/*
* Copyright (c) 1999-2005, 2007-2013 Todd C. Miller <Todd.Miller@courtesan.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* 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 <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
# include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif /* HAVE_STRINGS_H */
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include <pwd.h>
#include <errno.h>
#ifdef HAVE_PAM_PAM_APPL_H
# include <pam/pam_appl.h>
#else
# include <security/pam_appl.h>
#endif
#ifdef HAVE_LIBINTL_H
# if defined(__LINUX_PAM__)
# define PAM_TEXT_DOMAIN "Linux-PAM"
# elif defined(__sun__)
# define PAM_TEXT_DOMAIN "SUNW_OST_SYSOSPAM"
# endif
#endif
/* We don't want to translate the strings in the calls to dgt(). */
#ifdef PAM_TEXT_DOMAIN
# define dgt(d, t) dgettext(d, t)
#endif
#include "sudoers.h"
#include "sudo_auth.h"
/* Only OpenPAM and Linux PAM use const qualifiers. */
#if defined(_OPENPAM) || defined(OPENPAM_VERSION) || \
defined(__LIBPAM_VERSION) || defined(__LINUX_PAM__)
# define PAM_CONST const
#else
# define PAM_CONST
#endif
#ifndef PAM_DATA_SILENT
#define PAM_DATA_SILENT 0
#endif
static int converse(int, PAM_CONST struct pam_message **,
struct pam_response **, void *);
static char *def_prompt = "Password:";
static int getpass_error;
static pam_handle_t *pamh;
int
sudo_pam_init(struct passwd *pw, sudo_auth *auth)
{
static struct pam_conv pam_conv;
static int pam_status;
debug_decl(sudo_pam_init, SUDO_DEBUG_AUTH)
/* Initial PAM setup */
auth->data = (void *) &pam_status;
pam_conv.conv = converse;
pam_status = pam_start(ISSET(sudo_mode, MODE_LOGIN_SHELL) ?
def_pam_login_service : def_pam_service, pw->pw_name, &pam_conv, &pamh);
if (pam_status != PAM_SUCCESS) {
log_warning(USE_ERRNO|NO_MAIL, N_("unable to initialize PAM"));
debug_return_int(AUTH_FATAL);
}
/*
* Set PAM_RUSER to the invoking user (the "from" user).
* We set PAM_RHOST to avoid a bug in Solaris 7 and below.
*/
(void) pam_set_item(pamh, PAM_RUSER, user_name);
#ifdef __sun__
(void) pam_set_item(pamh, PAM_RHOST, user_host);
#endif
/*
* Some versions of pam_lastlog have a bug that
* will cause a crash if PAM_TTY is not set so if
* there is no tty, set PAM_TTY to the empty string.
*/
if (user_ttypath == NULL)
(void) pam_set_item(pamh, PAM_TTY, "");
else
(void) pam_set_item(pamh, PAM_TTY, user_ttypath);
/*
* If PAM session and setcred support is disabled we don't
* need to keep a sudo process around to close the session.
