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mod_auth.c
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mod_auth.c
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/*
* ProFTPD - FTP server daemon
* Copyright (c) 1997, 1998 Public Flood Software
* Copyright (c) 1999, 2000 MacGyver aka Habeeb J. Dihu <macgyver@tos.net>
* Copyright (c) 2001-2017 The ProFTPD Project team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA.
*
* As a special exemption, Public Flood Software/MacGyver aka Habeeb J. Dihu
* and other respective copyright holders give permission to link this program
* with OpenSSL, and distribute the resulting executable, without including
* the source code for OpenSSL in the source distribution.
*/
/* Authentication module for ProFTPD */
#include "conf.h"
#include "privs.h"
#ifdef HAVE_USERSEC_H
# include <usersec.h>
#endif
#ifdef HAVE_SYS_AUDIT_H
# include <sys/audit.h>
#endif
extern pid_t mpid;
module auth_module;
#ifdef PR_USE_LASTLOG
static unsigned char lastlog = FALSE;
#endif /* PR_USE_LASTLOG */
static unsigned char mkhome = FALSE;
static unsigned char authenticated_without_pass = FALSE;
static int TimeoutLogin = PR_TUNABLE_TIMEOUTLOGIN;
static int logged_in = FALSE;
static int auth_anon_allow_robots = FALSE;
static int auth_anon_allow_robots_enabled = FALSE;
static int auth_client_connected = FALSE;
static unsigned int auth_tries = 0;
static char *auth_pass_resp_code = R_230;
static pr_fh_t *displaylogin_fh = NULL;
static int TimeoutSession = 0;
static int saw_first_user_cmd = FALSE;
static const char *timing_channel = "timing";
static int auth_count_scoreboard(cmd_rec *, const char *);
static int auth_scan_scoreboard(void);
static int auth_sess_init(void);
/* auth_cmd_chk_cb() is hooked into the main server's auth_hook function,
* so that we can deny all commands until authentication is complete.
*
* Note: Once this function returns true (i.e. client has authenticated),
* it will ALWAYS return true. At least until REIN is implemented. Thus
* we have a flag for such a situation, to save on redundant lookups for
* the "authenticated" record.
*/
static int auth_have_authenticated = FALSE;
static int auth_cmd_chk_cb(cmd_rec *cmd) {
if (auth_have_authenticated == FALSE) {
unsigned char *authd;
authd = get_param_ptr(cmd->server->conf, "authenticated", FALSE);
if (authd == NULL ||
*authd == FALSE) {
pr_response_send(R_530, _("Please login with USER and PASS"));
return FALSE;
}
auth_have_authenticated = TRUE;
}
return TRUE;
}
static int auth_login_timeout_cb(CALLBACK_FRAME) {
pr_response_send_async(R_421,
_("Login timeout (%d %s): closing control connection"), TimeoutLogin,
TimeoutLogin != 1 ? "seconds" : "second");
/* It's possible that any listeners of this event might terminate the
* session process themselves (e.g. mod_ban). So write out that the
* TimeoutLogin has been exceeded to the log here, in addition to the
* scheduled session exit message.
