diff options
Diffstat (limited to 'sshconnect2.c')
| -rw-r--r-- | sshconnect2.c | 1920 |
1 files changed, 0 insertions, 1920 deletions
diff --git a/sshconnect2.c b/sshconnect2.c deleted file mode 100644 index c24b2027..00000000 --- a/sshconnect2.c +++ /dev/null @@ -1,1920 +0,0 @@ -/* $OpenBSD: sshconnect2.c,v 1.188 2011/05/24 07:15:47 djm Exp $ */ -/* - * Copyright (c) 2000 Markus Friedl. All rights reserved. - * Copyright (c) 2008 Damien Miller. 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" - -#include <sys/types.h> -#include <sys/socket.h> -#include <sys/wait.h> -#include <sys/stat.h> - -#include <errno.h> -#include <fcntl.h> -#include <netdb.h> -#include <pwd.h> -#include <signal.h> -#include <stdarg.h> -#include <stdio.h> -#include <string.h> -#include <unistd.h> -#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) -#include <vis.h> -#endif - -#include "openbsd-compat/sys-queue.h" - -#include "xmalloc.h" -#include "ssh.h" -#include "ssh2.h" -#include "buffer.h" -#include "packet.h" -#include "compat.h" -#include "cipher.h" -#include "key.h" -#include "kex.h" -#include "myproposal.h" -#include "sshconnect.h" -#include "authfile.h" -#include "dh.h" -#include "authfd.h" -#include "log.h" -#include "readconf.h" -#include "misc.h" -#include "match.h" -#include "dispatch.h" -#include "canohost.h" -#include "msg.h" -#include "pathnames.h" -#include "uidswap.h" -#include "hostfile.h" -#include "schnorr.h" -#include "jpake.h" - -#ifdef GSSAPI -#include "ssh-gss.h" -#endif - -/* import */ -extern char *client_version_string; -extern char *server_version_string; -extern Options options; - -/* - * SSH2 key exchange - */ - -u_char *session_id2 = NULL; -u_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("Host key verification failed."); - return 0; -} - -static char * -order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) -{ - char *oavail, *avail, *first, *last, *alg, *hostname, *ret; - size_t maxlen; - struct hostkeys *hostkeys; - int ktype; - u_int i; - - /* Find all hostkeys for this hostname */ - get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); - hostkeys = init_hostkeys(); - for (i = 0; i < options.num_user_hostfiles; i++) - load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); - for (i = 0; i < options.num_system_hostfiles; i++) - load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); - - oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); - maxlen = strlen(avail) + 1; - first = xmalloc(maxlen); - last = xmalloc(maxlen); - *first = *last = '\0'; - -#define ALG_APPEND(to, from) \ - do { \ - if (*to != '\0') \ - strlcat(to, ",", maxlen); \ - strlcat(to, from, maxlen); \ - } while (0) - - while ((alg = strsep(&avail, ",")) && *alg != '\0') { - if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC) - fatal("%s: unknown alg %s", __func__, alg); - if (lookup_key_in_hostkeys_by_type(hostkeys, - key_type_plain(ktype), NULL)) - ALG_APPEND(first, alg); - else - ALG_APPEND(last, alg); - } -#undef ALG_APPEND - xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last); - if (*first != '\0') - debug3("%s: prefer hostkeyalgs: %s", __func__, first); - - xfree(first); - xfree(last); - xfree(hostname); - xfree(oavail); - free_hostkeys(hostkeys); - - return ret; -} - -void -ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) -{ - Kex *kex; - - xxx_host = host; - xxx_hostaddr = hostaddr; - - if (options.ciphers == (char *)-1) { - logit("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@openssh.com,zlib,none"; - } else { - myproposal[PROPOSAL_COMP_ALGS_CTOS] = - myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; - } - 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; - else { - /* Prefer algorithms that we already have keys for */ - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = - order_hostkeyalgs(host, hostaddr, port); - } - if (options.kex_algorithms != NULL) - myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; - - if (options.rekey_limit) - packet_set_rekey_limit((u_int32_t)options.rekey_limit); - - /* start key exchange */ - kex = kex_setup(myproposal); - kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; - kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; - kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; - kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; - kex->kex[KEX_ECDH_SHA2] = kexecdh_client; - 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); - - if (options.use_roaming && !kex->roaming) { - debug("Roaming not allowed by server"); - options.use_roaming = 0; - } - - 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 -} - -/* - * Authenticate user - */ - -typedef struct Authctxt Authctxt; -typedef struct Authmethod Authmethod; -typedef struct identity Identity; -typedef struct idlist Idlist; - -struct identity { - TAILQ_ENTRY(identity) next; - AuthenticationConnection *ac; /* set if agent supports key */ - Key *key; /* public/private key */ - char *filename; /* comment for agent-only keys */ - int tried; - int isprivate; /* key points to the private key */ -}; -TAILQ_HEAD(idlist, identity); - -struct Authctxt { - const char *server_user; - const char *local_user; - const char *host; - const char *service; - Authmethod *method; - sig_atomic_t success; - char *authlist; - /* pubkey */ - Idlist keys; - AuthenticationConnection *agent; - /* hostbased */ - Sensitive *sensitive; - /* kbd-interactive */ - int info_req_seen; - /* generic */ - void *methoddata; -}; -struct Authmethod { - char *name; /* string to compare against server's list */ - int (*userauth)(Authctxt *authctxt); - void (*cleanup)(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, u_int32_t, void *); -void input_userauth_success_unexpected(int, u_int32_t, void *); -void input_userauth_failure(int, u_int32_t, void *); -void input_userauth_banner(int, u_int32_t, void *); -void input_userauth_error(int, u_int32_t, void *); -void input_userauth_info_req(int, u_int32_t, void *); -void input_userauth_pk_ok(int, u_int32_t, void *); -void input_userauth_passwd_changereq(int, u_int32_t, void *); -void input_userauth_jpake_server_step1(int, u_int32_t, void *); -void input_userauth_jpake_server_step2(int, u_int32_t, void *); -void input_userauth_jpake_server_confirm(int, u_int32_t, void *); - -int userauth_none(Authctxt *); -int userauth_pubkey(Authctxt *); -int userauth_passwd(Authctxt *); -int userauth_kbdint(Authctxt *); -int userauth_hostbased(Authctxt *); -int userauth_jpake(Authctxt *); - -void userauth_jpake_cleanup(Authctxt *); - -#ifdef GSSAPI -int userauth_gssapi(Authctxt *authctxt); -void input_gssapi_response(int type, u_int32_t, void *); -void input_gssapi_token(int type, u_int32_t, void *); -void input_gssapi_hash(int type, u_int32_t, void *); -void input_gssapi_error(int, u_int32_t, void *); -void input_gssapi_errtok(int, u_int32_t, void *); -#endif - -void userauth(Authctxt *, char *); - -static int sign_and_send_pubkey(Authctxt *, Identity *); -static void pubkey_prepare(Authctxt *); -static void pubkey_cleanup(Authctxt *); -static Key *load_identity_file(char *); - -static Authmethod *authmethod_get(char *authlist); -static Authmethod *authmethod_lookup(const char *name); -static char *authmethods_get(void); - -Authmethod authmethods[] = { -#ifdef GSSAPI - {"gssapi-with-mic", - userauth_gssapi, - NULL, - &options.gss_authentication, - NULL}, -#endif - {"hostbased", - userauth_hostbased, - NULL, - &options.hostbased_authentication, - NULL}, - {"publickey", - userauth_pubkey, - NULL, - &options.pubkey_authentication, - NULL}, -#ifdef JPAKE - {"jpake-01@openssh.com", - userauth_jpake, - userauth_jpake_cleanup, - &options.zero_knowledge_password_authentication, - &options.batch_mode}, -#endif - {"keyboard-interactive", - userauth_kbdint, - NULL, - &options.kbd_interactive_authentication, - &options.batch_mode}, - {"password", - userauth_passwd, - NULL, - &options.password_authentication, - &options.batch_mode}, - {"none", - userauth_none, - NULL, - NULL, - NULL}, - {NULL, NULL, NULL, NULL, NULL} -}; - -void -ssh_userauth2(const char *local_user, const char *server_user, char *host, - Sensitive *sensitive) -{ - Authctxt authctxt; - int type; - - if (options.challenge_response_authentication) - options.kbd_interactive_authentication = 1; - - packet_start(SSH2_MSG_SERVICE_REQUEST); - packet_put_cstring("ssh-userauth"); - packet_send(); - debug("SSH2_MSG_SERVICE_REQUEST sent"); - packet_write_wait(); - type = packet_read(); - if (type != SSH2_MSG_SERVICE_ACCEPT) - fatal("Server denied authentication request: %d", type); - if (packet_remaining() > 0) { - char *reply = packet_get_string(NULL); - debug2("service_accept: %s", reply); - xfree(reply); - } else { - debug2("buggy server: service_accept w/o service"); - } - packet_check_eom(); - debug("SSH2_MSG_SERVICE_ACCEPT received"); - - if (options.preferred_authentications == NULL) - options.preferred_authentications = authmethods_get(); - - /* setup authentication context */ - memset(&authctxt, 0, sizeof(authctxt)); - pubkey_prepare(&authctxt); - 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.methoddata = NULL; - authctxt.sensitive = sensitive; - authctxt.info_req_seen = 0; - 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 */ - - pubkey_cleanup(&authctxt); - dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); - - debug("Authentication succeeded (%s).", authctxt.method->name); -} - -void -userauth(Authctxt *authctxt, char *authlist) -{ - if (authctxt->method != NULL && authctxt->method->cleanup != NULL) - authctxt->method->cleanup(authctxt); - - if (authctxt->methoddata) { - xfree(authctxt->methoddata); - authctxt->methoddata = NULL; - } - 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; - - /* reset the per