openssh/auth-krb5.c

   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 1.2 2001/11/12 01:47:09 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 #ifndef HEIMDAL
  21 #define krb5_get_err_text(context,code) error_message(code)
  22 #endif /* !HEIMDAL */
  23
  24 extern ServerOptions     options;
  25
  26 static int
  27 krb5_init(void *context)
  28 {
  29         Authctxt *authctxt = (Authctxt *)context;
  30         krb5_error_code problem;
  31         static int cleanup_registered = 0;
  32
  33         if (authctxt->krb5_ctx == NULL) {
  34                 problem = krb5_init_context(&authctxt->krb5_ctx);
  35                 if (problem)
  36                         return (problem);
  37                 krb5_init_ets(authctxt->krb5_ctx);
  38         }
  39         if (!cleanup_registered) {
  40                 fatal_add_cleanup(krb5_cleanup_proc, authctxt);
  41                 cleanup_registered = 1;
  42         }
  43         return (0);
  44 }
  45
  46 /*
  47  * Try krb5 authentication. server_user is passed for logging purposes
  48  * only, in auth is received ticket, in client is returned principal
  49  * from the ticket
  50  */
  51 int
  52 auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client)
  53 {
  54         krb5_error_code problem;
  55         krb5_principal server;
  56         krb5_data reply;
  57         krb5_ticket *ticket;
  58         int fd, ret;
  59
  60         ret = 0;
  61         server = NULL;
  62         ticket = NULL;
  63         reply.length = 0;
  64
  65         problem = krb5_init(authctxt);
  66         if (problem)
  67                 goto err;
  68
  69         problem = krb5_auth_con_init(authctxt->krb5_ctx,
  70             &authctxt->krb5_auth_ctx);
  71         if (problem)
  72                 goto err;
  73
  74         fd = packet_get_connection_in();
  75 #ifdef HEIMDAL
  76         problem = krb5_auth_con_setaddrs_from_fd(authctxt->krb5_ctx,
  77             authctxt->krb5_auth_ctx, &fd);
  78 #else
  79         problem = krb5_auth_con_genaddrs(authctxt->krb5_ctx,
  80             authctxt->krb5_auth_ctx,fd,
  81             KRB5_AUTH_CONTEXT_GENERATE_REMOTE_FULL_ADDR |
  82             KRB5_AUTH_CONTEXT_GENERATE_LOCAL_FULL_ADDR);
  83 #endif
  84         if (problem)
  85                 goto err;
  86
  87         problem = krb5_sname_to_principal(authctxt->krb5_ctx,  NULL, NULL ,
  88             KRB5_NT_SRV_HST, &server);
  89         if (problem)
  90                 goto err;
  91
  92         problem = krb5_rd_req(authctxt->krb5_ctx, &authctxt->krb5_auth_ctx,
  93             auth, server, NULL, NULL, &ticket);
  94         if (problem)
  95                 goto err;
  96
  97 #ifdef HEIMDAL
  98         problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->client,
  99             &authctxt->krb5_user);
 100 #else
 101         problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->enc_part2->client,
 102             &authctxt->krb5_user);
 103 #endif
 104         if (problem)
 105                 goto err;
 106
 107         /* if client wants mutual auth */
 108         problem = krb5_mk_rep(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
 109             &reply);
 110         if (problem)
 111                 goto err;
 112
 113         /* Check .k5login authorization now. */
 114         if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
 115             authctxt->pw->pw_name))
 116                 goto err;
 117
 118         if (client)
 119                 krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
 120                     client);
 121
 122         packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE);
 123         packet_put_string((char *) reply.data, reply.length);
 124         packet_send();
 125         packet_write_wait();
 126
 127         ret = 1;
 128  err:
 129         if (server)
 130                 krb5_free_principal(authctxt->krb5_ctx, server);
 131         if (ticket)
 132                 krb5_free_ticket(authctxt->krb5_ctx, ticket);
 133         if (reply.length)
 134                 xfree(reply.data);
 135
 136         if (problem)
 137                 debug("Kerberos v5 authentication failed: %s",
 138                     krb5_get_err_text(authctxt->krb5_ctx, problem));
 139
 140         return (ret);
 141 }
 142
 143 int
 144 auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt)
 145 {
 146         krb5_error_code problem;
 147         krb5_ccache ccache = NULL;
 148         char *pname;
 149         krb5_creds **creds;
 150
 151         if (authctxt->pw == NULL || authctxt->krb5_user == NULL)
 152                 return (0);
 153
 154         temporarily_use_uid(authctxt->pw);
 155
 156 #ifdef HEIMDAL
 157         problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, &ccache);
 158 #else
 159 {
 160         char ccname[35];
 161
 162         snprintf(ccname, sizeof(ccname), "FILE:/tmp/krb5cc_%d", authctxt->pw->pw_uid);
 163         problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &ccache);
 164 }
 165 #endif
 166         if (problem)
 167                 goto fail;
 168
 169         problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
