/* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * Code to connect to a remote host, and to perform the client side of the * login (authentication) dialog. * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". */ #include "includes.h" RCSID("$OpenBSD: sshconnect1.c,v 1.52 2002/08/08 13:50:23 aaron Exp $"); #include #include #ifdef KRB4 #include #endif #ifdef KRB5 #include #ifndef HEIMDAL #define krb5_get_err_text(context,code) error_message(code) #endif /* !HEIMDAL */ #endif #ifdef AFS #include #include "radix.h" #endif #include "ssh.h" #include "ssh1.h" #include "xmalloc.h" #include "rsa.h" #include "buffer.h" #include "packet.h" #include "mpaux.h" #include "uidswap.h" #include "log.h" #include "readconf.h" #include "key.h" #include "authfd.h" #include "sshconnect.h" #include "authfile.h" #include "readpass.h" #include "cipher.h" #include "canohost.h" #include "auth.h" #ifdef GSSAPI #include "ssh-gss.h" #include "bufaux.h" /* * MD5 hash of host and session keys for verification. This is filled * in in ssh_login() and then checked in try_gssapi_authentication(). */ unsigned char ssh_key_digest[16]; #endif /* GSSAPI */ /* Session id for the current session. */ u_char session_id[16]; u_int supported_authentications = 0; extern Options options; extern char *__progname; /* * Checks if the user has an authentication agent, and if so, tries to * authenticate using the agent. */ static int try_agent_authentication(void) { int type; char *comment; AuthenticationConnection *auth; u_char response[16]; u_int i; Key *key; BIGNUM *challenge; /* Get connection to the agent. */ auth = ssh_get_authentication_connection(); if (!auth) return 0; if ((challenge = BN_new()) == NULL) fatal("try_agent_authentication: BN_new failed"); /* Loop through identities served by the agent. */ for (key = ssh_get_first_identity(auth, &comment, 1); key != NULL; key = ssh_get_next_identity(auth, &comment, 1)) { /* Try this identity. */ debug("Trying RSA authentication via agent with '%.100s'", comment); xfree(comment); /* Tell the server that we are willing to authenticate using this key. */ packet_start(SSH_CMSG_AUTH_RSA); packet_put_bignum(key->rsa->n); packet_send(); packet_write_wait(); /* Wait for server's response. */ type = packet_read(); /* The server sends failure if it doesn\'t like our key or does not support RSA authentication. */ if (type == SSH_SMSG_FAILURE) { debug("Server refused our key."); key_free(key); continue; } /* Otherwise it should have sent a challenge. */ if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) packet_disconnect("Protocol error during RSA authentication: %d", type); packet_get_bignum(challenge); packet_check_eom(); debug("Received RSA challenge from server."); /* Ask the agent to decrypt the challenge. */ if (!ssh_decrypt_challenge(auth, key, challenge, session_id, 1, response)) { /* * The agent failed to authenticate this identifier * although it advertised it supports this. Just * return a wrong value. */ log("Authentication agent failed to decrypt challenge."); memset(response, 0, sizeof(response)); } key_free(key); debug("Sending response to RSA challenge."); /* Send the decrypted challenge back to the server. */ packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); for (i = 0; i < 16; i++) packet_put_char(response[i]); packet_send(); packet_write_wait(); /* Wait for response from the server. */ type = packet_read(); /* The server returns success if it accepted the authentication. */ if (type == SSH_SMSG_SUCCESS) { ssh_close_authentication_connection(auth); BN_clear_free(challenge); debug("RSA authentication accepted by server."); return 1; } /* Otherwise it should return failure. */ if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error waiting RSA auth response: %d", type); } ssh_close_authentication_connection(auth); BN_clear_free(challenge); debug("RSA authentication using agent refused."); return 0; } /* * Computes the proper response to a RSA challenge, and sends the response to * the server. */ static void respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) { u_char buf[32], response[16]; MD5_CTX md; int i, len; /* Decrypt the challenge using the private key. */ /* XXX think about Bleichenbacher, too */ if (rsa_private_decrypt(challenge, challenge, prv) <= 0) packet_disconnect( "respond_to_rsa_challenge: rsa_private_decrypt failed"); /* Compute the response. */ /* The response is MD5 of decrypted challenge plus session id. */ len = BN_num_bytes(challenge); if (len <= 0 || len > sizeof(buf)) packet_disconnect( "respond_to_rsa_challenge: bad challenge length %d", len); memset(buf, 0, sizeof(buf)); BN_bn2bin(challenge, buf + sizeof(buf) - len); MD5_Init(&md); MD5_Update(&md, buf, 32); MD5_Update(&md, session_id, 16); MD5_Final(response, &md); debug("Sending response to host key RSA challenge."); /* Send the response back to the server. */ packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); for (i = 0; i < 16; i++) packet_put_char(response[i]); packet_send(); packet_write_wait(); memset(buf, 0, sizeof(buf)); memset(response, 0, sizeof(response)); memset(&md, 0, sizeof(md)); } /* * Checks if the user has authentication file, and if so, tries to authenticate * the user using it. */ static int try_rsa_authentication(int idx) { BIGNUM *challenge; Key *public, *private; char buf[300], *passphrase, *comment, *authfile; int i, type, quit; public = options.identity_keys[idx]; authfile = options.identity_files[idx]; comment = xstrdup(authfile); debug("Trying RSA authentication with key '%.100s'", comment); /* Tell the server that we are willing to authenticate using this key. */ packet_start(SSH_CMSG_AUTH_RSA); packet_put_bignum(public->rsa->n); packet_send(); packet_write_wait(); /* Wait