OpenSolaris_b135/cmd/ssh/ssh/sshconnect2.c
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include "includes.h"
RCSID("$OpenBSD: sshconnect2.c,v 1.107 2002/07/01 19:48:46 markus Exp $");
#include "ssh.h"
#include "ssh2.h"
#include "xmalloc.h"
#include "buffer.h"
#include "packet.h"
#include "compat.h"
#include "bufaux.h"
#include "cipher.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 "readpass.h"
#include "match.h"
#include "dispatch.h"
#include "canohost.h"
#include "msg.h"
#include "pathnames.h"
#include "g11n.h"
#ifdef GSSAPI
#include "ssh-gss.h"
extern Gssctxt *xxx_gssctxt;
#endif /* GSSAPI */
/* import */
extern char *client_version_string;
extern char *server_version_string;
extern Options options;
extern Buffer command;
/*
* SSH2 key exchange
*/
u_char *session_id2 = NULL;
int session_id2_len = 0;
char *xxx_host;
struct sockaddr *xxx_hostaddr;
Kex *xxx_kex = NULL;
static int
verify_host_key_callback(Key *hostkey)
{
if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
fatal("Host key verification failed.");
return 0;
}
static int
accept_host_key_callback(Key *hostkey)
{
if (accept_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
log("GSS-API authenticated host key addition to "
"known_hosts file failed");
return 0;
}
void
ssh_kex2(char *host, struct sockaddr *hostaddr)
{
Kex *kex;
Kex_hook_func kex_hook = NULL;
static char **myproposal;
myproposal = my_clnt_proposal;
xxx_host = host;
xxx_hostaddr = hostaddr;
#ifdef GSSAPI
/* Add the GSSAPI mechanisms currently supported on this client to
* the key exchange algorithm proposal */
if (options.gss_keyex)
kex_hook = ssh_gssapi_client_kex_hook;
#endif /* GSSAPI */
if (options.ciphers == (char *)-1) {
log("No valid ciphers for protocol version 2 given, using defaults.");
options.ciphers = NULL;
}
if (options.ciphers != NULL) {
myproposal[PROPOSAL_ENC_ALGS_CTOS] =
myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
}
myproposal[PROPOSAL_ENC_ALGS_CTOS] =
compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
myproposal[PROPOSAL_ENC_ALGS_STOC] =
compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
if (options.compression) {
myproposal[PROPOSAL_COMP_ALGS_CTOS] =
myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib,none";
} else {
myproposal[PROPOSAL_COMP_ALGS_CTOS] =
myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,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;
if (options.rekey_limit)
packet_set_rekey_limit((u_int32_t)options.rekey_limit);
if (datafellows & SSH_BUG_LOCALES_NOT_LANGTAGS) {
char *locale = setlocale(LC_ALL, "");
/* Solaris 9 SSHD expects a locale, not a langtag list */
myproposal[PROPOSAL_LANG_CTOS] = "";
if (locale != NULL && *locale != '\0' &&
strcmp(locale, "C") != 0)
myproposal[PROPOSAL_LANG_CTOS] = locale;
} else {
myproposal[PROPOSAL_LANG_CTOS] = g11n_getlangs();
}
/* Same languages proposal for both directions */
if (myproposal[PROPOSAL_LANG_CTOS] == NULL) {
myproposal[PROPOSAL_LANG_CTOS] = "";
myproposal[PROPOSAL_LANG_STOC] = "";
} else {
myproposal[PROPOSAL_LANG_STOC] =
myproposal[PROPOSAL_LANG_CTOS];
}
/* start key exchange */
kex = kex_setup(host, myproposal, kex_hook);
kex_start(kex);
kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
#ifdef GSSAPI
kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
kex->options.gss_deleg_creds = options.gss_deleg_creds;
#endif /* GSSAPI */
kex->client_version_string=client_version_string;
kex->server_version_string=server_version_string;
kex->verify_host_key=&verify_host_key_callback;
kex->accept_host_key=&accept_host_key_callback;
xxx_kex = kex;
dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
session_id2 = kex->session_id;
session_id2_len = kex->session_id_len;
#ifdef DEBUG_KEXDH
/* send 1st encrypted/maced/compressed message */
packet_start(SSH2_MSG_IGNORE);
packet_put_cstring("markus");
packet_send();
