| /* |
| * Copyright (c) 2000 Markus Friedl. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "includes.h" |
| RCSID("$OpenBSD: sshconnect2.c,v 1.77 2001/06/24 05:35:34 markus Exp $"); |
| |
| #include <openssl/bn.h> |
| #include <openssl/md5.h> |
| #include <openssl/dh.h> |
| #include <openssl/hmac.h> |
| |
| #include "ssh.h" |
| #include "ssh2.h" |
| #include "xmalloc.h" |
| #include "rsa.h" |
| #include "buffer.h" |
| #include "packet.h" |
| #include "uidswap.h" |
| #include "compat.h" |
| #include "bufaux.h" |
| #include "cipher.h" |
| #include "kex.h" |
| #include "myproposal.h" |
| #include "key.h" |
| #include "sshconnect.h" |
| #include "authfile.h" |
| #include "dh.h" |
| #include "authfd.h" |
| #include "log.h" |
| #include "readconf.h" |
| #include "readpass.h" |
| #include "match.h" |
| #include "dispatch.h" |
| #include "canohost.h" |
| |
| /* import */ |
| extern char *client_version_string; |
| extern char *server_version_string; |
| extern Options options; |
| |
| /* |
| * SSH2 key exchange |
| */ |
| |
| u_char *session_id2 = NULL; |
| int session_id2_len = 0; |
| |
| char *xxx_host; |
| struct sockaddr *xxx_hostaddr; |
| |
| Kex *xxx_kex = NULL; |
| |
| static int |
| verify_host_key_callback(Key *hostkey) |
| { |
| if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) |
| fatal("verify_host_key failed"); |
| return 0; |
| } |
| |
| void |
| ssh_kex2(char *host, struct sockaddr *hostaddr) |
| { |
| Kex *kex; |
| |
| xxx_host = host; |
| xxx_hostaddr = hostaddr; |
| |
| if (options.ciphers == (char *)-1) { |
| log("No valid ciphers for protocol version 2 given, using defaults."); |
| options.ciphers = NULL; |
| } |
| if (options.ciphers != NULL) { |
| myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
| myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
| } |
| myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
| compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); |
| myproposal[PROPOSAL_ENC_ALGS_STOC] = |
| compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); |
| if (options.compression) { |
| myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
| myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; |
| } else { |
| myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
| myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
| } |
| if (options.macs != NULL) { |
| myproposal[PROPOSAL_MAC_ALGS_CTOS] = |
| myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; |
| } |
| if (options.hostkeyalgorithms != NULL) |
| myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = |
| options.hostkeyalgorithms; |
| |
| /* start key exchange */ |
| kex = kex_setup(myproposal); |
| kex->client_version_string=client_version_string; |
| kex->server_version_string=server_version_string; |
| kex->verify_host_key=&verify_host_key_callback; |
| |
| xxx_kex = kex; |
| |
| dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
| |
| session_id2 = kex->session_id; |
| session_id2_len = kex->session_id_len; |
| |
| #ifdef DEBUG_KEXDH |
| /* send 1st encrypted/maced/compressed message */ |
| packet_start(SSH2_MSG_IGNORE); |
| packet_put_cstring("markus"); |
| packet_send(); |
| packet_write_wait(); |
| #endif |
| debug("done: ssh_kex2."); |
| } |
| |
| /* |
| * Authenticate user |
| */ |
| |
| typedef struct Authctxt Authctxt; |
| typedef struct Authmethod Authmethod; |
| |
| typedef int sign_cb_fn( |
| Authctxt *authctxt, Key *key, |
| u_char **sigp, int *lenp, u_char *data, int datalen); |
| |
| struct Authctxt { |
| const char *server_user; |
| const char *local_user; |
| const char *host; |
| const char *service; |
| Authmethod *method; |
| int success; |
| char *authlist; |
| /* pubkey */ |
| Key *last_key; |
| sign_cb_fn *last_key_sign; |
| int last_key_hint; |
| AuthenticationConnection *agent; |
| /* hostbased */ |
| Key **keys; |
| int nkeys; |
| }; |
| struct Authmethod { |
| char *name; /* string to compare against server's list */ |
