Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 1 | /* |
| 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 4 | * All rights reserved |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 5 | * Code to connect to a remote host, and to perform the client side of the |
| 6 | * login (authentication) dialog. |
| 7 | * |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 8 | * As far as I am concerned, the code I have written for this software |
| 9 | * can be used freely for any purpose. Any derived versions of this |
| 10 | * software must be clearly marked as such, and if the derived work is |
| 11 | * incompatible with the protocol description in the RFC file, it must be |
| 12 | * called by a name other than "ssh" or "Secure Shell". |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 13 | */ |
| 14 | |
| 15 | #include "includes.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 16 | |
| 17 | #include <openssl/bn.h> |
Damien Miller | 2ce18da | 2002-02-13 13:54:27 +1100 | [diff] [blame] | 18 | #include <openssl/md5.h> |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 19 | |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 20 | #include "ssh.h" |
| 21 | #include "ssh1.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 22 | #include "xmalloc.h" |
| 23 | #include "rsa.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 24 | #include "buffer.h" |
| 25 | #include "packet.h" |
Darren Tucker | e14e005 | 2004-05-13 16:30:44 +1000 | [diff] [blame] | 26 | #include "kex.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 27 | #include "uidswap.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 28 | #include "log.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 29 | #include "readconf.h" |
| 30 | #include "key.h" |
Damien Miller | 994cf14 | 2000-07-21 10:19:44 +1000 | [diff] [blame] | 31 | #include "authfd.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 32 | #include "sshconnect.h" |
| 33 | #include "authfile.h" |
Darren Tucker | e608ca2 | 2004-05-13 16:15:47 +1000 | [diff] [blame] | 34 | #include "misc.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 35 | #include "cipher.h" |
| 36 | #include "canohost.h" |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 37 | #include "auth.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 38 | |
| 39 | /* Session id for the current session. */ |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 40 | u_char session_id[16]; |
| 41 | u_int supported_authentications = 0; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 42 | |
| 43 | extern Options options; |
| 44 | extern char *__progname; |
| 45 | |
| 46 | /* |
| 47 | * Checks if the user has an authentication agent, and if so, tries to |
| 48 | * authenticate using the agent. |
| 49 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 50 | static int |
Ben Lindstrom | 31ca54a | 2001-02-09 02:11:24 +0000 | [diff] [blame] | 51 | try_agent_authentication(void) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 52 | { |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 53 | int type; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 54 | char *comment; |
| 55 | AuthenticationConnection *auth; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 56 | u_char response[16]; |
| 57 | u_int i; |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 58 | Key *key; |
| 59 | BIGNUM *challenge; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 60 | |
| 61 | /* Get connection to the agent. */ |
| 62 | auth = ssh_get_authentication_connection(); |
| 63 | if (!auth) |
| 64 | return 0; |
| 65 | |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 66 | if ((challenge = BN_new()) == NULL) |
| 67 | fatal("try_agent_authentication: BN_new failed"); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 68 | /* Loop through identities served by the agent. */ |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 69 | for (key = ssh_get_first_identity(auth, &comment, 1); |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 70 | key != NULL; |
| 71 | key = ssh_get_next_identity(auth, &comment, 1)) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 72 | |
| 73 | /* Try this identity. */ |
| 74 | debug("Trying RSA authentication via agent with '%.100s'", comment); |
| 75 | xfree(comment); |
| 76 | |
| 77 | /* Tell the server that we are willing to authenticate using this key. */ |
| 78 | packet_start(SSH_CMSG_AUTH_RSA); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 79 | packet_put_bignum(key->rsa->n); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 80 | packet_send(); |
| 81 | packet_write_wait(); |
| 82 | |
| 83 | /* Wait for server's response. */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 84 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 85 | |
Damien Miller | 788f212 | 2005-11-05 15:14:59 +1100 | [diff] [blame] | 86 | /* The server sends failure if it doesn't like our key or |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 87 | does not support RSA authentication. */ |
| 88 | if (type == SSH_SMSG_FAILURE) { |
| 89 | debug("Server refused our key."); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 90 | key_free(key); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 91 | continue; |
