freebsd-dev/lib/libpam/modules/pam_exec/pam_exec.c
Jean-Sébastien Pédron 3902d8a991 Fix error messages containing the executed command name
Before, we took the first argument to pam_exec(8). With the addition of
options in front of the command, this could be wrong.

Now, options are parsed before calling _pam_exec() and messages contain
the proper command name.

While here, fix a warning.

Sponsored by:	Yakaz (http://www.yakaz.com)
2012-04-12 14:02:59 +00:00

499 lines
12 KiB
C

/*-
* Copyright (c) 2001,2003 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by ThinkSec AS and
* NAI Labs, 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <security/pam_appl.h>
#include <security/pam_modules.h>
#include <security/openpam.h>
#define ENV_ITEM(n) { (n), #n }
static struct {
int item;
const char *name;
} env_items[] = {
ENV_ITEM(PAM_SERVICE),
ENV_ITEM(PAM_USER),
ENV_ITEM(PAM_TTY),
ENV_ITEM(PAM_RHOST),
ENV_ITEM(PAM_RUSER),
};
struct pe_opts {
int return_prog_exit_status;
};
#define PAM_RV_COUNT 24
static int
parse_options(const char *func, int *argc, const char **argv[],
struct pe_opts *options)
{
int i;
/*
* Parse options:
* return_prog_exit_status:
* use the program exit status as the return code of pam_exec
* --:
* stop options parsing; what follows is the command to execute
*/
options->return_prog_exit_status = 0;
for (i = 0; i < *argc; ++i) {
if (strcmp((*argv)[i], "return_prog_exit_status") == 0) {
openpam_log(PAM_LOG_DEBUG,
"%s: Option \"return_prog_exit_status\" enabled",
func);
options->return_prog_exit_status = 1;
} else {
if (strcmp((*argv)[i], "--") == 0) {
(*argc)--;
(*argv)++;
}
break;
}
}
(*argc) -= i;
(*argv) += i;
return (0);
}
static int
_pam_exec(pam_handle_t *pamh __unused,
const char *func, int flags __unused, int argc, const char *argv[],
struct pe_opts *options)
{
int envlen, i, nitems, pam_err, status;
int nitems_rv;
char **envlist, **tmp, *envstr;
volatile int childerr;
pid_t pid;
/*
* XXX For additional credit, divert child's stdin/stdout/stderr
* to the conversation function.
*/
/* Check there's a program name left after parsing options. */
if (argc < 1) {
openpam_log(PAM_LOG_ERROR, "%s: No program specified: aborting",
func);
return (PAM_SERVICE_ERR);
}
/*
* Set up the child's environment list. It consists of the PAM
* environment, plus a few hand-picked PAM items, the pam_sm_*
* function name calling it and, if return_prog_exit_status is
* set, the valid return codes numerical values.
*/
envlist = pam_getenvlist(pamh);
for (envlen = 0; envlist[envlen] != NULL; ++envlen)
/* nothing */ ;
nitems = sizeof(env_items) / sizeof(*env_items);
/* Count PAM return values put in the environment. */
nitems_rv = options->return_prog_exit_status ? PAM_RV_COUNT : 0;
tmp = realloc(envlist, (envlen + nitems + 1 + nitems_rv + 1) *
sizeof(*envlist));
if (tmp == NULL) {
openpam_free_envlist(envlist);
return (PAM_BUF_ERR);
}
envlist = tmp;
for (i = 0; i < nitems; ++i) {
const void *item;
pam_err = pam_get_item(pamh, env_items[i].item, &item);
if (pam_err != PAM_SUCCESS || item == NULL)
continue;
asprintf(&envstr, "%s=%s", env_items[i].name,
(const char *)item);
if (envstr == NULL) {
openpam_free_envlist(envlist);
return (PAM_BUF_ERR);
}
envlist[envlen++] = envstr;
envlist[envlen] = NULL;
}
/* Add the pam_sm_* function name to the environment. */
asprintf(&envstr, "PAM_SM_FUNC=%s", func);
if (envstr == NULL) {
openpam_free_envlist(envlist);
return (PAM_BUF_ERR);
}
envlist[envlen++] = envstr;
/* Add the PAM return values to the environment. */