| int (*userauth)(Authctxt *authctxt); |
| int *enabled; /* flag in option struct that enables method */ |
| int *batch_flag; /* flag in option struct that disables method */ |
| }; |
| |
| void input_userauth_success(int type, int plen, void *ctxt); |
| void input_userauth_failure(int type, int plen, void *ctxt); |
| void input_userauth_banner(int type, int plen, void *ctxt); |
| void input_userauth_error(int type, int plen, void *ctxt); |
| void input_userauth_info_req(int type, int plen, void *ctxt); |
| void input_userauth_pk_ok(int type, int plen, void *ctxt); |
| |
| int userauth_none(Authctxt *authctxt); |
| int userauth_pubkey(Authctxt *authctxt); |
| int userauth_passwd(Authctxt *authctxt); |
| int userauth_kbdint(Authctxt *authctxt); |
| int userauth_hostbased(Authctxt *authctxt); |
| |
| void userauth(Authctxt *authctxt, char *authlist); |
| |
| static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *); |
| static void clear_auth_state(Authctxt *); |
| |
| static Authmethod *authmethod_get(char *authlist); |
| static Authmethod *authmethod_lookup(const char *name); |
| static char *authmethods_get(void); |
| |
| Authmethod authmethods[] = { |
| {"publickey", |
| userauth_pubkey, |
| &options.pubkey_authentication, |
| NULL}, |
| {"hostbased", |
| userauth_hostbased, |
| &options.hostbased_authentication, |
| NULL}, |
| {"password", |
| userauth_passwd, |
| &options.password_authentication, |
| &options.batch_mode}, |
| {"keyboard-interactive", |
| userauth_kbdint, |
| &options.kbd_interactive_authentication, |
| &options.batch_mode}, |
| {"none", |
| userauth_none, |
| NULL, |
| NULL}, |
| {NULL, NULL, NULL, NULL} |
| }; |
| |
| void |
| ssh_userauth2(const char *local_user, const char *server_user, char *host, |
| Key **keys, int nkeys) |
| { |
| Authctxt authctxt; |
| int type; |
| int plen; |
| |
| if (options.challenge_response_authentication) |
| options.kbd_interactive_authentication = 1; |
| |
| debug("send SSH2_MSG_SERVICE_REQUEST"); |
| packet_start(SSH2_MSG_SERVICE_REQUEST); |
| packet_put_cstring("ssh-userauth"); |
| packet_send(); |
| packet_write_wait(); |
| type = packet_read(&plen); |
| if (type != SSH2_MSG_SERVICE_ACCEPT) { |
| fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); |
| } |
| if (packet_remaining() > 0) { |
| char *reply = packet_get_string(&plen); |
| debug("service_accept: %s", reply); |
| xfree(reply); |
| } else { |
| debug("buggy server: service_accept w/o service"); |
| } |
| packet_done(); |
| debug("got SSH2_MSG_SERVICE_ACCEPT"); |
| |
| if (options.preferred_authentications == NULL) |
| options.preferred_authentications = authmethods_get(); |
| |
| /* setup authentication context */ |
| authctxt.agent = ssh_get_authentication_connection(); |
| authctxt.server_user = server_user; |
| authctxt.local_user = local_user; |
| authctxt.host = host; |
| authctxt.service = "ssh-connection"; /* service name */ |
| authctxt.success = 0; |
| authctxt.method = authmethod_lookup("none"); |
| authctxt.authlist = NULL; |
| authctxt.keys = keys; |
| authctxt.nkeys = nkeys; |
| if (authctxt.method == NULL) |
| fatal("ssh_userauth2: internal error: cannot send userauth none request"); |
| |
| /* initial userauth request */ |
| userauth_none(&authctxt); |
| |
| dispatch_init(&input_userauth_error); |
| dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); |
| dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); |
| dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
| dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
| |
| if (authctxt.agent != NULL) |
| ssh_close_authentication_connection(authctxt.agent); |
| |
| debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
| } |
| void |
| userauth(Authctxt *authctxt, char *authlist) |
| { |
| if (authlist == NULL) { |
| authlist = authctxt->authlist; |
| } else { |
| if (authctxt->authlist) |
| xfree(authctxt->authlist); |
