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" |
Darren Tucker | 5cb30ad | 2004-08-12 22:40:24 +1000 | [diff] [blame] | 13 | RCSID("$OpenBSD: auth1.c,v 1.59 2004/07/28 09:40:29 markus Exp $"); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 14 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 15 | #include "xmalloc.h" |
| 16 | #include "rsa.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 17 | #include "ssh1.h" |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 18 | #include "packet.h" |
| 19 | #include "buffer.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 20 | #include "log.h" |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 21 | #include "servconf.h" |
| 22 | #include "compat.h" |
| 23 | #include "auth.h" |
Damien Miller | c7ef63d | 2002-02-05 12:21:42 +1100 | [diff] [blame] | 24 | #include "channels.h" |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 25 | #include "session.h" |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 26 | #include "uidswap.h" |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 27 | #include "monitor_wrap.h" |
Darren Tucker | c138667 | 2004-12-03 14:33:47 +1100 | [diff] [blame] | 28 | #include "buffer.h" |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 29 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 30 | /* import */ |
| 31 | extern ServerOptions options; |
Darren Tucker | c138667 | 2004-12-03 14:33:47 +1100 | [diff] [blame] | 32 | extern Buffer loginmsg; |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 33 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 34 | /* |
| 35 | * convert ssh auth msg type into description |
| 36 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 37 | static char * |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 38 | get_authname(int type) |
| 39 | { |
| 40 | static char buf[1024]; |
| 41 | switch (type) { |
| 42 | case SSH_CMSG_AUTH_PASSWORD: |
| 43 | return "password"; |
| 44 | case SSH_CMSG_AUTH_RSA: |
| 45 | return "rsa"; |
| 46 | case SSH_CMSG_AUTH_RHOSTS_RSA: |
| 47 | return "rhosts-rsa"; |
| 48 | case SSH_CMSG_AUTH_RHOSTS: |
| 49 | return "rhosts"; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 50 | case SSH_CMSG_AUTH_TIS: |
| 51 | case SSH_CMSG_AUTH_TIS_RESPONSE: |
| 52 | return "challenge-response"; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 53 | } |
| 54 | snprintf(buf, sizeof buf, "bad-auth-msg-%d", type); |
| 55 | return buf; |
| 56 | } |
| 57 | |
| 58 | /* |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 59 | * read packets, try to authenticate the user and |
| 60 | * return only if authentication is successful |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 61 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 62 | static void |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 63 | do_authloop(Authctxt *authctxt) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 64 | { |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 65 | int authenticated = 0; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 66 | u_int bits; |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 67 | Key *client_host_key; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 68 | BIGNUM *n; |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 69 | char *client_user, *password; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 70 | char info[1024]; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 71 | u_int dlen; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 72 | u_int ulen; |
Damien Miller | 4f9f42a | 2003-05-10 19:28:02 +1000 | [diff] [blame] | 73 | int prev, type = 0; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 74 | |
| 75 | debug("Attempting authentication for %s%.100s.", |
Darren Tucker | 5cb30ad | 2004-08-12 22:40:24 +1000 | [diff] [blame] | 76 | authctxt->valid ? "" : "invalid user ", authctxt->user); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 77 | |
| 78 | /* If the user has no password, accept authentication immediately. */ |
| 79 | if (options.password_authentication && |
Darren Tucker | 6aaa58c | 2003-08-02 22:24:49 +1000 | [diff] [blame] | 80 | #ifdef KRB5 |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 81 | (!options.kerberos_authentication || options.kerberos_or_local_passwd) && |
| 82 | #endif |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 83 | PRIVSEP(auth_password(authctxt, ""))) { |
Darren Tucker | a8c73d3 | 2004-06-23 09:17:54 +1000 | [diff] [blame] | 84 | #ifdef USE_PAM |
| 85 | if (options.use_pam && (PRIVSEP(do_pam_account()))) |
| 86 | #endif |
| 87 | { |
| 88 | auth_log(authctxt, 1, "without authentication", ""); |
| 89 | return; |
| 90 | } |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 91 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 92 | |
| 93 | /* Indicate that authentication is needed. */ |
| 94 | packet_start(SSH_SMSG_FAILURE); |
| 95 | packet_send(); |
| 96 | packet_write_wait(); |
| 97 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 98 | client_user = NULL; |
