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/*
* Copyright (c) 1999-2002 Todd C. Miller <Todd.Miller@courtesan.com>
* 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.
*
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 4. Products derived from this software may not be called "Sudo" nor
* may "Sudo" appear in their names without specific prior written
* permission from the author.
*
* THIS SOFTWARE IS PROVIDED ``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.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
#include "config.h"
#include <sys/types.h>
#include <sys/param.h>
#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
# include <stdlib.h>
# endif
#endif /* STDC_HEADERS */
#ifdef HAVE_STRING_H
# if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
# include <memory.h>
# endif
# include <string.h>
#else
# ifdef HAVE_STRINGS_H
# include <strings.h>
# endif
#endif /* HAVE_STRING_H */
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include <pwd.h>
#ifdef HAVE_PAM_PAM_APPL_H
# include <pam/pam_appl.h>
#else
# include <security/pam_appl.h>
#endif
#include "sudo.h"
#include "sudo_auth.h"
/* Only OpenPAM and Linux PAM use const qualifiers. */
#if defined(_OPENPAM) || defined(__LIBPAM_VERSION)
# define PAM_CONST const
#else
# define PAM_CONST
#endif
#ifndef lint
static const char rcsid[] = "$Sudo$";
#endif /* lint */
static int sudo_conv __P((int, PAM_CONST struct pam_message **,
struct pam_response **, VOID *));
static char *def_prompt;
#ifndef PAM_DATA_SILENT
#define PAM_DATA_SILENT 0
#endif
static pam_handle_t *pamh; /* global due to pam_prep_user() */
int
pam_init(pw, promptp, auth)
struct passwd *pw;
char **promptp;
sudo_auth *auth;
{
static struct pam_conv pam_conv;
static int pam_status;
/* Initial PAM setup */
if (auth != NULL)
auth->data = (VOID *) &pam_status;
pam_conv.conv = sudo_conv;
pam_status = pam_start("sudo", pw->pw_name, &pam_conv, &pamh);
if (pam_status != PAM_SUCCESS) {
log_error(USE_ERRNO|NO_EXIT|NO_MAIL,
"unable to initialize PAM");
return(AUTH_FATAL);
}
if (strcmp(user_tty, "unknown"))
(void) pam_set_item(pamh, PAM_TTY, user_tty);
return(AUTH_SUCCESS);
}
int
pam_verify(pw, prompt, auth)
struct passwd *pw;
char *prompt;
sudo_auth *auth;
{
const char *s;
int *pam_status = (int *) auth->data;
def_prompt = prompt; /* for sudo_conv */
/* PAM_SILENT prevents the authentication service from generating output. */
*pam_status = pam_authenticate(pamh, PAM_SILENT);
switch (*pam_status) {
case PAM_SUCCESS:
return(AUTH_SUCCESS);
case PAM_AUTH_ERR:
case PAM_MAXTRIES:
return(AUTH_FAILURE);
default:
if ((s = pam_strerror(pamh, *pam_status)))
log_error(NO_EXIT|NO_MAIL, "pam_authenticate: %s", s);
return(AUTH_FATAL);
}
}
int
pam_cleanup(pw, auth)
struct passwd *pw;
sudo_auth *auth;
{
int *pam_status = (int *) auth->data;
/* If successful, we can't close the session until pam_prep_user() */
if (auth->status == AUTH_SUCCESS)
return(AUTH_SUCCESS);
*pam_status = pam_end(pamh, *pam_status | PAM_DATA_SILENT);
return(*pam_status == PAM_SUCCESS ? AUTH_SUCCESS : AUTH_FAILURE);
}
int
pam_prep_user(pw)
struct passwd *pw;
{
if (pamh == NULL)
pam_init(pw, NULL, NULL);
/*
* Set PAM_USER to the user we are changing *to* and
* set PAM_RUSER to the user we are coming *from*.
*/
(void) pam_set_item(pamh, PAM_USER, pw->pw_name);
(void) pam_set_item(pamh, PAM_RUSER, user_name);
/*
* Set credentials (may include resource limits, device ownership, etc).
* We don't check the return value here because in Linux-PAM 0.75
* it returns the last saved return code, not the return code
* for the setcred module. Because we haven't called pam_authenticate(),
* this is not set and so pam_setcred() returns PAM_PERM_DENIED.
* We can't call pam_acct_mgmt() with Linux-PAM for a similar reason.
*/
(void) pam_setcred(pamh, PAM_ESTABLISH_CRED);
if (pam_end(pamh, PAM_SUCCESS | PAM_DATA_SILENT) == PAM_SUCCESS)
return(AUTH_SUCCESS);
else
return(AUTH_FAILURE);
}
/*
* ``Conversation function'' for PAM.
* XXX - does not handle PAM_BINARY_PROMPT
*/
static int
sudo_conv(num_msg, msg, response, appdata_ptr)
int num_msg;
PAM_CONST struct pam_message **msg;
struct pam_response **response;
VOID *appdata_ptr;
{
struct pam_response *pr;
PAM_CONST struct pam_message *pm;
const char *p = def_prompt;
char *pass;
int n, flags;
extern int nil_pw;
if ((*response = malloc(num_msg * sizeof(struct pam_response))) == NULL)
return(PAM_CONV_ERR);
zero_bytes(*response, num_msg * sizeof(struct pam_response));
for (pr = *response, pm = *msg, n = num_msg; n--; pr++, pm++) {
flags = tgetpass_flags;
switch (pm->msg_style) {
case PAM_PROMPT_ECHO_ON:
flags |= TGP_ECHO;
case PAM_PROMPT_ECHO_OFF:
/* Only override PAM prompt if it matches /^Password: ?/ */
if (strncmp(pm->msg, "Password:", 9) || (pm->msg[9] != '\0'
&& (pm->msg[9] != ' ' || pm->msg[10] != '\0')))
p = pm->msg;
/* Read the password. */
pass = tgetpass(p, def_passwd_timeout * 60, flags);
pr->resp = estrdup(pass ? pass : "");
if (*pr->resp == '\0')
nil_pw = 1; /* empty password */
else
zero_bytes(pass, strlen(pass));
break;
case PAM_TEXT_INFO:
if (pm->msg)
(void) puts(pm->msg);
break;
case PAM_ERROR_MSG:
if (pm->msg) {
(void) fputs(pm->msg, stderr);
(void) fputc('\n', stderr);
}
break;
default:
/* Zero and free allocated memory and return an error. */
for (pr = *response, n = num_msg; n--; pr++) {
if (pr->resp != NULL) {
zero_bytes(pr->resp, strlen(pr->resp));
free(pr->resp);
pr->resp = NULL;
}
}
zero_bytes(*response, num_msg * sizeof(struct pam_response));
free(*response);
*response = NULL;
return(PAM_CONV_ERR);
}
}
return(PAM_SUCCESS);
}
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