if (options->return_prog_exit_status) {
#define ADD_PAM_RV_TO_ENV(name) \
asprintf(&envstr, #name "=%d", name); \
if (envstr == NULL) { \
openpam_free_envlist(envlist); \
return (PAM_BUF_ERR); \
} \
envlist[envlen++] = envstr
/*
* CAUTION: When adding/removing an item in the list
* below, be sure to update the value of PAM_RV_COUNT.
*/
ADD_PAM_RV_TO_ENV(PAM_ABORT);
ADD_PAM_RV_TO_ENV(PAM_ACCT_EXPIRED);
ADD_PAM_RV_TO_ENV(PAM_AUTHINFO_UNAVAIL);
ADD_PAM_RV_TO_ENV(PAM_AUTHTOK_DISABLE_AGING);
ADD_PAM_RV_TO_ENV(PAM_AUTHTOK_ERR);
ADD_PAM_RV_TO_ENV(PAM_AUTHTOK_LOCK_BUSY);
ADD_PAM_RV_TO_ENV(PAM_AUTHTOK_RECOVERY_ERR);
ADD_PAM_RV_TO_ENV(PAM_AUTH_ERR);
ADD_PAM_RV_TO_ENV(PAM_BUF_ERR);
ADD_PAM_RV_TO_ENV(PAM_CONV_ERR);
ADD_PAM_RV_TO_ENV(PAM_CRED_ERR);
ADD_PAM_RV_TO_ENV(PAM_CRED_EXPIRED);
ADD_PAM_RV_TO_ENV(PAM_CRED_INSUFFICIENT);
ADD_PAM_RV_TO_ENV(PAM_CRED_UNAVAIL);
ADD_PAM_RV_TO_ENV(PAM_IGNORE);
ADD_PAM_RV_TO_ENV(PAM_MAXTRIES);
ADD_PAM_RV_TO_ENV(PAM_NEW_AUTHTOK_REQD);
ADD_PAM_RV_TO_ENV(PAM_PERM_DENIED);
ADD_PAM_RV_TO_ENV(PAM_SERVICE_ERR);
ADD_PAM_RV_TO_ENV(PAM_SESSION_ERR);
ADD_PAM_RV_TO_ENV(PAM_SUCCESS);
ADD_PAM_RV_TO_ENV(PAM_SYSTEM_ERR);
ADD_PAM_RV_TO_ENV(PAM_TRY_AGAIN);
ADD_PAM_RV_TO_ENV(PAM_USER_UNKNOWN);
}
envlist[envlen] = NULL;
/*
* Fork and run the command. By using vfork() instead of fork(),
* we can distinguish between an execve() failure and a non-zero
* exit status from the command.
*/
childerr = 0;
if ((pid = vfork()) == 0) {
execve(argv[0], (char * const *)argv, (char * const *)envlist);
childerr = errno;
_exit(1);
}
openpam_free_envlist(envlist);
if (pid == -1) {
openpam_log(PAM_LOG_ERROR, "%s: vfork(): %m", func);
return (PAM_SYSTEM_ERR);
}
while (waitpid(pid, &status, 0) == -1) {
if (errno == EINTR)
continue;
openpam_log(PAM_LOG_ERROR, "%s: waitpid(): %m", func);
return (PAM_SYSTEM_ERR);
}
if (childerr != 0) {
openpam_log(PAM_LOG_ERROR, "%s: execve(): %m", func);
return (PAM_SYSTEM_ERR);
}
if (WIFSIGNALED(status)) {
openpam_log(PAM_LOG_ERROR, "%s: %s caught signal %d%s",
func, argv[0], WTERMSIG(status),
WCOREDUMP(status) ? " (core dumped)" : "");
return (PAM_SERVICE_ERR);
}
if (!WIFEXITED(status)) {
openpam_log(PAM_LOG_ERROR, "%s: unknown status 0x%x",
func, status);
return (PAM_SERVICE_ERR);
}
if (options->return_prog_exit_status) {
openpam_log(PAM_LOG_DEBUG,
"%s: Use program exit status as return value: %d",
func, WEXITSTATUS(status));
return (WEXITSTATUS(status));
} else {
return (WEXITSTATUS(status) == 0 ?
PAM_SUCCESS : PAM_PERM_DENIED);
}
}
PAM_EXTERN int
pam_sm_authenticate(pam_handle_t *pamh, int flags,
int argc, const char *argv[])
{
int ret;
struct pe_opts options;
ret = parse_options(__func__, &argc, &argv, &options);
if (ret != 0)
return (PAM_SERVICE_ERR);
ret = _pam_exec(pamh, __func__, flags, argc, argv, &options);
/*
* We must check that the program returned a valid code for this
* function.
*/
switch (ret) {
case PAM_SUCCESS:
case PAM_ABORT:
case PAM_AUTHINFO_UNAVAIL:
case PAM_AUTH_ERR:
case PAM_BUF_ERR:
case PAM_CONV_ERR:
case PAM_CRED_INSUFFICIENT:
case PAM_IGNORE:
case PAM_MAXTRIES:
case PAM_PERM_DENIED:
case PAM_SERVICE_ERR:
case PAM_SYSTEM_ERR:
case PAM_USER_UNKNOWN:
break;
default:
openpam_log(PAM_LOG_ERROR, "%s returned invalid code %d",
argv[0], ret);
ret = PAM_SERVICE_ERR;
}
return (ret);
}
PAM_EXTERN int
pam_sm_setcred(pam_handle_t *pamh, int flags,
int argc, const char *argv[])
{
int ret;
struct pe_opts options;
ret = parse_options(__func__, &argc, &argv, &options);
if (ret != 0)
return (PAM_SERVICE_ERR);