packet_write_wait();
#endif
debug("done: ssh_kex2.");
}
/*
* Authenticate user
*/
typedef struct Authctxt Authctxt;
typedef struct Authmethod Authmethod;
typedef int sign_cb_fn(
Authctxt *authctxt, Key *key,
u_char **sigp, u_int *lenp, u_char *data, u_int datalen);
struct Authctxt {
const char *server_user;
const char *local_user;
const char *host;
const char *service;
Authmethod *method;
int success;
char *authlist;
/* pubkey */
Key *last_key;
sign_cb_fn *last_key_sign;
int last_key_hint;
AuthenticationConnection *agent;
/* hostbased */
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 *);
int userauth_none(Authctxt *);
int userauth_pubkey(Authctxt *);
int userauth_passwd(Authctxt *);
int userauth_kbdint(Authctxt *);
int userauth_hostbased(Authctxt *);
#ifdef GSSAPI
static int userauth_gssapi_keyex(Authctxt *authctxt);
static int userauth_gssapi(Authctxt *authctxt);
static void userauth_gssapi_cleanup(Authctxt *authctxt);
static void input_gssapi_response(int type, u_int32_t, void *);
static void input_gssapi_token(int type, u_int32_t, void *);
static void input_gssapi_hash(int type, u_int32_t, void *);
static void input_gssapi_error(int, u_int32_t, void *);
static void input_gssapi_errtok(int, u_int32_t, void *);
#endif /* GSSAPI */
void userauth(Authctxt *, char *);
static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *);
static void clear_auth_state(Authctxt *);
static Authmethod *authmethod_get(char *authlist);
static Authmethod *authmethod_lookup(const char *name);
static char *authmethods_get(void);
Authmethod authmethods[] = {
#ifdef GSSAPI
{"gssapi-keyex",
userauth_gssapi_keyex,
userauth_gssapi_cleanup,
&options.gss_keyex,
NULL},
{"gssapi-with-mic",
userauth_gssapi,
userauth_gssapi_cleanup,
&options.gss_authentication,
NULL},
#endif /* GSSAPI */
{"hostbased",
userauth_hostbased,
NULL,
&options.hostbased_authentication,
NULL},
{"publickey",
userauth_pubkey,
NULL,
&options.pubkey_authentication,
NULL},
{"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("send SSH2_MSG_SERVICE_REQUEST");
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("got SSH2_MSG_SERVICE_ACCEPT");
if (options.preferred_authentications == NULL)
options.preferred_authentications = authmethods_get();
/* setup authentication context */
memset(&authctxt, 0, sizeof(authctxt));
authctxt.agent = ssh_get_authentication_connection();
authctxt.server_user = server_user;
authctxt.local_user = local_user;
authctxt.host = host;
authctxt.service = "ssh-connection"; /* service name */
authctxt.success = 0;
authctxt.method = authmethod_lookup("none");
authctxt.authlist = NULL;
authctxt.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 */
if (authctxt.agent != NULL)
ssh_close_authentication_connection(authctxt.agent);
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 (authlist == NULL) {
authlist = authctxt->authlist;
} else {
if (authctxt->authlist)
xfree(authctxt->authlist);
authctxt->authlist = authlist;
}
for (;;) {
Authmethod *method = authmethod_get(authlist);
if (method == NULL)
fatal("Permission denied (%s).", authlist);
authctxt->method = method;
if (method->userauth(authctxt) != 0) {
debug2("we sent a %s packet, wait for reply", method->name);
break;
} else {
debug2("we did not send a packet, disable method");
method->enabled = NULL;
}
}
}
void
input_userauth_error(int type, u_int32_t seq, void *ctxt)
{
fatal("input_userauth_error: bad message during authentication: "
"type %d", type);
}
void
input_userauth_banner(int type, u_int32_t seq, void *ctxt)
{
char *msg, *lang;
debug3("input_userauth_banner");
msg = packet_get_utf8_string(NULL);
lang = packet_get_string(NULL);
/*
* Banner is a warning message according to RFC 4252. So, never print
* a banner in error log level or lower. If the log level is higher,
* use DisableBanner option to decide whether to display it or not.