| authctxt->authlist = authlist; |
| } |
| for (;;) { |
| Authmethod *method = authmethod_get(authlist); |
| if (method == NULL) |
| fatal("Permission denied (%s).", authlist); |
| authctxt->method = method; |
| if (method->userauth(authctxt) != 0) { |
| debug2("we sent a %s packet, wait for reply", method->name); |
| break; |
| } else { |
| debug2("we did not send a packet, disable method"); |
| method->enabled = NULL; |
| } |
| } |
| } |
| void |
| input_userauth_error(int type, int plen, void *ctxt) |
| { |
| fatal("input_userauth_error: bad message during authentication: " |
| "type %d", type); |
| } |
| void |
| input_userauth_banner(int type, int plen, void *ctxt) |
| { |
| char *msg, *lang; |
| debug3("input_userauth_banner"); |
| msg = packet_get_string(NULL); |
| lang = packet_get_string(NULL); |
| fprintf(stderr, "%s", msg); |
| xfree(msg); |
| xfree(lang); |
| } |
| void |
| input_userauth_success(int type, int plen, void *ctxt) |
| { |
| Authctxt *authctxt = ctxt; |
| if (authctxt == NULL) |
| fatal("input_userauth_success: no authentication context"); |
| if (authctxt->authlist) |
| xfree(authctxt->authlist); |
| clear_auth_state(authctxt); |
| authctxt->success = 1; /* break out */ |
| } |
| void |
| input_userauth_failure(int type, int plen, void *ctxt) |
| { |
| Authctxt *authctxt = ctxt; |
| char *authlist = NULL; |
| int partial; |
| |
| if (authctxt == NULL) |
| fatal("input_userauth_failure: no authentication context"); |
| |
| authlist = packet_get_string(NULL); |
| partial = packet_get_char(); |
| packet_done(); |
| |
| if (partial != 0) |
| log("Authenticated with partial success."); |
| debug("authentications that can continue: %s", authlist); |
| |
| clear_auth_state(authctxt); |
| userauth(authctxt, authlist); |
| } |
| void |
| input_userauth_pk_ok(int type, int plen, void *ctxt) |
| { |
| Authctxt *authctxt = ctxt; |
| Key *key = NULL; |
| Buffer b; |
| int alen, blen, sent = 0; |
| char *pkalg, *pkblob, *fp; |
| |
| if (authctxt == NULL) |
| fatal("input_userauth_pk_ok: no authentication context"); |
| if (datafellows & SSH_BUG_PKOK) { |
| /* this is similar to SSH_BUG_PKAUTH */ |
| debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); |
| pkblob = packet_get_string(&blen); |
| buffer_init(&b); |
| buffer_append(&b, pkblob, blen); |
| pkalg = buffer_get_string(&b, &alen); |
| buffer_free(&b); |
| } else { |
| pkalg = packet_get_string(&alen); |
| pkblob = packet_get_string(&blen); |
| } |
| packet_done(); |
| |
| debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", |
| pkalg, blen, authctxt->last_key, authctxt->last_key_hint); |
| |
| do { |
| if (authctxt->last_key == NULL || |
| authctxt->last_key_sign == NULL) { |
| debug("no last key or no sign cb"); |
| break; |
| } |
| if (key_type_from_name(pkalg) == KEY_UNSPEC) { |
| debug("unknown pkalg %s", pkalg); |
| break; |
| } |
| if ((key = key_from_blob(pkblob, blen)) == NULL) { |
| debug("no key from blob. pkalg %s", pkalg); |
| break; |
| } |
| fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
| debug2("input_userauth_pk_ok: fp %s", fp); |
| xfree(fp); |
| if (!key_equal(key, authctxt->last_key)) { |
| debug("key != last_key"); |
| break; |
| } |
| sent = sign_and_send_pubkey(authctxt, key, |
| authctxt->last_key_sign); |
| } while(0); |
| |
| if (key != NULL) |
| key_free(key); |
| xfree(pkalg); |
| xfree(pkblob); |
| |
| /* unregister */ |
| clear_auth_state(authctxt); |
| dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); |
| |
| /* try another method if we did not send a packet*/ |
| if (sent == 0) |
| userauth(authctxt, NULL); |
| |
| } |
| |
| int |
| userauth_none(Authctxt *authctxt) |
| { |
| /* initial userauth request */ |
| packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| packet_put_cstring(authctxt->server_user); |
| packet_put_cstring(authctxt->service); |
| packet_put_cstring(authctxt->method->name); |
| packet_send(); |
| return 1; |
| } |
| |