 170             authctxt->krb5_user);
 171         if (problem)
 172                 goto fail;
 173
 174 #ifdef HEIMDAL
 175         problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
 176             ccache, tgt);
 177         if (problem)
 178                 goto fail;
 179 #else
 180         problem = krb5_rd_cred(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
 181             tgt, &creds, NULL);
 182         if (problem)
 183                 goto fail;
 184         problem = krb5_cc_store_cred(authctxt->krb5_ctx, ccache, *creds);
 185         if (problem)
 186                 goto fail;
 187 #endif
 188
 189         authctxt->krb5_fwd_ccache = ccache;
 190         ccache = NULL;
 191
 192         authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
 193
 194         problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
 195             &pname);
 196         if (problem)
 197                 goto fail;
 198
 199         debug("Kerberos v5 TGT accepted (%s)", pname);
 200
 201         restore_uid();
 202
 203         return (1);
 204
 205  fail:
 206         if (problem)
 207                 debug("Kerberos v5 TGT passing failed: %s",
 208                     krb5_get_err_text(authctxt->krb5_ctx, problem));
 209         if (ccache)
 210                 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
 211
 212         restore_uid();
 213
 214         return (0);
 215 }
 216
 217 int
 218 auth_krb5_password(Authctxt *authctxt, const char *password)
 219 {
 220 #ifndef HEIMDAL
 221         krb5_creds creds;
 222         krb5_principal server;
 223 #endif
 224         krb5_error_code problem;
 225
 226         if (authctxt->pw == NULL)
 227                 return (0);
 228
 229         temporarily_use_uid(authctxt->pw);
 230
 231         problem = krb5_init(authctxt);
 232         if (problem)
 233                 goto out;
 234
 235         problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
 236                     &authctxt->krb5_user);
 237         if (problem)
 238                 goto out;
 239
 240 #ifdef HEIMDAL
 241         problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops,
 242             &authctxt->krb5_fwd_ccache);
 243 #else
 244         problem = krb5_cc_resolve(authctxt->krb5_ctx, "MEMORY:",
 245             &authctxt->krb5_fwd_ccache);
 246 #endif
 247         if (problem)
 248                 goto out;
 249
 250         problem = krb5_cc_initialize(authctxt->krb5_ctx,
 251             authctxt->krb5_fwd_ccache, authctxt->krb5_user);
 252         if (problem)
 253                 goto out;
 254
 255 #ifdef HEIMDAL
 256         problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
 257             authctxt->krb5_fwd_ccache, password, 1, NULL);
 258         if (problem)
 259                 goto out;
 260
 261 #else
 262         problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
 263             authctxt->krb5_user, password, NULL, NULL, 0, NULL, NULL);
 264         if (problem)
 265                 goto out;
 266
 267         problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
 268             KRB5_NT_SRV_HST, &server);
 269         if (problem)
 270                 goto out;
 271
 272         restore_uid();
 273         problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, NULL, NULL,
 274             NULL);
 275         temporarily_use_uid(authctxt->pw);
 276
 277         krb5_free_principal(authctxt->krb5_ctx, server);
 278         if (problem)
 279                 goto out;
 280
 281         problem = krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, &creds);
 282         if (problem)
 283                 goto out;
 284
 285 #endif /* HEIMDAL */
 286
 287         authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
 288
 289  out:
 290         restore_uid();
 291
 292         if (problem) {
 293                 debug("Kerberos password authentication failed: %s",
 294                     krb5_get_err_text(authctxt->krb5_ctx, problem));
 295
 296                 krb5_cleanup_proc(authctxt);
 297
 298                 if (options.kerberos_or_local_passwd)
 299                         return (-1);
 300                 else
 301                         return (0);
 302         }
 303         return (1);
 304 }
 305
 306 void
 307 krb5_cleanup_proc(void *context)
 308 {
 309         Authctxt *authctxt = (Authctxt *)context;
 310
 311         debug("krb5_cleanup_proc called");
 312         if (authctxt->krb5_fwd_ccache) {
 313                 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
 314                 authctxt->krb5_fwd_ccache = NULL;
 315         }
 316         if (authctxt->krb5_user) {
 317                 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
 318                 authctxt->krb5_user = NULL;
 319         }
 320         if (authctxt->krb5_auth_ctx) {
 321                 krb5_auth_con_free(authctxt->krb5_ctx,
 322                     authctxt->krb5_auth_ctx);
 323                 authctxt->krb5_auth_ctx = NULL;
 324         }
 325         if (authctxt->krb5_ctx) {
 326                 krb5_free_context(authctxt->krb5_ctx);
 327                 authctxt->krb5_ctx = NULL;
 328         }
 329 }
 330
 331 #endif /* KRB5 */