method handler */ - dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, - SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); - - /* and try new 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; - } - } -} - -/* ARGSUSED */ -void -input_userauth_error(int type, u_int32_t seq, void *ctxt) -{ - fatal("input_userauth_error: bad message during authentication: " - "type %d", type); -} - -/* ARGSUSED */ -void -input_userauth_banner(int type, u_int32_t seq, void *ctxt) -{ - char *msg, *raw, *lang; - u_int len; - - debug3("input_userauth_banner"); - raw = packet_get_string(&len); - lang = packet_get_string(NULL); - if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { - if (len > 65536) - len = 65536; - msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ - strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); - fprintf(stderr, "%s", msg); - xfree(msg); - } - xfree(raw); - xfree(lang); -} - -/* ARGSUSED */ -void -input_userauth_success(int type, u_int32_t seq, void *ctxt) -{ - Authctxt *authctxt = ctxt; - - if (authctxt == NULL) - fatal("input_userauth_success: no authentication context"); - if (authctxt->authlist) { - xfree(authctxt->authlist); - authctxt->authlist = NULL; - } - if (authctxt->method != NULL && authctxt->method->cleanup != NULL) - authctxt->method->cleanup(authctxt); - if (authctxt->methoddata) { - xfree(authctxt->methoddata); - authctxt->methoddata = NULL; - } - authctxt->success = 1; /* break out */ -} - -void -input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) -{ - Authctxt *authctxt = ctxt; - - if (authctxt == NULL) - fatal("%s: no authentication context", __func__); - - fatal("Unexpected authentication success during %s.", - authctxt->method->name); -} - -/* ARGSUSED */ -void -input_userauth_failure(int type, u_int32_t seq, 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_check_eom(); - - if (partial != 0) - logit("Authenticated with partial success."); - debug("Authentications that can continue: %s", authlist); - - userauth(authctxt, authlist); -} - -/* ARGSUSED */ -void -input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) -{ - Authctxt *authctxt = ctxt; - Key *key = NULL; - Identity *id = NULL; - Buffer b; - int pktype, sent = 0; - u_int alen, blen; - char *pkalg, *fp; - u_char *pkblob; - - 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_check_eom(); - - debug("Server accepts key: pkalg %s blen %u", pkalg, blen); - - if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { - debug("unknown pkalg %s", pkalg); - goto done; - } - if ((key = key_from_blob(pkblob, blen)) == NULL) { - debug("no key from blob. pkalg %s", pkalg); - goto done; - } - if (key->type != pktype) { - error("input_userauth_pk_ok: type mismatch " - "for decoded key (received %d, expected %d)", - key->type, pktype); - goto done; - } - fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); - debug2("input_userauth_pk_ok: fp %s", fp); - xfree(fp); - - /* - * search keys in the reverse order, because last candidate has been - * moved to the end of the queue. this also avoids confusion by - * duplicate keys - */ - TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { - if (key_equal(key, id->key)) { - sent = sign_and_send_pubkey(authctxt, id); - break; - } - } -done: - if (key != NULL) - key_free(key); - xfree(pkalg); - xfree(pkblob); - - /* try another method if we did not send a packet */ - if (sent == 0) - userauth(authctxt, NULL); -} - -#ifdef GSSAPI -int -userauth_gssapi(Authctxt *authctxt) -{ - Gssctxt *gssctxt = NULL; - static gss_OID_set gss_supported = NULL; - static u_int mech = 0; - OM_uint32 min; - int ok = 0; - - /* Try one GSSAPI method at a time, rather than sending them all at - * once. */ - - if (gss_supported == NULL) - gss_indicate_mechs(&min, &gss_supported); - - /* Check to see if the mechanism is usable before we offer it */ - while (mech < gss_supported->count && !ok) { - /* My DER encoding requires length<128 */ - if (gss_supported->elements[mech].length < 128 && - ssh_gssapi_check_mechanism(&gssctxt, - &gss_supported->elements[mech], authctxt->host)) { - ok = 1; /* Mechanism works */ - } else { - mech++; - } - } - - if (!ok) - return 0; - - authctxt->methoddata=(void *)gssctxt; - - 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_int(1); - - packet_put_int((gss_supported->elements[mech].length) + 2); - packet_put_char(SSH_GSS_OIDTYPE); - packet_put_char(gss_supported->elements[mech].length); - packet_put_raw(gss_supported->elements[mech].elements, - gss_supported->elements[mech].length); - - packet_send(); - - dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); - dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); - dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); - dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); - - mech++; /* Move along to next candidate */ - - return 1; -} - -static