| int |
| userauth_passwd(Authctxt *authctxt) |
| { |
| static int attempt = 0; |
| char prompt[80]; |
| char *password; |
| |
| if (attempt++ >= options.number_of_password_prompts) |
| return 0; |
| |
| if(attempt != 1) |
| error("Permission denied, please try again."); |
| |
| snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
| authctxt->server_user, authctxt->host); |
| password = read_passphrase(prompt, 0); |
| packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| packet_put_cstring(authctxt->server_user); |
| packet_put_cstring(authctxt->service); |
| packet_put_cstring(authctxt->method->name); |
| packet_put_char(0); |
| packet_put_cstring(password); |
| memset(password, 0, strlen(password)); |
| xfree(password); |
| packet_inject_ignore(64); |
| packet_send(); |
| return 1; |
| } |
| |
| void |
| clear_auth_state(Authctxt *authctxt) |
| { |
| /* XXX clear authentication state */ |
| if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { |
| debug3("clear_auth_state: key_free %p", authctxt->last_key); |
| key_free(authctxt->last_key); |
| } |
| authctxt->last_key = NULL; |
| authctxt->last_key_hint = -2; |
| authctxt->last_key_sign = NULL; |
| } |
| |
| static int |
| sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
| { |
| Buffer b; |
| u_char *blob, *signature; |
| int bloblen, slen; |
| int skip = 0; |
| int ret = -1; |
| int have_sig = 1; |
| |
| debug3("sign_and_send_pubkey"); |
| |
| if (key_to_blob(k, &blob, &bloblen) == 0) { |
| /* we cannot handle this key */ |
| debug3("sign_and_send_pubkey: cannot handle key"); |
| return 0; |
| } |
| /* data to be signed */ |
| buffer_init(&b); |
| if (datafellows & SSH_OLD_SESSIONID) { |
| buffer_append(&b, session_id2, session_id2_len); |
| skip = session_id2_len; |
| } else { |
| buffer_put_string(&b, session_id2, session_id2_len); |
| skip = buffer_len(&b); |
| } |
| buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
| buffer_put_cstring(&b, authctxt->server_user); |
| buffer_put_cstring(&b, |
| datafellows & SSH_BUG_PKSERVICE ? |
| "ssh-userauth" : |
| authctxt->service); |
| if (datafellows & SSH_BUG_PKAUTH) { |
| buffer_put_char(&b, have_sig); |
| } else { |
| buffer_put_cstring(&b, authctxt->method->name); |
| buffer_put_char(&b, have_sig); |
| buffer_put_cstring(&b, key_ssh_name(k)); |
| } |
| buffer_put_string(&b, blob, bloblen); |
| |
| /* generate signature */ |
| ret = (*sign_callback)(authctxt, k, &signature, &slen, |
| buffer_ptr(&b), buffer_len(&b)); |
| if (ret == -1) { |
| xfree(blob); |
| buffer_free(&b); |
| return 0; |
| } |
| #ifdef DEBUG_PK |
| buffer_dump(&b); |
| #endif |
| if (datafellows & SSH_BUG_PKSERVICE) { |
| buffer_clear(&b); |
| buffer_append(&b, session_id2, session_id2_len); |
| skip = session_id2_len; |
| buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
| buffer_put_cstring(&b, authctxt->server_user); |
| buffer_put_cstring(&b, authctxt->service); |
| buffer_put_cstring(&b, authctxt->method->name); |
| buffer_put_char(&b, have_sig); |
| if (!(datafellows & SSH_BUG_PKAUTH)) |
| buffer_put_cstring(&b, key_ssh_name(k)); |
| buffer_put_string(&b, blob, bloblen); |
| } |
| xfree(blob); |
| |
| /* append signature */ |
| buffer_put_string(&b, signature, slen); |
| xfree(signature); |
| |
| /* skip session id and packet type */ |
| if (buffer_len(&b) < skip + 1) |
| fatal("userauth_pubkey: internal error"); |
| buffer_consume(&b, skip + 1); |
| |
| /* put remaining data from buffer into packet */ |
| packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| packet_put_raw(buffer_ptr(&b), buffer_len(&b)); |
| buffer_free(&b); |
| packet_send(); |
| |
| return 1; |
| } |
| |
| static int |
| send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
| int hint) |
| { |
| u_char *blob; |
| int bloblen, have_sig = 0; |
| |
| debug3("send_pubkey_test"); |
| |
| if (key_to_blob(k, &blob, &bloblen) == 0) { |
| /* we cannot handle this key */ |