for server's response. */ type = packet_read(); /* * The server responds with failure if it doesn\'t like our key or * doesn\'t support RSA authentication. */ if (type == SSH_SMSG_FAILURE) { debug("Server refused our key."); xfree(comment); return 0; } /* Otherwise, the server should respond with a challenge. */ if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) packet_disconnect("Protocol error during RSA authentication: %d", type); /* Get the challenge from the packet. */ if ((challenge = BN_new()) == NULL) fatal("try_rsa_authentication: BN_new failed"); packet_get_bignum(challenge); packet_check_eom(); debug("Received RSA challenge from server."); /* * If the key is not stored in external hardware, we have to * load the private key. Try first with empty passphrase; if it * fails, ask for a passphrase. */ if (public->flags & KEY_FLAG_EXT) private = public; else private = key_load_private_type(KEY_RSA1, authfile, "", NULL); if (private == NULL && !options.batch_mode) { snprintf(buf, sizeof(buf), "Enter passphrase for RSA key '%.100s': ", comment); for (i = 0; i < options.number_of_password_prompts; i++) { passphrase = read_passphrase(buf, 0); if (strcmp(passphrase, "") != 0) { private = key_load_private_type(KEY_RSA1, authfile, passphrase, NULL); quit = 0; } else { debug2("no passphrase given, try next key"); quit = 1; } memset(passphrase, 0, strlen(passphrase)); xfree(passphrase); if (private != NULL || quit) break; debug2("bad passphrase given, try again..."); } } /* We no longer need the comment. */ xfree(comment); if (private == NULL) { if (!options.batch_mode) error("Bad passphrase."); /* Send a dummy response packet to avoid protocol error. */ packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); for (i = 0; i < 16; i++) packet_put_char(0); packet_send(); packet_write_wait(); /* Expect the server to reject it... */ packet_read_expect(SSH_SMSG_FAILURE); BN_clear_free(challenge); return 0; } /* Compute and send a response to the challenge. */ respond_to_rsa_challenge(challenge, private->rsa); /* Destroy the private key unless it in external hardware. */ if (!(private->flags & KEY_FLAG_EXT)) key_free(private); /* We no longer need the challenge. */ BN_clear_free(challenge); /* Wait for response from the server. */ type = packet_read(); if (type == SSH_SMSG_SUCCESS) { debug("RSA authentication accepted by server."); return 1; } if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error waiting RSA auth response: %d", type); debug("RSA authentication refused."); return 0; } /* * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv * authentication and RSA host authentication. */ static int try_rhosts_rsa_authentication(const char *local_user, Key * host_key) { int type; BIGNUM *challenge; debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); /* Tell the server that we are willing to authenticate using this key. */ packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); packet_put_cstring(local_user); packet_put_int(BN_num_bits(host_key->rsa->n)); packet_put_bignum(host_key->rsa->e); packet_put_bignum(host_key->rsa->n); packet_send(); packet_write_wait(); /* Wait for server's response. */ type = packet_read(); /* The server responds with failure if it doesn't admit our .rhosts authentication or doesn't know our host key. */ if (type == SSH_SMSG_FAILURE) { debug("Server refused our rhosts authentication or host key."); return 0; } /* Otherwise, the server should respond with a challenge. */ if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) packet_disconnect("Protocol error during RSA authentication: %d", type); /* Get the challenge from the packet. */ if ((challenge = BN_new()) == NULL) fatal("try_rhosts_rsa_authentication: BN_new failed"); packet_get_bignum(challenge); packet_check_eom(); debug("Received RSA challenge for host key from server."); /* Compute a response to the challenge. */ respond_to_rsa_challenge(challenge, host_key->rsa); /* We no longer need the challenge. */ BN_clear_free(challenge); /* Wait for response from the server. */ type = packet_read(); if (type == SSH_SMSG_SUCCESS) { debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); return 1; } if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error waiting RSA auth response: %d", type); debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); return 0; } #ifdef KRB4 static int try_krb4_authentication(void) { KTEXT_ST auth; /* Kerberos data */ char *reply; char inst[INST_SZ]; char *realm; CREDENTIALS cred; int r, type; socklen_t slen; Key_schedule schedule; u_long checksum, cksum; MSG_DAT msg_data; struct sockaddr_in local, foreign; struct stat st; /* Don't do anything if we don't have any tickets. */ if (stat(tkt_string(), &st) < 0) return 0; strlcpy(inst, (char *)krb_get_phost(get_canonical_hostname(1)), INST_SZ); realm = (char *)krb_realmofhost(get_canonical_hostname(1)); if (!realm) { debug("Kerberos v4: no realm for %s", get_canonical_hostname(1)); return 0; } /* This can really be anything. */ checksum = (u_long)getpid(); r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum); if (r != KSUCCESS) { debug("Kerberos v4 krb_mk_req failed: %s", krb_err_txt[r]); return 0; } /* Get session key to decrypt the server's reply with. */ r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred); if (r != KSUCCESS) { debug("get_cred failed: %s", krb_err_txt[r]); return 0; } des_key_sched((des_cblock *) cred.session, schedule); /* Send authentication info to server. */ packet_start(SSH_CMSG_AUTH_KERBEROS); packet_put_string((char *) auth.dat, auth.length); packet_send(); packet_write_wait(); /* Zero the buffer. */ (void) memset(auth.dat, 0, MAX_KTXT_LEN); slen = sizeof(local); memset(&local, 