*/
pr_log_pri(PR_LOG_INFO, "%s", "Login timeout exceeded, disconnected");
pr_event_generate("core.timeout-login", NULL);
pr_session_disconnect(&auth_module, PR_SESS_DISCONNECT_TIMEOUT,
"TimeoutLogin");
/* Do not restart the timer (should never be reached). */
return 0;
}
static int auth_session_timeout_cb(CALLBACK_FRAME) {
pr_event_generate("core.timeout-session", NULL);
pr_response_send_async(R_421,
_("Session Timeout (%d seconds): closing control connection"),
TimeoutSession);
pr_log_pri(PR_LOG_INFO, "%s", "FTP session timed out, disconnected");
pr_session_disconnect(&auth_module, PR_SESS_DISCONNECT_TIMEOUT,
"TimeoutSession");
/* no need to restart the timer -- session's over */
return 0;
}
/* Event listeners
*/
static void auth_exit_ev(const void *event_data, void *user_data) {
pr_auth_cache_clear();
/* Close the scoreboard descriptor that we opened. */
(void) pr_close_scoreboard(FALSE);
}
static void auth_sess_reinit_ev(const void *event_data, void *user_data) {
int res;
/* A HOST command changed the main_server pointer, reinitialize ourselves. */
pr_event_unregister(&auth_module, "core.exit", auth_exit_ev);
pr_event_unregister(&auth_module, "core.session-reinit", auth_sess_reinit_ev);
pr_timer_remove(PR_TIMER_LOGIN, &auth_module);
/* Reset the CreateHome setting. */
mkhome = FALSE;
/* Reset any MaxPasswordSize setting. */
(void) pr_auth_set_max_password_len(session.pool, 0);
#if defined(PR_USE_LASTLOG)
lastlog = FALSE;
#endif /* PR_USE_LASTLOG */
mkhome = FALSE;
res = auth_sess_init();
if (res < 0) {
pr_session_disconnect(&auth_module,
PR_SESS_DISCONNECT_SESSION_INIT_FAILED, NULL);
}
}
/* Initialization functions
*/
static int auth_init(void) {
/* Add the commands handled by this module to the HELP list. */
pr_help_add(C_USER, _("<sp> username"), TRUE);
pr_help_add(C_PASS, _("<sp> password"), TRUE);
pr_help_add(C_ACCT, _("is not implemented"), FALSE);
pr_help_add(C_REIN, _("is not implemented"), FALSE);
/* By default, enable auth checking */
set_auth_check(auth_cmd_chk_cb);
return 0;
}
static int auth_sess_init(void) {
config_rec *c = NULL;
unsigned char *tmp = NULL;
pr_event_register(&auth_module, "core.session-reinit", auth_sess_reinit_ev,
NULL);
/* Check for any MaxPasswordSize. */
c = find_config(main_server->conf, CONF_PARAM, "MaxPasswordSize", FALSE);
if (c != NULL) {
size_t len;
len = *((size_t *) c->argv[0]);
(void) pr_auth_set_max_password_len(session.pool, len);
}
/* Check for a server-specific TimeoutLogin */
c = find_config(main_server->conf, CONF_PARAM, "TimeoutLogin", FALSE);
if (c != NULL) {
TimeoutLogin = *((int *) c->argv[0]);
}
/* Start the login timer */
if (TimeoutLogin) {
pr_timer_remove(PR_TIMER_LOGIN, &auth_module);
pr_timer_add(TimeoutLogin, PR_TIMER_LOGIN, &auth_module,
auth_login_timeout_cb, "TimeoutLogin");
}
if (auth_client_connected == FALSE) {
int res = 0;
PRIVS_ROOT
res = pr_open_scoreboard(O_RDWR);
PRIVS_RELINQUISH
if (res < 0) {
switch (res) {
case PR_SCORE_ERR_BAD_MAGIC:
pr_log_debug(DEBUG0, "error opening scoreboard: bad/corrupted file");
break;
case PR_SCORE_ERR_OLDER_VERSION:
pr_log_debug(DEBUG0,
"error opening scoreboard: bad version (too old)");
break;
case PR_SCORE_ERR_NEWER_VERSION:
pr_log_debug(DEBUG0,
"error opening scoreboard: bad version (too new)");
break;
default:
pr_log_debug(DEBUG0, "error opening scoreboard: %s", strerror(errno));
break;
}
}
}
pr_event_register(&auth_module, "core.exit", auth_exit_ev, NULL);
if (auth_client_connected == FALSE) {
/* Create an entry in the scoreboard for this session, if we don't already
* have one.