*/
if (options.log_level > SYSLOG_LEVEL_ERROR) {
if (options.disable_banner == 0 ||
(options.disable_banner == SSH_NO_BANNER_IN_EXEC_MODE &&
buffer_len(&command) == 0)) {
msg = g11n_filter_string(msg);
(void) fprintf(stderr, "%s", msg);
}
}
xfree(msg);
xfree(lang);
}
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);
if (authctxt->method != NULL &&
authctxt->method->cleanup != NULL)
authctxt->method->cleanup(authctxt);
clear_auth_state(authctxt);
authctxt->success = 1; /* break out */
}
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)
log("Authenticated with partial success.");
debug("Authentications that can continue: %s", authlist);
clear_auth_state(authctxt);
userauth(authctxt, authlist);
}
void
input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Key *key = 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 lastkey %p hint %d",
pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
do {
if (authctxt->last_key == NULL ||
authctxt->last_key_sign == NULL) {
debug("no last key or no sign cb");
break;
}
if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
debug("unknown pkalg %s", pkalg);
break;
}
if ((key = key_from_blob(pkblob, blen)) == NULL) {
debug("no key from blob. pkalg %s", pkalg);
break;
}
if (key->type != pktype) {
error("input_userauth_pk_ok: type mismatch "
"for decoded key (received %d, expected %d)",
key->type, pktype);
break;
}
fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
debug2("input_userauth_pk_ok: fp %s", fp);
xfree(fp);
if (!key_equal(key, authctxt->last_key)) {
debug("key != last_key");
break;
}
sent = sign_and_send_pubkey(authctxt, key,
authctxt->last_key_sign);
} while (0);
if (key != NULL)
key_free(key);
xfree(pkalg);
xfree(pkblob);
/* unregister */
clear_auth_state(authctxt);
dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
/* try another method if we did not send a packet */
if (sent == 0)
userauth(authctxt, NULL);
}
#ifdef GSSAPI
int
userauth_gssapi(Authctxt *authctxt)
{
Gssctxt *gssctxt = NULL;
static int initialized = 0;
static int mech_idx = 0;
static gss_OID_set supported = GSS_C_NULL_OID_SET;
gss_OID mech = GSS_C_NULL_OID;
/* Things work better if we send one mechanism at a time, rather
* than them all at once. This means that if we fail at some point
* in the middle of a negotiation, we can come back and try something
* different. */
if (datafellows & SSH_OLD_GSSAPI) return 0;
/* Before we offer a mechanism, check that we can support it. Don't
* bother trying to get credentials - as the standard fallback will
* deal with that kind of failure.
*/
if (!initialized) {
initialized = 1;
ssh_gssapi_client_mechs(authctxt->host, &supported);
if (supported == GSS_C_NULL_OID_SET || supported->count == 0)
return (0);
} else if (supported != GSS_C_NULL_OID_SET) {
/* Try next mech, if any */
mech_idx++;
if (mech_idx >= supported->count)
return (0);
} else {
return (0);
}
mech = &supported->elements[mech_idx];
ssh_gssapi_build_ctx(&gssctxt, 1, mech);
authctxt->methoddata=(void *)gssctxt;
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_cstring(authctxt->server_user);
packet_put_cstring(authctxt->service);
packet_put_cstring(authctxt->method->name);
packet_put_int(1);
/* The newest gsskeyex draft stipulates that OIDs should
* be DER encoded, so we need to add the object type and
* length information back on */
if (datafellows & SSH_BUG_GSSAPI_BER) {
packet_put_string(mech->elements, mech->length);
} else {
packet_put_int((mech->length)+2);
packet_put_char(0x06);
packet_put_char(mech->length);
packet_put_raw(mech->elements, mech->length);
}
packet_send();
packet_write_wait();
