Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 3 | * All rights reserved |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 4 | * |
| 5 | * As far as I am concerned, the code I have written for this software |
| 6 | * can be used freely for any purpose. Any derived versions of this |
| 7 | * software must be clearly marked as such, and if the derived work is |
| 8 | * incompatible with the protocol description in the RFC file, it must be |
| 9 | * called by a name other than "ssh" or "Secure Shell". |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 10 | */ |
| 11 | |
| 12 | #include "includes.h" |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 13 | RCSID("$OpenBSD: auth1.c,v 1.11 2001/01/18 16:59:59 markus Exp $"); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 14 | |
Damien Miller | b8c656e | 2000-06-28 15:22:41 +1000 | [diff] [blame] | 15 | #ifdef HAVE_OSF_SIA |
| 16 | # include <sia.h> |
| 17 | # include <siad.h> |
| 18 | #endif |
| 19 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 20 | #include "xmalloc.h" |
| 21 | #include "rsa.h" |
| 22 | #include "ssh.h" |
| 23 | #include "packet.h" |
| 24 | #include "buffer.h" |
| 25 | #include "mpaux.h" |
| 26 | #include "servconf.h" |
| 27 | #include "compat.h" |
| 28 | #include "auth.h" |
| 29 | #include "session.h" |
| 30 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 31 | /* import */ |
| 32 | extern ServerOptions options; |
| 33 | extern char *forced_command; |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 34 | |
| 35 | #ifdef WITH_AIXAUTHENTICATE |
| 36 | extern char *aixloginmsg; |
| 37 | #endif /* WITH_AIXAUTHENTICATE */ |
Damien Miller | fe668e4 | 2000-07-08 10:44:13 +1000 | [diff] [blame] | 38 | #ifdef HAVE_OSF_SIA |
| 39 | extern int saved_argc; |
| 40 | extern char **saved_argv; |
| 41 | #endif /* HAVE_OSF_SIA */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 42 | |
| 43 | /* |
| 44 | * convert ssh auth msg type into description |
| 45 | */ |
| 46 | char * |
| 47 | get_authname(int type) |
| 48 | { |
| 49 | static char buf[1024]; |
| 50 | switch (type) { |
| 51 | case SSH_CMSG_AUTH_PASSWORD: |
| 52 | return "password"; |
| 53 | case SSH_CMSG_AUTH_RSA: |
| 54 | return "rsa"; |
| 55 | case SSH_CMSG_AUTH_RHOSTS_RSA: |
| 56 | return "rhosts-rsa"; |
| 57 | case SSH_CMSG_AUTH_RHOSTS: |
| 58 | return "rhosts"; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 59 | case SSH_CMSG_AUTH_TIS: |
| 60 | case SSH_CMSG_AUTH_TIS_RESPONSE: |
| 61 | return "challenge-response"; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 62 | #ifdef KRB4 |
| 63 | case SSH_CMSG_AUTH_KERBEROS: |
| 64 | return "kerberos"; |
| 65 | #endif |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 66 | } |
| 67 | snprintf(buf, sizeof buf, "bad-auth-msg-%d", type); |
| 68 | return buf; |
| 69 | } |
| 70 | |
| 71 | /* |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 72 | * read packets, try to authenticate the user and |
| 73 | * return only if authentication is successful |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 74 | */ |
| 75 | void |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 76 | do_authloop(Authctxt *authctxt) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 77 | { |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 78 | int authenticated = 0; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 79 | u_int bits; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 80 | RSA *client_host_key; |
| 81 | BIGNUM *n; |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 82 | char *client_user, *password; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 83 | char info[1024]; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 84 | u_int dlen; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 85 | int plen, nlen, elen; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 86 | u_int ulen; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 87 | int type = 0; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 88 | struct passwd *pw = authctxt->pw; |
| 89 | |
| 90 | debug("Attempting authentication for %s%.100s.", |
| 91 | authctxt->valid ? "" : "illegal user ", authctxt->user); |
| 92 | |
| 93 | /* If the user has no password, accept authentication immediately. */ |
| 94 | if (options.password_authentication && |
| 95 | #ifdef KRB4 |
| 96 | (!options.kerberos_authentication || options.kerberos_or_local_passwd) && |
| 97 | #endif |
