/*ARGSUSED*/
static int
input_userauth_request(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Authmethod *m = NULL;
char *user, *service, *method, *style = NULL;
int authenticated = 0;
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
user = packet_get_cstring(NULL);
service = packet_get_cstring(NULL);
method = packet_get_cstring(NULL);
debug("userauth-request for user %s service %s method %s", user, service, method);
debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
if (authctxt->attempt++ == 0) {
/* setup auth context */
authctxt->pw = PRIVSEP(getpwnamallow(user));
authctxt->user = xstrdup(user);
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("input_userauth_request: setting up authctxt for %s", user);
} else {
logit("input_userauth_request: invalid user %s", user);
authctxt->pw = fakepw();
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_INVALID_USER));
#endif
}
#ifdef USE_PAM
if (options.use_pam)
PRIVSEP(start_pam(authctxt));
#endif
setproctitle("%s%s", authctxt->valid ? user : "******",
use_privsep ? " [net]" : "");
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
if (use_privsep)
mm_inform_authserv(service, style);
userauth_banner();
if (auth2_setup_methods_lists(authctxt) != 0)
packet_disconnect("no authentication methods enabled");
} else if (strcmp(user, authctxt->user) != 0 ||
strcmp(service, authctxt->service) != 0) {
packet_disconnect("Change of username or service not allowed: "
"(%s,%s) -> (%s,%s)",
authctxt->user, authctxt->service, user, service);
}
/* reset state */
auth2_challenge_stop(authctxt);
#ifdef GSSAPI
/* XXX move to auth2_gssapi_stop() */
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif
authctxt->postponed = 0;
authctxt->server_caused_failure = 0;
/* try to authenticate user */
m = authmethod_lookup(authctxt, method);
if (m != NULL && authctxt->failures < options.max_authtries) {
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(authctxt);
}
userauth_finish(authctxt, authenticated, method, NULL);
free(service);
free(user);
free(method);
return 0;
}
void
userauth_finish(Authctxt *authctxt, int authenticated, const char *method,
const char *submethod)
{
char *methods;
int partial = 0;
if (!authctxt->valid && authenticated)
fatal("INTERNAL ERROR: authenticated invalid user %s",
authctxt->user);
if (authenticated && authctxt->postponed)
fatal("INTERNAL ERROR: authenticated and postponed");
/* Special handling for root */
if (authenticated && authctxt->pw->pw_uid == 0 &&
!auth_root_allowed(method)) {
authenticated = 0;
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
#endif
}
if (authenticated && options.num_auth_methods != 0) {
if (!auth2_update_methods_lists(authctxt, method, submethod)) {
authenticated = 0;
partial = 1;
}
}
/* Log before sending the reply */
auth_log(authctxt, authenticated, partial, method, submethod);
if (authctxt->postponed)
return;
#ifdef USE_PAM
if (options.use_pam && authenticated) {
if (!PRIVSEP(do_pam_account())) {
/* if PAM returned a message, send it to the user */
if (buffer_len(&loginmsg) > 0) {
buffer_append(&loginmsg, "\0", 1);
userauth_send_banner((const char *)buffer_ptr(&loginmsg));
packet_write_wait();
}
fatal("Access denied for user %s by PAM account "
"configuration", authctxt->user);
}
}
#endif
#ifdef _UNICOS
if (authenticated && cray_access_denied(authctxt->user)) {
authenticated = 0;
fatal("Access denied for user %s.", authctxt->user);
}
#endif /* _UNICOS */
if (authenticated == 1) {
/* turn off userauth */
dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
packet_start(SSH2_MSG_USERAUTH_SUCCESS);
packet_send();
packet_write_wait();
/* now we can break out */
authctxt->success = 1;
} else {
/* Allow initial try of "none" auth without failure penalty */
if (!partial && !authctxt->server_caused_failure &&
(authctxt->attempt > 1 || strcmp(method, "none") != 0))
authctxt->failures++;
if (authctxt->failures >= options.max_authtries) {
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
#endif
auth_maxtries_exceeded(authctxt);
}
methods = authmethods_get(authctxt);
debug3("%s: failure partial=%d next methods=\"%s\"", __func__,
partial, methods);
packet_start(SSH2_MSG_USERAUTH_FAILURE);
packet_put_cstring(methods);
packet_put_char(partial);
packet_send();
packet_write_wait();
free(methods);