| 99 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 100 | for (;;) { |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 101 | /* default to fail */ |
| 102 | authenticated = 0; |
| 103 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 104 | info[0] = '\0'; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 105 | |
| 106 | /* Get a packet from the client. */ |
Damien Miller | 4f9f42a | 2003-05-10 19:28:02 +1000 | [diff] [blame] | 107 | prev = type; |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 108 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 109 | |
Damien Miller | 4f9f42a | 2003-05-10 19:28:02 +1000 | [diff] [blame] | 110 | /* |
| 111 | * If we started challenge-response authentication but the |
| 112 | * next packet is not a response to our challenge, release |
| 113 | * the resources allocated by get_challenge() (which would |
| 114 | * normally have been released by verify_response() had we |
| 115 | * received such a response) |
| 116 | */ |
| 117 | if (prev == SSH_CMSG_AUTH_TIS && |
| 118 | type != SSH_CMSG_AUTH_TIS_RESPONSE) |
| 119 | abandon_challenge_response(authctxt); |
| 120 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 121 | /* Process the packet. */ |
| 122 | switch (type) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 123 | case SSH_CMSG_AUTH_RHOSTS_RSA: |
| 124 | if (!options.rhosts_rsa_authentication) { |
| 125 | verbose("Rhosts with RSA authentication disabled."); |
| 126 | break; |
| 127 | } |
| 128 | /* |
| 129 | * Get client user name. Note that we just have to |
| 130 | * trust the client; root on the client machine can |
| 131 | * claim to be any user. |
| 132 | */ |
| 133 | client_user = packet_get_string(&ulen); |
| 134 | |
| 135 | /* Get the client host key. */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 136 | client_host_key = key_new(KEY_RSA1); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 137 | bits = packet_get_int(); |
Damien Miller | d432ccf | 2002-01-22 23:14:44 +1100 | [diff] [blame] | 138 | packet_get_bignum(client_host_key->rsa->e); |
| 139 | packet_get_bignum(client_host_key->rsa->n); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 140 | |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 141 | if (bits != BN_num_bits(client_host_key->rsa->n)) |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 142 | verbose("Warning: keysize mismatch for client_host_key: " |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 143 | "actual %d, announced %d", |
Ben Lindstrom | cb72e4f | 2002-06-21 00:41:51 +0000 | [diff] [blame] | 144 | BN_num_bits(client_host_key->rsa->n), bits); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 145 | packet_check_eom(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 146 | |
Damien Miller | 3e3b514 | 2003-11-17 21:13:40 +1100 | [diff] [blame] | 147 | authenticated = auth_rhosts_rsa(authctxt, client_user, |
Damien Miller | d221ca6 | 2002-01-22 23:11:00 +1100 | [diff] [blame] | 148 | client_host_key); |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 149 | key_free(client_host_key); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 150 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 151 | snprintf(info, sizeof info, " ruser %.100s", client_user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 152 | break; |
| 153 | |
| 154 | case SSH_CMSG_AUTH_RSA: |
| 155 | if (!options.rsa_authentication) { |
| 156 | verbose("RSA authentication disabled."); |
| 157 | break; |
| 158 | } |
| 159 | /* RSA authentication requested. */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 160 | if ((n = BN_new()) == NULL) |
| 161 | fatal("do_authloop: BN_new failed"); |
Damien Miller | d432ccf | 2002-01-22 23:14:44 +1100 | [diff] [blame] | 162 | packet_get_bignum(n); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 163 | packet_check_eom(); |
Damien Miller | 3e3b514 | 2003-11-17 21:13:40 +1100 | [diff] [blame] | 164 | authenticated = auth_rsa(authctxt, n); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 165 | BN_clear_free(n); |
| 166 | break; |
| 167 | |
| 168 | case SSH_CMSG_AUTH_PASSWORD: |
| 169 | if (!options.password_authentication) { |
| 170 | verbose("Password authentication disabled."); |
| 171 | break; |
| 172 | } |
| 173 | /* |
| 174 | * Read user password. It is in plain text, but was |
| 175 | * transmitted over the encrypted channel so it is |
| 176 | * not visible to an outside observer. |
| 177 | */ |
| 178 | password = packet_get_string(&dlen); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 179 | packet_check_eom(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 180 | |
Kevin Steves | 12aaa04 | 2001-01-24 21:23:39 +0000 | [diff] [blame] | 181 | /* Try authentication with the password. */ |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 182 | authenticated = PRIVSEP(auth_password(authctxt, password)); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 183 | |
| 184 | memset(password, 0, strlen(password)); |
| 185 | xfree(password); |
| 186 | break; |