| debug3("send_pubkey_test: cannot handle key"); |
| return 0; |
| } |
| /* register callback for USERAUTH_PK_OK message */ |
| authctxt->last_key_sign = sign_callback; |
| authctxt->last_key_hint = hint; |
| authctxt->last_key = k; |
| dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); |
| |
| packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| packet_put_cstring(authctxt->server_user); |
| packet_put_cstring(authctxt->service); |
| packet_put_cstring(authctxt->method->name); |
| packet_put_char(have_sig); |
| if (!(datafellows & SSH_BUG_PKAUTH)) |
| packet_put_cstring(key_ssh_name(k)); |
| packet_put_string(blob, bloblen); |
| xfree(blob); |
| packet_send(); |
| return 1; |
| } |
| |
| static Key * |
| load_identity_file(char *filename) |
| { |
| Key *private; |
| char prompt[300], *passphrase; |
| int quit, i; |
| struct stat st; |
| |
| if (stat(filename, &st) < 0) { |
| debug3("no such identity: %s", filename); |
| return NULL; |
| } |
| private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); |
| if (private == NULL) { |
| if (options.batch_mode) |
| return NULL; |
| snprintf(prompt, sizeof prompt, |
| "Enter passphrase for key '%.100s': ", filename); |
| for (i = 0; i < options.number_of_password_prompts; i++) { |
| passphrase = read_passphrase(prompt, 0); |
| if (strcmp(passphrase, "") != 0) { |
| private = key_load_private_type(KEY_UNSPEC, filename, |
| passphrase, NULL); |
| quit = 0; |
| } else { |
| debug2("no passphrase given, try next key"); |
| quit = 1; |
| } |
| memset(passphrase, 0, strlen(passphrase)); |
| xfree(passphrase); |
| if (private != NULL || quit) |
| break; |
| debug2("bad passphrase given, try again..."); |
| } |
| } |
| return private; |
| } |
| |
| static int |
| identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
| u_char *data, int datalen) |
| { |
| Key *private; |
| int idx, ret; |
| |
| idx = authctxt->last_key_hint; |
| if (idx < 0) |
| return -1; |
| private = load_identity_file(options.identity_files[idx]); |
| if (private == NULL) |
| return -1; |
| ret = key_sign(private, sigp, lenp, data, datalen); |
| key_free(private); |
| return ret; |
| } |
| |
| static int |
| agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
| u_char *data, int datalen) |
| { |
| return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
| } |
| |
| static int |
| key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
| u_char *data, int datalen) |
| { |
| return key_sign(key, sigp, lenp, data, datalen); |
| } |
| |
| static int |
| userauth_pubkey_agent(Authctxt *authctxt) |
| { |
| static int called = 0; |
| int ret = 0; |
| char *comment; |
| Key *k; |
| |
| if (called == 0) { |
| if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
| debug2("userauth_pubkey_agent: no keys at all"); |
| called = 1; |
| } |
| k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
| if (k == NULL) { |
| debug2("userauth_pubkey_agent: no more keys"); |
| } else { |
| debug("userauth_pubkey_agent: testing agent key %s", comment); |
| xfree(comment); |
| ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
| if (ret == 0) |
| key_free(k); |
| } |
| if (ret == 0) |
| debug2("userauth_pubkey_agent: no message sent"); |
| return ret; |
| } |
| |
| int |
| userauth_pubkey(Authctxt *authctxt) |
| { |
| static int idx = 0; |
| int sent = 0; |
| Key *key; |
| char *filename; |
| |
| if (authctxt->agent != NULL) { |
| do { |
| sent = userauth_pubkey_agent(authctxt); |
| } while(!sent && authctxt->agent->howmany > 0); |
| } |
| while (!sent && idx < options.num_identity_files) { |
| key = options.identity_keys[idx]; |
| filename = options.identity_files[idx]; |
| if (key == NULL) { |
| debug("try privkey: %s", filename); |
| key = load_identity_file(filename); |
| if (key != NULL) { |
| sent = sign_and_send_pubkey(authctxt, key, |
| key_sign_cb); |
| key_free(key); |
| } |
| } else if (key->type != KEY_RSA1) { |
| debug("try pubkey: %s", filename); |