0, sizeof(local)); if (getsockname(packet_get_connection_in(), (struct sockaddr *)&local, &slen) < 0) debug("getsockname failed: %s", strerror(errno)); slen = sizeof(foreign); memset(&foreign, 0, sizeof(foreign)); if (getpeername(packet_get_connection_in(), (struct sockaddr *)&foreign, &slen) < 0) { debug("getpeername failed: %s", strerror(errno)); fatal_cleanup(); } /* Get server reply. */ type = packet_read(); switch (type) { case SSH_SMSG_FAILURE: /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ debug("Kerberos v4 authentication failed."); return 0; break; case SSH_SMSG_AUTH_KERBEROS_RESPONSE: /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ debug("Kerberos v4 authentication accepted."); /* Get server's response. */ reply = packet_get_string((u_int *) &auth.length); if (auth.length >= MAX_KTXT_LEN) fatal("Kerberos v4: Malformed response from server"); memcpy(auth.dat, reply, auth.length); xfree(reply); packet_check_eom(); /* * If his response isn't properly encrypted with the session * key, and the decrypted checksum fails to match, he's * bogus. Bail out. */ r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session, &foreign, &local, &msg_data); if (r != KSUCCESS) { debug("Kerberos v4 krb_rd_priv failed: %s", krb_err_txt[r]); packet_disconnect("Kerberos v4 challenge failed!"); } /* Fetch the (incremented) checksum that we supplied in the request. */ memcpy((char *)&cksum, (char *)msg_data.app_data, sizeof(cksum)); cksum = ntohl(cksum); /* If it matches, we're golden. */ if (cksum == checksum + 1) { debug("Kerberos v4 challenge successful."); return 1; } else packet_disconnect("Kerberos v4 challenge failed!"); break; default: packet_disconnect("Protocol error on Kerberos v4 response: %d", type); } return 0; } #endif /* KRB4 */ #ifdef KRB5 static int try_krb5_authentication(krb5_context *context, krb5_auth_context *auth_context) { krb5_error_code problem; const char *tkfile; struct stat buf; krb5_ccache ccache = NULL; const char *remotehost; krb5_data ap; int type; krb5_ap_rep_enc_part *reply = NULL; int ret; memset(&ap, 0, sizeof(ap)); problem = krb5_init_context(context); if (problem) { debug("Kerberos v5: krb5_init_context failed"); ret = 0; goto out; } problem = krb5_auth_con_init(*context, auth_context); if (problem) { debug("Kerberos v5: krb5_auth_con_init failed"); ret = 0; goto out; } #ifndef HEIMDAL problem = krb5_auth_con_setflags(*context, *auth_context, KRB5_AUTH_CONTEXT_RET_TIME); if (problem) { debug("Keberos v5: krb5_auth_con_setflags failed"); ret = 0; goto out; } #endif tkfile = krb5_cc_default_name(*context); if (strncmp(tkfile, "FILE:", 5) == 0) tkfile += 5; if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) { debug("Kerberos v5: could not get default ccache (permission denied)."); ret = 0; goto out; } problem = krb5_cc_default(*context, &ccache); if (problem) { debug("Kerberos v5: krb5_cc_default failed: %s", krb5_get_err_text(*context, problem)); ret = 0; goto out; } remotehost = get_canonical_hostname(1); problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED, "host", remotehost, NULL, ccache, &ap); if (problem) { debug("Kerberos v5: krb5_mk_req failed: %s", krb5_get_err_text(*context, problem)); ret = 0; goto out; } packet_start(SSH_CMSG_AUTH_KERBEROS); packet_put_string((char *) ap.data, ap.length); packet_send(); packet_write_wait(); xfree(ap.data); ap.length = 0; type = packet_read(); switch (type) { case SSH_SMSG_FAILURE: /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ debug("Kerberos v5 authentication failed."); ret = 0; break; case SSH_SMSG_AUTH_KERBEROS_RESPONSE: /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ debug("Kerberos v5 authentication accepted."); /* Get server's response. */ ap.data = packet_get_string((unsigned int *) &ap.length); packet_check_eom(); /* XXX je to dobre? */ problem = krb5_rd_rep(*context, *auth_context, &ap, &reply); if (problem) { ret = 0; } ret = 1; break; default: packet_disconnect("Protocol error on Kerberos v5 response: %d", type); ret = 0; break; } out: if (ccache != NULL) krb5_cc_close(*context, ccache); if (reply != NULL) krb5_free_ap_rep_enc_part(*context, reply); if (ap.length > 0) #ifdef HEIMDAL krb5_data_free(&ap); #else krb5_free_data_contents(*context, &ap); #endif return (ret); } static void send_krb5_tgt(krb5_context context, krb5_auth_context auth_context) { int fd, type; krb5_error_code problem; krb5_data outbuf; krb5_ccache ccache = NULL; krb5_creds creds; #ifdef HEIMDAL krb5_kdc_flags flags; #else int forwardable; #endif const char *remotehost; memset(&creds, 0, sizeof(creds)); memset(&outbuf, 0, sizeof(outbuf)); fd = packet_get_connection_in(); #ifdef HEIMDAL problem = krb5_auth_con_setaddrs_from_fd(context, auth_context, &fd); #else problem = krb5_auth_con_genaddrs(context, auth_context, fd, KRB5_AUTH_CONTEXT_GENERATE_REMOTE_FULL_ADDR | KRB5_AUTH_CONTEXT_GENERATE_LOCAL_FULL_ADDR); #endif if (problem) goto out; problem = krb5_cc_default(context, &ccache); if (problem) goto out; problem = krb5_cc_get_principal(context, ccache, &creds.client); if (problem) goto out; remotehost = get_canonical_hostname(1); #ifdef HEIMDAL problem = krb5_build_principal(context, &creds.server, strlen(creds.client->realm), creds.client->realm, "krbtgt", creds.client->realm, NULL); #else problem = krb5_build_principal(context, &creds.server, creds.client->realm.length, creds.client->realm.data, "host", remotehost, NULL); #endif if (problem) goto out; creds.times.endtime = 0; #ifdef HEIMDAL flags.i = 0; flags.b.forwarded = 1; flags.b.forwardable = krb5_config_get_bool(context, NULL, "libdefaults", "forwardable", NULL); problem = krb5_get_forwarded_creds(context, auth_context, ccache, flags.i, remotehost, &creds, &outbuf); #else