ret = _pam_exec(pamh, __func__, flags, argc, argv, &options);
/*
* We must check that the program returned a valid code for this
* function.
*/
switch (ret) {
case PAM_SUCCESS:
case PAM_ABORT:
case PAM_BUF_ERR:
case PAM_CONV_ERR:
case PAM_CRED_ERR:
case PAM_CRED_EXPIRED:
case PAM_CRED_UNAVAIL:
case PAM_IGNORE:
case PAM_PERM_DENIED:
case PAM_SERVICE_ERR:
case PAM_SYSTEM_ERR:
case PAM_USER_UNKNOWN:
break;
default:
openpam_log(PAM_LOG_ERROR, "%s returned invalid code %d",
argv[0], ret);
ret = PAM_SERVICE_ERR;
}
return (ret);
}
PAM_EXTERN int
pam_sm_acct_mgmt(pam_handle_t *pamh, int flags,
int argc, const char *argv[])
{
int ret;
struct pe_opts options;
ret = parse_options(__func__, &argc, &argv, &options);
if (ret != 0)
return (PAM_SERVICE_ERR);
ret = _pam_exec(pamh, __func__, flags, argc, argv, &options);
/*
* We must check that the program returned a valid code for this
* function.
*/
switch (ret) {
case PAM_SUCCESS:
case PAM_ABORT:
case PAM_ACCT_EXPIRED:
case PAM_AUTH_ERR:
case PAM_BUF_ERR:
case PAM_CONV_ERR:
case PAM_IGNORE:
case PAM_NEW_AUTHTOK_REQD:
case PAM_PERM_DENIED:
case PAM_SERVICE_ERR:
case PAM_SYSTEM_ERR:
case PAM_USER_UNKNOWN:
break;
default:
openpam_log(PAM_LOG_ERROR, "%s returned invalid code %d",
argv[0], ret);
ret = PAM_SERVICE_ERR;
}
return (ret);
}
PAM_EXTERN int
pam_sm_open_session(pam_handle_t *pamh, int flags,
int argc, const char *argv[])
{
int ret;
struct pe_opts options;
ret = parse_options(__func__, &argc, &argv, &options);
if (ret != 0)
return (PAM_SERVICE_ERR);
ret = _pam_exec(pamh, __func__, flags, argc, argv, &options);
/*
* We must check that the program returned a valid code for this
* function.
*/
switch (ret) {
case PAM_SUCCESS:
case PAM_ABORT:
case PAM_BUF_ERR:
case PAM_CONV_ERR:
case PAM_IGNORE:
case PAM_PERM_DENIED:
case PAM_SERVICE_ERR:
case PAM_SESSION_ERR:
case PAM_SYSTEM_ERR:
break;
default:
openpam_log(PAM_LOG_ERROR, "%s returned invalid code %d",
argv[0], ret);
ret = PAM_SERVICE_ERR;
}
return (ret);
}
PAM_EXTERN int
pam_sm_close_session(pam_handle_t *pamh, int flags,
int argc, const char *argv[])
{
int ret;
struct pe_opts options;
ret = parse_options(__func__, &argc, &argv, &options);
if (ret != 0)
return (PAM_SERVICE_ERR);
ret = _pam_exec(pamh, __func__, flags, argc, argv, &options);
/*
* We must check that the program returned a valid code for this
* function.
*/
switch (ret) {
case PAM_SUCCESS:
case PAM_ABORT:
case PAM_BUF_ERR:
case PAM_CONV_ERR:
case PAM_IGNORE:
case PAM_PERM_DENIED:
case PAM_SERVICE_ERR:
case PAM_SESSION_ERR:
case PAM_SYSTEM_ERR:
break;
default:
openpam_log(PAM_LOG_ERROR, "%s returned invalid code %d",
argv[0], ret);
ret = PAM_SERVICE_ERR;
}
return (ret);
}
PAM_EXTERN int
pam_sm_chauthtok(pam_handle_t *pamh, int flags,
int argc, const char *argv[])
{
int ret;
struct pe_opts options;
ret = parse_options(__func__, &argc, &argv, &options);
if (ret != 0)
return (PAM_SERVICE_ERR);
ret = _pam_exec(pamh, __func__, flags, argc, argv, &options);
/*
* We must check that the program returned a valid code for this
* function.
*/
switch (ret) {
case PAM_SUCCESS:
case PAM_ABORT:
case PAM_AUTHTOK_DISABLE_AGING:
case PAM_AUTHTOK_ERR:
case PAM_AUTHTOK_LOCK_BUSY:
case PAM_AUTHTOK_RECOVERY_ERR:
case PAM_BUF_ERR:
case PAM_CONV_ERR:
case PAM_IGNORE:
case PAM_PERM_DENIED:
case PAM_SERVICE_ERR:
case PAM_SYSTEM_ERR:
case PAM_TRY_AGAIN:
break;
default:
openpam_log(PAM_LOG_ERROR, "%s returned invalid code %d",
argv[0], ret);
ret = PAM_SERVICE_ERR;
}
return (ret);
}
PAM_MODULE_ENTRY("pam_exec");