}
}
void
userauth_finish(Authctxt *authctxt, int authenticated, char *method)
{
char *methods;
if (!authctxt->valid && authenticated)
fatal("INTERNAL ERROR: authenticated invalid user %s",
authctxt->user);
/* Special handling for root */
if (authenticated && authctxt->pw->pw_uid == 0 &&
!auth_root_allowed(method)) {
authenticated = 0;
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
#endif
}
#ifdef USE_PAM
if (options.use_pam && authenticated) {
if (!PRIVSEP(do_pam_account())) {
/* if PAM returned a message, send it to the user */
if (buffer_len(&loginmsg) > 0) {
buffer_append(&loginmsg, "\0", 1);
userauth_send_banner(buffer_ptr(&loginmsg));
packet_write_wait();
}
fatal("Access denied for user %s by PAM account "
"configuration", authctxt->user);
}
}
#endif
#ifdef _UNICOS
if (authenticated && cray_access_denied(authctxt->user)) {
authenticated = 0;
fatal("Access denied for user %s.",authctxt->user);
}
#endif /* _UNICOS */
/* Log before sending the reply */
auth_log(authctxt, authenticated, method, " ssh2");
if (authctxt->postponed)
return;
/* XXX todo: check if multiple auth methods are needed */
if (authenticated == 1) {
/* turn off userauth */
dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
packet_start(SSH2_MSG_USERAUTH_SUCCESS);
packet_send();
packet_write_wait();
/* now we can break out */
authctxt->success = 1;
} else {
/* Allow initial try of "none" auth without failure penalty */
if (!authctxt->server_caused_failure &&
(authctxt->attempt > 1 || strcmp(method, "none") != 0))
authctxt->failures++;
if (authctxt->failures >= options.max_authtries) {
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
#endif
packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
}
methods = authmethods_get();
packet_start(SSH2_MSG_USERAUTH_FAILURE);
packet_put_cstring(methods);
packet_put_char(0); /* XXX partial success, unused */
packet_send();
packet_write_wait();
xfree(methods);
}
}
/*
* read packets, try to authenticate the user and
* return only if authentication is successful
*/
static void
do_authloop(Authctxt *authctxt)
{
int authenticated = 0;
char info[1024];
int prev = 0, type = 0;
const struct AuthMethod1 *meth;
debug("Attempting authentication for %s%.100s.",
authctxt->valid ? "" : "invalid user ", authctxt->user);
/* If the user has no password, accept authentication immediately. */
if (options.permit_empty_passwd && options.password_authentication &&
#ifdef KRB5
(!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
#endif
PRIVSEP(auth_password(authctxt, ""))) {
#ifdef USE_PAM
if (options.use_pam && (PRIVSEP(do_pam_account())))
#endif
{
auth_log(authctxt, 1, "without authentication", "");
return;
}
}
/* Indicate that authentication is needed. */
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
for (;;) {
/* default to fail */
authenticated = 0;
info[0] = '\0';
/* Get a packet from the client. */
prev = type;
type = packet_read();
/*
* If we started challenge-response authentication but the
* next packet is not a response to our challenge, release
* the resources allocated by get_challenge() (which would
* normally have been released by verify_response() had we
* received such a response)
*/
if (prev == SSH_CMSG_AUTH_TIS &&
type != SSH_CMSG_AUTH_TIS_RESPONSE)
abandon_challenge_response(authctxt);
if (authctxt->failures >= options.max_authtries)
goto skip;
if ((meth = lookup_authmethod1(type)) == NULL) {
logit("Unknown message during authentication: "
"type %d", type);
goto skip;
}
if (!*(meth->enabled)) {
verbose("%s authentication disabled.", meth->name);
goto skip;
}
authenticated = meth->method(authctxt, info, sizeof(info));
if (authenticated == -1)
continue; /* "postponed" */
#ifdef BSD_AUTH
if (authctxt->as) {
auth_close(authctxt->as);
authctxt->as = NULL;
}
#endif
if (!authctxt->valid && authenticated)
fatal("INTERNAL ERROR: authenticated invalid user %s",
authctxt->user);
#ifdef _UNICOS
if (authenticated && cray_access_denied(authctxt->user)) {
authenticated = 0;
fatal("Access denied for user %s.",authctxt->user);
}
#endif /* _UNICOS */
#ifndef HAVE_CYGWIN
/* Special handling for root */
if (authenticated && authctxt->pw->pw_uid == 0 &&
!auth_root_allowed(meth->name)) {
authenticated = 0;
# ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
# endif
}
#endif