forwardable = 1; problem = krb5_fwd_tgt_creds(context, auth_context, remotehost, creds.client, creds.server, ccache, forwardable, &outbuf); #endif if (problem) goto out; packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); packet_put_string((char *)outbuf.data, outbuf.length); packet_send(); packet_write_wait(); type = packet_read(); if (type == SSH_SMSG_SUCCESS) { char *pname; krb5_unparse_name(context, creds.client, &pname); debug("Kerberos v5 TGT forwarded (%s).", pname); xfree(pname); } else debug("Kerberos v5 TGT forwarding failed."); return; out: if (problem) debug("Kerberos v5 TGT forwarding failed: %s", krb5_get_err_text(context, problem)); if (creds.client) krb5_free_principal(context, creds.client); if (creds.server) krb5_free_principal(context, creds.server); if (ccache) krb5_cc_close(context, ccache); if (outbuf.data) xfree(outbuf.data); } #endif /* KRB5 */ #ifdef AFS static void send_krb4_tgt(void) { CREDENTIALS *creds; struct stat st; char buffer[4096], pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ]; int problem, type; /* Don't do anything if we don't have any tickets. */ if (stat(tkt_string(), &st) < 0) return; creds = xmalloc(sizeof(*creds)); problem = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm); if (problem) goto out; problem = krb_get_cred("krbtgt", prealm, prealm, creds); if (problem) goto out; if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) { problem = RD_AP_EXP; goto out; } creds_to_radix(creds, (u_char *)buffer, sizeof(buffer)); packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); packet_put_cstring(buffer); packet_send(); packet_write_wait(); type = packet_read(); if (type == SSH_SMSG_SUCCESS) debug("Kerberos v4 TGT forwarded (%s%s%s@%s).", creds->pname, creds->pinst[0] ? "." : "", creds->pinst, creds->realm); else debug("Kerberos v4 TGT rejected."); xfree(creds); return; out: debug("Kerberos v4 TGT passing failed: %s", krb_err_txt[problem]); xfree(creds); } static void send_afs_tokens(void) { CREDENTIALS creds; struct ViceIoctl parms; struct ClearToken ct; int i, type, len; char buf[2048], *p, *server_cell; char buffer[8192]; /* Move over ktc_GetToken, here's something leaner. */ for (i = 0; i < 100; i++) { /* just in case */ parms.in = (char *) &i; parms.in_size = sizeof(i); parms.out = buf; parms.out_size = sizeof(buf); if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) break; p = buf; /* Get secret token. */ memcpy(&creds.ticket_st.length, p, sizeof(u_int)); if (creds.ticket_st.length > MAX_KTXT_LEN) break; p += sizeof(u_int); memcpy(creds.ticket_st.dat, p, creds.ticket_st.length); p += creds.ticket_st.length; /* Get clear token. */ memcpy(&len, p, sizeof(len)); if (len != sizeof(struct ClearToken)) break; p += sizeof(len); memcpy(&ct, p, len); p += len; p += sizeof(len); /* primary flag */ server_cell = p; /* Flesh out our credentials. */ strlcpy(creds.service, "afs", sizeof(creds.service)); creds.instance[0] = '\0'; strlcpy(creds.realm, server_cell, REALM_SZ); memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ); creds.issue_date = ct.BeginTimestamp; creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp); creds.kvno = ct.AuthHandle; snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId); creds.pinst[0] = '\0'; /* Encode token, ship it off. */ if (creds_to_radix(&creds, (u_char *)buffer, sizeof(buffer)) <= 0) break; packet_start(SSH_CMSG_HAVE_AFS_TOKEN); packet_put_cstring(buffer); packet_send(); packet_write_wait(); /* Roger, Roger. Clearance, Clarence. What's your vector, Victor? */ type = packet_read(); if (type == SSH_SMSG_FAILURE) debug("AFS token for cell %s rejected.", server_cell); else if (type != SSH_SMSG_SUCCESS) packet_disconnect("Protocol error on AFS token response: %d", type); } } #endif /* AFS */ /* * Tries to authenticate with any string-based challenge/response system. * Note that the client code is not tied to s/key or TIS. */ static int try_challenge_response_authentication(void) { int type, i; u_int clen; char prompt[1024]; char *challenge, *response; debug("Doing challenge response authentication."); for (i = 0; i < options.number_of_password_prompts; i++) { /* request a challenge */ packet_start(SSH_CMSG_AUTH_TIS); packet_send(); packet_write_wait(); type = packet_read(); if (type != SSH_SMSG_FAILURE && type != SSH_SMSG_AUTH_TIS_CHALLENGE) { packet_disconnect("Protocol error: got %d in response " "to SSH_CMSG_AUTH_TIS", type); } if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { debug("No challenge."); return 0; } challenge = packet_get_string(&clen); packet_check_eom(); snprintf(prompt, sizeof prompt, "%s%s", challenge, strchr(challenge, '\n') ? "" : "\nResponse: "); xfree(challenge); if (i != 0) error("Permission denied, please try again."); if (options.cipher == SSH_CIPHER_NONE) log("WARNING: Encryption is disabled! " "Response will be transmitted in clear text."); response = read_passphrase(prompt, 0); if (strcmp(response, "") == 0) { xfree(response); break; } packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); ssh_put_password(response); memset(response, 0, strlen(response)); xfree(response); packet_send(); packet_write_wait(); type = packet_read(); if (type == SSH_SMSG_SUCCESS) return 1; if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error: got %d in response " "to SSH_CMSG_AUTH_TIS_RESPONSE", type); } /* failure */ return 0; } /* * Tries to authenticate with plain passwd authentication. */ static int try_password_authentication(char *prompt) { int type, i; char *password; debug("Doing password authentication."); if (options.cipher == SSH_CIPHER_NONE) log("WARNING: Encryption is disabled! Password will be transmitted in clear text."); for (i = 0; i < options.number_of_password_prompts; i++) { if (i != 0) error("Permission denied, please try again."); password = read_passphrase(prompt, 0); packet_start(SSH_CMSG_AUTH_PASSWORD); ssh_put_password(password); memset(password, 0, strlen(password)); xfree(password); packet_send(); packet_write_wait(); type = packet_read(); if (type == SSH_SMSG_SUCCESS) return 1; if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error: got %d in response to passwd auth", type); } /* failure */ return 0; } #ifdef GSSAPI #ifdef GSI char * get_gsi_name() { OM_uint32 maj_stat; OM_uint32 min_stat; gss_name_t pname = GSS_C_NO_NAME; gss_buffer_desc tmpname; gss_buffer_t tmpnamed = &tmpname; char *retname; gss_OID_set oidset; gss_cred_id_t gss_cred = GSS_C_NO_CREDENTIAL; gss_create_empty_oid_set(&min_stat,&oidset); gss_add_oid_set_member(&min_stat,&supported_mechs[GSS_GSI].oid,&oidset); maj_stat = gss_acquire_cred(&min_stat, GSS_C_NO_NAME, GSS_C_INDEFINITE, oidset, GSS_C_INITIATE, &gss_cred, NULL, NULL); if (maj_stat != GSS_S_COMPLETE) { goto error; } debug("calling gss_inquire_cred"); maj_stat = gss_inquire_cred(&min_stat, gss_cred, &pname, NULL, NULL, NULL); if (maj_stat != GSS_S_COMPLETE) { goto error; } maj_stat = gss_display_name(&min_stat, pname, tmpnamed, NULL); if (maj_stat != GSS_S_COMPLETE) { goto error; } debug("gss_display_name finsished"); retname = (char *)malloc(tmpname.length + 1); if (!retname) { goto error; } memcpy(retname, tmpname.value, tmpname.length); retname[tmpname.length] = '\0'; gss_release_name(&min_stat, &pname); gss_release_buffer(&min_stat, tmpnamed); return retname; error: debug("Failed to set GSI username from credentials"); ssh_gssapi_error(&supported_mechs[GSS_GSI].oid, maj_stat, min_stat); return NULL; } #endif /* GSI */ int try_gssapi_authentication(char *host, Options *options) { char *service_name = NULL; gss_buffer_desc name_tok; gss_buffer_desc send_tok; gss_buffer_desc recv_tok; gss_buffer_desc *token_ptr; gss_name_t target_name = NULL; gss_ctx_id_t gss_context; gss_OID_desc mech_oid; gss_OID name_type; gss_OID_set gss_mechs, my_mechs; int my_mech_num, i, present; OM_uint32 maj_stat; OM_uint32 min_stat; int ret_stat = 0; /* 1 == success */ OM_uint32 req_flags = 0; OM_uint32 ret_flags; int type; char *xhost; unsigned int slen; Gssctxt *ctx = NULL; /* Make a copy of the host name, in case it was returned by a * previous call to gethostbyname(). */ xhost = xstrdup(host); /* Make sure we have the FQHN. Some GSSAPI implementations don't do * this for us themselves */ resolve_hostname(&xhost); /* * Default flags */ req_flags |= GSS_C_REPLAY_FLAG; /* Do mutual authentication */ req_flags |= GSS_C_MUTUAL_FLAG; service_name = (char *) xmalloc(strlen("host") + strlen(xhost) + 2 /* 1 for '@', 1 for NUL */); sprintf(service_name, "host@%s", xhost); xfree(xhost); xhost = NULL; name_type = GSS_C_NT_HOSTBASED_SERVICE; debug("Service name is %s", service_name); /* Forward credentials? */ #ifdef GSSAPI if(options->gss_deleg_creds) { debug("Delegating GSSAPI credentials"); req_flags |= GSS_C_DELEG_FLAG; } #endif /* GSSAPI */ debug("req_flags = %u", (unsigned int)req_flags); name_tok.value = service_name; name_tok.length = strlen(service_name) + 1; maj_stat = gss_import_name(&min_stat, &name_tok, name_type, &target_name); free(service_name); service_name = NULL; if (maj_stat != GSS_S_COMPLETE) { ssh_gssapi_error(GSS_C_NO_OID, maj_stat, min_stat); goto cleanup; } maj_stat = gss_indicate_mechs(&min_stat, &gss_mechs); if (maj_stat != GSS_S_COMPLETE) { ssh_gssapi_error(GSS_C_NO_OID, maj_stat, min_stat); goto cleanup; } /* The GSSAPI supports the mechs in gss_mechs, but which ones do we have credentials for? We only get one try, so we don't want to propose a mechanism we know is going to fail. */ maj_stat = gss_create_empty_oid_set(&min_stat, &my_mechs); for (i=0; supported_mechs[i].name != NULL; i++) { maj_stat = gss_test_oid_set_member(&min_stat, &supported_mechs[i].oid, gss_mechs, &present); if (present) { if (!GSS_ERROR(ssh_gssapi_client_ctx(&ctx, &supported_mechs[i].oid, host))) { maj_stat = gss_add_oid_set_member(&min_stat, &supported_mechs[i].oid, &my_mechs); debug("GSSAPI mechanism %s supported", supported_mechs[i].name); } else { debug("no credentials for GSSAPI mechanism %s", supported_mechs[i].name); } } else { debug("GSSAPI mechanism %s not supported", supported_mechs[i].name); } } /* * Send over a packet to the daemon, letting it know we're doing * GSSAPI and our mech_oid(s). */ debug("Sending mech oid(s) to server"); packet_start(SSH_CMSG_AUTH_GSSAPI); packet_put_int(my_mechs->count); /* Number of mechs we're sending */ #ifdef GSI /* Send GSI before Kerberos, because if GSI fails, we can always fall back and try regular Kerberos authentication with our Kerberos cred. */ maj_stat = gss_test_oid_set_member(&min_stat, &supported_mechs[GSS_GSI].oid, my_mechs, &present); if (present) { packet_put_string(supported_mechs[GSS_GSI].oid.elements, supported_mechs[GSS_GSI].oid.length); } #endif for (my_mech_num = 0; my_mech_num < my_mechs->count; my_mech_num++) { #ifdef GSI /* Skip GSI. We already sent it above. */ if ((my_mechs->elements[my_mech_num].length == supported_mechs[GSS_GSI].oid.length) && memcmp(my_mechs->elements[my_mech_num].elements, supported_mechs[GSS_GSI].oid.elements, my_mechs->elements[my_mech_num].length) == 0) { continue; } #endif packet_put_string(my_mechs->elements[my_mech_num].elements, my_mechs->elements[my_mech_num].length); } packet_send(); packet_write_wait(); /* * Get reply from the daemon to see if our mech was acceptable */ type = packet_read(); switch (type) { case SSH_SMSG_AUTH_GSSAPI_RESPONSE: debug("Server accepted mechanism"); /* Successful negotiation */ break; case SSH_MSG_AUTH_GSSAPI_ABORT: debug("Unable to negotiate GSSAPI mechanism type with server"); packet_get_all(); goto cleanup; default: packet_disconnect("Protocol error during GSSAPI authentication:" " packet type %d received", type); /* Does not return */ } /* Read the mechanism the server returned */ mech_oid.elements = packet_get_string(&slen); mech_oid.length = slen; /* safe typecast */ packet_get_all(); /* * Perform the context-establishement loop. * * On each pass through the loop, token_ptr points to the token * to send to the server (or GSS_C_NO_BUFFER on the first pass). * Every generated token is stored in send_tok which is then * transmitted to the server; every received token is stored in * recv_tok, which token_ptr is then set to, to be processed by * the next call to gss_init_sec_context. * * GSS-API guarantees that send_tok's length will be non-zero * if and only if the server is expecting another token from us, * and that gss_init_sec_context returns GSS_S_CONTINUE_NEEDED if * and only if the server has another token to send us. */ token_ptr = GSS_C_NO_BUFFER; gss_context = GSS_C_NO_CONTEXT; do { maj_stat = gss_init_sec_context(&min_stat, GSS_C_NO_CREDENTIAL, &gss_context, target_name, &mech_oid, req_flags, 0, NULL, /* no channel bindings */ token_ptr, NULL, /* ignore mech type */ &send_tok, &ret_flags, NULL); /* ignore time_rec */ if (token_ptr != GSS_C_NO_BUFFER) (void) gss_release_buffer(&min_stat, &recv_tok); if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED) { ssh_gssapi_error(&mech_oid, maj_stat, min_stat); /* Send an abort message */ packet_start(SSH_MSG_AUTH_GSSAPI_ABORT); packet_send(); packet_write_wait(); goto cleanup; } if (send_tok.length != 0) { debug("Sending authenticaton token..."); packet_start(SSH_MSG_AUTH_GSSAPI_TOKEN); packet_put_string((char *) send_tok.value, send_tok.length); packet_send(); packet_write_wait(); (void) gss_release_buffer(&min_stat, &send_tok); } if (maj_stat == GSS_S_CONTINUE_NEEDED) { debug("Continue needed. Reading response..."); type = packet_read(); switch(type) { case SSH_MSG_AUTH_GSSAPI_TOKEN: /* This is what we expected */ break; case SSH_MSG_AUTH_GSSAPI_ABORT: debug("Server aborted GSSAPI authentication."); packet_get_all(); goto cleanup; default: packet_disconnect("Protocol error during GSSAPI authentication:" " packet type %d received", type); /* Does not return */ } recv_tok.value = packet_get_string(&slen); recv_tok.length=slen; /* safe typecast */ packet_get_all(); token_ptr = &recv_tok; } } while (maj_stat == GSS_S_CONTINUE_NEEDED); /* Success */ ret_stat = 1; debug("GSSAPI authentication successful"); /* * Read hash of host and server keys and make sure it * matches what we got earlier. */ debug("Reading hash of server and host keys..."); type = packet_read(); if (type == SSH_MSG_AUTH_GSSAPI_ABORT) { debug("Server aborted GSSAPI authentication."); packet_get_all(); ret_stat = 0; goto cleanup; } else if (type == SSH_SMSG_AUTH_GSSAPI_HASH) { gss_buffer_desc wrapped_buf; gss_buffer_desc unwrapped_buf; int conf_state; gss_qop_t qop_state; wrapped_buf.value = packet_get_string(&slen); wrapped_buf.length=slen; /* safe typecast */ packet_get_all(); maj_stat = gss_unwrap(&min_stat, gss_context, &wrapped_buf, &unwrapped_buf, &conf_state, &qop_state); if (maj_stat != GSS_S_COMPLETE) { ssh_gssapi_error(&mech_oid, maj_stat, min_stat); packet_disconnect("Verification of SSHD keys through GSSAPI-secured channel failed: " "Unwrapping of hash failed."); } if (unwrapped_buf.length != sizeof(ssh_key_digest)) { packet_disconnect("Verification of SSHD keys through GSSAPI-secured channel failed: " "Size of key hashes do not match (%d != %d)!", (int)unwrapped_buf.length, (int)sizeof(ssh_key_digest)); } if (memcmp(ssh_key_digest, unwrapped_buf.value, sizeof(ssh_key_digest)) != 0) { packet_disconnect("Verification of SSHD keys through GSSAPI-secured channel failed: " "Hashes don't match!"); } debug("Verified SSHD keys through GSSAPI-secured channel."); gss_release_buffer(&min_stat, &unwrapped_buf); } else { packet_disconnect("Protocol error during GSSAPI authentication:" "packet type %d received", type); /* Does not return */ } cleanup: if (target_name != NULL) (void) gss_release_name(&min_stat, &target_name); return ret_stat; } #endif /* GSSAPI */ /* * SSH1 key exchange */ void ssh_kex(char *host, struct sockaddr *hostaddr) { int i; BIGNUM *key; Key *host_key, *server_key; int bits, rbits; int ssh_cipher_default = SSH_CIPHER_3DES; u_char session_key[SSH_SESSION_KEY_LENGTH]; u_char cookie[8]; u_int supported_ciphers; u_int server_flags, client_flags; u_int32_t rand = 0; debug("Waiting for server public key."); /* Wait for a public key packet from the server. */ packet_read_expect(SSH_SMSG_PUBLIC_KEY); /* Get cookie from the packet. */ for (i = 0; i < 8; i++) cookie[i] = packet_get_char(); /* Get the public key. */ server_key = key_new(KEY_RSA1); bits = packet_get_int(); packet_get_bignum(server_key->rsa->e); packet_get_bignum(server_key->rsa->n); rbits = BN_num_bits(server_key->rsa->n); if (bits != rbits) { log("Warning: Server lies about size of server public key: " "actual size is %d bits vs. announced %d.", rbits, bits); log("Warning: This may be due to an old implementation of ssh."); } /* Get the host key. */ host_key = key_new(KEY_RSA1); bits = packet_get_int(); packet_get_bignum(host_key->rsa->e); packet_get_bignum(host_key->rsa->n); rbits = BN_num_bits(host_key->rsa->n); if (bits != rbits) { log("Warning: Server lies about size of server host key: " "actual size is %d bits vs. announced %d.", rbits, bits); log("Warning: This may be due to an old implementation of ssh."); } #ifdef GSSAPI { MD5_CTX md5context; Buffer buf; unsigned char *data; unsigned int data_len; /* * Hash