*/
if (!def_pam_session && !def_pam_setcred)
auth->end_session = NULL;
debug_return_int(AUTH_SUCCESS);
}
int
sudo_pam_verify(struct passwd *pw, char *prompt, sudo_auth *auth)
{
const char *s;
int *pam_status = (int *) auth->data;
debug_decl(sudo_pam_verify, SUDO_DEBUG_AUTH)
def_prompt = prompt; /* for converse */
/* PAM_SILENT prevents the authentication service from generating output. */
*pam_status = pam_authenticate(pamh, PAM_SILENT);
switch (*pam_status) {
case PAM_SUCCESS:
*pam_status = pam_acct_mgmt(pamh, PAM_SILENT);
switch (*pam_status) {
case PAM_SUCCESS:
debug_return_int(AUTH_SUCCESS);
case PAM_AUTH_ERR:
log_warning(NO_MAIL, N_("account validation failure, "
"is your account locked?"));
debug_return_int(AUTH_FATAL);
case PAM_NEW_AUTHTOK_REQD:
log_warning(NO_MAIL, N_("Account or password is "
"expired, reset your password and try again"));
*pam_status = pam_chauthtok(pamh,
PAM_CHANGE_EXPIRED_AUTHTOK);
if (*pam_status == PAM_SUCCESS)
debug_return_int(AUTH_SUCCESS);
if ((s = pam_strerror(pamh, *pam_status)) != NULL) {
log_warning(NO_MAIL,
N_("unable to change expired password: %s"), s);
}
debug_return_int(AUTH_FAILURE);
case PAM_AUTHTOK_EXPIRED:
log_warning(NO_MAIL,
N_("Password expired, contact your system administrator"));
debug_return_int(AUTH_FATAL);
case PAM_ACCT_EXPIRED:
log_warning(NO_MAIL,
N_("Account expired or PAM config lacks an \"account\" "
"section for sudo, contact your system administrator"));
debug_return_int(AUTH_FATAL);
}
/* FALLTHROUGH */
case PAM_AUTH_ERR:
case PAM_AUTHINFO_UNAVAIL:
if (getpass_error) {
/* error or ^C from tgetpass() */
debug_return_int(AUTH_INTR);
}
/* FALLTHROUGH */
case PAM_MAXTRIES:
case PAM_PERM_DENIED:
debug_return_int(AUTH_FAILURE);
default:
if ((s = pam_strerror(pamh, *pam_status)) != NULL)
log_warning(NO_MAIL, N_("PAM authentication error: %s"), s);
debug_return_int(AUTH_FATAL);
}
}
int
sudo_pam_cleanup(struct passwd *pw, sudo_auth *auth)
{
int *pam_status = (int *) auth->data;
debug_decl(sudo_pam_cleanup, SUDO_DEBUG_AUTH)
/* If successful, we can't close the session until sudo_pam_end_session() */
if (*pam_status != PAM_SUCCESS || auth->end_session == NULL) {
*pam_status = pam_end(pamh, *pam_status | PAM_DATA_SILENT);
pamh = NULL;
}
debug_return_int(*pam_status == PAM_SUCCESS ? AUTH_SUCCESS : AUTH_FAILURE);
}
int
sudo_pam_begin_session(struct passwd *pw, char **user_envp[], sudo_auth *auth)
{
int status = AUTH_SUCCESS;
int *pam_status = (int *) auth->data;
debug_decl(sudo_pam_begin_session, SUDO_DEBUG_AUTH)
/*
* If there is no valid user we cannot open a PAM session.
* This is not an error as sudo can run commands with arbitrary
* uids, it just means we are done from a session management standpoint.
*/
if (pw == NULL) {
if (pamh != NULL) {
(void) pam_end(pamh, PAM_SUCCESS | PAM_DATA_SILENT);
pamh = NULL;
}
goto done;
}
/*
* Update PAM_USER to reference the user we are running the command
* as, as opposed to the user we authenticated as.
*/
(void) pam_set_item(pamh, PAM_USER, pw->pw_name);
/*
* Set credentials (may include resource limits, device ownership, etc).
* We don't worry about a failure from pam_setcred() since with
* stacked PAM auth modules a failure from one module may override
* PAM_SUCCESS from another. For example, given a non-local user,
* pam_unix will fail but pam_ldap or pam_sss may succeed, but if
* pam_unix is first in the stack, pam_setcred() will fail.
*/
if (def_pam_setcred)
(void) pam_setcred(pamh, PAM_ESTABLISH_CRED);
if (def_pam_session) {
*pam_status = pam_open_session(pamh, 0);
if (*pam_status != PAM_SUCCESS) {
(void) pam_end(pamh, *pam_status | PAM_DATA_SILENT);
pamh = NULL;
status = AUTH_FAILURE;
}
}
#ifdef HAVE_PAM_GETENVLIST
/*
* Update environment based on what is stored in pamh.
* If no authentication is done we will only have environment
* variables if pam_env is called via session.
