Author: dumbbell
Date: Mon Mar 26 12:18:15 2012
New Revision: 233507
URL: http://svn.freebsd.org/changeset/base/233507
Log:
Use program exit status as pam_exec return code (optional)
pam_exec(8) now accepts a new option "return_prog_exit_status". When
set, the program exit status is used as the pam_exec return code. It
allows the program to tell why the step failed (eg. user unknown).
However, if it exits with a code not allowed by the calling PAM service
module function (see $PAM_SM_FUNC below), a warning is logged and
PAM_SERVICE_ERR is returned.
The following changes are related to this new feature but they apply no
matter if the "return_prog_exit_status" option is set or not.
The environment passed to the program is extended:
o $PAM_SM_FUNC contains the name of the PAM service module function
(eg. pam_sm_authenticate).
o All valid PAM return codes' numerical values are available
through variables named after the return code name. For instance,
$PAM_SUCCESS, $PAM_USER_UNKNOWN or $PAM_PERM_DENIED.
pam_exec return code better reflects what went on:
o If the program exits with !0, the return code is now
PAM_PERM_DENIED, not PAM_SYSTEM_ERR.
o If the program fails because of a signal (WIFSIGNALED) or doesn't
terminate normally (!WIFEXITED), the return code is now
PAM_SERVICE_ERR, not PAM_SYSTEM_ERR.
o If a syscall in pam_exec fails, the return code remains
PAM_SYSTEM_ERR.
waitpid(2) is called in a loop. If it returns because of EINTR, do it
again. Before, it would return PAM_SYSTEM_ERR without waiting for the
child to exit.
Several log messages now include the PAM service module function name.
The man page is updated accordingly.
Reviewed by: gleb@, des@
Sponsored by: Yakaz (http://www.yakaz.com)
MFC after: 2 weeks
Modified:
head/lib/libpam/modules/pam_exec/pam_exec.8
head/lib/libpam/modules/pam_exec/pam_exec.c
Modified: head/lib/libpam/modules/pam_exec/pam_exec.8
==============================================================================
--- head/lib/libpam/modules/pam_exec/pam_exec.8 Mon Mar 26 11:48:47 2012
(r233506)
+++ head/lib/libpam/modules/pam_exec/pam_exec.8 Mon Mar 26 12:18:15 2012
(r233507)
@@ -32,7 +32,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd February 1, 2005
+.Dd February 8, 2012
.Dt PAM_EXEC 8
.Os
.Sh NAME
@@ -45,9 +45,25 @@
.Pa pam_exec
.Op Ar arguments
.Sh DESCRIPTION
-The exec service module for PAM executes the program designated by its
-first argument, with its remaining arguments as command-line
-arguments.
+The exec service module for PAM executes the program designated by
+its first argument if no options are specified, with its remaining
+arguments as command-line arguments.
+If options are specified, the program and its arguments follow the last
+option or
+.Cm --
+if the program name conflicts with an option name.
+.Pp
+The following options may be passed before the program and its
+arguments:
+.Bl -tag -width ".Cm return_prog_exit_status"
+.It Cm return_prog_exit_status
+Use the program exit status as the return code of the pam_sm_* function.
+It must be a valid return value for this function.
+.It Cm --
+Stop options parsing;
+program and its arguments follow.
+.El
+.Pp
The child's environment is set to the current PAM environment list,
as returned by
.Xr pam_getenvlist 3 .
@@ -56,13 +72,69 @@ variables:
.Ev PAM_RHOST ,
.Ev PAM_RUSER ,
.Ev PAM_SERVICE ,
-.Ev PAM_TTY ,
+.Ev PAM_SM_FUNC ,
+.Ev PAM_TTY
and
.Ev PAM_USER .
+.Pp
+The
+.Ev PAM_SM_FUNC
+variable contains the name of the PAM service module function being
+called.
+It may be:
+.Bl -dash -offset indent -compact
+.It
+pam_sm_acct_mgmt
+.It
+pam_sm_authenticate
+.It
+pam_sm_chauthtok
+.It
+pam_sm_close_session
+.It
+pam_sm_open_session
+.It
+pam_sm_setcred
+.El
+.Pp
+If
+.Cm return_prog_exit_status
+is not set (default), the
+.Ev PAM_SM_FUNC
+function returns
+.Er PAM_SUCCESS
+if the program exit status is 0,
+.Er PAM_PERM_DENIED
+otherwise.