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,&input_gssapi_response);
return 1;
}
void
input_gssapi_response(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt;
OM_uint32 status,ms;
u_int oidlen;
char *oidv;
gss_buffer_desc send_tok;
if (authctxt == NULL)
fatal("input_gssapi_response: no authentication context");
gssctxt = authctxt->methoddata;
/* Setup our OID */
oidv=packet_get_string(&oidlen);
if (datafellows & SSH_BUG_GSSAPI_BER) {
if (!ssh_gssapi_check_mech_oid(gssctxt,oidv,oidlen)) {
gss_OID oid;
oid = ssh_gssapi_make_oid(oidlen, oidv);
debug("Server returned different OID (%s) than expected (%s)",
ssh_gssapi_oid_to_str(oid),
ssh_gssapi_oid_to_str(gssctxt->desired_mech));
ssh_gssapi_release_oid(&oid);
clear_auth_state(authctxt);
userauth(authctxt,NULL);
return;
}
} else {
if(oidv[0]!=0x06 || oidv[1]!=oidlen-2) {
debug("Badly encoded mechanism OID received");
clear_auth_state(authctxt);
userauth(authctxt,NULL);
return;
}
if (!ssh_gssapi_check_mech_oid(gssctxt,oidv+2,oidlen-2)) {
gss_OID oid;
oid = ssh_gssapi_make_oid(oidlen-2, oidv+2);
debug("Server returned different OID (%s) than expected (%s)",
ssh_gssapi_oid_to_str(oid),
ssh_gssapi_oid_to_str(gssctxt->desired_mech));
clear_auth_state(authctxt);
userauth(authctxt,NULL);
return;
}
}
packet_check_eom();
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);
status = ssh_gssapi_init_ctx(gssctxt, authctxt->host,
options.gss_deleg_creds,
GSS_C_NO_BUFFER, &send_tok);
if (GSS_ERROR(status)) {
if (send_tok.length>0) {
packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
packet_put_string(send_tok.value,send_tok.length);
packet_send();
packet_write_wait();
}
/* Start again with next method on list */
debug("Trying to start again");
clear_auth_state(authctxt);
userauth(authctxt,NULL);
return;
}
/* We must have data to send */
packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
packet_put_string(send_tok.value,send_tok.length);
packet_send();
packet_write_wait();
gss_release_buffer(&ms, &send_tok);
}
void
input_gssapi_token(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt;
gss_buffer_desc send_tok, recv_tok, g_mic_data;
Buffer mic_data;
OM_uint32 status;
u_int slen;
if (authctxt == NULL || authctxt->method == NULL)
fatal("input_gssapi_response: no authentication context");
gssctxt = authctxt->methoddata;
recv_tok.value=packet_get_string(&slen);
recv_tok.length=slen; /* safe typecast */
status=ssh_gssapi_init_ctx(gssctxt, authctxt->host,
options.gss_deleg_creds,
&recv_tok, &send_tok);
packet_check_eom();
if (GSS_ERROR(status)) {
if (send_tok.length>0) {
packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
packet_put_string(send_tok.value,send_tok.length);
packet_send();
packet_write_wait();
}
/* Start again with the next method in the list */
clear_auth_state(authctxt);
userauth(authctxt,NULL);
return;
}
if (send_tok.length>0) {
packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
packet_put_string(send_tok.value,send_tok.length);
packet_send();
packet_write_wait();
}
if (status != GSS_S_COMPLETE)
return;
/* Make data buffer to MIC */
buffer_init(&mic_data);
buffer_put_string(&mic_data, session_id2, session_id2_len);
buffer_put_char(&mic_data, SSH2_MSG_USERAUTH_REQUEST);
buffer_put_cstring(&mic_data, authctxt->server_user);
buffer_put_cstring(&mic_data, authctxt->service);
buffer_put_cstring(&mic_data, authctxt->method->name);
/* Make MIC */
g_mic_data.value = buffer_ptr(&mic_data);
g_mic_data.length = buffer_len(&mic_data);
status = ssh_gssapi_get_mic(gssctxt, &g_mic_data, &send_tok);
buffer_clear(&mic_data);
if (GSS_ERROR(status) || send_tok.length == 0) {
/*
* Oops, now what? There's no error token...