| 92 | } |
| 93 | /* Otherwise it should have sent a challenge. */ |
| 94 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) |
| 95 | packet_disconnect("Protocol error during RSA authentication: %d", |
| 96 | type); |
| 97 | |
Damien Miller | d432ccf | 2002-01-22 23:14:44 +1100 | [diff] [blame] | 98 | packet_get_bignum(challenge); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 99 | packet_check_eom(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 100 | |
| 101 | debug("Received RSA challenge from server."); |
| 102 | |
| 103 | /* Ask the agent to decrypt the challenge. */ |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 104 | if (!ssh_decrypt_challenge(auth, key, challenge, session_id, 1, response)) { |
| 105 | /* |
| 106 | * The agent failed to authenticate this identifier |
| 107 | * although it advertised it supports this. Just |
| 108 | * return a wrong value. |
| 109 | */ |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 110 | logit("Authentication agent failed to decrypt challenge."); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 111 | memset(response, 0, sizeof(response)); |
| 112 | } |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 113 | key_free(key); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 114 | debug("Sending response to RSA challenge."); |
| 115 | |
| 116 | /* Send the decrypted challenge back to the server. */ |
| 117 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); |
| 118 | for (i = 0; i < 16; i++) |
| 119 | packet_put_char(response[i]); |
| 120 | packet_send(); |
| 121 | packet_write_wait(); |
| 122 | |
| 123 | /* Wait for response from the server. */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 124 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 125 | |
| 126 | /* The server returns success if it accepted the authentication. */ |
| 127 | if (type == SSH_SMSG_SUCCESS) { |
Ben Lindstrom | 48bd7c1 | 2001-01-09 00:35:42 +0000 | [diff] [blame] | 128 | ssh_close_authentication_connection(auth); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 129 | BN_clear_free(challenge); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 130 | debug("RSA authentication accepted by server."); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 131 | return 1; |
| 132 | } |
| 133 | /* Otherwise it should return failure. */ |
| 134 | if (type != SSH_SMSG_FAILURE) |
| 135 | packet_disconnect("Protocol error waiting RSA auth response: %d", |
| 136 | type); |
| 137 | } |
Ben Lindstrom | 48bd7c1 | 2001-01-09 00:35:42 +0000 | [diff] [blame] | 138 | ssh_close_authentication_connection(auth); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 139 | BN_clear_free(challenge); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 140 | debug("RSA authentication using agent refused."); |
| 141 | return 0; |
| 142 | } |
| 143 | |
| 144 | /* |
| 145 | * Computes the proper response to a RSA challenge, and sends the response to |
| 146 | * the server. |
| 147 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 148 | static void |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 149 | respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) |
| 150 | { |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 151 | u_char buf[32], response[16]; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 152 | MD5_CTX md; |
| 153 | int i, len; |
| 154 | |
| 155 | /* Decrypt the challenge using the private key. */ |
Damien Miller | 7650bc6 | 2001-01-30 09:27:26 +1100 | [diff] [blame] | 156 | /* XXX think about Bleichenbacher, too */ |
| 157 | if (rsa_private_decrypt(challenge, challenge, prv) <= 0) |
| 158 | packet_disconnect( |
| 159 | "respond_to_rsa_challenge: rsa_private_decrypt failed"); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 160 | |
| 161 | /* Compute the response. */ |
| 162 | /* The response is MD5 of decrypted challenge plus session id. */ |
| 163 | len = BN_num_bytes(challenge); |
Damien Miller | eccb9de | 2005-06-17 12:59:34 +1000 | [diff] [blame] | 164 | if (len <= 0 || (u_int)len > sizeof(buf)) |
Damien Miller | 7650bc6 | 2001-01-30 09:27:26 +1100 | [diff] [blame] | 165 | packet_disconnect( |
| 166 | "respond_to_rsa_challenge: bad challenge length %d", len); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 167 | |
| 168 | memset(buf, 0, sizeof(buf)); |
| 169 | BN_bn2bin(challenge, buf + sizeof(buf) - len); |
| 170 | MD5_Init(&md); |
| 171 | MD5_Update(&md, buf, 32); |
| 172 | MD5_Update(&md, session_id, 16); |
| 173 | MD5_Final(response, &md); |
| 174 | |
| 175 | debug("Sending response to host key RSA challenge."); |
| 176 | |
| 177 | /* Send the response back to the server. */ |
| 178 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); |
| 179 | for (i = 0; i < 16; i++) |
| 180 | packet_put_char(response[i]); |
| 181 | packet_send(); |
| 182 | packet_write_wait(); |
| 183 | |
| 184 | memset(buf, 0, sizeof(buf)); |
| 185 | memset(response, 0, sizeof(response)); |
| 186 | memset(&md, 0, sizeof(md)); |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * Checks if the user has authentication file, and if so, tries to authenticate |
| 191 | * the user using it. |
| 192 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 193 | static int |