the server and host keys. Later we will check them against * a hash sent over a secure channel to make sure they are legit. */ debug("Calculating MD5 hash of server and host keys..."); /* Write all the keys to a temporary buffer */ buffer_init(&buf); /* Server key */ buffer_put_bignum(&buf, server_key->rsa->e); buffer_put_bignum(&buf, server_key->rsa->n); /* Host key */ buffer_put_bignum(&buf, host_key->rsa->e); buffer_put_bignum(&buf, host_key->rsa->n); /* Get the resulting data */ data = (unsigned char *) buffer_ptr(&buf); data_len = buffer_len(&buf); /* And hash it */ MD5_Init(&md5context); MD5_Update(&md5context, data, data_len); MD5_Final(ssh_key_digest, &md5context); /* Clean up */ buffer_clear(&buf); buffer_free(&buf); } #endif /* GSSAPI */ /* Get protocol flags. */ server_flags = packet_get_int(); packet_set_protocol_flags(server_flags); supported_ciphers = packet_get_int(); supported_authentications = packet_get_int(); packet_check_eom(); debug("Received server public key (%d bits) and host key (%d bits).", BN_num_bits(server_key->rsa->n), BN_num_bits(host_key->rsa->n)); if (verify_host_key(host, hostaddr, host_key) == -1) fatal("Host key verification failed."); client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; compute_session_id(session_id, cookie, host_key->rsa->n, server_key->rsa->n); /* Generate a session key. */ arc4random_stir(); /* * Generate an encryption key for the session. The key is a 256 bit * random number, interpreted as a 32-byte key, with the least * significant 8 bits being the first byte of the key. */ for (i = 0; i < 32; i++) { if (i % 4 == 0) rand = arc4random(); session_key[i] = rand & 0xff; rand >>= 8; } /* * According to the protocol spec, the first byte of the session key * is the highest byte of the integer. The session key is xored with * the first 16 bytes of the session id. */ if ((key = BN_new()) == NULL) fatal("respond_to_rsa_challenge: BN_new failed"); BN_set_word(key, 0); for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { BN_lshift(key, key, 8); if (i < 16) BN_add_word(key, session_key[i] ^ session_id[i]); else BN_add_word(key, session_key[i]); } /* * Encrypt the integer using the public key and host key of the * server (key with smaller modulus first). */ if (BN_cmp(server_key->rsa->n, host_key->rsa->n) < 0) { /* Public key has smaller modulus. */ if (BN_num_bits(host_key->rsa->n) < BN_num_bits(server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { fatal("respond_to_rsa_challenge: host_key %d < server_key %d + " "SSH_KEY_BITS_RESERVED %d", BN_num_bits(host_key->rsa->n), BN_num_bits(server_key->rsa->n), SSH_KEY_BITS_RESERVED); } rsa_public_encrypt(key, key, server_key->rsa); rsa_public_encrypt(key, key, host_key->rsa); } else { /* Host key has smaller modulus (or they are equal). */ if (BN_num_bits(server_key->rsa->n) < BN_num_bits(host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { fatal("respond_to_rsa_challenge: server_key %d < host_key %d + " "SSH_KEY_BITS_RESERVED %d", BN_num_bits(server_key->rsa->n), BN_num_bits(host_key->rsa->n), SSH_KEY_BITS_RESERVED); } rsa_public_encrypt(key, key, host_key->rsa); rsa_public_encrypt(key, key, server_key->rsa); } /* Destroy the public keys since we no longer need them. */ key_free(server_key); key_free(host_key); if (options.cipher == SSH_CIPHER_NOT_SET) { if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default)) options.cipher = ssh_cipher_default; } else if (options.cipher == SSH_CIPHER_ILLEGAL || !(cipher_mask_ssh1(1) & (1 << options.cipher))) { log("No valid SSH1 cipher, using %.100s instead.", cipher_name(ssh_cipher_default)); options.cipher = ssh_cipher_default; } /* Check that the selected cipher is supported. */ if (!(supported_ciphers & (1 << options.cipher))) fatal("Selected cipher type %.100s not supported by server.", cipher_name(options.cipher)); debug("Encryption type: %.100s", cipher_name(options.cipher)); /* Send the encrypted session key to the server. */ packet_start(SSH_CMSG_SESSION_KEY); packet_put_char(options.cipher); /* Send the cookie back to the server. */ for (i = 0; i < 8; i++) packet_put_char(cookie[i]); /* Send and destroy the encrypted encryption key integer. */ packet_put_bignum(key); BN_clear_free(key); /* Send protocol flags. */ packet_put_int(client_flags); /* Send the packet now. */ packet_send(); packet_write_wait(); debug("Sent encrypted session key."); /* Set the encryption key. */ packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); /* We will no longer need the session key here. Destroy any extra copies. */ memset(session_key, 0, sizeof(session_key)); /* * Expect a success message from the server. Note that this message * will be received in encrypted form. */ packet_read_expect(SSH_SMSG_SUCCESS); debug("Received encrypted confirmation."); } /* * Authenticate user */ void ssh_userauth1(const char *local_user, const char *server_user, char *host, Sensitive *sensitive) { #ifdef GSSAPI #ifdef GSI const char *save_server_user = NULL; #endif /* GSI */ #endif /* GSSAPI */ #ifdef KRB5 krb5_context context = NULL; krb5_auth_context auth_context = NULL; #endif int i, type; if (supported_authentications == 0) fatal("ssh_userauth1: server supports no auth methods"); #ifdef GSSAPI #ifdef GSI /* if no user given, tack on the subject name after the server_user. * This will allow us to run gridmap early to get real user * This name will start with /C= */ if ((supported_authentications & (1 << SSH_AUTH_GSSAPI)) && options.gss_authentication) { char * retname; char * newname; save_server_user = server_user; retname = get_gsi_name(); if (retname) { debug("passing gssapi name '%s'", retname); if (server_user) { newname = (char *) malloc(strlen(retname) + strlen(server_user) + 