1 /* $OpenBSD: auth.h,v 1.88 2016/05/04 14:04:40 markus 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 void *kbdintctxt; 61 char *info; /* Extra info for next auth_log */ 62 auth_session_t *as; 63 char **auth_methods; /* modified from server config */ 64 u_int num_auth_methods; 65 #ifdef KRB5 66 krb5_context krb5_ctx; 67 krb5_ccache krb5_fwd_ccache; 68 krb5_principal krb5_user; 69 char *krb5_ticket_file; 70 #endif 71 void *methoddata; 72 73 struct sshkey **prev_userkeys; 74 u_int nprev_userkeys; 75 }; 76 /* 77 * Every authentication method has to handle authentication requests for 78 * non-existing users, or for users that are not allowed to login. In this 79 * case 'valid' is set to 0, but 'user' points to the username requested by 80 * the client. 81 */ 82 83 struct Authmethod { 84 char *name; 85 int (*userauth)(Authctxt *authctxt); 86 int *enabled; 87 }; 88 89 /* 90 * Keyboard interactive device: 91 * init_ctx returns: non NULL upon success 92 * query returns: 0 - success, otherwise failure 93 * respond returns: 0 - success, 1 - need further interaction, 94 * otherwise - failure 95 */ 96 struct KbdintDevice 97 { 98 const char *name; 99 void* (*init_ctx)(Authctxt*); 100 int (*query)(void *ctx, char **name, char **infotxt, 101 u_int *numprompts, char ***prompts, u_int **echo_on); 102 int (*respond)(void *ctx, u_int numresp, char **responses); 103 void (*free_ctx)(void *ctx); 104 }; 105 106 int auth_rhosts(struct passwd *, const char *); 107 int 108 auth_rhosts2(struct passwd *, const char *, const char *, const char *); 109 110 int auth_rhosts_rsa(Authctxt *, char *, Key *); 111 int auth_password(Authctxt *, const char *); 112 int auth_rsa(Authctxt *, BIGNUM *); 113 int auth_rsa_challenge_dialog(Key *); 114 BIGNUM *auth_rsa_generate_challenge(Key *); 115 int auth_rsa_verify_response(Key *, BIGNUM *, u_char[]); 116 int auth_rsa_key_allowed(struct passwd *, BIGNUM *, Key **); 117 118 int auth_rhosts_rsa_key_allowed(struct passwd *, const char *, 119 const char *, Key *); 120 int hostbased_key_allowed(struct passwd *, const char *, char *, Key *); 121 int user_key_allowed(struct passwd *, Key *, int); 122 void pubkey_auth_info(Authctxt *, const Key *, const char *, ...) 123 __attribute__((__format__ (printf, 3, 4))); 124 void auth2_record_userkey(Authctxt *, struct sshkey *); 125 int auth2_userkey_already_used(Authctxt *, struct sshkey *); 126 127 struct stat; 128 int auth_secure_path(const char *, struct stat *, const char *, uid_t, 129 char *, size_t); 130 131 #ifdef KRB5 132 int auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *); 133 int auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt); 134 int auth_krb5_password(Authctxt *authctxt, const char *password); 135 void krb5_cleanup_proc(Authctxt *authctxt); 136 #endif /* KRB5 */ 137 138 void do_authentication(Authctxt *); 139 void do_authentication2(Authctxt *); 140 141 void auth_info(Authctxt *authctxt, const char *, ...) 142 __attribute__((__format__ (printf, 2, 3))) 143 __attribute__((__nonnull__ (2))); 144 void auth_log(Authctxt *, int, int, const char *, const char *); 145 void auth_maxtries_exceeded(Authctxt *) __attribute__((noreturn)); 146 void userauth_finish(Authctxt *, int, const char *, const char *); 147 int auth_root_allowed(const char *); 148 149 char *auth2_read_banner(void); 150 int auth2_methods_valid(const char *, int); 151 int auth2_update_methods_lists(Authctxt *, const char *, const char *); 152 int auth2_setup_methods_lists(Authctxt *); 153 int auth2_method_allowed(Authctxt *, const char *, const char *); 154 155 void privsep_challenge_enable(void); 156 157 int auth2_challenge(Authctxt *, char *); 158 void auth2_challenge_stop(Authctxt *); 159 int bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **); 160 int bsdauth_respond(void *, u_int, char **); 161 162 int allowed_user(struct passwd *); 163 struct passwd * getpwnamallow(const char *user); 164 165 char *get_challenge(Authctxt *); 166 int verify_response(Authctxt *, const char *); 167 168 char *expand_authorized_keys(const char *, struct passwd *pw); 169 char *authorized_principals_file(struct passwd *); 170 171 FILE *auth_openkeyfile(const char *, struct passwd *, int); 172 FILE *auth_openprincipals(const char *, struct passwd *, int); 173 int auth_key_is_revoked(Key *); 174 175 const char *auth_get_canonical_hostname(struct ssh *, int); 176 177 HostStatus 178 check_key_in_hostfiles(struct passwd *, Key *, const char *, 179 const char *, const char *); 180 181 /* hostkey handling */ 182 Key *get_hostkey_by_index(int); 183 Key *get_hostkey_public_by_index(int, struct ssh *); 184 Key *get_hostkey_public_by_type(int, int, struct ssh *); 185 Key *get_hostkey_private_by_type(int, int, struct ssh *); 186 int get_hostkey_index(Key *, int, struct ssh *); 187 int ssh1_session_key(BIGNUM *); 188 int sshd_hostkey_sign(Key *, Key *, u_char **, size_t *, 189 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