#ifdef USE_PAM
if (options.use_pam && authenticated &&
!PRIVSEP(do_pam_account())) {
char *msg;
size_t len;
error("Access denied for user %s by PAM account "
"configuration", authctxt->user);
len = buffer_len(&loginmsg);
buffer_append(&loginmsg, "\0", 1);
msg = buffer_ptr(&loginmsg);
/* strip trailing newlines */
if (len > 0)
while (len > 0 && msg[--len] == '\n')
msg[len] = '\0';
else
msg = "Access denied.";
packet_disconnect("%s", msg);
}
#endif
skip:
/* Log before sending the reply */
auth_log(authctxt, authenticated, get_authname(type), info);
if (client_user != NULL) {
xfree(client_user);
client_user = NULL;
}
if (authenticated)
return;
if (++authctxt->failures >= options.max_authtries) {
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
#endif
packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
}
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
}
}
/*ARGSUSED*/
static void
input_userauth_request(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Authmethod *m = NULL;
char *user, *service, *method, *style = NULL;
int authenticated = 0;
#ifdef HAVE_LOGIN_CAP
login_cap_t *lc;
const char *from_host, *from_ip;
from_host = get_canonical_hostname(options.use_dns);
from_ip = get_remote_ipaddr();
#endif
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
user = packet_get_cstring(NULL);
service = packet_get_cstring(NULL);
method = packet_get_cstring(NULL);
debug("userauth-request for user %s service %s method %s", user, service, method);
debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
if (authctxt->attempt++ == 0) {
/* setup auth context */
authctxt->pw = PRIVSEP(getpwnamallow(user));
authctxt->user = xstrdup(user);
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("input_userauth_request: setting up authctxt for %s", user);
} else {
logit("input_userauth_request: invalid user %s", user);
authctxt->pw = fakepw();
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_INVALID_USER));
#endif
}
#ifdef USE_PAM
if (options.use_pam)
PRIVSEP(start_pam(authctxt));
#endif
setproctitle("%s%s", authctxt->valid ? user : "******",
use_privsep ? " [net]" : "");
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
if (use_privsep)
mm_inform_authserv(service, style);
userauth_banner();
} else if (strcmp(user, authctxt->user) != 0 ||
strcmp(service, authctxt->service) != 0) {
packet_disconnect("Change of username or service not allowed: "
"(%s,%s) -> (%s,%s)",
authctxt->user, authctxt->service, user, service);
}
#ifdef HAVE_LOGIN_CAP
if (authctxt->pw != NULL) {
lc = login_getpwclass(authctxt->pw);
if (lc == NULL)
lc = login_getclassbyname(NULL, authctxt->pw);
if (!auth_hostok(lc, from_host, from_ip)) {
logit("Denied connection for %.200s from %.200s [%.200s].",
authctxt->pw->pw_name, from_host, from_ip);
packet_disconnect("Sorry, you are not allowed to connect.");
}
if (!auth_timeok(lc, time(NULL))) {
logit("LOGIN %.200s REFUSED (TIME) FROM %.200s",
authctxt->pw->pw_name, from_host);
packet_disconnect("Logins not available right now.");
}
login_close(lc);
lc = NULL;
}
#endif /* HAVE_LOGIN_CAP */
/* reset state */
auth2_challenge_stop(authctxt);
#ifdef JPAKE
auth2_jpake_stop(authctxt);
#endif
#ifdef GSSAPI
/* XXX move to auth2_gssapi_stop() */
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif
authctxt->postponed = 0;
/* try to authenticate user */
m = authmethod_lookup(method);
if (m != NULL && authctxt->failures < options.max_authtries) {
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(authctxt);
}
userauth_finish(authctxt, authenticated, method);
xfree(service);
xfree(user);
xfree(method);
}
struct passwd *
getpwnamallow(const char *user)
{
#ifdef HAVE_LOGIN_CAP
extern login_cap_t *lc;
#ifdef BSD_AUTH
auth_session_t *as;
#endif
#endif
struct passwd *pw;
struct connection_info *ci = get_connection_info(1, options.use_dns);
ci->user = user;
parse_server_match_config(&options, ci);
#if defined(_AIX) && defined(HAVE_SETAUTHDB)
aix_setauthdb(user);
#endif
pw = getpwnam(user);
#if defined(_AIX) && defined(HAVE_SETAUTHDB)
aix_restoreauthdb();
#endif
#ifdef HAVE_CYGWIN
/*
* Windows usernames are case-insensitive. To avoid later problems
* when trying to match the username, the user is only allowed to
* login if the username is given in the same case as stored in the
* user database.