| 187 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 188 | case SSH_CMSG_AUTH_TIS: |
| 189 | debug("rcvd SSH_CMSG_AUTH_TIS"); |
Ben Lindstrom | 551ea37 | 2001-06-05 18:56:16 +0000 | [diff] [blame] | 190 | if (options.challenge_response_authentication == 1) { |
| 191 | char *challenge = get_challenge(authctxt); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 192 | if (challenge != NULL) { |
| 193 | debug("sending challenge '%s'", challenge); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 194 | packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 195 | packet_put_cstring(challenge); |
Ben Lindstrom | 551ea37 | 2001-06-05 18:56:16 +0000 | [diff] [blame] | 196 | xfree(challenge); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 197 | packet_send(); |
| 198 | packet_write_wait(); |
| 199 | continue; |
| 200 | } |
| 201 | } |
| 202 | break; |
| 203 | case SSH_CMSG_AUTH_TIS_RESPONSE: |
| 204 | debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); |
Ben Lindstrom | 551ea37 | 2001-06-05 18:56:16 +0000 | [diff] [blame] | 205 | if (options.challenge_response_authentication == 1) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 206 | char *response = packet_get_string(&dlen); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 207 | packet_check_eom(); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 208 | authenticated = verify_response(authctxt, response); |
| 209 | memset(response, 'r', dlen); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 210 | xfree(response); |
| 211 | } |
| 212 | break; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 213 | |
| 214 | default: |
| 215 | /* |
| 216 | * Any unknown messages will be ignored (and failure |
| 217 | * returned) during authentication. |
| 218 | */ |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 219 | logit("Unknown message during authentication: type %d", type); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 220 | break; |
| 221 | } |
Damien Miller | 60396b0 | 2001-02-18 17:01:00 +1100 | [diff] [blame] | 222 | #ifdef BSD_AUTH |
| 223 | if (authctxt->as) { |
| 224 | auth_close(authctxt->as); |
| 225 | authctxt->as = NULL; |
| 226 | } |
| 227 | #endif |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 228 | if (!authctxt->valid && authenticated) |
| 229 | fatal("INTERNAL ERROR: authenticated invalid user %s", |
| 230 | authctxt->user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 231 | |
Tim Rice | 81ed518 | 2002-09-25 17:38:46 -0700 | [diff] [blame] | 232 | #ifdef _UNICOS |
Tim Rice | 81ed518 | 2002-09-25 17:38:46 -0700 | [diff] [blame] | 233 | if (authenticated && cray_access_denied(authctxt->user)) { |
| 234 | authenticated = 0; |
| 235 | fatal("Access denied for user %s.",authctxt->user); |
| 236 | } |
| 237 | #endif /* _UNICOS */ |
| 238 | |
Kevin Steves | ef4eea9 | 2001-02-05 12:42:17 +0000 | [diff] [blame] | 239 | #ifdef HAVE_CYGWIN |
| 240 | if (authenticated && |
Ben Lindstrom | e35bf12 | 2004-06-22 03:37:11 +0000 | [diff] [blame] | 241 | !check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD, |
| 242 | authctxt->pw)) { |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 243 | packet_disconnect("Authentication rejected for uid %d.", |
Ben Lindstrom | e35bf12 | 2004-06-22 03:37:11 +0000 | [diff] [blame] | 244 | authctxt->pw == NULL ? -1 : authctxt->pw->pw_uid); |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 245 | authenticated = 0; |
| 246 | } |
Ben Lindstrom | 5dc8150 | 2001-01-19 06:10:29 +0000 | [diff] [blame] | 247 | #else |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 248 | /* Special handling for root */ |
Damien Miller | 556f931 | 2003-02-24 11:59:26 +1100 | [diff] [blame] | 249 | if (authenticated && authctxt->pw->pw_uid == 0 && |
Ben Lindstrom | d8a9021 | 2001-02-15 03:08:27 +0000 | [diff] [blame] | 250 | !auth_root_allowed(get_authname(type))) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 251 | authenticated = 0; |
Ben Lindstrom | 5dc8150 | 2001-01-19 06:10:29 +0000 | [diff] [blame] | 252 | #endif |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 253 | |
Damien Miller | 1f499fd | 2003-08-25 13:08:49 +1000 | [diff] [blame] | 254 | #ifdef USE_PAM |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 255 | if (options.use_pam && authenticated && |
Darren Tucker | c138667 | 2004-12-03 14:33:47 +1100 | [diff] [blame] | 256 | !PRIVSEP(do_pam_account())) { |
| 257 | char *msg; |
| 258 | size_t len; |
| 259 | |
| 260 | error("Access denied for user %s by PAM account " |
| 261 | "configuration", authctxt->user); |
| 262 | len = buffer_len(&loginmsg); |
| 263 | buffer_append(&loginmsg, "\0", 1); |
| 264 | msg = buffer_ptr(&loginmsg); |
| 265 | /* strip trailing newlines */ |
| 266 | if (len > 0) |
| 267 | while (len > 0 && msg[--len] == '\n') |
| 268 | msg[len] = '\0'; |
| 269 | else |
| 270 | msg = "Access denied."; |
| 271 | packet_disconnect(msg); |
| 272 | } |
Damien Miller | 1f499fd | 2003-08-25 13:08:49 +1000 | [diff] [blame] | 273 | #endif |
| 274 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 275 | /* Log before sending the reply */ |