Ben Lindstrom | c5b6800 | 2001-07-04 04:52:03 +0000 | [diff] [blame] | 194 | try_rsa_authentication(int idx) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 195 | { |
| 196 | BIGNUM *challenge; |
Ben Lindstrom | 0520945 | 2001-06-25 05:16:02 +0000 | [diff] [blame] | 197 | Key *public, *private; |
Ben Lindstrom | c5b6800 | 2001-07-04 04:52:03 +0000 | [diff] [blame] | 198 | char buf[300], *passphrase, *comment, *authfile; |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 199 | int i, type, quit; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 200 | |
Ben Lindstrom | c5b6800 | 2001-07-04 04:52:03 +0000 | [diff] [blame] | 201 | public = options.identity_keys[idx]; |
| 202 | authfile = options.identity_files[idx]; |
| 203 | comment = xstrdup(authfile); |
| 204 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 205 | debug("Trying RSA authentication with key '%.100s'", comment); |
| 206 | |
| 207 | /* Tell the server that we are willing to authenticate using this key. */ |
| 208 | packet_start(SSH_CMSG_AUTH_RSA); |
| 209 | packet_put_bignum(public->rsa->n); |
| 210 | packet_send(); |
| 211 | packet_write_wait(); |
| 212 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 213 | /* Wait for server's response. */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 214 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 215 | |
| 216 | /* |
Damien Miller | 788f212 | 2005-11-05 15:14:59 +1100 | [diff] [blame] | 217 | * The server responds with failure if it doesn't like our key or |
| 218 | * doesn't support RSA authentication. |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 219 | */ |
| 220 | if (type == SSH_SMSG_FAILURE) { |
| 221 | debug("Server refused our key."); |
| 222 | xfree(comment); |
| 223 | return 0; |
| 224 | } |
| 225 | /* Otherwise, the server should respond with a challenge. */ |
| 226 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) |
| 227 | packet_disconnect("Protocol error during RSA authentication: %d", type); |
| 228 | |
| 229 | /* Get the challenge from the packet. */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 230 | if ((challenge = BN_new()) == NULL) |
| 231 | fatal("try_rsa_authentication: BN_new failed"); |
Damien Miller | d432ccf | 2002-01-22 23:14:44 +1100 | [diff] [blame] | 232 | packet_get_bignum(challenge); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 233 | packet_check_eom(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 234 | |
| 235 | debug("Received RSA challenge from server."); |
| 236 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 237 | /* |
Ben Lindstrom | c5b6800 | 2001-07-04 04:52:03 +0000 | [diff] [blame] | 238 | * If the key is not stored in external hardware, we have to |
| 239 | * load the private key. Try first with empty passphrase; if it |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 240 | * fails, ask for a passphrase. |
| 241 | */ |
Ben Lindstrom | e143f61 | 2002-08-20 18:41:15 +0000 | [diff] [blame] | 242 | if (public->flags & KEY_FLAG_EXT) |
Ben Lindstrom | c5b6800 | 2001-07-04 04:52:03 +0000 | [diff] [blame] | 243 | private = public; |
| 244 | else |
| 245 | private = key_load_private_type(KEY_RSA1, authfile, "", NULL); |
Ben Lindstrom | 0520945 | 2001-06-25 05:16:02 +0000 | [diff] [blame] | 246 | if (private == NULL && !options.batch_mode) { |
| 247 | snprintf(buf, sizeof(buf), |
| 248 | "Enter passphrase for RSA key '%.100s': ", comment); |
| 249 | for (i = 0; i < options.number_of_password_prompts; i++) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 250 | passphrase = read_passphrase(buf, 0); |
Ben Lindstrom | 0520945 | 2001-06-25 05:16:02 +0000 | [diff] [blame] | 251 | if (strcmp(passphrase, "") != 0) { |
| 252 | private = key_load_private_type(KEY_RSA1, |
| 253 | authfile, passphrase, NULL); |
| 254 | quit = 0; |
| 255 | } else { |
| 256 | debug2("no passphrase given, try next key"); |
| 257 | quit = 1; |
| 258 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 259 | memset(passphrase, 0, strlen(passphrase)); |
| 260 | xfree(passphrase); |
Ben Lindstrom | 0520945 | 2001-06-25 05:16:02 +0000 | [diff] [blame] | 261 | if (private != NULL || quit) |
| 262 | break; |
| 263 | debug2("bad passphrase given, try again..."); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 264 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 265 | } |
| 266 | /* We no longer need the comment. */ |
| 267 | xfree(comment); |
| 268 | |
Ben Lindstrom | 0520945 | 2001-06-25 05:16:02 +0000 | [diff] [blame] | 269 | if (private == NULL) { |
| 270 | if (!options.batch_mode) |
| 271 | error("Bad passphrase."); |
| 272 | |
| 273 | /* Send a dummy response packet to avoid protocol error. */ |
| 274 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); |
| 275 | for (i = 0; i < 16; i++) |
| 276 | packet_put_char(0); |
| 277 | packet_send(); |
| 278 | packet_write_wait(); |
| 279 | |
| 280 | /* Expect the server to reject it... */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 281 | packet_read_expect(SSH_SMSG_FAILURE); |
Ben Lindstrom | 0520945 | 2001-06-25 05:16:02 +0000 | [diff] [blame] | 282 | BN_clear_free(challenge); |
| 283 | return 0; |
| 284 | } |
| 285 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 286 | /* Compute and send a response to the challenge. */ |