| sent = send_pubkey_test(authctxt, key, |
| identity_sign_cb, idx); |
| } |
| idx++; |
| } |
| return sent; |
| } |
| |
| /* |
| * Send userauth request message specifying keyboard-interactive method. |
| */ |
| int |
| userauth_kbdint(Authctxt *authctxt) |
| { |
| static int attempt = 0; |
| |
| if (attempt++ >= options.number_of_password_prompts) |
| return 0; |
| |
| debug2("userauth_kbdint"); |
| packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| packet_put_cstring(authctxt->server_user); |
| packet_put_cstring(authctxt->service); |
| packet_put_cstring(authctxt->method->name); |
| packet_put_cstring(""); /* lang */ |
| packet_put_cstring(options.kbd_interactive_devices ? |
| options.kbd_interactive_devices : ""); |
| packet_send(); |
| |
| dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); |
| return 1; |
| } |
| |
| /* |
| * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
| */ |
| void |
| input_userauth_info_req(int type, int plen, void *ctxt) |
| { |
| Authctxt *authctxt = ctxt; |
| char *name, *inst, *lang, *prompt, *response; |
| u_int num_prompts, i; |
| int echo = 0; |
| |
| debug2("input_userauth_info_req"); |
| |
| if (authctxt == NULL) |
| fatal("input_userauth_info_req: no authentication context"); |
| |
| name = packet_get_string(NULL); |
| inst = packet_get_string(NULL); |
| lang = packet_get_string(NULL); |
| if (strlen(name) > 0) |
| log(name); |
| if (strlen(inst) > 0) |
| log(inst); |
| xfree(name); |
| xfree(inst); |
| xfree(lang); |
| |
| num_prompts = packet_get_int(); |
| /* |
| * Begin to build info response packet based on prompts requested. |
| * We commit to providing the correct number of responses, so if |
| * further on we run into a problem that prevents this, we have to |
| * be sure and clean this up and send a correct error response. |
| */ |
| packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); |
| packet_put_int(num_prompts); |
| |
| debug2("input_userauth_info_req: num_prompts %d", num_prompts); |
| for (i = 0; i < num_prompts; i++) { |
| prompt = packet_get_string(NULL); |
| echo = packet_get_char(); |
| |
| response = read_passphrase(prompt, echo ? RP_ECHO : 0); |
| |
| packet_put_cstring(response); |
| memset(response, 0, strlen(response)); |
| xfree(response); |
| xfree(prompt); |
| } |
| packet_done(); /* done with parsing incoming message. */ |
| |
| packet_inject_ignore(64); |
| packet_send(); |
| } |
| |
| /* |
| * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign |
| * will be setuid-root and the sbit can be removed from /usr/bin/ssh. |
| */ |
| int |
| userauth_hostbased(Authctxt *authctxt) |
| { |
| Key *private = NULL; |
| Buffer b; |
| u_char *signature, *blob; |
| char *chost, *pkalg, *p; |
| const char *service; |
| u_int blen, slen; |
| int ok, i, len, found = 0; |
| |
| p = get_local_name(packet_get_connection_in()); |
| if (p == NULL) { |
| error("userauth_hostbased: cannot get local ipaddr/name"); |
| return 0; |
| } |
| len = strlen(p) + 2; |
| chost = xmalloc(len); |
| strlcpy(chost, p, len); |
| strlcat(chost, ".", len); |
| debug2("userauth_hostbased: chost %s", chost); |
| /* check for a useful key */ |
| for (i = 0; i < authctxt->nkeys; i++) { |
| private = authctxt->keys[i]; |
| if (private && private->type != KEY_RSA1) { |
| found = 1; |
| /* we take and free the key */ |
| authctxt->keys[i] = NULL; |
| break; |
| } |
| } |
| if (!found) { |
| xfree(chost); |
| return 0; |
| } |
| if (key_to_blob(private, &blob, &blen) == 0) { |
| key_free(private); |
| xfree(chost); |
| return 0; |
| } |
| service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : |
| authctxt->service; |
| pkalg = xstrdup(key_ssh_name(private)); |
| buffer_init(&b); |
| /* construct data */ |
| buffer_put_string(&b, session_id2, session_id2_len); |
| buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
| buffer_put_cstring(&b, authctxt->server_user); |
| buffer_put_cstring(&b, service); |