* Next userauth
*/
debug("GSS_GetMIC() failed! - "
"Abandoning GSSAPI userauth");
clear_auth_state(authctxt);
userauth(authctxt,NULL);
return;
}
packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
packet_put_string(send_tok.value,send_tok.length);
packet_send();
packet_write_wait();
}
void
input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
{
OM_uint32 min_status;
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt;
gss_buffer_desc send_tok, recv_tok;
if (authctxt == NULL)
fatal("input_gssapi_response: no authentication context");
gssctxt = authctxt->methoddata;
recv_tok.value=packet_get_string(&recv_tok.length);
/* Stick it into GSSAPI and see what it says */
(void) ssh_gssapi_init_ctx(gssctxt, authctxt->host,
options.gss_deleg_creds,
&recv_tok, &send_tok);
xfree(recv_tok.value);
(void) gss_release_buffer(&min_status, &send_tok);
debug("Server sent a GSS-API error token during GSS userauth -- %s",
ssh_gssapi_last_error(gssctxt, NULL, NULL));
packet_check_eom();
/* We can't send a packet to the server */
/* The draft says that we should wait for the server to fail
* before starting the next authentication. So, we clear the
* state, but don't do anything else
*/
clear_auth_state(authctxt);
return;
}
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();
fprintf(stderr, "Server GSSAPI Error:\n%s (%d, %d)\n", msg, maj, min);
xfree(msg);
xfree(lang);
}
int
userauth_gssapi_keyex(Authctxt *authctxt)
{
Gssctxt *gssctxt;
gss_buffer_desc send_tok;
OM_uint32 status;
static int attempt = 0;
if (authctxt == NULL || authctxt->method == NULL)
fatal("input_gssapi_response: no authentication context");
if (xxx_gssctxt == NULL || xxx_gssctxt->context == GSS_C_NO_CONTEXT)
return 0;
if (strcmp(authctxt->method->name, "gssapi-keyex") == 0)
authctxt->methoddata = gssctxt = xxx_gssctxt;
if (attempt++ >= 1)
return 0;
if (strcmp(authctxt->method->name, "gssapi-keyex") == 0) {
gss_buffer_desc g_mic_data;
Buffer mic_data;
debug2("Authenticating with GSS-API context from key exchange (w/ MIC)");
/* Make data buffer to MIC */
buffer_init(&mic_data);
buffer_put_string(&mic_data, session_id2, session_id2_len);
buffer_put_char(&mic_data, SSH2_MSG_USERAUTH_REQUEST);
buffer_put_cstring(&mic_data, authctxt->server_user);
buffer_put_cstring(&mic_data, authctxt->service);
buffer_put_cstring(&mic_data, authctxt->method->name);
/* Make MIC */
g_mic_data.value = buffer_ptr(&mic_data);
g_mic_data.length = buffer_len(&mic_data);
status = ssh_gssapi_get_mic(gssctxt, &g_mic_data, &send_tok);
buffer_clear(&mic_data);
if (GSS_ERROR(status) || send_tok.length == 0) {
/*
* Oops, now what? There's no error token...
* Next userauth
*/
debug("GSS_GetMIC() failed! - "
"Abandoning GSSAPI userauth");
clear_auth_state(authctxt);
userauth(authctxt,NULL);
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(send_tok.value,send_tok.length); /* MIC */
packet_send();
packet_write_wait();
(void) gss_release_buffer(&status, &send_tok);
} else if (strcmp(authctxt->method->name, "external-keyx") == 0) {
debug2("Authentication with deprecated \"external-keyx\""
" method not supported");
return 0;
}
return 1;
}
static
void
userauth_gssapi_cleanup(Authctxt *authctxt)
{
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR,NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,NULL);
if (authctxt == NULL ||
authctxt->method == NULL ||
authctxt->methoddata == NULL)
return;
if (strncmp(authctxt->method->name, "gssapi", strlen("gssapi")) == 0) {
ssh_gssapi_delete_ctx((Gssctxt **)&authctxt->methoddata);
}
}
#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), gettext("%.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
*/
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_utf8_string(NULL);
if (strlen(info) != 0) {
info = g11n_filter_string(info);
log("%s", info);
}
xfree(info);
lang = packet_get_string(NULL);
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),
gettext("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),
gettext("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),
gettext("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);
log("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);
}
static void
clear_auth_state(Authctxt *authctxt)
{
/* XXX clear authentication state */
dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, NULL);
#ifdef GSSAPI
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR,NULL);
#endif /* GSSAPI */
if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
debug3("clear_auth_state: key_free %p", authctxt->last_key);
key_free(authctxt->last_key);
}
authctxt->last_key = NULL;
authctxt->last_key_hint = -2;
authctxt->last_key_sign = NULL;
}
static int
sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
{
Buffer b;
u_char *blob, *signature;
u_int bloblen, slen;
int skip = 0;
int ret = -1;
int have_sig = 1;
debug3("sign_and_send_pubkey");
if (key_to_blob(k, &blob, &bloblen) == 0) {
/* we cannot handle this key */
debug3("sign_and_send_pubkey: cannot handle key");
return 0;
}
/* data to be signed */
buffer_init(&b);
if (datafellows & SSH_OLD_SESSIONID) {
buffer_append(&b, session_id2, session_id2_len);
skip = session_id2_len;
} else {
buffer_put_string(&b, session_id2, session_id2_len);
skip = buffer_len(&b);
}
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
buffer_put_cstring(&b, authctxt->server_user);
buffer_put_cstring(&b,
datafellows & SSH_BUG_PKSERVICE ?