| 287 | respond_to_rsa_challenge(challenge, private->rsa); |
| 288 | |
Ben Lindstrom | c5b6800 | 2001-07-04 04:52:03 +0000 | [diff] [blame] | 289 | /* Destroy the private key unless it in external hardware. */ |
| 290 | if (!(private->flags & KEY_FLAG_EXT)) |
| 291 | key_free(private); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 292 | |
| 293 | /* We no longer need the challenge. */ |
| 294 | BN_clear_free(challenge); |
| 295 | |
| 296 | /* Wait for response from the server. */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 297 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 298 | if (type == SSH_SMSG_SUCCESS) { |
| 299 | debug("RSA authentication accepted by server."); |
| 300 | return 1; |
| 301 | } |
| 302 | if (type != SSH_SMSG_FAILURE) |
| 303 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); |
| 304 | debug("RSA authentication refused."); |
| 305 | return 0; |
| 306 | } |
| 307 | |
| 308 | /* |
| 309 | * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv |
| 310 | * authentication and RSA host authentication. |
| 311 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 312 | static int |
Ben Lindstrom | d0fca42 | 2001-03-26 13:44:06 +0000 | [diff] [blame] | 313 | try_rhosts_rsa_authentication(const char *local_user, Key * host_key) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 314 | { |
| 315 | int type; |
| 316 | BIGNUM *challenge; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 317 | |
| 318 | debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); |
| 319 | |
| 320 | /* Tell the server that we are willing to authenticate using this key. */ |
| 321 | packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); |
Ben Lindstrom | 664408d | 2001-06-09 01:42:01 +0000 | [diff] [blame] | 322 | packet_put_cstring(local_user); |
Ben Lindstrom | d0fca42 | 2001-03-26 13:44:06 +0000 | [diff] [blame] | 323 | packet_put_int(BN_num_bits(host_key->rsa->n)); |
| 324 | packet_put_bignum(host_key->rsa->e); |
| 325 | packet_put_bignum(host_key->rsa->n); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 326 | packet_send(); |
| 327 | packet_write_wait(); |
| 328 | |
| 329 | /* Wait for server's response. */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 330 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 331 | |
| 332 | /* The server responds with failure if it doesn't admit our |
| 333 | .rhosts authentication or doesn't know our host key. */ |
| 334 | if (type == SSH_SMSG_FAILURE) { |
| 335 | debug("Server refused our rhosts authentication or host key."); |
| 336 | return 0; |
| 337 | } |
| 338 | /* Otherwise, the server should respond with a challenge. */ |
| 339 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) |
| 340 | packet_disconnect("Protocol error during RSA authentication: %d", type); |
| 341 | |
| 342 | /* Get the challenge from the packet. */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 343 | if ((challenge = BN_new()) == NULL) |
| 344 | fatal("try_rhosts_rsa_authentication: BN_new failed"); |
Damien Miller | d432ccf | 2002-01-22 23:14:44 +1100 | [diff] [blame] | 345 | packet_get_bignum(challenge); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 346 | packet_check_eom(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 347 | |
| 348 | debug("Received RSA challenge for host key from server."); |
| 349 | |
| 350 | /* Compute a response to the challenge. */ |
Ben Lindstrom | d0fca42 | 2001-03-26 13:44:06 +0000 | [diff] [blame] | 351 | respond_to_rsa_challenge(challenge, host_key->rsa); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 352 | |
| 353 | /* We no longer need the challenge. */ |
| 354 | BN_clear_free(challenge); |
| 355 | |
| 356 | /* Wait for response from the server. */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 357 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 358 | if (type == SSH_SMSG_SUCCESS) { |
| 359 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); |
| 360 | return 1; |
| 361 | } |
| 362 | if (type != SSH_SMSG_FAILURE) |
| 363 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); |
| 364 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); |
| 365 | return 0; |
| 366 | } |
| 367 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 368 | /* |
| 369 | * Tries to authenticate with any string-based challenge/response system. |
| 370 | * Note that the client code is not tied to s/key or TIS. |
| 371 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 372 | static int |
Ben Lindstrom | 551ea37 | 2001-06-05 18:56:16 +0000 | [diff] [blame] | 373 | try_challenge_response_authentication(void) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 374 | { |
| 375 | int type, i; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 376 | u_int clen; |
Ben Lindstrom | a65c78a | 2000-12-10 22:57:30 +0000 | [diff] [blame] | 377 | char prompt[1024]; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 378 | char *challenge, *response; |
Ben Lindstrom | bdfb4df | 2001-10-03 17:12:43 +0000 | [diff] [blame] | 379 | |
| 380 | debug("Doing challenge response authentication."); |
| 381 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 382 | for (i = 0; i < options.number_of_password_prompts; i++) { |