*/
if (pr_scoreboard_entry_get(PR_SCORE_CLIENT_ADDR) == NULL) {
if (pr_scoreboard_entry_add() < 0) {
pr_log_pri(PR_LOG_NOTICE, "notice: unable to add scoreboard entry: %s",
strerror(errno));
}
pr_scoreboard_entry_update(session.pid,
PR_SCORE_USER, "(none)",
PR_SCORE_SERVER_PORT, main_server->ServerPort,
PR_SCORE_SERVER_ADDR, session.c->local_addr, session.c->local_port,
PR_SCORE_SERVER_LABEL, main_server->ServerName,
PR_SCORE_CLIENT_ADDR, session.c->remote_addr,
PR_SCORE_CLIENT_NAME, session.c->remote_name,
PR_SCORE_CLASS, session.conn_class ? session.conn_class->cls_name : "",
PR_SCORE_PROTOCOL, "ftp",
PR_SCORE_BEGIN_SESSION, time(NULL),
NULL);
}
} else {
/* We're probably handling a HOST comand, and the server changed; just
* update the SERVER_LABEL field.
*/
pr_scoreboard_entry_update(session.pid,
PR_SCORE_SERVER_LABEL, main_server->ServerName,
NULL);
}
/* Should we create the home for a user, if they don't have one? */
tmp = get_param_ptr(main_server->conf, "CreateHome", FALSE);
if (tmp != NULL &&
*tmp == TRUE) {
mkhome = TRUE;
} else {
mkhome = FALSE;
}
#ifdef PR_USE_LASTLOG
/* Use the lastlog file, if supported and requested. */
tmp = get_param_ptr(main_server->conf, "UseLastlog", FALSE);
if (tmp &&
*tmp == TRUE) {
lastlog = TRUE;
} else {
lastlog = FALSE;
}
#endif /* PR_USE_LASTLOG */
/* Scan the scoreboard now, in order to tally up certain values for
* substituting in any of the Display* file variables. This function
* also performs the MaxConnectionsPerHost enforcement.
*/
auth_scan_scoreboard();
auth_client_connected = TRUE;
return 0;
}
static int do_auth(pool *p, xaset_t *conf, const char *u, char *pw) {
char *cpw = NULL;
config_rec *c;
if (conf != NULL) {
c = find_config(conf, CONF_PARAM, "UserPassword", FALSE);
while (c != NULL) {
pr_signals_handle();
if (strcmp(c->argv[0], u) == 0) {
cpw = (char *) c->argv[1];
break;
}
c = find_config_next(c, c->next, CONF_PARAM, "UserPassword", FALSE);
}
}
if (cpw != NULL) {
if (pr_auth_getpwnam(p, u) == NULL) {
int xerrno = errno;
if (xerrno == ENOENT) {
pr_log_pri(PR_LOG_NOTICE, "no such user '%s'", u);
}
errno = xerrno;
return PR_AUTH_NOPWD;
}
return pr_auth_check(p, cpw, u, pw);
}
return pr_auth_authenticate(p, u, pw);
}
/* Command handlers
*/
static void login_failed(pool *p, const char *user) {
#ifdef HAVE_LOGINFAILED
char *host, *sess_ttyname;
int res, xerrno;
host = pr_netaddr_get_dnsstr(session.c->remote_addr);
sess_ttyname = pr_session_get_ttyname(p);
PRIVS_ROOT
res = loginfailed((char *) user, host, sess_ttyname, AUDIT_FAIL);
xerrno = errno;
PRIVS_RELINQUISH
if (res < 0) {
pr_trace_msg("auth", 3, "AIX loginfailed() error for user '%s', "
"host '%s', tty '%s', reason %d: %s", user, host, sess_ttyname,
AUDIT_FAIL, strerror(errno));
}
#endif /* HAVE_LOGINFAILED */
}
MODRET auth_err_pass(cmd_rec *cmd) {
const char *user;
user = pr_table_get(session.notes, "mod_auth.orig-user", NULL);
if (user != NULL) {
login_failed(cmd->tmp_pool, user);
}
/* Remove the stashed original USER name here in a LOG_CMD_ERR handler, so
* that other modules, who may want to lookup the original USER parameter on
* a failed login in an earlier command handler phase, have a chance to do
* so. This removal of the USER parameter on failure was happening directly
* in the CMD handler previously, thus preventing POST_CMD_ERR handlers from
* using USER.
