl/rsa.h> 34 35 #include <bsd_auth.h> 36 #ifdef KRB5 37 #include <krb5.h> 38 #endif 39 40 struct ssh; 41 struct sshkey; 42 43 typedef struct Authctxt Authctxt; 44 typedef struct Authmethod Authmethod; 45 typedef struct KbdintDevice KbdintDevice; 46 47 struct Authctxt { 48 sig_atomic_t success; 49 int authenticated; /* authenticated and alarms cancelled */ 50 int postponed; /* authentication needs another step */ 51 int valid; /* user exists and is allowed to login */ 52 int attempt; 53 int failures; 54 int server_caused_failure; 55 int force_pwchange; 56 char *user; /* username sent by the client */ 57 char *service; 58 struct passwd *pw; /* set if 'valid' */ 59 char *style; 60 61 /* Method lists for multiple authentication */ 62 char **auth_methods; /* modified from server config */ 63 u_int num_auth_methods; 64 65 /* Authentication method-specific data */ 66 void *methoddata; 67 void *kbdintctxt; 68 auth_session_t *as; 69 #ifdef KRB5 70 krb5_context krb5_ctx; 71 krb5_ccache krb5_fwd_ccache; 72 krb5_principal krb5_user; 73 char *krb5_ticket_file; 74 #endif 75 76 /* Authentication keys already used; these will be refused henceforth */ 77 struct sshkey **prev_keys; 78 u_int nprev_keys; 79 80 /* Last used key and ancilliary information from active auth method */ 81 struct sshkey *auth_method_key; 82 char *auth_method_info; 83 84 /* Information exposed to session */ 85 struct sshbuf *session_info; /* Auth info for environment */ 86 }; 87 88 /* 89 * Every authentication method has to handle authentication requests for 90 * non-existing users, or for users that are not allowed to login. In this 91 * case 'valid' is set to 0, but 'user' points to the username requested by 92 * the client. 93 */ 94 95 struct Authmethod { 96 char *name; 97 int (*userauth)(struct ssh *); 98 int *enabled; 99 }; 100 101 /* 102 * Keyboard interactive device: 103 * init_ctx returns: non NULL upon success 104 * query returns: 0 - success, otherwise failure 105 * respond returns: 0 - success, 1 - need further interaction, 106 * otherwise - failure 107 */ 108 struct KbdintDevice 109 { 110 const char *name; 111 void* (*init_ctx)(Authctxt*); 112 int (*query)(void *ctx, char **name, char **infotxt, 113 u_int *numprompts, char ***prompts, u_int **echo_on); 114 int (*respond)(void *ctx, u_int numresp, char **responses); 115 void (*free_ctx)(void *ctx); 116 }; 117 118 int 119 auth_rhosts2(struct passwd *, const char *, const char *, const char *); 120 121 int auth_password(Authctxt *, const char *); 122 123 int hostbased_key_allowed(struct passwd *, const char *, char *, 124 struct sshkey *); 125 int user_key_allowed(struct passwd *, struct sshkey *, int); 126 int auth2_key_already_used(Authctxt *, const struct sshkey *); 127 128 /* 129 * Handling auth method-specific information for logging and prevention 130 * of key reuse during multiple authentication. 131 */ 132 void auth2_authctxt_reset_info(Authctxt *); 133 void auth2_record_key(Authctxt *, int, const struct sshkey *); 134 void auth2_record_info(Authctxt *authctxt, const char *, ...) 135 __attribute__((__format__ (printf, 2, 3))) 136 __attribute__((__nonnull__ (2))); 137 void auth2_update_session_info(Authctxt *, const char *, const char *); 138 139 #ifdef KRB5 140 int auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *); 141 int auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt); 142 int auth_krb5_password(Authctxt *authctxt, const char *password); 143 void krb5_cleanup_proc(Authctxt *authctxt); 144 #endif /* KRB5 */ 145 146 void do_authentication2(Authctxt *); 147 148 void auth_log(Authctxt *, int, int, const char *, const char *); 149 void auth_maxtries_exceeded(Authctxt *) __attribute__((noreturn)); 150 void userauth_finish(struct ssh *, int, const char *, const char *); 151 int auth_root_allowed(const char *); 152 153 char *auth2_read_banner(void); 154 int auth2_methods_valid(const char *, int); 155 int auth2_update_methods_lists(Authctxt *, const char *, const char *); 156 int auth2_setup_methods_lists(Authctxt *); 157 int auth2_method_allowed(Authctxt *, const char *, const char *); 158 159 void privsep_challenge_enable(void); 160 161 int auth2_challenge(struct ssh *, char *); 162 void auth2_challenge_stop(struct ssh *); 163 int bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **); 164 int bsdauth_respond(void *, u_int, char **); 165 166 int allowed_user(struct passwd *); 167 struct passwd * getpwnamallow(const char *user); 168 169 char *expand_authorized_keys(const char *, struct passwd *pw); 170 char *authorized_principals_file(struct passwd *); 171 172 FILE *auth_openkeyfile(const char *, struct passwd *, int); 173 FILE *auth_openprincipals(const char *, struct passwd *, int); 174 int auth_key_is_revoked(struct sshkey *); 175 176 const char *auth_get_canonical_hostname(struct ssh *, int); 177 178 HostStatus 179 check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *, 180 const char *, const char *); 181 182 /* hostkey handling */ 183 struct sshkey *get_hostkey_by_index(int); 184 struct sshkey *get_hostkey_public_by_index(int, struct ssh *); 185 struct sshkey *get_hostkey_public_by_type(int, int, struct ssh *); 186 struct sshkey *get_hostkey_private_by_type(int, int, struct ssh *); 187 int get_hostkey_index(struct sshkey *, int, struct ssh *); 188 int sshd_hostkey_sign(struct sshkey *, struct sshkey *, u_char **, 189 size_t *, const u_char *, size_t, const char *, u_int); 190 191 /* debug messages during authentication */ 192 void auth_debug_add(const char *fmt,...) __attribute__((format(printf, 1, 2))); 193 void auth_debug_send(void); 194 void auth_debug_reset(void); 195 196 struct passwd *fakepw(void); 197 198 #endif 199