Ben Lindstrom | a65c78a | 2000-12-10 22:57:30 +0000 | [diff] [blame] | 383 | /* request a challenge */ |
| 384 | packet_start(SSH_CMSG_AUTH_TIS); |
| 385 | packet_send(); |
| 386 | packet_write_wait(); |
| 387 | |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 388 | type = packet_read(); |
Ben Lindstrom | a65c78a | 2000-12-10 22:57:30 +0000 | [diff] [blame] | 389 | if (type != SSH_SMSG_FAILURE && |
| 390 | type != SSH_SMSG_AUTH_TIS_CHALLENGE) { |
| 391 | packet_disconnect("Protocol error: got %d in response " |
Ben Lindstrom | 95fb2dd | 2001-01-23 03:12:10 +0000 | [diff] [blame] | 392 | "to SSH_CMSG_AUTH_TIS", type); |
Ben Lindstrom | a65c78a | 2000-12-10 22:57:30 +0000 | [diff] [blame] | 393 | } |
| 394 | if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { |
Ben Lindstrom | 95fb2dd | 2001-01-23 03:12:10 +0000 | [diff] [blame] | 395 | debug("No challenge."); |
Ben Lindstrom | a65c78a | 2000-12-10 22:57:30 +0000 | [diff] [blame] | 396 | return 0; |
| 397 | } |
| 398 | challenge = packet_get_string(&clen); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 399 | packet_check_eom(); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 400 | snprintf(prompt, sizeof prompt, "%s%s", challenge, |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 401 | strchr(challenge, '\n') ? "" : "\nResponse: "); |
Ben Lindstrom | a65c78a | 2000-12-10 22:57:30 +0000 | [diff] [blame] | 402 | xfree(challenge); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 403 | if (i != 0) |
| 404 | error("Permission denied, please try again."); |
Ben Lindstrom | a65c78a | 2000-12-10 22:57:30 +0000 | [diff] [blame] | 405 | if (options.cipher == SSH_CIPHER_NONE) |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 406 | logit("WARNING: Encryption is disabled! " |
Damien Miller | f61c015 | 2002-04-23 20:56:02 +1000 | [diff] [blame] | 407 | "Response will be transmitted in clear text."); |
Ben Lindstrom | a65c78a | 2000-12-10 22:57:30 +0000 | [diff] [blame] | 408 | response = read_passphrase(prompt, 0); |
| 409 | if (strcmp(response, "") == 0) { |
| 410 | xfree(response); |
| 411 | break; |
| 412 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 413 | packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); |
Damien Miller | 79438cc | 2001-02-16 12:34:57 +1100 | [diff] [blame] | 414 | ssh_put_password(response); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 415 | memset(response, 0, strlen(response)); |
| 416 | xfree(response); |
| 417 | packet_send(); |
| 418 | packet_write_wait(); |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 419 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 420 | if (type == SSH_SMSG_SUCCESS) |
| 421 | return 1; |
| 422 | if (type != SSH_SMSG_FAILURE) |
| 423 | packet_disconnect("Protocol error: got %d in response " |
Ben Lindstrom | 95fb2dd | 2001-01-23 03:12:10 +0000 | [diff] [blame] | 424 | "to SSH_CMSG_AUTH_TIS_RESPONSE", type); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 425 | } |
| 426 | /* failure */ |
| 427 | return 0; |
| 428 | } |
| 429 | |
| 430 | /* |
| 431 | * Tries to authenticate with plain passwd authentication. |
| 432 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 433 | static int |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 434 | try_password_authentication(char *prompt) |
| 435 | { |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 436 | int type, i; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 437 | char *password; |
| 438 | |
| 439 | debug("Doing password authentication."); |
| 440 | if (options.cipher == SSH_CIPHER_NONE) |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 441 | logit("WARNING: Encryption is disabled! Password will be transmitted in clear text."); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 442 | for (i = 0; i < options.number_of_password_prompts; i++) { |
| 443 | if (i != 0) |
| 444 | error("Permission denied, please try again."); |
| 445 | password = read_passphrase(prompt, 0); |
| 446 | packet_start(SSH_CMSG_AUTH_PASSWORD); |
Damien Miller | 79438cc | 2001-02-16 12:34:57 +1100 | [diff] [blame] | 447 | ssh_put_password(password); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 448 | memset(password, 0, strlen(password)); |
| 449 | xfree(password); |
| 450 | packet_send(); |
| 451 | packet_write_wait(); |
| 452 | |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 453 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 454 | if (type == SSH_SMSG_SUCCESS) |
| 455 | return 1; |
| 456 | if (type != SSH_SMSG_FAILURE) |
| 457 | packet_disconnect("Protocol error: got %d in response to passwd auth", type); |
| 458 | } |
| 459 | /* failure */ |
| 460 | return 0; |
| 461 | } |
| 462 | |
| 463 | /* |
| 464 | * SSH1 key exchange |
| 465 | */ |
| 466 | void |
| 467 | ssh_kex(char *host, struct sockaddr *hostaddr) |
| 468 | { |
| 469 | int i; |
| 470 | BIGNUM *key; |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 471 | Key *host_key, *server_key; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 472 | int bits, rbits; |
| 473 | int ssh_cipher_default = SSH_CIPHER_3DES; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 474 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
| 475 | u_char cookie[8]; |
| 476 | u_int supported_ciphers; |
