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/*-
* Copyright (c) 2002-2003 Networks Associates Technology, Inc.
* Copyright (c) 2004-2011 Dag-Erling Smørgrav
* All rights reserved.
*
* This software was developed for the FreeBSD Project by ThinkSec AS and
* Network Associates Laboratories, the Security Research Division of
* Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
* ("CBOSS"), as part of the DARPA CHATS research program.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*
* $Id: pam_get_authtok.c 807 2014-09-09 09:41:32Z des $
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <sys/param.h>
#include <stdlib.h>
#include <string.h>
#include <security/pam_appl.h>
#include <security/openpam.h>
#include "openpam_impl.h"
#include "openpam_strlset.h"
static const char authtok_prompt[] = "Password:";
static const char authtok_prompt_remote[] = "Password for %u@%h:";
static const char oldauthtok_prompt[] = "Old Password:";
static const char newauthtok_prompt[] = "New Password:";
/*
* OpenPAM extension
*
* Retrieve authentication token
*/
int
pam_get_authtok(pam_handle_t *pamh,
int item,
const char **authtok,
const char *prompt)
{
char prompt_buf[1024];
size_t prompt_size;
const void *oldauthtok, *prevauthtok, *promptp;
const char *prompt_option, *default_prompt;
const void *lhost, *rhost;
char *resp, *resp2;
int pitem, r, style, twice;
ENTER();
if (pamh == NULL || authtok == NULL)
RETURNC(PAM_SYSTEM_ERR);
*authtok = NULL;
twice = 0;
switch (item) {
case PAM_AUTHTOK:
pitem = PAM_AUTHTOK_PROMPT;
prompt_option = "authtok_prompt";
default_prompt = authtok_prompt;
r = pam_get_item(pamh, PAM_RHOST, &rhost);
if (r == PAM_SUCCESS && rhost != NULL) {
r = pam_get_item(pamh, PAM_HOST, &lhost);
if (r == PAM_SUCCESS && lhost != NULL) {
if (strcmp(rhost, lhost) != 0)
default_prompt = authtok_prompt_remote;
}
}
r = pam_get_item(pamh, PAM_OLDAUTHTOK, &oldauthtok);
if (r == PAM_SUCCESS && oldauthtok != NULL) {
default_prompt = newauthtok_prompt;
twice = 1;
}
break;
case PAM_OLDAUTHTOK:
pitem = PAM_OLDAUTHTOK_PROMPT;
prompt_option = "oldauthtok_prompt";
default_prompt = oldauthtok_prompt;
twice = 0;
break;
default:
RETURNC(PAM_SYMBOL_ERR);
}
if (openpam_get_option(pamh, "try_first_pass") ||
openpam_get_option(pamh, "use_first_pass")) {
r = pam_get_item(pamh, item, &prevauthtok);
if (r == PAM_SUCCESS && prevauthtok != NULL) {
*authtok = prevauthtok;
RETURNC(PAM_SUCCESS);
} else if (openpam_get_option(pamh, "use_first_pass")) {
RETURNC(r == PAM_SUCCESS ? PAM_AUTH_ERR : r);
}
}
/* pam policy overrides the module's choice */
if ((promptp = openpam_get_option(pamh, prompt_option)) != NULL)
prompt = promptp;
/* no prompt provided, see if there is one tucked away somewhere */
if (prompt == NULL)
if (pam_get_item(pamh, pitem, &promptp) && promptp != NULL)
prompt = promptp;
/* fall back to hardcoded default */
if (prompt == NULL)
prompt = default_prompt;
/* expand */
prompt_size = sizeof prompt_buf;
r = openpam_subst(pamh, prompt_buf, &prompt_size, prompt);
if (r == PAM_SUCCESS && prompt_size <= sizeof prompt_buf)
prompt = prompt_buf;
style = openpam_get_option(pamh, "echo_pass") ?
PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF;
r = pam_prompt(pamh, style, &resp, "%s", prompt);
if (r != PAM_SUCCESS)
RETURNC(r);
if (twice) {
r = pam_prompt(pamh, style, &resp2, "Retype %s", prompt);
if (r != PAM_SUCCESS) {
strlset(resp, 0, PAM_MAX_RESP_SIZE);
FREE(resp);
RETURNC(r);
}
if (strcmp(resp, resp2) != 0) {
strlset(resp, 0, PAM_MAX_RESP_SIZE);
FREE(resp);
}
strlset(resp2, 0, PAM_MAX_RESP_SIZE);
FREE(resp2);
}
if (resp == NULL)
RETURNC(PAM_TRY_AGAIN);
r = pam_set_item(pamh, item, resp);
strlset(resp, 0, PAM_MAX_RESP_SIZE);
FREE(resp);
if (r != PAM_SUCCESS)
RETURNC(r);
r = pam_get_item(pamh, item, (const void **)authtok);
RETURNC(r);
}
/*
* Error codes:
*
* =pam_get_item
* =pam_prompt
* =pam_set_item
* !PAM_SYMBOL_ERR
* PAM_TRY_AGAIN
*/
/**
* The =pam_get_authtok function either prompts the user for an
* authentication token or retrieves a cached authentication token,
* depending on circumstances.
* Either way, a pointer to the authentication token is stored in the
* location pointed to by the =authtok argument, and the corresponding PAM
* item is updated.
*
* The =item argument must have one of the following values:
*
* =PAM_AUTHTOK:
* Returns the current authentication token, or the new token
* when changing authentication tokens.
* =PAM_OLDAUTHTOK:
* Returns the previous authentication token when changing
* authentication tokens.
*
* The =prompt argument specifies a prompt to use if no token is cached.
* If it is =NULL, the =PAM_AUTHTOK_PROMPT or =PAM_OLDAUTHTOK_PROMPT item,
* as appropriate, will be used.
* If that item is also =NULL, a hardcoded default prompt will be used.
* Additionally, when =pam_get_authtok is called from a service module,
* the prompt may be affected by module options as described below.
* The prompt is then expanded using =openpam_subst before it is passed to
* the conversation function.
*
* If =item is set to =PAM_AUTHTOK and there is a non-null =PAM_OLDAUTHTOK
* item, =pam_get_authtok will ask the user to confirm the new token by
* retyping it.
* If there is a mismatch, =pam_get_authtok will return =PAM_TRY_AGAIN.
*
* MODULE OPTIONS
*
* When called by a service module, =pam_get_authtok will recognize the
* following module options:
*
* ;authtok_prompt:
* Prompt to use when =item is set to =PAM_AUTHTOK.
* This option overrides both the =prompt argument and the
* =PAM_AUTHTOK_PROMPT item.
* ;echo_pass:
* If the application's conversation function allows it, this
* lets the user see what they are typing.
* This should only be used for non-reusable authentication
* tokens.
* ;oldauthtok_prompt:
* Prompt to use when =item is set to =PAM_OLDAUTHTOK.
* This option overrides both the =prompt argument and the
* =PAM_OLDAUTHTOK_PROMPT item.
* ;try_first_pass:
* If the requested item is non-null, return it without
* prompting the user.
* Typically, the service module will verify the token, and
* if it does not match, clear the item before calling
* =pam_get_authtok a second time.
* ;use_first_pass:
* Do not prompt the user at all; just return the cached
* value, or =PAM_AUTH_ERR if there is none.
*
* >pam_conv
* >pam_get_item
* >pam_get_user
* >openpam_get_option
* >openpam_subst
*/
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