"ssh-userauth" :
authctxt->service);
if (datafellows & SSH_BUG_PKAUTH) {
buffer_put_char(&b, have_sig);
} else {
buffer_put_cstring(&b, authctxt->method->name);
buffer_put_char(&b, have_sig);
buffer_put_cstring(&b, key_ssh_name(k));
}
buffer_put_string(&b, blob, bloblen);
/* generate signature */
ret = (*sign_callback)(authctxt, k, &signature, &slen,
buffer_ptr(&b), buffer_len(&b));
if (ret == -1) {
xfree(blob);
buffer_free(&b);
return 0;
}
#ifdef DEBUG_PK
buffer_dump(&b);
#endif
if (datafellows & SSH_BUG_PKSERVICE) {
buffer_clear(&b);
buffer_append(&b, session_id2, session_id2_len);
skip = session_id2_len;
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
buffer_put_cstring(&b, authctxt->server_user);
buffer_put_cstring(&b, authctxt->service);
buffer_put_cstring(&b, authctxt->method->name);
buffer_put_char(&b, have_sig);
if (!(datafellows & SSH_BUG_PKAUTH))
buffer_put_cstring(&b, key_ssh_name(k));
buffer_put_string(&b, blob, bloblen);
}
xfree(blob);
/* append signature */
buffer_put_string(&b, signature, slen);
xfree(signature);
/* skip session id and packet type */
if (buffer_len(&b) < skip + 1)
fatal("userauth_pubkey: internal error");
buffer_consume(&b, skip + 1);
/* put remaining data from buffer into packet */
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_raw(buffer_ptr(&b), buffer_len(&b));
buffer_free(&b);
packet_send();
return 1;
}
static int
send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
int hint)
{
u_char *blob;
u_int bloblen, have_sig = 0;
debug3("send_pubkey_test");
if (key_to_blob(k, &blob, &bloblen) == 0) {
/* we cannot handle this key */
debug3("send_pubkey_test: cannot handle key");
return 0;
}
/* register callback for USERAUTH_PK_OK message */
authctxt->last_key_sign = sign_callback;
authctxt->last_key_hint = hint;
authctxt->last_key = k;
dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_cstring(authctxt->server_user);
packet_put_cstring(authctxt->service);
packet_put_cstring(authctxt->method->name);
packet_put_char(have_sig);
if (!(datafellows & SSH_BUG_PKAUTH))
packet_put_cstring(key_ssh_name(k));
packet_put_string(blob, bloblen);
xfree(blob);
packet_send();
return 1;
}
static Key *
load_identity_file(char *filename)
{
Key *private;
char prompt[300], *passphrase;
int quit, i;
struct stat st;
if (stat(filename, &st) < 0) {
debug3("no such identity: %s", filename);
return NULL;
}
private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
if (private == NULL) {
if (options.batch_mode)
return NULL;
snprintf(prompt, sizeof prompt,
gettext("Enter passphrase for key '%.100s': "), filename);
for (i = 0; i < options.number_of_password_prompts; i++) {
passphrase = read_passphrase(prompt, 0);
if (strcmp(passphrase, "") != 0) {
private = key_load_private_type(KEY_UNSPEC, filename,
passphrase, NULL);
quit = 0;
} else {
debug2("no passphrase given, try next key");
quit = 1;
}
memset(passphrase, 0, strlen(passphrase));
xfree(passphrase);
if (private != NULL || quit)
break;
debug2("bad passphrase given, try again...");
}
}
return private;
}
static int
identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