*/
if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
logit("Login name %.100s does not match stored username %.100s",
user, pw->pw_name);
pw = NULL;
}
#endif
if (pw == NULL) {
logit("Invalid user %.100s from %.100s",
user, get_remote_ipaddr());
#ifdef CUSTOM_FAILED_LOGIN
record_failed_login(user,
get_canonical_hostname(options.use_dns), "ssh");
#endif
#ifdef SSH_AUDIT_EVENTS
audit_event(SSH_INVALID_USER);
#endif /* SSH_AUDIT_EVENTS */
return (NULL);
}
if (!allowed_user(pw))
return (NULL);
#ifdef HAVE_LOGIN_CAP
if ((lc = login_getclass(pw->pw_class)) == NULL) {
debug("unable to get login class: %s", user);
return (NULL);
}
#ifdef BSD_AUTH
if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
debug("Approval failure for %s", user);
pw = NULL;
}
if (as != NULL)
auth_close(as);
#endif
#endif
if (pw != NULL)
return (pwcopy(pw));
return (NULL);
}
void
auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
{
void (*authlog) (const char *fmt,...) = verbose;
char *authmsg;
/* Raise logging level */
if (authenticated == 1 ||
!authctxt->valid ||
authctxt->failures >= options.max_authtries / 2 ||
strcmp(method, "password") == 0)
authlog = logit;
if (authctxt->postponed)
authmsg = "Postponed";
else
authmsg = authenticated ? "Accepted" : "Failed";
authlog("%s %s for %s%.100s from %.200s port %d%s",
authmsg,
method,
authctxt->valid ? "" : "invalid user ",
authctxt->user,
get_remote_ipaddr(),
get_remote_port(),
info);
#ifdef CUSTOM_FAILED_LOGIN
if (authenticated == 0 && !authctxt->postponed &&
(strcmp(method, "password") == 0 ||
strncmp(method, "keyboard-interactive", 20) == 0 ||
strcmp(method, "challenge-response") == 0))
record_failed_login(authctxt->user,
get_canonical_hostname(options.use_dns), "ssh");
#endif
#ifdef SSH_AUDIT_EVENTS
if (authenticated == 0 && !authctxt->postponed) {
ssh_audit_event_t event;
debug3("audit failed auth attempt, method %s euid %d",
method, (int)geteuid());
/*
* Because the auth loop is used in both monitor and slave,
* we must be careful to send each event only once and with
* enough privs to write the event.
*/
event = audit_classify_auth(method);
switch(event) {
case SSH_AUTH_FAIL_NONE:
case SSH_AUTH_FAIL_PASSWD:
case SSH_AUTH_FAIL_KBDINT:
if (geteuid() == 0)
audit_event(event);
break;
case SSH_AUTH_FAIL_PUBKEY:
case SSH_AUTH_FAIL_HOSTBASED:
case SSH_AUTH_FAIL_GSSAPI:
/*
* This is required to handle the case where privsep
* is enabled but it's root logging in, since
* use_privsep won't be cleared until after a
* successful login.
