/* $OpenBSD: sshconnect2.c,v 1.170 2008/11/04 08:22:13 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 #include #include #include #include #include #include #include #include #include #include #include #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) #include #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 "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; } void ssh_kex2(char *host, struct sockaddr *hostaddr) { Kex *kex; #ifdef GSSAPI char *orig = NULL, *gss = NULL; char *gss_host = NULL; #endif xxx_host = host; xxx_hostaddr = hostaddr; #ifdef GSSAPI if (options.gss_keyex) { /* Add the GSSAPI mechanisms currently supported on this * client to the key exchange algorithm proposal */ orig = myproposal[PROPOSAL_KEX_ALGS]; if (options.gss_trust_dns) gss_host = (char *)get_canonical_hostname(1); else gss_host = host; gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity); if (gss) { debug("Offering GSSAPI proposal: %s", gss); xasprintf(&myproposal[PROPOSAL_KEX_ALGS], "%s,%s", gss, orig); } } #endif 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; #ifdef GSSAPI /* If we've got GSSAPI algorithms, then we also support the * 'null' hostkey, as a last resort */ if (options.gss_keyex && gss) { orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]; xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS], "%s,null", orig); xfree(gss); } #endif 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; #ifdef GSSAPI if (options.gss_keyex) { kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client; kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client; kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client; } #endif kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; kex->verify_host_key=&verify_host_key_callback; #ifdef GSSAPI if (options.gss_keyex) { kex->gss_deleg_creds = options.gss_deleg_creds; kex->gss_trust_dns = options.gss_trust_dns; kex->gss_client = options.gss_client_identity; kex->gss_host = gss_host; } #endif 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 } /* * 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; int 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_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 *); int userauth_gsskeyex(Authctxt *authctxt); #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-keyex", userauth_gsskeyex, &options.gss_authentication, NULL}, {"gssapi-with-mic", userauth_gssapi, NULL, &options.gss_authentication, NULL}, {"gssapi", userauth_gssapi, &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->methoddata) { xfree(authctxt->methoddata); authctxt->methoddata = NULL; } authctxt->success = 1; /* break out */ } /* 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; const char *gss_host; int old_gssapi_method; if (options.gss_trust_dns) gss_host = get_canonical_hostname(1); else gss_host = authctxt->host; /* Try one GSSAPI method at a time, rather than sending them all at * once. */ if (gss_supported == NULL) if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) { gss_supported = NULL; return 0; } /* 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], gss_host, options.gss_client_identity)) { 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); old_gssapi_method = !strcmp(authctxt->method->name, "gssapi"); /* Versions of Debian ssh-krb5 prior to 3.8.1p1-1 don't expect * tagged OIDs. As such we include both tagged and untagged oids * for the old gssapi method. * We only include tagged oids for the new gssapi-with-mic method. */ packet_put_int(old_gssapi_method ? 2 : 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); if (old_gssapi_method) { packet_put_int(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) { int old_gssapi_method = !strcmp(authctxt->method->name, "gssapi"); /* send either complete or MIC, depending on mechanism */ if (old_gssapi_method || !(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; u_int oidlen; u_char *oidv, *oidv_free; if (authctxt == NULL) fatal("input_gssapi_response: no authentication context"); gssctxt = authctxt->methoddata; /* Setup our OID */ oidv = packet_get_string(&oidlen); oidv_free = oidv; if (oidlen <= 2 || oidv[0] != SSH_GSS_OIDTYPE || oidv[1] != oidlen - 2) { debug("Badly encoded mechanism OID received"); if (oidlen < 2) { xfree(oidv_free); userauth(authctxt, NULL); return; } } else { oidlen -= 2; oidv += 2; } if (!ssh_gssapi_check_oid(gssctxt, oidv, oidlen)) fatal("Server returned different OID than expected"); packet_check_eom(); xfree(oidv_free); 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); } int userauth_gsskeyex(Authctxt *authctxt) { Buffer b; gss_buffer_desc gssbuf; gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; OM_uint32 ms; static int attempt = 0; if (attempt++ >= 1) return (0); if (gss_kex_context == NULL) { debug("No valid Key exchange context"); return (0); } ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service, "gssapi-keyex"); gssbuf.value = buffer_ptr(&b); gssbuf.length = buffer_len(&b); if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) { buffer_free(&b); 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_string(mic.value, mic.length); packet_send(); buffer_free(&b); gss_release_buffer(&ms, &mic); return (1); } #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; 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_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]; 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, authctxt->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, authctxt->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, authctxt->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; debug3("sign_and_send_pubkey"); 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, 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++) { if (options.identity_files[i] == NULL) continue; key = options.identity_keys[i]; if (key && key->type == KEY_RSA1) 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 public key: %s", id->filename); sent = send_pubkey_test(authctxt, id); } else if (id->key == NULL && id->filename) { 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: no 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) { 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, myname[NI_MAXHOST]; const char *service; u_int blen, slen; int ok, i, len, 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 = NULL; if (packet_connection_is_on_socket()) p = get_local_name(packet_get_connection_in()); if (p == NULL) { if (gethostname(myname, sizeof(myname)) == -1) { verbose("userauth_hostbased: gethostname: %s", strerror(errno)); } else p = xstrdup(myname); } if (p == NULL) { error("userauth_hostbased: cannot get local ipaddr/name"); key_free(private); xfree(blob); return 0; } len = strlen(p) + 2; 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); return 1; } void userauth_jpake_cleanup(Authctxt *authctxt) { debug3("%s: clean up", __func__); if (authctxt->methoddata != NULL) { jpake_free(authctxt->methoddata); authctxt->methoddata = NULL; } } #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); return current; } } } 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; }