| 477 | u_int server_flags, client_flags; |
Darren Tucker | 3f9fdc7 | 2004-06-22 12:56:01 +1000 | [diff] [blame] | 478 | u_int32_t rnd = 0; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 479 | |
| 480 | debug("Waiting for server public key."); |
| 481 | |
| 482 | /* Wait for a public key packet from the server. */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 483 | packet_read_expect(SSH_SMSG_PUBLIC_KEY); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 484 | |
| 485 | /* Get cookie from the packet. */ |
| 486 | for (i = 0; i < 8; i++) |
| 487 | cookie[i] = packet_get_char(); |
| 488 | |
| 489 | /* Get the public key. */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 490 | server_key = key_new(KEY_RSA1); |
| 491 | bits = packet_get_int(); |
Damien Miller | d432ccf | 2002-01-22 23:14:44 +1100 | [diff] [blame] | 492 | packet_get_bignum(server_key->rsa->e); |
| 493 | packet_get_bignum(server_key->rsa->n); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 494 | |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 495 | rbits = BN_num_bits(server_key->rsa->n); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 496 | if (bits != rbits) { |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 497 | logit("Warning: Server lies about size of server public key: " |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 498 | "actual size is %d bits vs. announced %d.", rbits, bits); |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 499 | logit("Warning: This may be due to an old implementation of ssh."); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 500 | } |
| 501 | /* Get the host key. */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 502 | host_key = key_new(KEY_RSA1); |
| 503 | bits = packet_get_int(); |
Damien Miller | d432ccf | 2002-01-22 23:14:44 +1100 | [diff] [blame] | 504 | packet_get_bignum(host_key->rsa->e); |
| 505 | packet_get_bignum(host_key->rsa->n); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 506 | |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 507 | rbits = BN_num_bits(host_key->rsa->n); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 508 | if (bits != rbits) { |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 509 | logit("Warning: Server lies about size of server host key: " |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 510 | "actual size is %d bits vs. announced %d.", rbits, bits); |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 511 | logit("Warning: This may be due to an old implementation of ssh."); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 512 | } |
| 513 | |
| 514 | /* Get protocol flags. */ |
| 515 | server_flags = packet_get_int(); |
| 516 | packet_set_protocol_flags(server_flags); |
| 517 | |
| 518 | supported_ciphers = packet_get_int(); |
| 519 | supported_authentications = packet_get_int(); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 520 | packet_check_eom(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 521 | |
| 522 | debug("Received server public key (%d bits) and host key (%d bits).", |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 523 | BN_num_bits(server_key->rsa->n), BN_num_bits(host_key->rsa->n)); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 524 | |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 525 | if (verify_host_key(host, hostaddr, host_key) == -1) |
Damien Miller | 59d9fb9 | 2001-10-10 15:03:11 +1000 | [diff] [blame] | 526 | fatal("Host key verification failed."); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 527 | |
| 528 | client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; |
| 529 | |
Darren Tucker | e14e005 | 2004-05-13 16:30:44 +1000 | [diff] [blame] | 530 | derive_ssh1_session_id(host_key->rsa->n, server_key->rsa->n, cookie, session_id); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 531 | |
| 532 | /* Generate a session key. */ |
| 533 | arc4random_stir(); |
| 534 | |
| 535 | /* |
| 536 | * Generate an encryption key for the session. The key is a 256 bit |
| 537 | * random number, interpreted as a 32-byte key, with the least |
| 538 | * significant 8 bits being the first byte of the key. |
| 539 | */ |
| 540 | for (i = 0; i < 32; i++) { |
| 541 | if (i % 4 == 0) |
Darren Tucker | 3f9fdc7 | 2004-06-22 12:56:01 +1000 | [diff] [blame] | 542 | rnd = arc4random(); |
| 543 | session_key[i] = rnd & 0xff; |
| 544 | rnd >>= 8; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 545 | } |
| 546 | |
| 547 | /* |
| 548 | * According to the protocol spec, the first byte of the session key |
| 549 | * is the highest byte of the integer. The session key is xored with |
| 550 | * the first 16 bytes of the session id. |
| 551 | */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 552 | if ((key = BN_new()) == NULL) |
| 553 | fatal("respond_to_rsa_challenge: BN_new failed"); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 554 | BN_set_word(key, 0); |
| 555 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { |
| 556 | BN_lshift(key, key, 8); |
| 557 | if (i < 16) |
| 558 | BN_add_word(key, session_key[i] ^ session_id[i]); |
| 559 | else |
| 560 | BN_add_word(key, session_key[i]); |
| 561 | } |
| 562 | |
| 563 | /* |
