1 /* $OpenBSD: auth.h,v 1.96 2018/04/10 00:10:49 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 #ifdef HAVE_LOGIN_CAP 36 #include <login_cap.h> 37 #endif 38 #ifdef BSD_AUTH 39 #include <bsd_auth.h> 40 #endif 41 #ifdef KRB5 42 #include <krb5.h> 43 #endif 44 45 struct passwd; 46 struct ssh; 47 struct sshbuf; 48 struct sshkey; 49 struct sshauthopt; 50 51 typedef struct Authctxt Authctxt; 52 typedef struct Authmethod Authmethod; 53 typedef struct KbdintDevice KbdintDevice; 54 55 struct Authctxt { 56 sig_atomic_t success; 57 int authenticated; /* authenticated and alarms cancelled */ 58 int postponed; /* authentication needs another step */ 59 int valid; /* user exists and is allowed to login */ 60 int attempt; 61 int failures; 62 int server_caused_failure; 63 int force_pwchange; 64 char *user; /* username sent by the client */ 65 char *service; 66 struct passwd *pw; /* set if 'valid' */ 67 char *style; 68 69 /* Method lists for multiple authentication */ 70 char **auth_methods; /* modified from server config */ 71 u_int num_auth_methods; 72 73 /* Authentication method-specific data */ 74 void *methoddata; 75 void *kbdintctxt; 76 #ifdef BSD_AUTH 77 auth_session_t *as; 78 #endif 79 #ifdef KRB5 80 krb5_context krb5_ctx; 81 krb5_ccache krb5_fwd_ccache; 82 krb5_principal krb5_user; 83 char *krb5_ticket_file; 84 char *krb5_ccname; 85 #endif 86 struct sshbuf *loginmsg; 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 struct Authmethod { 108 char *name; 109 int (*userauth)(struct ssh *); 110 int *enabled; 111 }; 112 113 /* 114 * Keyboard interactive device: 115 * init_ctx returns: non NULL upon success 116 * query returns: 0 - success, otherwise failure 117 * respond returns: 0 - success, 1 - need further interaction, 118 * otherwise - failure 119 */ 120 struct KbdintDevice 121 { 122 const char *name; 123 void* (*init_ctx)(Authctxt*); 124 int (*query)(void *ctx, char **name, char **infotxt, 125 u_int *numprompts, char ***prompts, u_int **echo_on); 126 int (*respond)(void *ctx, u_int numresp, char **responses); 127 void (*free_ctx)(void *ctx); 128 }; 129 130 int 131 auth_rhosts2(struct passwd *, const char *, const char *, const char *); 132 133 int auth_password(struct ssh *, const char *); 134 135 int hostbased_key_allowed(struct passwd *, const char *, char *, 136 struct sshkey *); 137 int user_key_allowed(struct ssh *, struct passwd *, struct sshkey *, int, 138 struct sshauthopt **); 139 int auth2_key_already_used(Authctxt *, const struct sshkey *); 140 141 /* 142 * Handling auth method-specific information for logging and prevention 143 * of key reuse during multiple authentication. 144 */ 145 void auth2_authctxt_reset_info(Authctxt *); 146 void auth2_record_key(Authctxt *, int, const struct sshkey *); 147 void auth2_record_info(Authctxt *authctxt, const char *, ...) 148 __attribute__((__format__ (printf, 2, 3))) 149 __attribute__((__nonnull__ (2))); 150 void auth2_update_session_info(Authctxt *, const char *, const char *); 151 152 #ifdef KRB5 153 int auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *); 154 int auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt); 155 int auth_krb5_password(Authctxt *authctxt, const char *password); 156 void krb5_cleanup_proc(Authctxt *authctxt); 157 #endif /* KRB5 */ 158 159 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) 160 #include <shadow.h> 161 int auth_shadow_acctexpired(struct spwd *); 162 int auth_shadow_pwexpired(Authctxt *); 163 #endif 164 165 #include "auth-pam.h" 166 #include "audit.h" 167 void remove_kbdint_device(const char *); 168 169 void do_authentication2(Authctxt *); 170 171 void auth_log(Authctxt *, int, int, const char *, const char *); 172 void auth_maxtries_exceeded(Authctxt *) __attribute__((noreturn)); 173 void userauth_finish(struct ssh *, int, const char *, const char *); 174 int auth_root_allowed(struct ssh *, const char *); 175 176 void userauth_send_banner(const char *); 177 178 char *auth2_read_banner(void); 179 int auth2_methods_valid(const char *, int); 180 int auth2_update_methods_lists(Authctxt *, const char *, const char *); 181 int auth2_setup_methods_lists(Authctxt *); 182 int auth2_method_allowed(Authctxt *, const char *, const char *); 183 184 void privsep_challenge_enable(void); 185 186 int auth2_challenge(struct ssh *, char *); 187 void auth2_challenge_stop(struct ssh *); 188 int bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **); 189 int bsdauth_respond(void *, u_int, char **); 190 191 int allowed_user(struct passwd *); 192 struct passwd * getpwnamallow(const char *user); 193 194 char *expand_authorized_keys(const char *, struct passwd *pw); 195 char *authorized_principals_file(struct passwd *); 196 197 FILE *auth_openkeyfile(const char *, struct passwd *, int); 198 FILE *auth_openprincipals(const char *, struct passwd *, int); 199 int auth_key_is_revoked(struct sshkey *); 200 201 const char *auth_get_canonical_hostname(struct ssh *, int); 202 203 HostStatus 204 check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *, 205 const char *, const char *); 206 207 /* hostkey handling */ 208 struct sshkey *get_hostkey_by_index(int); 209 struct sshkey *get_hostkey_public_by_index(int, struct ssh *); 210 struct sshkey *get_hostkey_public_by_type(int, int, struct ssh *); 211 struct sshkey *get_hostkey_private_by_type(int, int, struct ssh *); 212 int get_hostkey_index(struct sshkey *, int, struct ssh *); 213 int sshd_hostkey_sign(struct sshkey *, struct sshkey *, u_char **, 214 size_t *, const u_char *, size_t, const char *, u_int); 215 216 /* Key / cert options linkage to auth layer */ 217 const struct sshauthopt *auth_options(struct ssh *); 218 int auth_activate_options(struct ssh *, struct sshauthopt *); 219 void auth_restrict_session(struct ssh *); 220 int auth_authorise_keyopts(struct ssh *, struct passwd *pw, 221 struct sshauthopt *, int, const char *); 222 void auth_log_authopts(const char *, const struct sshauthopt *, int); 223 224 /* debug messages during authentication */ 225 void auth_debug_add(const char *fmt,...) 226 __attribute__((format(printf, 1, 2))); 227 void auth_debug_send(void); 228 void auth_debug_reset(void); 229 230 struct passwd *fakepw(void); 231 232 #define SSH_SUBPROCESS_STDOUT_DISCARD (1) /* Discard stdout */ 233 #define SSH_SUBPROCESS_STDOUT_CAPTURE (1<<1) /* Redirect stdout */ 234 #define SSH_SUBPROCESS_STDERR_DISCARD (1<<2) /* Discard stderr */ 235 pid_t subprocess(const char *, struct passwd *, 236 const char *, int, char **, FILE **, u_int flags); 237 238 int sys_auth_passwd(struct ssh *, const char *); 239 240 #if defined(KRB5) && !defined(HEIMDAL) 241 #include <krb5.h> 242 krb5_error_code ssh_krb5_cc_gen(krb5_context, krb5_ccache *); 243 #endif 244 #endif 245