Ben Lindstrom | b100ec9 | 2001-01-19 05:37:32 +0000 | [diff] [blame^] | 98 | #ifdef USE_PAM |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 99 | auth_pam_password(pw, password)) { |
| 100 | #else |
| 101 | auth_password(pw, "")) { |
| 102 | #endif |
| 103 | auth_log(authctxt, 1, "without authentication", ""); |
| 104 | return; |
| 105 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 106 | |
| 107 | /* Indicate that authentication is needed. */ |
| 108 | packet_start(SSH_SMSG_FAILURE); |
| 109 | packet_send(); |
| 110 | packet_write_wait(); |
| 111 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 112 | client_user = NULL; |
| 113 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 114 | for (;;) { |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 115 | /* default to fail */ |
| 116 | authenticated = 0; |
| 117 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 118 | info[0] = '\0'; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 119 | |
| 120 | /* Get a packet from the client. */ |
| 121 | type = packet_read(&plen); |
| 122 | |
| 123 | /* Process the packet. */ |
| 124 | switch (type) { |
| 125 | #ifdef AFS |
| 126 | case SSH_CMSG_HAVE_KERBEROS_TGT: |
| 127 | if (!options.kerberos_tgt_passing) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 128 | verbose("Kerberos tgt passing disabled."); |
| 129 | break; |
| 130 | } else { |
| 131 | /* Accept Kerberos tgt. */ |
| 132 | char *tgt = packet_get_string(&dlen); |
| 133 | packet_integrity_check(plen, 4 + dlen, type); |
| 134 | if (!auth_kerberos_tgt(pw, tgt)) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 135 | verbose("Kerberos tgt REFUSED for %.100s", authctxt->user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 136 | xfree(tgt); |
| 137 | } |
| 138 | continue; |
| 139 | |
| 140 | case SSH_CMSG_HAVE_AFS_TOKEN: |
| 141 | if (!options.afs_token_passing || !k_hasafs()) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 142 | verbose("AFS token passing disabled."); |
| 143 | break; |
| 144 | } else { |
| 145 | /* Accept AFS token. */ |
| 146 | char *token_string = packet_get_string(&dlen); |
| 147 | packet_integrity_check(plen, 4 + dlen, type); |
| 148 | if (!auth_afs_token(pw, token_string)) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 149 | verbose("AFS token REFUSED for %.100s", authctxt->user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 150 | xfree(token_string); |
| 151 | } |
| 152 | continue; |
| 153 | #endif /* AFS */ |
| 154 | #ifdef KRB4 |
| 155 | case SSH_CMSG_AUTH_KERBEROS: |
| 156 | if (!options.kerberos_authentication) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 157 | verbose("Kerberos authentication disabled."); |
| 158 | break; |
| 159 | } else { |
| 160 | /* Try Kerberos v4 authentication. */ |
| 161 | KTEXT_ST auth; |
| 162 | char *tkt_user = NULL; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 163 | char *kdata = packet_get_string((u_int *) &auth.length); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 164 | packet_integrity_check(plen, 4 + auth.length, type); |
| 165 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 166 | if (authctxt->valid) { |
| 167 | if (auth.length < MAX_KTXT_LEN) |
| 168 | memcpy(auth.dat, kdata, auth.length); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 169 | authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); |
| 170 | if (authenticated) { |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 171 | snprintf(info, sizeof info, |
| 172 | " tktuser %.100s", tkt_user); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 173 | xfree(tkt_user); |
| 174 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 175 | } |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 176 | xfree(kdata); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 177 | } |
| 178 | break; |
| 179 | #endif /* KRB4 */ |
| 180 | |
| 181 | case SSH_CMSG_AUTH_RHOSTS: |
| 182 | if (!options.rhosts_authentication) { |
| 183 | verbose("Rhosts authentication disabled."); |
| 184 | break; |
| 185 | } |
| 186 | /* |
| 187 | * Get client user name. Note that we just have to |
| 188 | * trust the client; this is one reason why rhosts |
| 189 | * authentication is insecure. (Another is |
| 190 | * IP-spoofing on a local network.) |
| 191 | */ |
| 192 | client_user = packet_get_string(&ulen); |
| 193 | packet_integrity_check(plen, 4 + ulen, type); |
