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/* pam_ftp module */
/*
* $Id: pam_ftp.c,v 1.2 1997/02/15 16:23:59 morgan Exp morgan $
*
* Written by Andrew Morgan <morgan@parc.power.net> 1996/3/11
*
* $Log: pam_ftp.c,v $
* Revision 1.2 1997/02/15 16:23:59 morgan
* fixed logging to avoid a fixed buffer size
*
* Revision 1.1 1996/12/01 03:17:57 morgan
* Initial revision
*
*
*/
#define PLEASE_ENTER_PASSWORD "Password required for %s."
#define GUEST_LOGIN_PROMPT "Guest login ok, " \
"send your complete e-mail address as password."
/* the following is a password that "can't be correct" */
#define BLOCK_PASSWORD "\177BAD PASSWPRD\177"
#ifdef linux
# define _GNU_SOURCE
# include <features.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <stdarg.h>
#include <string.h>
/*
* here, we make a definition for the externally accessible function
* in this file (this definition is required for static a module
* but strongly encouraged generally) it is used to instruct the
* modules include file to define the function prototypes.
*/
#define PAM_SM_AUTH
#include <security/pam_modules.h>
#include <security/_pam_macros.h>
/* some syslogging */
static void _pam_log(int err, const char *format, ...)
{
va_list args;
va_start(args, format);
openlog("PAM-ftp", LOG_CONS|LOG_PID, LOG_AUTH);
vsyslog(err, format, args);
va_end(args);
closelog();
}
static int converse(pam_handle_t *pamh, int nargs
, struct pam_message **message
, struct pam_response **response)
{
int retval;
struct pam_conv *conv;
D(("begin to converse\n"));
retval = pam_get_item( pamh, PAM_CONV, (const void **) &conv ) ;
if ( retval == PAM_SUCCESS ) {
retval = conv->conv(nargs, ( const struct pam_message ** ) message
, response, conv->appdata_ptr);
D(("returned from application's conversation function\n"));
if (retval != PAM_SUCCESS) {
_pam_log(LOG_DEBUG, "conversation failure [%s]"
, pam_strerror(pamh, retval));
}
} else {
_pam_log(LOG_ERR, "couldn't obtain coversation function [%s]"
, pam_strerror(pamh, retval));
}
D(("ready to return from module conversation\n"));
return retval; /* propagate error status */
}
/* argument parsing */
#define PAM_DEBUG_ARG 01
#define PAM_IGNORE_EMAIL 02
#define PAM_NO_ANON 04
static int _pam_parse(int argc, const char **argv, char **users)
{
int ctrl=0;
/* step through arguments */
for (ctrl=0; argc-- > 0; ++argv) {
/* generic options */
if (!strcmp(*argv,"debug"))
ctrl |= PAM_DEBUG_ARG;
else if (!strncmp(*argv,"users=",6)) {
*users = x_strdup(6+*argv);
if (*users == NULL) {
ctrl |= PAM_NO_ANON;
_pam_log(LOG_CRIT, "failed to duplicate user list - anon off");
}
} else if (!strcmp(*argv,"ignore")) {
ctrl |= PAM_IGNORE_EMAIL;
} else {
_pam_log(LOG_ERR,"pam_parse: unknown option; %s",*argv);
}
}
return ctrl;
}
/*
* check if name is in list or default list. place users name in *_user
* return 1 if listed 0 if not.
*/
static int lookup(const char *name, char *list, const char **_user)
{
int anon = 0;
*_user = name; /* this is the default */
if (list) {
const char *l;
char *x;
x = list;
while ((l = strtok(x, ","))) {
x = NULL;
if (!strcmp(name, l)) {
*_user = list;
anon = 1;
}
}
} else {
#define MAX_L 2
static const char *l[MAX_L] = { "ftp", "anonymous" };
int i;
for (i=0; i<MAX_L; ++i) {
if (!strcmp(l[i], name)) {
*_user = l[0];
anon = 1;
break;
}
}
}
return anon;
}
/* --- authentication management functions (only) --- */
PAM_EXTERN
int pam_sm_authenticate(pam_handle_t *pamh,int flags,int argc
,const char **argv)
{
int retval, anon=0, ctrl;
const char *user;
char *users=NULL;
/*
* this module checks if the user name is ftp or annonymous. If
* this is the case, it can set the PAM_RUSER to the entered email
* address and SUCCEEDS, otherwise it FAILS.
*/
ctrl = _pam_parse(argc, argv, &users);
retval = pam_get_user(pamh, &user, NULL);
if (retval != PAM_SUCCESS || user == NULL) {
_pam_log(LOG_ERR, "no user specified");
return PAM_USER_UNKNOWN;
}
if (!(ctrl & PAM_NO_ANON)) {
anon = lookup(user, users, &user);
}
if (anon) {
retval = pam_set_item(pamh, PAM_USER, (const void *)user);
if (retval != PAM_SUCCESS || user == NULL) {
_pam_log(LOG_ERR, "user resetting failed");
return PAM_USER_UNKNOWN;
}
}
/*
* OK. we require an email address for user or the user's password.
* - build conversation and get their input.
*/
{
struct pam_message msg[1], *mesg[1];
struct pam_response *resp=NULL;
const char *token;
char *prompt=NULL;
int i=0;
mesg[i] = &msg[i];
msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
if (anon) {
prompt = malloc(sizeof(PLEASE_ENTER_PASSWORD + strlen(user)));
sprintf(prompt, PLEASE_ENTER_PASSWORD, user);
msg[i].msg = prompt;
} else {
msg[i].msg = GUEST_LOGIN_PROMPT;
}
retval = converse(pamh, ++i, mesg, &resp);
_pam_overwrite(prompt);
_pam_drop(prompt);
if (retval != PAM_SUCCESS) {
if (resp != NULL)
_pam_drop_reply(resp,i);
return PAM_AUTHINFO_UNAVAIL;
}
if (anon) {
/* XXX: Some effort should be made to verify this email address! */
if (!(ctrl & PAM_IGNORE_EMAIL)) {
token = strtok(resp->resp, "@");
retval = pam_set_item(pamh, PAM_RUSER, token);
if (token && retval != PAM_SUCCESS) {
token = strtok(NULL, "@");
retval = pam_set_item(pamh, PAM_RHOST, token);
}
}
} else {
/*
* we have a password so set AUTHTOK
*/
(void) pam_set_item(pamh, PAM_AUTHTOK, resp->resp);
/*
* this module failed, but the next one might succeed with
* this password.
*/
retval = PAM_AUTH_ERR;
}
if (resp) { /* clean up */
_pam_drop_reply(resp, i);
}
/* success or failure */
return retval;
}
}
PAM_EXTERN
int pam_sm_setcred(pam_handle_t *pamh,int flags,int argc
,const char **argv)
{
return PAM_IGNORE;
}
#ifdef PAM_STATIC
/* static module data */
struct pam_module _pam_ftp_modstruct = {
"pam_ftp",
pam_sm_authenticate,
pam_sm_setcred,
NULL,
NULL,
NULL,
NULL,
};
#endif
/* end of module definition */
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