1 /* 2 * Dropbear SSH 3 * 4 * Copyright (c) 2002,2003 Matt Johnston 5 * Copyright (c) 2004 by Mihnea Stoenescu 6 * All rights reserved. 7 * 8 * Permission is hereby granted, free of charge, to any person obtaining a copy 9 * of this software and associated documentation files (the "Software"), to deal 10 * in the Software without restriction, including without limitation the rights 11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 12 * copies of the Software, and to permit persons to whom the Software is 13 * furnished to do so, subject to the following conditions: 14 * 15 * The above copyright notice and this permission notice shall be included in 16 * all copies or substantial portions of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 24 * SOFTWARE. */ 25 26 #include "includes.h" 27 #include "buffer.h" 28 #include "dbutil.h" 29 #include "session.h" 30 #include "ssh.h" 31 #include "runopts.h" 32 #include "auth.h" 33 34 #ifdef ENABLE_CLI_PUBKEY_AUTH 35 static void send_msg_userauth_pubkey(sign_key *key, int type, int realsign); 36 37 /* Called when we receive a SSH_MSG_USERAUTH_FAILURE for a pubkey request. 38 * We use it to remove the key we tried from the list */ 39 void cli_pubkeyfail() { 40 41 struct SignKeyList *keyitem; 42 struct SignKeyList **previtem; 43 44 TRACE(("enter cli_pubkeyfail")) 45 previtem = &cli_opts.privkeys; 46 47 /* Find the key we failed with, and remove it */ 48 for (keyitem = cli_opts.privkeys; keyitem != NULL; keyitem = keyitem->next) { 49 if (keyitem == cli_ses.lastprivkey) { 50 *previtem = keyitem->next; 51 } 52 previtem = &keyitem; 53 } 54 55 sign_key_free(cli_ses.lastprivkey->key); /* It won't be used again */ 56 m_free(cli_ses.lastprivkey); 57 58 TRACE(("leave cli_pubkeyfail")) 59 } 60 61 void recv_msg_userauth_pk_ok() { 62 63 struct SignKeyList *keyitem = NULL; 64 buffer* keybuf = NULL; 65 char* algotype = NULL; 66 unsigned int algolen; 67 int keytype; 68 unsigned int remotelen; 69 70 TRACE(("enter recv_msg_userauth_pk_ok")) 71 72 algotype = buf_getstring(ses.payload, &algolen); 73 keytype = signkey_type_from_name(algotype, algolen); 74 TRACE(("recv_msg_userauth_pk_ok: type %d", keytype)) 75 m_free(algotype); 76 77 keybuf = buf_new(MAX_PUBKEY_SIZE); 78 79 remotelen = buf_getint(ses.payload); 80 81 /* Iterate through our keys, find which one it was that matched, and 82 * send a real request with that key */ 83 for (keyitem = cli_opts.privkeys; keyitem != NULL; keyitem = keyitem->next) { 84 85 if (keyitem->type != keytype) { 86 /* Types differed */ 87 TRACE(("types differed")) 88 continue; 89 } 90 91 /* Now we compare the contents of the key */ 92 keybuf->pos = keybuf->len = 0; 93 buf_put_pub_key(keybuf, keyitem->key, keytype); 94 buf_setpos(keybuf, 0); 95 buf_incrpos(keybuf, 4); /* first int is the length of the remainder (ie 96 remotelen) which has already been taken from 97 the remote buffer */ 98 99 100 if (keybuf->len-4 != remotelen) { 101 TRACE(("lengths differed: localh %d remote %d", keybuf->len, remotelen)) 102 /* Lengths differed */ 103 continue; 104 } 105 if (memcmp(buf_getptr(keybuf, remotelen), 106 buf_getptr(ses.payload, remotelen), remotelen) != 0) { 107 /* Data didn't match this key */ 108 TRACE(("data differed")) 109 continue; 110 } 111 112 /* Success */ 113 break; 114 } 115 buf_free(keybuf); 116 117 if (keyitem != NULL) { 118 TRACE(("matching key")) 119 /* XXX TODO: if it's an encrypted key, here we ask for their 120 * password */ 121 send_msg_userauth_pubkey(keyitem->key, keytype, 1); 122 } else { 123 TRACE(("That was whacky. We got told that a key was valid, but it didn't match our list. Sounds like dodgy code on Dropbear's part")) 124 } 125 126 TRACE(("leave recv_msg_userauth_pk_ok")) 127 } 128 129 /* TODO: make it take an agent reference to use as well */ 130 static void send_msg_userauth_pubkey(sign_key *key, int type, int realsign) { 131 132 const char *algoname = NULL; 133 int algolen; 134 buffer* sigbuf = NULL; 135 136 TRACE(("enter send_msg_userauth_pubkey")) 137 CHECKCLEARTOWRITE(); 138 139 buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_REQUEST); 140 141 buf_putstring(ses.writepayload, cli_opts.username, 142 strlen(cli_opts.username)); 143 144 buf_putstring(ses.writepayload, SSH_SERVICE_CONNECTION, 145 SSH_SERVICE_CONNECTION_LEN); 146 147 buf_putstring(ses.writepayload, AUTH_METHOD_PUBKEY, 148 AUTH_METHOD_PUBKEY_LEN); 149 150 buf_putbyte(ses.writepayload, realsign); 151 152 algoname = signkey_name_from_type(type, &algolen); 153 154 buf_putstring(ses.writepayload, algoname, algolen); 155 buf_put_pub_key(ses.writepayload, key, type); 156 157 if (realsign) { 158 TRACE(("realsign")) 159 /* We put the signature as well - this contains string(session id), then 160 * the contents of the write payload to this point */ 161 sigbuf = buf_new(4 + SHA1_HASH_SIZE + ses.writepayload->len); 162 buf_putstring(sigbuf, ses.session_id, SHA1_HASH_SIZE); 163 buf_putbytes(sigbuf, ses.writepayload->data, ses.writepayload->len); 164 buf_put_sign(ses.writepayload, key, type, sigbuf->data, sigbuf->len); 165 buf_free(sigbuf); /* Nothing confidential in the buffer */ 166 } 167 168 encrypt_packet(); 169 TRACE(("leave send_msg_userauth_pubkey")) 170 } 171 172 int cli_auth_pubkey() { 173 174 TRACE(("enter cli_auth_pubkey")) 175 176 if (cli_opts.privkeys != NULL) { 177 /* Send a trial request */ 178 send_msg_userauth_pubkey(cli_opts.privkeys->key, 179 cli_opts.privkeys->type, 0); 180 cli_ses.lastprivkey = cli_opts.privkeys; 181 TRACE(("leave cli_auth_pubkey-success")) 182 return 1; 183 } else { 184 TRACE(("leave cli_auth_pubkey-failure")) 185 return 0; 186 } 187 } 188 #endif /* Pubkey auth */ 189