4); if (newname) { strcpy(newname, server_user); if(options.implicit) { strcat(newname,":i:"); } else { strcat(newname,":x:"); } strcat(newname, retname); server_user = newname; free(retname); } } } debug("server_user %s", server_user); } #endif /* GSI */ #endif /* GSSAPI */ /* Send the name of the user to log in as on the server. */ packet_start(SSH_CMSG_USER); packet_put_cstring(server_user); packet_send(); packet_write_wait(); #if defined(GSI) if(save_server_user) { server_user = save_server_user; } #endif /* * The server should respond with success if no authentication is * needed (the user has no password). Otherwise the server responds * with failure. */ type = packet_read(); /* check whether the connection was accepted without authentication. */ if (type == SSH_SMSG_SUCCESS) goto success; if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", type); #ifdef GSSAPI /* Try GSSAPI authentication */ if ((supported_authentications & (1 << SSH_AUTH_GSSAPI)) && options.gss_authentication) { debug("Trying GSSAPI authentication..."); try_gssapi_authentication(host, &options); /* * XXX Hmmm. Kerberos authentication only reads a packet if it thinks * the authentication went OK, but the server seems to always send * a packet back. So I'm not sure if I'm missing something or * the Kerberos code is broken. - vwelch 1/27/99 */ type = packet_read(); if (type == SSH_SMSG_SUCCESS) return; /* Successful connection. */ if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error: got %d in response to Kerberos auth", type); debug("GSSAPI authentication failed"); } #endif /* GSSAPI */ #ifdef KRB5 if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && options.kerberos_authentication) { debug("Trying Kerberos v5 authentication."); if (try_krb5_authentication(&context, &auth_context)) { type = packet_read(); if (type == SSH_SMSG_SUCCESS) goto success; if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error: got %d in response to Kerberos v5 auth", type); } } #endif /* KRB5 */ #ifdef KRB4 if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && options.kerberos_authentication) { debug("Trying Kerberos v4 authentication."); if (try_krb4_authentication()) { type = packet_read(); if (type == SSH_SMSG_SUCCESS) goto success; if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error: got %d in response to Kerberos v4 auth", type); } } #endif /* KRB4 */ /* * Use rhosts authentication if running in privileged socket and we * do not wish to remain anonymous. */ if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && options.rhosts_authentication) { debug("Trying rhosts authentication."); packet_start(SSH_CMSG_AUTH_RHOSTS); packet_put_cstring(local_user); packet_send(); packet_write_wait(); /* The server should respond with success or failure. */ type = packet_read(); if (type == SSH_SMSG_SUCCESS) goto success; if (type != SSH_SMSG_FAILURE) packet_disconnect("Protocol error: got %d in response to rhosts auth", type); } /* * Try .rhosts or /etc/hosts.equiv authentication with RSA host * authentication. */ if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && options.rhosts_rsa_authentication) { for (i = 0; i < sensitive->nkeys; i++) { if (sensitive->keys[i] != NULL && sensitive->keys[i]->type == KEY_RSA1 && try_rhosts_rsa_authentication(local_user, sensitive->keys[i])) goto success; } } /* Try RSA authentication if the server supports it. */ if ((supported_authentications & (1 << SSH_AUTH_RSA)) && options.rsa_authentication) { /* * Try RSA authentication using the authentication agent. The * agent is tried first because no passphrase is needed for * it, whereas identity files may require passphrases. */ if (try_agent_authentication()) goto success; /* Try RSA authentication for each identity. */ for (i = 0; i < options.num_identity_files; i++) if (options.identity_keys[i] != NULL && options.identity_keys[i]->type == KEY_RSA1 && try_rsa_authentication(i)) goto success; } /* Try challenge response authentication if the server supports it. */ if ((supported_authentications & (1 << SSH_AUTH_TIS)) && options.challenge_response_authentication && !options.batch_mode) { if (try_challenge_response_authentication()) goto success; } /* Try password authentication if the server supports it. */ if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && options.password_authentication && !options.batch_mode) { char prompt[80]; snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", server_user, host); if (try_password_authentication(prompt)) goto success; } /* All authentication methods have failed. Exit with an error message. */ fatal("Permission denied."); /* NOTREACHED */ success: #ifdef KRB5 /* Try Kerberos v5 TGT passing. */ if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && options.kerberos_tgt_passing && context && auth_context) { if (options.cipher == SSH_CIPHER_NONE) log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); send_krb5_tgt(context, auth_context); } if (auth_context) krb5_auth_con_free(context, auth_context); if (context) krb5_free_context(context); #endif #ifdef AFS /* Try Kerberos v4 TGT passing if the server supports it. */ if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && options.kerberos_tgt_passing) { if (options.cipher == SSH_CIPHER_NONE) log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); send_krb4_tgt(); } /* Try AFS token passing if the server supports it. */ if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) && options.afs_token_passing && k_hasafs()) { if (options.cipher == SSH_CIPHER_NONE) log("WARNING: Encryption is disabled! Token will be transmitted in the clear!"); send_afs_tokens(); } #endif /* AFS */ return; /* need statement after label */ }