1 /* 2 * Kerberos v5 authentication and ticket-passing routines. 3 * 4 * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $ 5 * $OpenBSD: auth-krb5.c,v 1.1 2001/06/26 16:15:23 dugsong Exp $ 6 */ 7 8 #include "includes.h" 9 #include "ssh.h" 10 #include "ssh1.h" 11 #include "packet.h" 12 #include "xmalloc.h" 13 #include "log.h" 14 #include "servconf.h" 15 #include "uidswap.h" 16 #include "auth.h" 17 18 #ifdef KRB5 19 #include <krb5.h> 20 21 extern ServerOptions options; 22 23 static int 24 krb5_init(void *context) 25 { 26 Authctxt *authctxt = (Authctxt *)context; 27 krb5_error_code problem; 28 static int cleanup_registered = 0; 29 30 if (authctxt->krb5_ctx == NULL) { 31 problem = krb5_init_context(&authctxt->krb5_ctx); 32 if (problem) 33 return (problem); 34 krb5_init_ets(authctxt->krb5_ctx); 35 } 36 if (!cleanup_registered) { 37 fatal_add_cleanup(krb5_cleanup_proc, authctxt); 38 cleanup_registered = 1; 39 } 40 return (0); 41 } 42 43 /* 44 * Try krb5 authentication. server_user is passed for logging purposes 45 * only, in auth is received ticket, in client is returned principal 46 * from the ticket 47 */ 48 int 49 auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client) 50 { 51 krb5_error_code problem; 52 krb5_principal server; 53 krb5_data reply; 54 krb5_ticket *ticket; 55 int fd; 56 57 server = NULL; 58 ticket = NULL; 59 reply.length = 0; 60 61 problem = krb5_init(authctxt); 62 if (problem) 63 goto err; 64 65 problem = krb5_auth_con_init(authctxt->krb5_ctx, 66 &authctxt->krb5_auth_ctx); 67 if (problem) 68 goto err; 69 70 fd = packet_get_connection_in(); 71 problem = krb5_auth_con_setaddrs_from_fd(authctxt->krb5_ctx, 72 authctxt->krb5_auth_ctx, &fd); 73 if (problem) 74 goto err; 75 76 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL , 77 KRB5_NT_SRV_HST, &server); 78 if (problem) 79 goto err; 80 81 problem = krb5_rd_req(authctxt->krb5_ctx, &authctxt->krb5_auth_ctx, 82 auth, server, NULL, NULL, &ticket); 83 if (problem) 84 goto err; 85 86 problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->client, 87 &authctxt->krb5_user); 88 if (problem) 89 goto err; 90 91 /* if client wants mutual auth */ 92 problem = krb5_mk_rep(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, 93 &reply); 94 if (problem) 95 goto err; 96 97 /* Check .k5login authorization now. */ 98 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, 99 authctxt->pw->pw_name)) 100 goto err; 101 102 if (client) 103 krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user, 104 client); 105 106 packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE); 107 packet_put_string((char *) reply.data, reply.length); 108 packet_send(); 109 packet_write_wait(); 110 111 err: 112 if (server) 113 krb5_free_principal(authctxt->krb5_ctx, server); 114 if (ticket) 115 krb5_free_ticket(authctxt->krb5_ctx, ticket); 116 if (reply.length) 117 xfree(reply.data); 118 119 if (problem) { 120 debug("Kerberos v5 authentication failed: %s", 121 krb5_get_err_text(authctxt->krb5_ctx, problem)); 122 return (0); 123 } 124 return (1); 125 } 126 127 int 128 auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt) 129 { 130 krb5_error_code problem; 131 krb5_ccache ccache = NULL; 132 char *pname; 133 134 if (authctxt->pw == NULL || authctxt->krb5_user == NULL) 135 return (0); 136 137 temporarily_use_uid(authctxt->pw); 138 139 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, &ccache); 140 if (problem) 141 goto fail; 142 143 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, 144 authctxt->krb5_user); 145 if (problem) 146 goto fail; 147 148 problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, 149 ccache, tgt); 150 if (problem) 151 goto fail; 152 153 authctxt->krb5_fwd_ccache = ccache; 154 ccache = NULL; 155 156 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 157 158 problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user, 159 &pname); 160 if (problem) 161 goto fail; 162 163 debug("Kerberos v5 TGT accepted (%s)", pname); 164 165 restore_uid(); 166 167 return (1); 168 169 fail: 170 if (problem) 171 debug("Kerberos v5 TGT passing failed: %s", 172 krb5_get_err_text(authctxt->krb5_ctx, problem)); 173 if (ccache) 174 krb5_cc_destroy(authctxt->krb5_ctx, ccache); 175 176 restore_uid(); 177 178 return (0); 179 } 180 181 int 182 auth_krb5_password(Authctxt *authctxt, const char *password) 183 { 184 krb5_error_code problem; 185 186 if (authctxt->pw == NULL) 187 return (0); 188 189 temporarily_use_uid(authctxt->pw); 190 191 problem = krb5_init(authctxt); 192 if (problem) 193 goto out; 194 195 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, 196 &authctxt->krb5_user); 197 if (problem) 198 goto out; 199 200 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, 201 &authctxt->krb5_fwd_ccache); 202 if (problem) 203 goto out; 204 205 problem = krb5_cc_initialize(authctxt->krb5_ctx, 206 authctxt->krb5_fwd_ccache, authctxt->krb5_user); 207 if (problem) 208 goto out; 209 210 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, 211 authctxt->krb5_fwd_ccache, password, 1, NULL); 212 if (problem) 213 goto out; 214 215 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 216 217 out: 218 restore_uid(); 219 220 if (problem) { 221 debug("Kerberos password authentication failed: %s", 222 krb5_get_err_text(authctxt->krb5_ctx, problem)); 223 224 krb5_cleanup_proc(authctxt); 225 226 if (options.kerberos_or_local_passwd) 227 return (-1); 228 else 229 return (0); 230 } 231 return (1); 232 } 233 234 void 235 krb5_cleanup_proc(void *context) 236 { 237 Authctxt *authctxt = (Authctxt *)context; 238 239 debug("krb5_cleanup_proc called"); 240 if (authctxt->krb5_fwd_ccache) { 241 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); 242 authctxt->krb5_fwd_ccache = NULL; 243 } 244 if (authctxt->krb5_user) { 245 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); 246 authctxt->krb5_user = NULL; 247 } 248 if (authctxt->krb5_auth_ctx) { 249 krb5_auth_con_free(authctxt->krb5_ctx, 250 authctxt->krb5_auth_ctx); 251 authctxt->krb5_auth_ctx = NULL; 252 } 253 if (authctxt->krb5_ctx) { 254 krb5_free_context(authctxt->krb5_ctx); 255 authctxt->krb5_ctx = NULL; 256 } 257 } 258 259 #endif /* KRB5 */ 260