OM_uint32 -process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) -{ - Authctxt *authctxt = ctxt; - Gssctxt *gssctxt = authctxt->methoddata; - gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; - gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; - gss_buffer_desc gssbuf; - OM_uint32 status, ms, flags; - Buffer b; - - status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, - recv_tok, &send_tok, &flags); - - if (send_tok.length > 0) { - if (GSS_ERROR(status)) - packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); - else - packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); - - packet_put_string(send_tok.value, send_tok.length); - packet_send(); - gss_release_buffer(&ms, &send_tok); - } - - if (status == GSS_S_COMPLETE) { - /* send either complete or MIC, depending on mechanism */ - if (!(flags & GSS_C_INTEG_FLAG)) { - packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); - packet_send(); - } else { - ssh_gssapi_buildmic(&b, authctxt->server_user, - authctxt->service, "gssapi-with-mic"); - - gssbuf.value = buffer_ptr(&b); - gssbuf.length = buffer_len(&b); - - status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); - - if (!GSS_ERROR(status)) { - packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); - packet_put_string(mic.value, mic.length); - - packet_send(); - } - - buffer_free(&b); - gss_release_buffer(&ms, &mic); - } - } - - return status; -} - -/* ARGSUSED */ -void -input_gssapi_response(int type, u_int32_t plen, void *ctxt) -{ - Authctxt *authctxt = ctxt; - Gssctxt *gssctxt; - int oidlen; - char *oidv; - - if (authctxt == NULL) - fatal("input_gssapi_response: no authentication context"); - gssctxt = authctxt->methoddata; - - /* Setup our OID */ - oidv = packet_get_string(&oidlen); - - if (oidlen <= 2 || - oidv[0] != SSH_GSS_OIDTYPE || - oidv[1] != oidlen - 2) { - xfree(oidv); - debug("Badly encoded mechanism OID received"); - userauth(authctxt, NULL); - return; - } - - if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) - fatal("Server returned different OID than expected"); - - packet_check_eom(); - - xfree(oidv); - - if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { - /* Start again with next method on list */ - debug("Trying to start again"); - userauth(authctxt, NULL); - return; - } -} - -/* ARGSUSED */ -void -input_gssapi_token(int type, u_int32_t plen, void *ctxt) -{ - Authctxt *authctxt = ctxt; - gss_buffer_desc recv_tok; - OM_uint32 status; - u_int slen; - - if (authctxt == NULL) - fatal("input_gssapi_response: no authentication context"); - - recv_tok.value = packet_get_string(&slen); - recv_tok.length = slen; /* safe typecast */ - - packet_check_eom(); - - status = process_gssapi_token(ctxt, &recv_tok); - - xfree(recv_tok.value); - - if (GSS_ERROR(status)) { - /* Start again with the next method in the list */ - userauth(authctxt, NULL); - return; - } -} - -/* ARGSUSED */ -void -input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) -{ - Authctxt *authctxt = ctxt; - Gssctxt *gssctxt; - gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; - gss_buffer_desc recv_tok; - OM_uint32 status, ms; - u_int len; - - if (authctxt == NULL) - fatal("input_gssapi_response: no authentication context"); - gssctxt = authctxt->methoddata; - - recv_tok.value = packet_get_string(&len); - recv_tok.length = len; - - packet_check_eom(); - - /* Stick it into GSSAPI and see what it says */ - status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, - &recv_tok, &send_tok, NULL); - - xfree(recv_tok.value); - gss_release_buffer(&ms, &send_tok); - - /* Server will be returning a failed packet after this one */ -} - -/* ARGSUSED */ -void -input_gssapi_error(int type, u_int32_t plen, void *ctxt) -{ - OM_uint32 maj, min; - char *msg; - char *lang; - - maj=packet_get_int(); - min=packet_get_int(); - msg=packet_get_string(NULL); - lang=packet_get_string(NULL); - - packet_check_eom(); - - debug("Server GSSAPI Error:\n%s", msg); - xfree(msg); - xfree(lang); -} -#endif /* GSSAPI */ - -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[150]; - char *password; - const char *host = options.host_key_alias ? options.host_key_alias : - authctxt->host; - - 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, 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_add_padding(64); - packet_send(); - - dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, - &input_userauth_passwd_changereq); - - return 1; -} - -/* - * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST - */ -/* ARGSUSED */ -void -input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) -{ - Authctxt *authctxt = ctxt; - char *info, *lang, *password = NULL, *retype = NULL; - char prompt[150]; - const char *host = options.host_key_alias ? options.host_key_alias : - authctxt->host; - - debug2("input_userauth_passwd_changereq"); - - if (authctxt == NULL) - fatal("input_userauth_passwd_changereq: " - "no authentication context"); - - info = packet_get_string(NULL); - lang = packet_get_string(NULL); - if (strlen(info) > 0) - logit("%s", info); - xfree(info); - xfree(lang); - 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(1); /* additional info */ - snprintf(prompt, sizeof(prompt), - "Enter %.30s@%.128s's old password: ", - authctxt->server_user, host); - password = read_passphrase(prompt, 0); - packet_put_cstring(password); - memset(password, 0, strlen(password)); - xfree(password); - password = NULL; - while (password == NULL) { - snprintf(prompt, sizeof(prompt), - "Enter %.30s@%.128s's new password: ", - authctxt->server_user, host); - password = read_passphrase(prompt, RP_ALLOW_EOF); - if (password == NULL) { - /* bail out */ - return; - } - snprintf(prompt, sizeof(prompt), - "Retype %.30s@%.128s's new password: ", - authctxt->server_user, host); - retype = read_passphrase(prompt, 0); - if (strcmp(password, retype) != 0) { - memset(password, 0, strlen(password)); - xfree(password); - logit("Mismatch; try again, EOF to quit."); - password = NULL; - } - memset(retype, 0, strlen(retype)); - xfree(retype); - } - packet_put_cstring(password); - memset(password, 0, strlen(password)); - xfree(password); - packet_add_padding(64); - packet_send(); - - dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, - &input_userauth_passwd_changereq); -} - -#ifdef JPAKE -static char * -pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) -{ - /* OpenBSD crypt(3) handles all of these */ - if (strcmp(crypt_scheme, "crypt") == 0 || - strcmp(crypt_scheme, "bcrypt") == 0 || - strcmp(crypt_scheme, "md5crypt") == 0 || - strcmp(crypt_scheme, "crypt-extended") == 0) - return xstrdup(crypt(password, salt)); - error("%s: unsupported password encryption scheme \"%.100s\"", - __func__, crypt_scheme); - return NULL; -} - -static BIGNUM * -jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, - const char *salt) -{ - char prompt[256], *password, *crypted; - u_char *secret; - u_int secret_len; - BIGNUM *ret; - - snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", - authctxt->server_user, authctxt->host); - password = read_passphrase(prompt, 0); - - if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { - logit("Disabling %s authentication", authctxt->method->name); - authctxt->method->enabled = NULL; - /* Continue with an empty password to fail gracefully */ - crypted = xstrdup(""); - } - -#ifdef JPAKE_DEBUG - debug3("%s: salt = %s", __func__, salt); - debug3("%s: scheme = %s", __func__, crypt_scheme); - debug3("%s: crypted = %s", __func__, crypted); -#endif - - if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), - &secret, &secret_len) != 0) - fatal("%s: hash_buffer", __func__); - - bzero(password, strlen(password)); - bzero(crypted, strlen(crypted)); - xfree(password); - xfree(crypted); - - if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) - fatal("%s: BN_bin2bn (secret)", __func__); - bzero(secret, secret_len); - xfree(secret); - - return ret; -} - -/* ARGSUSED */ -void -input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) -{ - Authctxt *authctxt = ctxt; - struct jpake_ctx *pctx = authctxt->methoddata; - u_char *x3_proof, *x4_proof, *x2_s_proof; - u_int x3_proof_len, x4_proof_len, x2_s_proof_len; - char *crypt_scheme, *salt; - - /* Disable this message */ - dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); - - if ((pctx->g_x3 = BN_new()) == NULL || - (pctx->g_x4 = BN_new()) == NULL) - fatal("%s: BN_new", __func__); - - /* Fetch step 1 values */ - crypt_scheme = packet_get_string(NULL); - salt = packet_get_string(NULL); - pctx->server_id = packet_get_string(&pctx->server_id_len); - packet_get_bignum2(pctx->g_x3); - packet_get_bignum2(pctx->g_x4); - x3_proof = packet_get_string(&x3_proof_len); - x4_proof = packet_get_string(&x4_proof_len); - packet_check_eom(); - - JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); - - /* Obtain password and derive secret */ - pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); - bzero(crypt_scheme, strlen(crypt_scheme)); - bzero(salt, strlen(salt)); - xfree(crypt_scheme); - xfree(salt); - JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); - - /* Calculate step 2 values */ - jpake_step2(pctx->grp, pctx->s, pctx->g_x1, - pctx->g_x3, pctx->g_x4, pctx->x2, - pctx->server_id, pctx->server_id_len, - pctx->client_id, pctx->client_id_len, - x3_proof, x3_proof_len, - x4_proof, x4_proof_len, - &pctx->a, - &x2_s_proof, &x2_s_proof_len); - - bzero(x3_proof, x3_proof_len); - bzero(x4_proof, x4_proof_len); - xfree(x3_proof); - xfree(x4_proof); - - JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); - - /* Send values for step 2 */ - packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); - packet_put_bignum2(pctx->a); - packet_put_string(x2_s_proof, x2_s_proof_len); - packet_send(); - - bzero(x2_s_proof, x2_s_proof_len); - xfree(x2_s_proof); - - /* Expect