u_char *data, u_int datalen)
{
Key *private;
int idx, ret;
idx = authctxt->last_key_hint;
if (idx < 0)
return -1;
/* private key is stored in external hardware */
if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
private = load_identity_file(options.identity_files[idx]);
if (private == NULL)
return -1;
ret = key_sign(private, sigp, lenp, data, datalen);
key_free(private);
return ret;
}
static int
agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
u_char *data, u_int datalen)
{
return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
}
static int
key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
u_char *data, u_int datalen)
{
return key_sign(key, sigp, lenp, data, datalen);
}
static int
userauth_pubkey_agent(Authctxt *authctxt)
{
static int called = 0;
int ret = 0;
char *comment;
Key *k;
if (called == 0) {
if (ssh_get_num_identities(authctxt->agent, 2) == 0)
debug2("userauth_pubkey_agent: no keys at all");
called = 1;
}
k = ssh_get_next_identity(authctxt->agent, &comment, 2);
if (k == NULL) {
debug2("userauth_pubkey_agent: no more keys");
} else {
debug("Offering agent key: %s", comment);
xfree(comment);
ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
if (ret == 0)
key_free(k);
}
if (ret == 0)
debug2("userauth_pubkey_agent: no message sent");
return ret;
}
int
userauth_pubkey(Authctxt *authctxt)
{
static int idx = 0;
int sent = 0;
Key *key;
char *filename;
if (authctxt->agent != NULL) {
do {
sent = userauth_pubkey_agent(authctxt);
} while (!sent && authctxt->agent->howmany > 0);
}
while (!sent && idx < options.num_identity_files) {
key = options.identity_keys[idx];
filename = options.identity_files[idx];
if (key == NULL) {
debug("Trying private key: %s", filename);
key = load_identity_file(filename);
if (key != NULL) {
sent = sign_and_send_pubkey(authctxt, key,
key_sign_cb);
key_free(key);
}
} else if (key->type != KEY_RSA1) {
debug("Trying public key: %s", filename);
sent = send_pubkey_test(authctxt, key,
identity_sign_cb, idx);
}
idx++;
}
return sent;
}
/*
* Send userauth request message specifying keyboard-interactive method.
*/
int
userauth_kbdint(Authctxt *authctxt)
{
static int attempt = 0;
if (attempt++ >= options.number_of_password_prompts)
return 0;
/* 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;
/*
* We assume that ASCII is used for user name although it is defined
* by the protocol to use UTF-8 encoding. Therefore, we don't perform
* code conversion from UTF-8 to native codeset for the user name
* string.
*/
name = packet_get_string(NULL);
inst = packet_get_utf8_string(NULL);
lang = packet_get_string(NULL);
if (strlen(name) != 0) {
name = g11n_filter_string(name);
log("%s", name);
}
if (strlen(inst) != 0) {
inst = g11n_filter_string(inst);
log("%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_utf8_string(NULL);
echo = packet_get_char();
prompt = g11n_filter_string(prompt);
response = read_passphrase(prompt, echo ? RP_ECHO : 0);
/*
* We assume that ASCII is used for password as well. We
* don't perform code conversion from native codeset to
* UTF-8 for the password string.