*/
pr_table_remove(session.notes, "mod_auth.orig-user", NULL);
return PR_HANDLED(cmd);
}
MODRET auth_log_pass(cmd_rec *cmd) {
/* Only log, to the syslog, that the login has succeeded here, where we
* know that the login has definitely succeeded.
*/
pr_log_auth(PR_LOG_INFO, "%s %s: Login successful.",
(session.anon_config != NULL) ? "ANON" : C_USER, session.user);
if (cmd->arg != NULL) {
size_t passwd_len;
/* And scrub the memory holding the password sent by the client, for
* safety/security.
*/
passwd_len = strlen(cmd->arg);
pr_memscrub(cmd->arg, passwd_len);
}
return PR_DECLINED(cmd);
}
static void login_succeeded(pool *p, const char *user) {
#ifdef HAVE_LOGINSUCCESS
char *host, *msg = NULL, *sess_ttyname;
int res, xerrno;
host = pr_netaddr_get_dnsstr(session.c->remote_addr);
sess_ttyname = pr_session_get_ttyname(p);
PRIVS_ROOT
res = loginsuccess((char *) user, host, sess_ttyname, &msg);
xerrno = errno;
PRIVS_RELINQUISH
if (res == 0) {
if (msg != NULL) {
pr_trace_msg("auth", 14, "AIX loginsuccess() report: %s", msg);
}
} else {
pr_trace_msg("auth", 3, "AIX loginsuccess() error for user '%s', "
"host '%s', tty '%s': %s", user, host, sess_ttyname, strerror(errno));
}
if (msg != NULL) {
free(msg);
}
#endif /* HAVE_LOGINSUCCESS */
}
MODRET auth_post_pass(cmd_rec *cmd) {
config_rec *c = NULL;
const char *grantmsg = NULL, *user;
unsigned int ctxt_precedence = 0;
unsigned char have_user_timeout, have_group_timeout, have_class_timeout,
have_all_timeout, *root_revoke = NULL, *authenticated;
struct stat st;
/* Was there a precending USER command? Was the client successfully
* authenticated?
*/
authenticated = get_param_ptr(cmd->server->conf, "authenticated", FALSE);
/* Clear the list of auth-only modules. */
pr_auth_clear_auth_only_modules();
if (authenticated != NULL &&
*authenticated == TRUE) {
/* At this point, we can look up the Protocols config if the client
* has been authenticated, which may have been tweaked via mod_ifsession's
* user/group/class-specific sections.
*/
c = find_config(main_server->conf, CONF_PARAM, "Protocols", FALSE);
if (c != NULL) {
register unsigned int i;
array_header *protocols;
char **elts;
const char *protocol;
protocols = c->argv[0];
elts = protocols->elts;
protocol = pr_session_get_protocol(PR_SESS_PROTO_FL_LOGOUT);
/* We only want to check for 'ftp' in the configured Protocols list
* if a) a RFC2228 mechanism (e.g. SSL or GSS) is not in use, and
* b) an SSH protocol is not in use.
*/
if (session.rfc2228_mech == NULL &&
strncmp(protocol, "SSH2", 5) != 0) {
int allow_ftp = FALSE;
for (i = 0; i < protocols->nelts; i++) {
char *proto;
proto = elts[i];
if (proto != NULL) {
if (strncasecmp(proto, "ftp", 4) == 0) {
allow_ftp = TRUE;
break;
}
}
}
if (!allow_ftp) {
pr_log_debug(DEBUG0, "%s", "ftp protocol denied by Protocols config");
pr_response_send(R_530, "%s", _("Login incorrect."));
pr_session_disconnect(&auth_module, PR_SESS_DISCONNECT_CONFIG_ACL,
"Denied by Protocols setting");
}
}
}
}
user = pr_table_get(session.notes, "mod_auth.orig-user", NULL);
/* Count up various quantities in the scoreboard, checking them against
* the Max* limits to see if the session should be barred from going
* any further.