| 564 | * Encrypt the integer using the public key and host key of the |
| 565 | * server (key with smaller modulus first). |
| 566 | */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 567 | if (BN_cmp(server_key->rsa->n, host_key->rsa->n) < 0) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 568 | /* Public key has smaller modulus. */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 569 | if (BN_num_bits(host_key->rsa->n) < |
| 570 | BN_num_bits(server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { |
| 571 | fatal("respond_to_rsa_challenge: host_key %d < server_key %d + " |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 572 | "SSH_KEY_BITS_RESERVED %d", |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 573 | BN_num_bits(host_key->rsa->n), |
| 574 | BN_num_bits(server_key->rsa->n), |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 575 | SSH_KEY_BITS_RESERVED); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 576 | } |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 577 | rsa_public_encrypt(key, key, server_key->rsa); |
| 578 | rsa_public_encrypt(key, key, host_key->rsa); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 579 | } else { |
| 580 | /* Host key has smaller modulus (or they are equal). */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 581 | if (BN_num_bits(server_key->rsa->n) < |
| 582 | BN_num_bits(host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { |
| 583 | fatal("respond_to_rsa_challenge: server_key %d < host_key %d + " |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 584 | "SSH_KEY_BITS_RESERVED %d", |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 585 | BN_num_bits(server_key->rsa->n), |
| 586 | BN_num_bits(host_key->rsa->n), |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 587 | SSH_KEY_BITS_RESERVED); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 588 | } |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 589 | rsa_public_encrypt(key, key, host_key->rsa); |
| 590 | rsa_public_encrypt(key, key, server_key->rsa); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 591 | } |
| 592 | |
| 593 | /* Destroy the public keys since we no longer need them. */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 594 | key_free(server_key); |
| 595 | key_free(host_key); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 596 | |
Damien Miller | e39cacc | 2000-11-29 12:18:44 +1100 | [diff] [blame] | 597 | if (options.cipher == SSH_CIPHER_NOT_SET) { |
| 598 | if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default)) |
| 599 | options.cipher = ssh_cipher_default; |
Darren Tucker | 5cb30ad | 2004-08-12 22:40:24 +1000 | [diff] [blame] | 600 | } else if (options.cipher == SSH_CIPHER_INVALID || |
Damien Miller | e39cacc | 2000-11-29 12:18:44 +1100 | [diff] [blame] | 601 | !(cipher_mask_ssh1(1) & (1 << options.cipher))) { |
Damien Miller | 996acd2 | 2003-04-09 20:59:48 +1000 | [diff] [blame] | 602 | logit("No valid SSH1 cipher, using %.100s instead.", |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 603 | cipher_name(ssh_cipher_default)); |
| 604 | options.cipher = ssh_cipher_default; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 605 | } |
| 606 | /* Check that the selected cipher is supported. */ |
| 607 | if (!(supported_ciphers & (1 << options.cipher))) |
| 608 | fatal("Selected cipher type %.100s not supported by server.", |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 609 | cipher_name(options.cipher)); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 610 | |
| 611 | debug("Encryption type: %.100s", cipher_name(options.cipher)); |
| 612 | |
| 613 | /* Send the encrypted session key to the server. */ |
| 614 | packet_start(SSH_CMSG_SESSION_KEY); |
| 615 | packet_put_char(options.cipher); |
| 616 | |
| 617 | /* Send the cookie back to the server. */ |
| 618 | for (i = 0; i < 8; i++) |
| 619 | packet_put_char(cookie[i]); |
| 620 | |
| 621 | /* Send and destroy the encrypted encryption key integer. */ |
| 622 | packet_put_bignum(key); |
| 623 | BN_clear_free(key); |
| 624 | |
| 625 | /* Send protocol flags. */ |
| 626 | packet_put_int(client_flags); |
| 627 | |
| 628 | /* Send the packet now. */ |
| 629 | packet_send(); |
| 630 | packet_write_wait(); |
| 631 | |
| 632 | debug("Sent encrypted session key."); |
| 633 | |
| 634 | /* Set the encryption key. */ |
| 635 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); |
| 636 | |
| 637 | /* We will no longer need the session key here. Destroy any extra copies. */ |
| 638 | memset(session_key, 0, sizeof(session_key)); |
| 639 | |
| 640 | /* |
| 641 | * Expect a success message from the server. Note that this message |
| 642 | * will be received in encrypted form. |
| 643 | */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 644 | packet_read_expect(SSH_SMSG_SUCCESS); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 645 | |
| 646 | debug("Received encrypted confirmation."); |
| 647 | } |
| 648 | |
| 649 | /* |
| 650 | * Authenticate user |
| 651 | */ |
| 652 | void |
Ben Lindstrom | 5eabda3 | 2001-04-12 23:34:34 +0000 | [diff] [blame] | 653 | ssh_userauth1(const char *local_user, const char *server_user, char *host, |