*/
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) {
seteuid(getuid());
setuid(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);
ssh_msg_send(to[1], version, &b);
if (ssh_msg_recv(from[0], &b) < 0) {
error("ssh_keysign: no reply");
buffer_clear(&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_clear(&b);
return -1;
}
*sigp = buffer_get_string(&b, lenp);
buffer_clear(&b);
return 0;
}
int
userauth_hostbased(Authctxt *authctxt)
{
Key *private = NULL;
Sensitive *sensitive = authctxt->sensitive;
Buffer b;
u_char *signature, *blob;
char *chost, *pkalg, *p;
const char *service;
u_int blen, slen;
int ok, i, len, found = 0;
static int last_hostkey = -1;
/* check for a useful key */
for (i = 0; i < sensitive->nkeys; i++) {
private = sensitive->keys[i];
if (private && private->type != KEY_RSA1 && i > last_hostkey) {
found = 1;
last_hostkey = i;
/* we take and free the key */
sensitive->keys[i] = NULL;
break;
}
}
if (!found) {
debug("No more client hostkeys for hostbased authentication");
return 0;
}
if (key_to_blob(private, &blob, &blen) == 0) {
key_free(private);
return 0;
}
/* figure out a name for the client host */
p = get_local_name(packet_get_connection_in());
if (p == NULL) {
error("userauth_hostbased: cannot get local ipaddr/name");
key_free(private);
return 0;
}
service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
authctxt->service;
pkalg = xstrdup(key_ssh_name(private));
len = strlen(p) + 2;
chost = xmalloc(len);
strlcpy(chost, p, len);
strlcat(chost, ".", len);
xfree(p);
debug2("userauth_hostbased: chost %s, pkalg %s", chost, pkalg);
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);
return 0;
}
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_cstring(authctxt->server_user);
packet_put_cstring(authctxt->service);
packet_put_cstring(authctxt->method->name);
packet_put_cstring(pkalg);
packet_put_string(blob, blen);
packet_put_cstring(chost);
packet_put_cstring(authctxt->local_user);
packet_put_string(signature, slen);
memset(signature, 's', slen);
xfree(signature);
xfree(chost);
xfree(pkalg);
packet_send();
return 1;
}
/* find auth method */
/*
* given auth method name, if configurable options permit this method fill
* in auth_ident field and return true, otherwise return false.
*/
static int
authmethod_is_enabled(Authmethod *method)
{
if (method == NULL)
return 0;
/* return false if options indicate this method is disabled */
if (method->enabled == NULL || *method->enabled == 0)
return 0;
/* return false if batch mode is enabled but method needs interactive mode */
if (method->batch_flag != NULL && *method->batch_flag != 0)
return 0;
return 1;
}
static Authmethod *
authmethod_lookup(const char *name)
{
Authmethod *method = NULL;
if (name != NULL) {
for (method = authmethods; method->name != NULL; method++) {
if (strcmp(name, method->name) == 0)
return method;
}
}
debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
return NULL;
}
/* XXX internal state */
static Authmethod *current = NULL;
static char *supported = NULL;
static char *preferred = NULL;
/*
* Given the authentication method list sent by the server, return the
* next method we should try. If the server initially sends a nil list,
* use a built-in default list.
*/
static Authmethod *
authmethod_get(char *authlist)
{
char *name = NULL;
u_int next;
/* Use a suitable default if we're passed a nil list. */
if (authlist == NULL || strlen(authlist) == 0)
authlist = options.preferred_authentications;
if (supported == NULL || strcmp(authlist, supported) != 0) {
debug3("start over, passed a different list %s", authlist);
if (supported != NULL)
xfree(supported);
supported = xstrdup(authlist);
preferred = options.preferred_authentications;
debug3("preferred %s", preferred);
current = NULL;
} else if (current != NULL && authmethod_is_enabled(current))
return current;
for (;;) {
if ((name = match_list(preferred, supported, &next)) == NULL) {
debug("No more authentication methods to try.");
current = NULL;
return NULL;
}
preferred += next;
debug3("authmethod_lookup %s", name);
debug3("remaining preferred: %s", preferred);
if ((current = authmethod_lookup(name)) != NULL &&
authmethod_is_enabled(current)) {
debug3("authmethod_is_enabled %s", name);
debug("Next authentication method: %s", name);
xfree(name);
return current;
}
xfree(name);
}
}
static char *
authmethods_get(void)
{
Authmethod *method = NULL;
Buffer b;
char *list;
buffer_init(&b);
for (method = authmethods; method->name != NULL; method++) {
if (authmethod_is_enabled(method)) {
if (buffer_len(&b) > 0)
buffer_append(&b, ",", 1);
buffer_append(&b, method->name, strlen(method->name));
}
}
buffer_append(&b, "\0", 1);
list = xstrdup(buffer_ptr(&b));
buffer_free(&b);
return list;
}