*/
if (geteuid() == 0)
audit_event(event);
else
PRIVSEP(audit_event(event));
break;
default:
error("unknown authentication audit event %d", event);
}
}
#endif
}
void
auth_log(Authctxt *authctxt, int authenticated, int partial,
const char *method, const char *submethod, const char *info)
{
void (*authlog) (const char *fmt,...) = verbose;
char *authmsg;
if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
return;
/* Raise logging level */
if (authenticated == 1 ||
!authctxt->valid ||
authctxt->failures >= options.max_authtries / 2 ||
strcmp(method, "password") == 0)
authlog = logit;
if (authctxt->postponed)
authmsg = "Postponed";
else if (partial)
authmsg = "Partial";
else
authmsg = authenticated ? "Accepted" : "Failed";
authlog("%s %s%s%s for %s%.100s from %.200s port %d%s",
authmsg,
method,
submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
authctxt->valid ? "" : "invalid user ",
authctxt->user,
get_remote_ipaddr(),
get_remote_port(),
info);
#ifdef NERSC_MOD
char* t1buf = encode_string(authctxt->user, strlen(authctxt->user) );
char* t2buf = encode_string(method, strlen(method) );
char* t3buf = encode_string(authmsg, strlen(authmsg) );
s_audit("auth_info_3", "count=%i uristring=%s uristring=%s uristring=%s addr=%.200s port=%d/tcp addr=%s port=%s/tcp",
client_session_id, t3buf, t1buf, t2buf, get_remote_ipaddr(), get_remote_port(), n_ntop,
n_port);
free(t1buf);
free(t2buf);
free(t3buf);
#endif
#ifdef CUSTOM_FAILED_LOGIN
if (authenticated == 0 && !authctxt->postponed &&
(strcmp(method, "password") == 0 ||
strncmp(method, "keyboard-interactive", 20) == 0 ||
strcmp(method, "challenge-response") == 0))
record_failed_login(authctxt->user,
get_canonical_hostname(options.use_dns), "ssh");
# ifdef WITH_AIXAUTHENTICATE
if (authenticated)
sys_auth_record_login(authctxt->user,
get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
# endif
#endif
#ifdef SSH_AUDIT_EVENTS
if (authenticated == 0 && !authctxt->postponed)
audit_event(audit_classify_auth(method));
#endif
}
void
auth_log(Authctxt *authctxt, int authenticated, int partial,
const char *method, const char *submethod)
{
struct ssh *ssh = active_state; /* XXX */
void (*authlog) (const char *fmt,...) = verbose;
const char *authmsg;
char *extra = NULL;
if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
return;
/* Raise logging level */
if (authenticated == 1 ||
!authctxt->valid ||
authctxt->failures >= options.max_authtries / 2 ||
strcmp(method, "password") == 0)
authlog = logit;
if (authctxt->postponed)
authmsg = "Postponed";
else if (partial)
authmsg = "Partial";
else {
authmsg = authenticated ? "Accepted" : "Failed";
if (authenticated)
BLACKLIST_NOTIFY(BLACKLIST_AUTH_OK, "ssh");
}
if ((extra = format_method_key(authctxt)) == NULL) {
if (authctxt->auth_method_info != NULL)
extra = xstrdup(authctxt->auth_method_info);
}
authlog("%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s",
authmsg,
method,
submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
authctxt->valid ? "" : "invalid user ",
authctxt->user,
ssh_remote_ipaddr(ssh),
ssh_remote_port(ssh),
extra != NULL ? ": " : "",
extra != NULL ? extra : "");
free(extra);
#ifdef CUSTOM_FAILED_LOGIN
if (authenticated == 0 && !authctxt->postponed &&
(strcmp(method, "password") == 0 ||
strncmp(method, "keyboard-interactive", 20) == 0 ||
strcmp(method, "challenge-response") == 0))
record_failed_login(authctxt->user,
auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
# ifdef WITH_AIXAUTHENTICATE
if (authenticated)
sys_auth_record_login(authctxt->user,
auth_get_canonical_hostname(ssh, options.use_dns), "ssh",
&loginmsg);
# endif
#endif
#ifdef SSH_AUDIT_EVENTS
if (authenticated == 0 && !authctxt->postponed)
audit_event(audit_classify_auth(method));
#endif
}