| 194 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 195 | /* Try to authenticate using /etc/hosts.equiv and .rhosts. */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 196 | authenticated = auth_rhosts(pw, client_user); |
| 197 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 198 | snprintf(info, sizeof info, " ruser %.100s", client_user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 199 | break; |
| 200 | |
| 201 | case SSH_CMSG_AUTH_RHOSTS_RSA: |
| 202 | if (!options.rhosts_rsa_authentication) { |
| 203 | verbose("Rhosts with RSA authentication disabled."); |
| 204 | break; |
| 205 | } |
| 206 | /* |
| 207 | * Get client user name. Note that we just have to |
| 208 | * trust the client; root on the client machine can |
| 209 | * claim to be any user. |
| 210 | */ |
| 211 | client_user = packet_get_string(&ulen); |
| 212 | |
| 213 | /* Get the client host key. */ |
| 214 | client_host_key = RSA_new(); |
| 215 | if (client_host_key == NULL) |
| 216 | fatal("RSA_new failed"); |
| 217 | client_host_key->e = BN_new(); |
| 218 | client_host_key->n = BN_new(); |
| 219 | if (client_host_key->e == NULL || client_host_key->n == NULL) |
| 220 | fatal("BN_new failed"); |
| 221 | bits = packet_get_int(); |
| 222 | packet_get_bignum(client_host_key->e, &elen); |
| 223 | packet_get_bignum(client_host_key->n, &nlen); |
| 224 | |
| 225 | if (bits != BN_num_bits(client_host_key->n)) |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 226 | verbose("Warning: keysize mismatch for client_host_key: " |
Damien Miller | bd483e7 | 2000-04-30 10:00:53 +1000 | [diff] [blame] | 227 | "actual %d, announced %d", BN_num_bits(client_host_key->n), bits); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 228 | packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); |
| 229 | |
| 230 | authenticated = auth_rhosts_rsa(pw, client_user, client_host_key); |
| 231 | RSA_free(client_host_key); |
| 232 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 233 | snprintf(info, sizeof info, " ruser %.100s", client_user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 234 | break; |
| 235 | |
| 236 | case SSH_CMSG_AUTH_RSA: |
| 237 | if (!options.rsa_authentication) { |
| 238 | verbose("RSA authentication disabled."); |
| 239 | break; |
| 240 | } |
| 241 | /* RSA authentication requested. */ |
| 242 | n = BN_new(); |
| 243 | packet_get_bignum(n, &nlen); |
| 244 | packet_integrity_check(plen, nlen, type); |
| 245 | authenticated = auth_rsa(pw, n); |
| 246 | BN_clear_free(n); |
| 247 | break; |
| 248 | |
| 249 | case SSH_CMSG_AUTH_PASSWORD: |
| 250 | if (!options.password_authentication) { |
| 251 | verbose("Password authentication disabled."); |
| 252 | break; |
| 253 | } |
| 254 | /* |
| 255 | * Read user password. It is in plain text, but was |
| 256 | * transmitted over the encrypted channel so it is |
| 257 | * not visible to an outside observer. |
| 258 | */ |
| 259 | password = packet_get_string(&dlen); |
| 260 | packet_integrity_check(plen, 4 + dlen, type); |
| 261 | |
| 262 | #ifdef USE_PAM |
| 263 | /* Do PAM auth with password */ |
| 264 | authenticated = auth_pam_password(pw, password); |
Damien Miller | b8c656e | 2000-06-28 15:22:41 +1000 | [diff] [blame] | 265 | #elif defined(HAVE_OSF_SIA) |
| 266 | /* Do SIA auth with password */ |
Damien Miller | b8c656e | 2000-06-28 15:22:41 +1000 | [diff] [blame] | 267 | if (sia_validate_user(NULL, saved_argc, saved_argv, |
| 268 | get_canonical_hostname(), pw->pw_name, NULL, 0, |
| 269 | NULL, password) == SIASUCCESS) { |
| 270 | authenticated = 1; |
| 271 | } |
| 272 | #else /* !USE_PAM && !HAVE_OSF_SIA */ |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 273 | /* Try authentication with the password. */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 274 | authenticated = auth_password(pw, password); |
| 275 | #endif /* USE_PAM */ |
| 276 | |
| 277 | memset(password, 0, strlen(password)); |
| 278 | xfree(password); |
| 279 | break; |
| 280 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 281 | #ifdef SKEY /* ISSUE: Is this right? we don't define |
| 282 | having skey_authentication in |
| 283 | servconf.h by default so I assume |
| 284 | we need to deal with this via #ifdef |
| 285 | in some reasonable way */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 286 | case SSH_CMSG_AUTH_TIS: |
| 287 | debug("rcvd SSH_CMSG_AUTH_TIS"); |
| 288 | if (options.skey_authentication == 1) { |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 289 | char *challenge = get_challenge(authctxt, authctxt->style); |