*/
if (user_envp != NULL) {
char **pam_envp = pam_getenvlist(pamh);
if (pam_envp != NULL) {
/* Merge pam env with user env. */
env_init(*user_envp);
env_merge(pam_envp);
*user_envp = env_get();
env_init(NULL);
efree(pam_envp);
/* XXX - we leak any duplicates that were in pam_envp */
}
}
#endif /* HAVE_PAM_GETENVLIST */
done:
debug_return_int(status);
}
int
sudo_pam_end_session(struct passwd *pw, sudo_auth *auth)
{
int status = AUTH_SUCCESS;
debug_decl(sudo_pam_end_session, SUDO_DEBUG_AUTH)
if (pamh != NULL) {
/*
* Update PAM_USER to reference the user we are running the command
* as, as opposed to the user we authenticated as.
* XXX - still needed now that session init is in parent?
*/
(void) pam_set_item(pamh, PAM_USER, pw->pw_name);
if (def_pam_session)
(void) pam_close_session(pamh, PAM_SILENT);
if (def_pam_setcred)
(void) pam_setcred(pamh, PAM_DELETE_CRED | PAM_SILENT);
if (pam_end(pamh, PAM_SUCCESS | PAM_DATA_SILENT) != PAM_SUCCESS)
status = AUTH_FAILURE;
pamh = NULL;
}
debug_return_int(status);
}
/*
* ``Conversation function'' for PAM.
* XXX - does not handle PAM_BINARY_PROMPT
*/
static int
converse(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 *prompt;
char *pass;
int n, type, std_prompt;
int ret = PAM_AUTH_ERR;
debug_decl(converse, SUDO_DEBUG_AUTH)
if ((*response = malloc(num_msg * sizeof(struct pam_response))) == NULL)
debug_return_int(PAM_SYSTEM_ERR);
memset(*response, 0, num_msg * sizeof(struct pam_response));
for (pr = *response, pm = *msg, n = num_msg; n--; pr++, pm++) {
type = SUDO_CONV_PROMPT_ECHO_OFF;
switch (pm->msg_style) {
case PAM_PROMPT_ECHO_ON:
type = SUDO_CONV_PROMPT_ECHO_ON;
/* FALLTHROUGH */
case PAM_PROMPT_ECHO_OFF:
prompt = def_prompt;
/* Error out if the last password read was interrupted. */
if (getpass_error)
goto done;
/* Is the sudo prompt standard? (If so, we'll just use PAM's) */
std_prompt = strncmp(def_prompt, "Password:", 9) == 0 &&
(def_prompt[9] == '\0' ||
(def_prompt[9] == ' ' && def_prompt[10] == '\0'));
/* Only override PAM prompt if it matches /^Password: ?/ */
#if defined(PAM_TEXT_DOMAIN) && defined(HAVE_LIBINTL_H)
if (!def_passprompt_override && (std_prompt ||
(strcmp(pm->msg, dgt(PAM_TEXT_DOMAIN, "Password: ")) &&
strcmp(pm->msg, dgt(PAM_TEXT_DOMAIN, "Password:")))))
prompt = pm->msg;
#else
if (!def_passprompt_override && (std_prompt ||
strncmp(pm->msg, "Password:", 9) || (pm->msg[9] != '\0'
&& (pm->msg[9] != ' ' || pm->msg[10] != '\0'))))
prompt = pm->msg;
#endif
/* Read the password unless interrupted. */
pass = auth_getpass(prompt, def_passwd_timeout * 60, type);
if (pass == NULL) {
/* Error (or ^C) reading password, don't try again. */
getpass_error = 1;
#if (defined(__darwin__) || defined(__APPLE__)) && !defined(OPENPAM_VERSION)
pass = "";
#else
goto done;
#endif
}
pr->resp = estrdup(pass);
memset_s(pass, SUDO_CONV_REPL_MAX, 0, 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:
ret = PAM_CONV_ERR;
goto done;
}
}
ret = PAM_SUCCESS;
done:
if (ret != PAM_SUCCESS) {
/* Zero and free allocated memory and return an error. */
for (pr = *response, n = num_msg; n--; pr++) {
if (pr->resp != NULL) {
memset_s(pr->resp, SUDO_CONV_REPL_MAX, 0, strlen(pr->resp));
free(pr->resp);
pr->resp = NULL;
}
}
free(*response);
*response = NULL;
}
debug_return_int(ret);
}
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