Ben Lindstrom | 1bad256 | 2002-06-06 19:57:33 +0000 | [diff] [blame] | 654 | Sensitive *sensitive) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 655 | { |
| 656 | int i, type; |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 657 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 658 | if (supported_authentications == 0) |
Ben Lindstrom | 5eabda3 | 2001-04-12 23:34:34 +0000 | [diff] [blame] | 659 | fatal("ssh_userauth1: server supports no auth methods"); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 660 | |
| 661 | /* Send the name of the user to log in as on the server. */ |
| 662 | packet_start(SSH_CMSG_USER); |
Ben Lindstrom | 664408d | 2001-06-09 01:42:01 +0000 | [diff] [blame] | 663 | packet_put_cstring(server_user); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 664 | packet_send(); |
| 665 | packet_write_wait(); |
| 666 | |
| 667 | /* |
| 668 | * The server should respond with success if no authentication is |
| 669 | * needed (the user has no password). Otherwise the server responds |
| 670 | * with failure. |
| 671 | */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 672 | type = packet_read(); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 673 | |
| 674 | /* check whether the connection was accepted without authentication. */ |
| 675 | if (type == SSH_SMSG_SUCCESS) |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 676 | goto success; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 677 | if (type != SSH_SMSG_FAILURE) |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 678 | packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", type); |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 679 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 680 | /* |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 681 | * Try .rhosts or /etc/hosts.equiv authentication with RSA host |
| 682 | * authentication. |
| 683 | */ |
| 684 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && |
Ben Lindstrom | 5eabda3 | 2001-04-12 23:34:34 +0000 | [diff] [blame] | 685 | options.rhosts_rsa_authentication) { |
Ben Lindstrom | 1bad256 | 2002-06-06 19:57:33 +0000 | [diff] [blame] | 686 | for (i = 0; i < sensitive->nkeys; i++) { |
| 687 | if (sensitive->keys[i] != NULL && |
| 688 | sensitive->keys[i]->type == KEY_RSA1 && |
| 689 | try_rhosts_rsa_authentication(local_user, |
| 690 | sensitive->keys[i])) |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 691 | goto success; |
Ben Lindstrom | 5eabda3 | 2001-04-12 23:34:34 +0000 | [diff] [blame] | 692 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 693 | } |
| 694 | /* Try RSA authentication if the server supports it. */ |
| 695 | if ((supported_authentications & (1 << SSH_AUTH_RSA)) && |
| 696 | options.rsa_authentication) { |
| 697 | /* |
| 698 | * Try RSA authentication using the authentication agent. The |
| 699 | * agent is tried first because no passphrase is needed for |
| 700 | * it, whereas identity files may require passphrases. |
| 701 | */ |
| 702 | if (try_agent_authentication()) |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 703 | goto success; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 704 | |
| 705 | /* Try RSA authentication for each identity. */ |
| 706 | for (i = 0; i < options.num_identity_files; i++) |
Ben Lindstrom | 266dfdf | 2001-03-09 00:12:22 +0000 | [diff] [blame] | 707 | if (options.identity_keys[i] != NULL && |
| 708 | options.identity_keys[i]->type == KEY_RSA1 && |
Ben Lindstrom | c5b6800 | 2001-07-04 04:52:03 +0000 | [diff] [blame] | 709 | try_rsa_authentication(i)) |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 710 | goto success; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 711 | } |
Ben Lindstrom | 95fb2dd | 2001-01-23 03:12:10 +0000 | [diff] [blame] | 712 | /* Try challenge response authentication if the server supports it. */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 713 | if ((supported_authentications & (1 << SSH_AUTH_TIS)) && |
Ben Lindstrom | 551ea37 | 2001-06-05 18:56:16 +0000 | [diff] [blame] | 714 | options.challenge_response_authentication && !options.batch_mode) { |
| 715 | if (try_challenge_response_authentication()) |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 716 | goto success; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 717 | } |
| 718 | /* Try password authentication if the server supports it. */ |
| 719 | if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && |
| 720 | options.password_authentication && !options.batch_mode) { |
| 721 | char prompt[80]; |
| 722 | |
Ben Lindstrom | e055716 | 2001-02-11 00:00:24 +0000 | [diff] [blame] | 723 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 724 | server_user, host); |
| 725 | if (try_password_authentication(prompt)) |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 726 | goto success; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 727 | } |
| 728 | /* All authentication methods have failed. Exit with an error message. */ |
| 729 | fatal("Permission denied."); |
| 730 | /* NOTREACHED */ |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 731 | |
| 732 | success: |
Damien Miller | 40eb1d8 | 2001-07-14 12:16:59 +1000 | [diff] [blame] | 733 | return; /* need statement after label */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 734 | } |