| 290 | if (challenge != NULL) { |
| 291 | debug("sending challenge '%s'", challenge); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 292 | packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 293 | packet_put_cstring(challenge); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 294 | packet_send(); |
| 295 | packet_write_wait(); |
| 296 | continue; |
| 297 | } |
| 298 | } |
| 299 | break; |
| 300 | case SSH_CMSG_AUTH_TIS_RESPONSE: |
| 301 | debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); |
| 302 | if (options.skey_authentication == 1) { |
| 303 | char *response = packet_get_string(&dlen); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 304 | debug("got response '%s'", response); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 305 | packet_integrity_check(plen, 4 + dlen, type); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 306 | authenticated = verify_response(authctxt, response); |
| 307 | memset(response, 'r', dlen); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 308 | xfree(response); |
| 309 | } |
| 310 | break; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 311 | #endif /* ISSUE: End of wrong SKEY defines */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 312 | |
| 313 | default: |
| 314 | /* |
| 315 | * Any unknown messages will be ignored (and failure |
| 316 | * returned) during authentication. |
| 317 | */ |
| 318 | log("Unknown message during authentication: type %d", type); |
| 319 | break; |
| 320 | } |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 321 | if (!authctxt->valid && authenticated) |
| 322 | fatal("INTERNAL ERROR: authenticated invalid user %s", |
| 323 | authctxt->user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 324 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 325 | #ifdef HAVE_CYGWIN /* ISSUE: Right place? */ |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 326 | if (authenticated && |
Damien Miller | b70b61f | 2000-09-16 16:25:12 +1100 | [diff] [blame] | 327 | !check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD,pw->pw_uid)) { |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 328 | packet_disconnect("Authentication rejected for uid %d.", |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 329 | (int)pw->pw_uid); |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 330 | authenticated = 0; |
| 331 | } |
| 332 | #endif |
| 333 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 334 | /* Special handling for root */ |
| 335 | if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed()) |
| 336 | authenticated = 0; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 337 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 338 | #ifdef USE_PAM /* ISSUE: Right place? */ |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 339 | if (authenticated && !do_pam_account(pw->pw_name, client_user)) |
| 340 | authenticated = 0; |
| 341 | #endif |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 342 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 343 | /* Log before sending the reply */ |
| 344 | auth_log(authctxt, authenticated, get_authname(type), info); |
| 345 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 346 | if (client_user != NULL) { |
| 347 | xfree(client_user); |
| 348 | client_user = NULL; |
| 349 | } |
| 350 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 351 | if (authenticated) |
| 352 | return; |
| 353 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 354 | if (authctxt->failures++ > AUTH_FAIL_MAX) { |
Damien Miller | d2c208a | 2000-05-17 22:00:02 +1000 | [diff] [blame] | 355 | #ifdef WITH_AIXAUTHENTICATE |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 356 | loginfailed(user,get_canonical_hostname(),"ssh"); |
Damien Miller | d2c208a | 2000-05-17 22:00:02 +1000 | [diff] [blame] | 357 | #endif /* WITH_AIXAUTHENTICATE */ |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 358 | packet_disconnect(AUTH_FAIL_MSG, authctxt->user); |
Damien Miller | d2c208a | 2000-05-17 22:00:02 +1000 | [diff] [blame] | 359 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 360 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 361 | packet_start(SSH_SMSG_FAILURE); |
| 362 | packet_send(); |
| 363 | packet_write_wait(); |
| 364 | } |
| 365 | } |
| 366 | |
| 367 | /* |
| 368 | * Performs authentication of an incoming connection. Session key has already |