step 2 packet from peer */ - dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, - input_userauth_jpake_server_step2); -} - -/* ARGSUSED */ -void -input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) -{ - Authctxt *authctxt = ctxt; - struct jpake_ctx *pctx = authctxt->methoddata; - u_char *x4_s_proof; - u_int x4_s_proof_len; - - /* Disable this message */ - dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); - - if ((pctx->b = BN_new()) == NULL) - fatal("%s: BN_new", __func__); - - /* Fetch step 2 values */ - packet_get_bignum2(pctx->b); - x4_s_proof = packet_get_string(&x4_s_proof_len); - packet_check_eom(); - - JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); - - /* Derive shared key and calculate confirmation hash */ - jpake_key_confirm(pctx->grp, pctx->s, pctx->b, - pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, - pctx->client_id, pctx->client_id_len, - pctx->server_id, pctx->server_id_len, - session_id2, session_id2_len, - x4_s_proof, x4_s_proof_len, - &pctx->k, - &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); - - bzero(x4_s_proof, x4_s_proof_len); - xfree(x4_s_proof); - - JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); - - /* Send key confirmation proof */ - packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); - packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); - packet_send(); - - /* Expect confirmation from peer */ - dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, - input_userauth_jpake_server_confirm); -} - -/* ARGSUSED */ -void -input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) -{ - Authctxt *authctxt = ctxt; - struct jpake_ctx *pctx = authctxt->methoddata; - - /* Disable this message */ - dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); - - pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); - packet_check_eom(); - - JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); - - /* Verify expected confirmation hash */ - if (jpake_check_confirm(pctx->k, - pctx->server_id, pctx->server_id_len, - session_id2, session_id2_len, - pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) - debug("%s: %s success", __func__, authctxt->method->name); - else { - debug("%s: confirmation mismatch", __func__); - /* XXX stash this so if auth succeeds then we can warn/kill */ - } - - userauth_jpake_cleanup(authctxt); -} -#endif /* JPAKE */ - -static int -identity_sign(Identity *id, u_char **sigp, u_int *lenp, - u_char *data, u_int datalen) -{ - Key *prv; - int ret; - - /* the agent supports this key */ - if (id->ac) - return (ssh_agent_sign(id->ac, id->key, sigp, lenp, - data, datalen)); - /* - * we have already loaded the private key or - * the private key is stored in external hardware - */ - if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) - return (key_sign(id->key, sigp, lenp, data, datalen)); - /* load the private key from the file */ - if ((prv = load_identity_file(id->filename)) == NULL) - return (-1); - ret = key_sign(prv, sigp, lenp, data, datalen); - key_free(prv); - return (ret); -} - -static int -sign_and_send_pubkey(Authctxt *authctxt, Identity *id) -{ - Buffer b; - u_char *blob, *signature; - u_int bloblen, slen; - u_int skip = 0; - int ret = -1; - int have_sig = 1; - char *fp; - - fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); - debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); - xfree(fp); - - if (key_to_blob(id->key, &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(id->key)); - } - buffer_put_string(&b, blob, bloblen); - - /* generate signature */ - ret = identity_sign(id, &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(id->key)); - 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, Identity *id) -{ - u_char *blob; - u_int bloblen, have_sig = 0; - - debug3("send_pubkey_test"); - - if (key_to_blob(id->key, &blob, &bloblen) == 0) { - /* we cannot handle this key */ - debug3("send_pubkey_test: cannot handle key"); - return 0; - } - /* register callback for USERAUTH_PK_OK message */ - 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(id->key)); - 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 perm_ok = 0, 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, &perm_ok); - if (!perm_ok) - return 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, 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; -} - -/* - * try keys in the following order: - * 1. agent keys that are found in the config file - * 2. other agent keys - * 3. keys that are only listed in the config file - */ -static void -pubkey_prepare(Authctxt *authctxt) -{ - Identity *id; - Idlist agent, files, *preferred; - Key *key; - AuthenticationConnection *ac; - char *comment; - int i, found; - - TAILQ_INIT(&agent); /* keys from the agent */ - TAILQ_INIT(&files); /* keys