| buffer_put_cstring(&b, authctxt->method->name); |
| buffer_put_cstring(&b, pkalg); |
| buffer_put_string(&b, blob, blen); |
| buffer_put_cstring(&b, chost); |
| buffer_put_cstring(&b, authctxt->local_user); |
| #ifdef DEBUG_PK |
| buffer_dump(&b); |
| #endif |
| debug2("xxx: chost %s", chost); |
| ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b)); |
| key_free(private); |
| buffer_free(&b); |
| if (ok != 0) { |
| error("key_sign failed"); |
| xfree(chost); |
| xfree(pkalg); |
| return 0; |
| } |
| packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| packet_put_cstring(authctxt->server_user); |
| packet_put_cstring(authctxt->service); |
| packet_put_cstring(authctxt->method->name); |
| packet_put_cstring(pkalg); |
| packet_put_string(blob, blen); |
| packet_put_cstring(chost); |
| packet_put_cstring(authctxt->local_user); |
| packet_put_string(signature, slen); |
| memset(signature, 's', slen); |
| xfree(signature); |
| xfree(chost); |
| xfree(pkalg); |
| |
| packet_send(); |
| return 1; |
| } |
| |
| /* find auth method */ |
| |
| /* |
| * given auth method name, if configurable options permit this method fill |
| * in auth_ident field and return true, otherwise return false. |
| */ |
| static int |
| authmethod_is_enabled(Authmethod *method) |
| { |
| if (method == NULL) |
| return 0; |
| /* return false if options indicate this method is disabled */ |
| if (method->enabled == NULL || *method->enabled == 0) |
| return 0; |
| /* return false if batch mode is enabled but method needs interactive mode */ |
| if (method->batch_flag != NULL && *method->batch_flag != 0) |
| return 0; |
| return 1; |
| } |
| |
| static Authmethod * |
| authmethod_lookup(const char *name) |
| { |
| Authmethod *method = NULL; |
| if (name != NULL) |
| for (method = authmethods; method->name != NULL; method++) |
| if (strcmp(name, method->name) == 0) |
| return method; |
| debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); |
| return NULL; |
| } |
| |
| /* XXX internal state */ |
| static Authmethod *current = NULL; |
| static char *supported = NULL; |
| static char *preferred = NULL; |
| /* |
| * Given the authentication method list sent by the server, return the |
| * next method we should try. If the server initially sends a nil list, |
| * use a built-in default list. |
| */ |
| static Authmethod * |
| authmethod_get(char *authlist) |
| { |
| |
| char *name = NULL; |
| int next; |
| |
| /* Use a suitable default if we're passed a nil list. */ |
| if (authlist == NULL || strlen(authlist) == 0) |
| authlist = options.preferred_authentications; |
| |
| if (supported == NULL || strcmp(authlist, supported) != 0) { |
| debug3("start over, passed a different list %s", authlist); |
| if (supported != NULL) |
| xfree(supported); |
| supported = xstrdup(authlist); |
| preferred = options.preferred_authentications; |
| debug3("preferred %s", preferred); |
| current = NULL; |
| } else if (current != NULL && authmethod_is_enabled(current)) |
| return current; |
| |
| for (;;) { |
| if ((name = match_list(preferred, supported, &next)) == NULL) { |
| debug("no more auth methods to try"); |
| current = NULL; |
| return NULL; |
| } |
| preferred += next; |
| debug3("authmethod_lookup %s", name); |
| debug3("remaining preferred: %s", preferred); |
| if ((current = authmethod_lookup(name)) != NULL && |
| authmethod_is_enabled(current)) { |
| debug3("authmethod_is_enabled %s", name); |
| debug("next auth method to try is %s", name); |
| return current; |
| } |
| } |
| } |
| |
| |
| #define DELIM "," |
| char * |
| authmethods_get(void) |
| { |
| Authmethod *method = NULL; |
| char buf[1024]; |
| |
| buf[0] = '\0'; |
| for (method = authmethods; method->name != NULL; method++) { |
| if (authmethod_is_enabled(method)) { |
| if (buf[0] != '\0') |
| strlcat(buf, DELIM, sizeof buf); |
| strlcat(buf, method->name, sizeof buf); |
| } |
| } |
| return xstrdup(buf); |
| } |