*/
auth_count_scoreboard(cmd, session.user);
/* Check for dynamic configuration. This check needs to be after the
* setting of any possible anon_config, as that context may be allowed
* or denied .ftpaccess-parsing separately from the containing server.
*/
if (pr_fsio_stat(session.cwd, &st) != -1)
build_dyn_config(cmd->tmp_pool, session.cwd, &st, TRUE);
have_user_timeout = have_group_timeout = have_class_timeout =
have_all_timeout = FALSE;
c = find_config(TOPLEVEL_CONF, CONF_PARAM, "TimeoutSession", FALSE);
while (c != NULL) {
pr_signals_handle();
if (c->argc == 3) {
if (strncmp(c->argv[1], "user", 5) == 0) {
if (pr_expr_eval_user_or((char **) &c->argv[2]) == TRUE) {
if (*((unsigned int *) c->argv[1]) > ctxt_precedence) {
/* Set the context precedence. */
ctxt_precedence = *((unsigned int *) c->argv[1]);
TimeoutSession = *((int *) c->argv[0]);
have_group_timeout = have_class_timeout = have_all_timeout = FALSE;
have_user_timeout = TRUE;
}
}
} else if (strncmp(c->argv[1], "group", 6) == 0) {
if (pr_expr_eval_group_and((char **) &c->argv[2]) == TRUE) {
if (*((unsigned int *) c->argv[1]) > ctxt_precedence) {
/* Set the context precedence. */
ctxt_precedence = *((unsigned int *) c->argv[1]);
TimeoutSession = *((int *) c->argv[0]);
have_user_timeout = have_class_timeout = have_all_timeout = FALSE;
have_group_timeout = TRUE;
}
}
} else if (strncmp(c->argv[1], "class", 6) == 0) {
if (session.conn_class != NULL &&
strcmp(session.conn_class->cls_name, c->argv[2]) == 0) {
if (*((unsigned int *) c->argv[1]) > ctxt_precedence) {
/* Set the context precedence. */
ctxt_precedence = *((unsigned int *) c->argv[1]);
TimeoutSession = *((int *) c->argv[0]);
have_user_timeout = have_group_timeout = have_all_timeout = FALSE;
have_class_timeout = TRUE;
}
}
}
} else {
if (*((unsigned int *) c->argv[1]) > ctxt_precedence) {
/* Set the context precedence. */
ctxt_precedence = *((unsigned int *) c->argv[1]);
TimeoutSession = *((int *) c->argv[0]);
have_user_timeout = have_group_timeout = have_class_timeout = FALSE;
have_all_timeout = TRUE;
}
}
c = find_config_next(c, c->next, CONF_PARAM, "TimeoutSession", FALSE);
}
/* If configured, start a session timer. The timer ID value for
* session timers will not be #defined, as I think that is a bad approach.
* A better mechanism would be to use the random timer ID generation, and
* store the returned ID in order to later remove the timer.
*/
if (have_user_timeout || have_group_timeout ||
have_class_timeout || have_all_timeout) {
pr_log_debug(DEBUG4, "setting TimeoutSession of %d seconds for current %s",
TimeoutSession,
have_user_timeout ? "user" : have_group_timeout ? "group" :
have_class_timeout ? "class" : "all");
pr_timer_add(TimeoutSession, PR_TIMER_SESSION, &auth_module,
auth_session_timeout_cb, "TimeoutSession");
}
/* Handle a DisplayLogin file. */
if (displaylogin_fh) {
if (!(session.sf_flags & SF_ANON)) {
if (pr_display_fh(displaylogin_fh, NULL, auth_pass_resp_code, 0) < 0) {
pr_log_debug(DEBUG6, "unable to display DisplayLogin file '%s': %s",
displaylogin_fh->fh_path, strerror(errno));
}
pr_fsio_close(displaylogin_fh);
displaylogin_fh = NULL;
} else {
/* We're an <Anonymous> login, but there was a previous DisplayLogin
* configured which was picked up earlier. Close that filehandle,
* and look for a new one.