from the config file */ - preferred = &authctxt->keys; - TAILQ_INIT(preferred); /* preferred order of keys */ - - /* list of keys stored in the filesystem */ - for (i = 0; i < options.num_identity_files; i++) { - key = options.identity_keys[i]; - if (key && key->type == KEY_RSA1) - continue; - if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) - continue; - options.identity_keys[i] = NULL; - id = xcalloc(1, sizeof(*id)); - id->key = key; - id->filename = xstrdup(options.identity_files[i]); - TAILQ_INSERT_TAIL(&files, id, next); - } - /* list of keys supported by the agent */ - if ((ac = ssh_get_authentication_connection())) { - for (key = ssh_get_first_identity(ac, &comment, 2); - key != NULL; - key = ssh_get_next_identity(ac, &comment, 2)) { - found = 0; - TAILQ_FOREACH(id, &files, next) { - /* agent keys from the config file are preferred */ - if (key_equal(key, id->key)) { - key_free(key); - xfree(comment); - TAILQ_REMOVE(&files, id, next); - TAILQ_INSERT_TAIL(preferred, id, next); - id->ac = ac; - found = 1; - break; - } - } - if (!found && !options.identities_only) { - id = xcalloc(1, sizeof(*id)); - id->key = key; - id->filename = comment; - id->ac = ac; - TAILQ_INSERT_TAIL(&agent, id, next); - } - } - /* append remaining agent keys */ - for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { - TAILQ_REMOVE(&agent, id, next); - TAILQ_INSERT_TAIL(preferred, id, next); - } - authctxt->agent = ac; - } - /* append remaining keys from the config file */ - for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { - TAILQ_REMOVE(&files, id, next); - TAILQ_INSERT_TAIL(preferred, id, next); - } - TAILQ_FOREACH(id, preferred, next) { - debug2("key: %s (%p)", id->filename, id->key); - } -} - -static void -pubkey_cleanup(Authctxt *authctxt) -{ - Identity *id; - - if (authctxt->agent != NULL) - ssh_close_authentication_connection(authctxt->agent); - for (id = TAILQ_FIRST(&authctxt->keys); id; - id = TAILQ_FIRST(&authctxt->keys)) { - TAILQ_REMOVE(&authctxt->keys, id, next); - if (id->key) - key_free(id->key); - if (id->filename) - xfree(id->filename); - xfree(id); - } -} - -int -userauth_pubkey(Authctxt *authctxt) -{ - Identity *id; - int sent = 0; - - while ((id = TAILQ_FIRST(&authctxt->keys))) { - if (id->tried++) - return (0); - /* move key to the end of the queue */ - TAILQ_REMOVE(&authctxt->keys, id, next); - TAILQ_INSERT_TAIL(&authctxt->keys, id, next); - /* - * send a test message if we have the public key. for - * encrypted keys we cannot do this and have to load the - * private key instead - */ - if (id->key && id->key->type != KEY_RSA1) { - debug("Offering %s public key: %s", key_type(id->key), - id->filename); - sent = send_pubkey_test(authctxt, id); - } else if (id->key == NULL) { - debug("Trying private key: %s", id->filename); - id->key = load_identity_file(id->filename); - if (id->key != NULL) { - id->isprivate = 1; - sent = sign_and_send_pubkey(authctxt, id); - key_free(id->key); - id->key = NULL; - } - } - if (sent) - return (sent); - } - return (0); -} - -/* - * 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; - /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ - if (attempt > 1 && !authctxt->info_req_seen) { - debug3("userauth_kbdint: disable: no info_req_seen"); - dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); - 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, u_int32_t seq, 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"); - - authctxt->info_req_seen = 1; - - name = packet_get_string(NULL); - inst = packet_get_string(NULL); - lang = packet_get_string(NULL); - if (strlen(name) > 0) - logit("%s", name); - if (strlen(inst) > 0) - logit("%s", 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_check_eom(); /* done with parsing incoming message. */ - - packet_add_padding(64); - packet_send(); -} - -static int -ssh_keysign(Key *key, u_char **sigp, u_int *lenp, - u_char *data, u_int datalen) -{ - Buffer b; - struct stat st; - pid_t pid; - int to[2], from[2], status, version = 2; - - debug2("ssh_keysign called"); - - if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { - error("ssh_keysign: not installed: %s", strerror(errno)); - return -1; - } - if (fflush(stdout) != 0) - error("ssh_keysign: fflush: %s", strerror(errno)); - if (pipe(to) < 0) { - error("ssh_keysign: pipe: %s", strerror(errno)); - return -1; - } - if (pipe(from) < 0) { - error("ssh_keysign: pipe: %s", strerror(errno)); - return -1; - } - if ((pid = fork()) < 0) { - error("ssh_keysign: fork: %s", strerror(errno)); - return -1; - } - if (pid == 0) { - /* keep the socket on exec */ - fcntl(packet_get_connection_in(), F_SETFD, 0); - permanently_drop_suid(getuid()); - close(from[0]); - if (dup2(from[1], STDOUT_FILENO) < 0) - fatal("ssh_keysign: dup2: %s", strerror(errno)); - close(to[1]); - if (dup2(to[0], STDIN_FILENO) < 0) - fatal("ssh_keysign: dup2: %s", strerror(errno)); - close(from[1]); - close(to[0]); - execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); - fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, - strerror(errno)); - } - close(from[1]); - close(to[0]); - - buffer_init(&b); - buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ - buffer_put_string(&b, data, datalen); - if (ssh_msg_send(to[1], version, &b) == -1) - fatal("ssh_keysign: couldn't send request"); - - if (ssh_msg_recv(from[0], &b) < 0) { - error("ssh_keysign: no reply"); - buffer_free(&b); - return -1; - } - close(from[0]); - close(to[1]); - - while (waitpid(pid, &status, 0) < 0) - if (errno != EINTR) - break; - - if (buffer_get_char(&b) != version) { - error("ssh_keysign: bad version"); - buffer_free(&b); - return -1; - } - *sigp = buffer_get_string(&b, lenp); - buffer_free(&b); - - return 0; -} - -int -userauth_hostbased(Authctxt *authctxt) -{ - Key *private = NULL; - Sensitive *sensitive = authctxt->sensitive; - Buffer b; - u_char *signature, *blob; - char *chost, *pkalg, *p; - const char *service; - u_int blen, slen; - int ok, i, found = 0; - - /* check for a useful key */ - for (i = 0; i < sensitive->nkeys; i++) { - private = sensitive->keys[i]; - if (private && private->type != KEY_RSA1) { - found = 1; - /* we take and free the key */ - sensitive->keys[i] = NULL; - break; - } - } - if (!found) { - debug("No more client hostkeys for hostbased authentication."); - return 0; - } - if (key_to_blob(private, &blob, &blen) == 0) { - key_free(private); - return 0; - } - /* figure out a name for the client host */ - p = get_local_name(packet_get_connection_in()); - if (p == NULL) { - error("userauth_hostbased: cannot get local ipaddr/name"); - key_free(private); - xfree(blob); - return 0; - } - xasprintf(&chost, "%s.", p); - debug2("userauth_hostbased: chost %s", chost); - xfree(p); - - 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 - if (sensitive->external_keysign) - ok = ssh_keysign(private, &signature, &slen, - buffer_ptr(&b), buffer_len(&b)); - else - 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); - xfree(blob); - 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); - xfree(blob); - - packet_send(); - return 1; -} - -#ifdef JPAKE -int -userauth_jpake(Authctxt *authctxt) -{ - struct jpake_ctx *pctx; - u_char *x1_proof, *x2_proof; - u_int x1_proof_len, x2_proof_len; - static int attempt = 0; /* XXX share with userauth_password's? */ - - if (attempt++ >= options.number_of_password_prompts) - return 0; - if (attempt != 1) - error("Permission denied, please try again."); - - if (authctxt->methoddata != NULL) - fatal("%s: authctxt->methoddata already set (%p)", - __func__, authctxt->methoddata); - - authctxt->methoddata = pctx = jpake_new(); - - /* - * Send request immediately, to get the protocol going while - * we do the initial computations. - */ - 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(); - packet_write_wait(); - - jpake_step1(pctx->grp, - &pctx->client_id, &pctx->client_id_len, - &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, - &x1_proof, &x1_proof_len, - &x2_proof, &x2_proof_len); - - JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); - - packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); - packet_put_string(pctx->client_id, pctx->client_id_len); - packet_put_bignum2(pctx->g_x1); - packet_put_bignum2(pctx->g_x2); - packet_put_string(x1_proof, x1_proof_len); - packet_put_string(x2_proof, x2_proof_len); - packet_send(); - - bzero(x1_proof, x1_proof_len); - bzero(x2_proof, x2_proof_len); - xfree(x1_proof); - xfree(x2_proof); - - /* Expect step 1 packet from peer */ - dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, - input_userauth_jpake_server_step1); - dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, - &input_userauth_success_unexpected); - - return 1; -} - -void -userauth_jpake_cleanup(Authctxt *authctxt) -{ - debug3("%s: clean up", __func__); - if (authctxt->methoddata != NULL) { - jpake_free(authctxt->methoddata); - authctxt->methoddata = NULL; - } - dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); -} -#endif /* JPAKE */ - -/* 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; - u_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 authentication 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 authentication method: %s", name); - xfree(name); - return current; - } - } - if (name != NULL) - xfree(name); -} - -static char * -authmethods_get(void) -{ - Authmethod *method = NULL; - Buffer b; - char *list; - - buffer_init(&b); - for (method = authmethods; method->name != NULL; method++) { - if (authmethod_is_enabled(method)) { - if (buffer_len(&b) > 0) - buffer_append(&b, ",", 1); - buffer_append(&b, method->name, strlen(method->name)); - } - } - buffer_append(&b, "\0", 1); - list = xstrdup(buffer_ptr(&b)); - buffer_free(&b); - return list; -} - |