Damien Miller | 964fed5 | 2001-09-25 12:58:23 +1000 | [diff] [blame^] | 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 */ |