| 276 | auth_log(authctxt, authenticated, get_authname(type), info); |
| 277 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 278 | if (client_user != NULL) { |
| 279 | xfree(client_user); |
| 280 | client_user = NULL; |
| 281 | } |
| 282 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 283 | if (authenticated) |
| 284 | return; |
| 285 | |
Darren Tucker | 89413db | 2004-05-24 10:36:23 +1000 | [diff] [blame] | 286 | if (authctxt->failures++ > options.max_authtries) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 287 | packet_disconnect(AUTH_FAIL_MSG, authctxt->user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 288 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 289 | packet_start(SSH_SMSG_FAILURE); |
| 290 | packet_send(); |
| 291 | packet_write_wait(); |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | /* |
| 296 | * Performs authentication of an incoming connection. Session key has already |
| 297 | * been exchanged and encryption is enabled. |
| 298 | */ |
Darren Tucker | 3e33cec | 2003-10-02 16:12:36 +1000 | [diff] [blame] | 299 | void |
| 300 | do_authentication(Authctxt *authctxt) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 301 | { |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 302 | u_int ulen; |
Ben Lindstrom | c822638 | 2002-04-10 16:22:09 +0000 | [diff] [blame] | 303 | char *user, *style = NULL; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 304 | |
| 305 | /* Get the name of the user that we wish to log in as. */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 306 | packet_read_expect(SSH_CMSG_USER); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 307 | |
| 308 | /* Get the user name. */ |
| 309 | user = packet_get_string(&ulen); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 310 | packet_check_eom(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 311 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 312 | if ((style = strchr(user, ':')) != NULL) |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 313 | *style++ = '\0'; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 314 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 315 | authctxt->user = user; |
| 316 | authctxt->style = style; |
| 317 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 318 | /* Verify that the user is a valid user. */ |
Ben Lindstrom | 7ebb635 | 2002-03-22 03:04:08 +0000 | [diff] [blame] | 319 | if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL) |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 320 | authctxt->valid = 1; |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 321 | else { |
Darren Tucker | 5cb30ad | 2004-08-12 22:40:24 +1000 | [diff] [blame] | 322 | debug("do_authentication: invalid user %s", user); |
Damien Miller | 856f0be | 2003-09-03 07:32:45 +1000 | [diff] [blame] | 323 | authctxt->pw = fakepw(); |
| 324 | } |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 325 | |
Damien Miller | 30d1f84 | 2004-07-21 20:48:53 +1000 | [diff] [blame] | 326 | setproctitle("%s%s", authctxt->valid ? user : "unknown", |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 327 | use_privsep ? " [net]" : ""); |
Ben Lindstrom | c1ba31f | 2001-02-15 03:14:11 +0000 | [diff] [blame] | 328 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 329 | #ifdef USE_PAM |
Damien Miller | 4e448a3 | 2003-05-14 15:11:48 +1000 | [diff] [blame] | 330 | if (options.use_pam) |
Darren Tucker | dbf7a74 | 2004-03-08 23:04:06 +1100 | [diff] [blame] | 331 | PRIVSEP(start_pam(authctxt)); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 332 | #endif |
| 333 | |
| 334 | /* |
| 335 | * 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] | 336 | * the server. (Unless you are running Windows) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 337 | */ |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 338 | #ifndef HAVE_CYGWIN |
Ben Lindstrom | 7ebb635 | 2002-03-22 03:04:08 +0000 | [diff] [blame] | 339 | if (!use_privsep && getuid() != 0 && authctxt->pw && |
| 340 | authctxt->pw->pw_uid != getuid()) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 341 | packet_disconnect("Cannot change user when server not running as root."); |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 342 | #endif |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 343 | |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 344 | /* |
Kevin Steves | 12aaa04 | 2001-01-24 21:23:39 +0000 | [diff] [blame] | 345 | * Loop until the user has been authenticated or the connection is |
| 346 | * closed, do_authloop() returns only if authentication is successful |
| 347 | */ |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 348 | do_authloop(authctxt); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 349 | |
| 350 | /* The user has been authenticated and accepted. */ |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 351 | packet_start(SSH_SMSG_SUCCESS); |
| 352 | packet_send(); |
| 353 | packet_write_wait(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 354 | } |