| 369 | * been exchanged and encryption is enabled. |
| 370 | */ |
| 371 | void |
| 372 | do_authentication() |
| 373 | { |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 374 | Authctxt *authctxt; |
| 375 | struct passwd *pw; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 376 | int plen; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 377 | u_int ulen; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 378 | char *user, *style = NULL; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 379 | |
| 380 | /* Get the name of the user that we wish to log in as. */ |
| 381 | packet_read_expect(&plen, SSH_CMSG_USER); |
| 382 | |
| 383 | /* Get the user name. */ |
| 384 | user = packet_get_string(&ulen); |
| 385 | packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); |
| 386 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 387 | if ((style = strchr(user, ':')) != NULL) |
| 388 | *style++ = 0; |
| 389 | |
| 390 | authctxt = authctxt_new(); |
| 391 | authctxt->user = user; |
| 392 | authctxt->style = style; |
| 393 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 394 | setproctitle("%s", user); |
| 395 | |
| 396 | #ifdef AFS |
| 397 | /* If machine has AFS, set process authentication group. */ |
| 398 | if (k_hasafs()) { |
| 399 | k_setpag(); |
| 400 | k_unlog(); |
| 401 | } |
| 402 | #endif /* AFS */ |
| 403 | |
| 404 | /* Verify that the user is a valid user. */ |
| 405 | pw = getpwnam(user); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 406 | if (pw && allowed_user(pw)) { |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 407 | authctxt->valid = 1; |
| 408 | pw = pwcopy(pw); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 409 | } else { |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 410 | debug("do_authentication: illegal user %s", user); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 411 | pw = NULL; |
| 412 | } |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 413 | authctxt->pw = pw; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 414 | |
| 415 | #ifdef USE_PAM |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 416 | if (pw) |
Damien Miller | 22e22bf | 2001-01-19 15:46:38 +1100 | [diff] [blame] | 417 | start_pam(user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 418 | #endif |
| 419 | |
| 420 | /* |
| 421 | * If we are not running as root, the user must have the same uid as |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 422 | * the server. (Unless you are running Windows) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 423 | */ |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 424 | #ifndef HAVE_CYGWIN |
| 425 | if (getuid() != 0 && pw && pw->pw_uid != getuid()) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 426 | packet_disconnect("Cannot change user when server not running as root."); |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 427 | #endif |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 428 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 429 | /* |
| 430 | * Loop until the user has been authenticated or the connection is |
| 431 | * closed, do_authloop() returns only if authentication is successful |
| 432 | */ |
| 433 | do_authloop(authctxt); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 434 | |
| 435 | /* The user has been authenticated and accepted. */ |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 436 | packet_start(SSH_SMSG_SUCCESS); |
| 437 | packet_send(); |
| 438 | packet_write_wait(); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 439 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 440 | #ifdef WITH_AIXAUTHENTICATE |
Damien Miller | d2c208a | 2000-05-17 22:00:02 +1000 | [diff] [blame] | 441 | /* We don't have a pty yet, so just label the line as "ssh" */ |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 442 | if (loginsuccess(authctxt->user,get_canonical_hostname(),"ssh",&aixloginmsg) < 0) |
Damien Miller | d2c208a | 2000-05-17 22:00:02 +1000 | [diff] [blame] | 443 | aixloginmsg = NULL; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 444 | #endif /* WITH_AIXAUTHENTICATE */ |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 445 | |
| 446 | xfree(authctxt->user); |
| 447 | xfree(authctxt); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 448 | |
| 449 | /* Perform session preparation. */ |
| 450 | do_authenticated(pw); |
| 451 | } |