*/
char *displaylogin;
pr_fsio_close(displaylogin_fh);
displaylogin_fh = NULL;
displaylogin = get_param_ptr(TOPLEVEL_CONF, "DisplayLogin", FALSE);
if (displaylogin) {
if (pr_display_file(displaylogin, NULL, auth_pass_resp_code, 0) < 0) {
pr_log_debug(DEBUG6, "unable to display DisplayLogin file '%s': %s",
displaylogin, strerror(errno));
}
}
}
} else {
char *displaylogin = get_param_ptr(TOPLEVEL_CONF, "DisplayLogin", FALSE);
if (displaylogin) {
if (pr_display_file(displaylogin, NULL, auth_pass_resp_code, 0) < 0) {
pr_log_debug(DEBUG6, "unable to display DisplayLogin file '%s': %s",
displaylogin, strerror(errno));
}
}
}
grantmsg = get_param_ptr(TOPLEVEL_CONF, "AccessGrantMsg", FALSE);
if (grantmsg == NULL) {
/* Append the final greeting lines. */
if (session.sf_flags & SF_ANON) {
pr_response_add(auth_pass_resp_code, "%s",
_("Anonymous access granted, restrictions apply"));
} else {
pr_response_add(auth_pass_resp_code, _("User %s logged in"), user);
}
} else {
/* Handle any AccessGrantMsg directive. */
grantmsg = sreplace(cmd->tmp_pool, grantmsg, "%u", user, NULL);
pr_response_add(auth_pass_resp_code, "%s", grantmsg);
}
login_succeeded(cmd->tmp_pool, user);
/* A RootRevoke value of 0 indicates 'false', 1 indicates 'true', and
* 2 indicates 'NonCompliantActiveTransfer'. We will drop root privs for any
* RootRevoke value greater than 0.
*/
root_revoke = get_param_ptr(TOPLEVEL_CONF, "RootRevoke", FALSE);
if (root_revoke != NULL &&
*root_revoke > 0) {
pr_signals_block();
PRIVS_ROOT
PRIVS_REVOKE
pr_signals_unblock();
/* Disable future attempts at UID/GID manipulation. */
session.disable_id_switching = TRUE;
if (*root_revoke == 1) {
/* If the server's listening port is less than 1024, block PORT
* commands (effectively allowing only passive connections, which is
* not necessarily a Bad Thing). Only log this here -- the blocking
* will need to occur in mod_core's handling of the PORT/EPRT commands.
*/
if (session.c->local_port < 1024) {
pr_log_debug(DEBUG0,
"RootRevoke in effect, active data transfers may not succeed");
}
}
pr_log_debug(DEBUG0, "RootRevoke in effect, dropped root privs");
}
c = find_config(TOPLEVEL_CONF, CONF_PARAM, "AnonAllowRobots", FALSE);
if (c != NULL) {
auth_anon_allow_robots = *((int *) c->argv[0]);
}
return PR_DECLINED(cmd);
}
/* Handle group based authentication, only checked if pw based fails. */
static config_rec *auth_group(pool *p, const char *user, char **group,
char **ournamep, char **anonnamep, char *pass) {
config_rec *c;
char *ourname = NULL, *anonname = NULL;
char **grmem;
struct group *grp;
ourname = get_param_ptr(main_server->conf, "UserName", FALSE);
if (ournamep != NULL &&
ourname != NULL) {
*ournamep = ourname;
}
c = find_config(main_server->conf, CONF_PARAM, "GroupPassword", TRUE);
if (c) do {
grp = pr_auth_getgrnam(p, c->argv[0]);
if (grp == NULL) {
continue;
}
for (grmem = grp->gr_mem; *grmem; grmem++) {
if (strcmp(*grmem, user) == 0) {
if (pr_auth_check(p, c->argv[1], user, pass) == 0) {
break;
}
}
}
if (*grmem) {
if (group != NULL) {
*group = c->argv[0];
}
if (c->parent != NULL) {
c = c->parent;
}
if (c->config_type == CONF_ANON) {
anonname = get_param_ptr(c->subset, "UserName", FALSE);
}
if (anonnamep != NULL) {
*anonnamep = anonname;
}
if (anonnamep != NULL &&
!anonname &&
ourname != NULL) {
*anonnamep = ourname;
}
break;
}
} while((c = find_config_next(c, c->next, CONF_PARAM, "GroupPassword",
TRUE)) != NULL);
return c;
}
/* Determine any applicable chdirs. */
static const char *get_default_chdir(pool *p, xaset_t *conf) {
config_rec *c;
const char *dir = NULL;
c = find_config(conf, CONF_PARAM, "DefaultChdir", FALSE);
while (c != NULL) {
int res;
pr_signals_handle();
/* Check the groups acl */
if (c->argc < 2) {
dir = c->argv[0];
break;
}
res = pr_expr_eval_group_and(((char **) c->argv)+1);
if (res) {
dir = c->argv[0];
break;
}
c = find_config_next(c, c->next, CONF_PARAM, "DefaultChdir", FALSE);
}
/* If the directory is relative, concatenate w/ session.cwd. */
if (dir != NULL &&
*dir != '/' &&
*dir != '~') {
dir = pdircat(p, session.cwd, dir, NULL);
}
/* Check for any expandable variables. */
if (dir != NULL) {
dir = path_subst_uservar(p, &dir);
}
return dir;
}
/* Determine if the user (non-anon) needs a default root dir other than /. */
static int get_default_root(pool *p, int allow_symlinks, const char **root) {
config_rec *c = NULL;
const char *dir = NULL;
int res;
c = find_config(main_server->conf, CONF_PARAM, "DefaultRoot", FALSE);
while (c != NULL) {
pr_signals_handle();
/* Check the groups acl */
if (c->argc < 2) {
dir = c->argv[0];
break;
}
res = pr_expr_eval_group_and(((char **) c->argv)+1);
if (res) {
dir = c->argv[0];
break;
}
c = find_config_next(c, c->next, CONF_PARAM, "DefaultRoot", FALSE);
}
if (dir != NULL) {
const char *new_dir;
/* Check for any expandable variables. */
new_dir = path_subst_uservar(p, &dir);
if (new_dir != NULL) {
dir = new_dir;
}
if (strncmp(dir, "/", 2) == 0) {
dir = NULL;
} else {
char *realdir;
int xerrno = 0;
if (allow_symlinks == FALSE) {
char *path, target_path[PR_TUNABLE_PATH_MAX + 1];
struct stat st;
size_t pathlen;
/* First, deal with any possible interpolation. dir_realpath() will
* do this for us, but dir_realpath() ALSO automatically follows
* symlinks, which is what we do NOT want to do here.
*/
path = pstrdup(p, dir);
if (*path != '/') {
if (*path == '~') {
if (pr_fs_interpolate(dir, target_path,
sizeof(target_path)-1) < 0) {
return -1;
}
path = target_path;
}
}
/* Note: lstat(2) is sensitive to the presence of a trailing slash on
* the path, particularly in the case of a symlink to a directory.
* Thus to get the correct test, we need to remove any trailing slash
* that might be present. Subtle.
*/
pathlen = strlen(path);
if (pathlen > 1 &&
path[pathlen-1] == '/') {
path[pathlen-1] = '\0';
}
pr_fs_clear_cache2(path);
res = pr_fsio_lstat(path, &st);
if (res < 0) {
xerrno = errno;
pr_log_pri(PR_LOG_WARNING, "error: unable to check %s: %s", path,
strerror(xerrno));
errno = xerrno;
return -1;
}
if (S_ISLNK(st.st_mode)) {
pr_log_pri(PR_LOG_WARNING,
"error: DefaultRoot %s is a symlink (denied by AllowChrootSymlinks "
"config)", path);
errno = EPERM;
return -1;
}
}
/* We need to be the final user here so that if the user has their home
* directory with a mode the user proftpd is running (i.e. the User
* directive) as can not traverse down, we can still have the default
* root.
*/
pr_fs_clear_cache2(dir);
PRIVS_USER
realdir = dir_realpath(p, dir);
xerrno = errno;
PRIVS_RELINQUISH
if (realdir) {
dir = realdir;
} else {
/* Try to provide a more informative message. */
char interp_dir[PR_TUNABLE_PATH_MAX + 1];
memset(interp_dir, '\0', sizeof(interp_dir));
(void) pr_fs_interpolate(dir, interp_dir, sizeof(interp_dir)-1);
pr_log_pri(PR_LOG_NOTICE,
"notice: unable to use DefaultRoot '%s' [resolved to '%s']: %s",
dir, interp_dir, strerror(xerrno));
errno = xerrno;
}
}
}
*root = dir;
return 0;
}
static struct passwd *passwd_dup(pool *p, struct passwd *pw) {
struct passwd *npw;
npw = pcalloc(p, sizeof(struct passwd));
npw->pw_name = pstrdup(p, pw->pw_name);
npw->pw_passwd = pstrdup(p, pw->pw_passwd);
npw->pw_uid = pw->pw_uid;
npw->pw_gid = pw->pw_gid;
npw->pw_gecos = pstrdup(p, pw->pw_gecos);
npw->pw_dir = pstrdup(p, pw->pw_dir);
npw->pw_shell = pstrdup(p, pw->pw_shell);
return npw;
}
static void ensure_open_passwd(pool *p) {
/* Make sure pass/group is open. */
pr_auth_setpwent(p);
pr_auth_setgrent(p);
/* On some unices the following is necessary to ensure the files
* are open (BSDI 3.1)
*/
pr_auth_getpwent(p);
pr_auth_getgrent(p);
/* Per Debian bug report:
* https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=717235
* we might want to do another set{pw,gr}ent(), to play better with
* some NSS modules.
*/
pr_auth_setpwent(p);
pr_auth_setgrent(p);
}
/* Next function (the biggie) handles all authentication, setting
* up chroot() jail, etc.
*/
static int setup_env(pool *p, cmd_rec *cmd, const char *user, char *pass) {
struct passwd *pw;
config_rec *c, *tmpc;
const char *defchdir = NULL, *defroot = NULL, *origuser, *sess_ttyname;
char *ourname = NULL, *anonname = NULL, *anongroup = NULL, *ugroup = NULL;
char *xferlog = NULL;
int aclp, i, res = 0, allow_chroot_symlinks = TRUE, showsymlinks;
unsigned char *wtmp_log = NULL, *anon_require_passwd = NULL;
/********************* Authenticate the user here *********************/
session.hide_password = TRUE;
origuser = user;
c = pr_auth_get_anon_config(p, &user, &ourname, &anonname);
if (c != NULL) {
session.anon_config = c;
}
if (user == NULL) {
pr_log_auth(PR_LOG_NOTICE, "USER %s: user is not a UserAlias from %s [%s] "
"to %s:%i", origuser, session.c->remote_name,
pr_netaddr_get_ipstr(session.c->remote_addr),
pr_netaddr_get_ipstr(session.c->local_addr), session.c->local_port);
goto auth_failure;
}