+.Pp
+If
+.Cm return_prog_exit_status
+is set, the program exit status is used.
+It should be
+.Er PAM_SUCCESS
+or one of the error codes allowed by the calling
+.Ev PAM_SM_FUNC
+function.
+The valid codes are documented in each function man page.
+If the exit status is not a valid return code,
+.Er PAM_SERVICE_ERR
+is returned.
+Each valid codes numerical value is available as an environment variable
+(eg.\&
+.Ev PAM_SUCESS ,
+.Ev PAM_USER_UNKNOWN ,
+etc).
+This is useful in shell scripts for instance.
.Sh SEE ALSO
.Xr pam_get_item 3 ,
.Xr pam.conf 5 ,
-.Xr pam 8
+.Xr pam 8 ,
+.Xr pam_sm_acct_mgmt 8 ,
+.Xr pam_sm_authenticate 8 ,
+.Xr pam_sm_chauthtok 8,
+.Xr pam_sm_close_session 8 ,
+.Xr pam_sm_open_session 8 ,
+.Xr pam_sm_setcred 8 .
.Sh AUTHORS
The
.Nm
Modified: head/lib/libpam/modules/pam_exec/pam_exec.c
==============================================================================
--- head/lib/libpam/modules/pam_exec/pam_exec.c Mon Mar 26 11:48:47 2012
(r233506)
+++ head/lib/libpam/modules/pam_exec/pam_exec.c Mon Mar 26 12:18:15 2012
(r233507)
@@ -60,32 +60,71 @@ static struct {
ENV_ITEM(PAM_RUSER),
};
+#define PAM_RV_COUNT 24
+
static int
-_pam_exec(pam_handle_t *pamh __unused, int flags __unused,
- int argc, const char *argv[])
+_pam_exec(pam_handle_t *pamh __unused,
+ const char *func, int flags __unused, int argc, const char *argv[])
{
- int envlen, i, nitems, pam_err, status;
- char *env, **envlist, **tmp;
+ int envlen, i, nitems, pam_err, status, return_prog_exit_status;
+ int nitems_rv;
+ char *env, **envlist, **tmp, *envstr;
volatile int childerr;
pid_t pid;
- if (argc < 1)
- return (PAM_SERVICE_ERR);
-
/*
* XXX For additional credit, divert child's stdin/stdout/stderr
* to the conversation function.
*/
/*
- * Set up the child's environment list. It consists of the PAM
- * environment, plus a few hand-picked PAM items.
+ * 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
+ */
+ 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);
+ return_prog_exit_status = 1;
+ } else {
+ if (strcmp(argv[i], "--") == 0) {
+ argc--;
+ argv++;
+ }
+
+ break;
+ }
+ }
+
+ argc -= i;
+ argv += i;
+
+ /* 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);
- tmp = realloc(envlist, (envlen + nitems + 1) * sizeof(*envlist));
+ /* Count PAM return values put in the environment. */
+ nitems_rv = 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);
@@ -93,7 +132,6 @@ _pam_exec(pam_handle_t *pamh __unused, i
envlist = tmp;
for (i = 0; i < nitems; ++i) {
const void *item;
- char *envstr;
pam_err = pam_get_item(pamh, env_items[i].item, &item);
if (pam_err != PAM_SUCCESS || item == NULL)
@@ -107,10 +145,59 @@ _pam_exec(pam_handle_t *pamh __unused, i
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 (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 code from the command.
+ * exit status from the command.
*/
childerr = 0;
if ((pid = vfork()) == 0) {
@@ -120,81 +207,246 @@ _pam_exec(pam_handle_t *pamh __unused, i
}
openpam_free_envlist(envlist);
if (pid == -1) {
- openpam_log(PAM_LOG_ERROR, "vfork(): %m");
+ openpam_log(PAM_LOG_ERROR, "%s: vfork(): %m", func);
return (PAM_SYSTEM_ERR);
}
- if (waitpid(pid, &status, 0) == -1) {
- openpam_log(PAM_LOG_ERROR, "waitpid(): %m");
+ 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, "execve(): %m");
+ openpam_log(PAM_LOG_ERROR, "%s: execve(): %m", func);
return (PAM_SYSTEM_ERR);
}
if (WIFSIGNALED(status)) {
- openpam_log(PAM_LOG_ERROR, "%s caught signal %d%s",
- argv[0], WTERMSIG(status),
+ openpam_log(PAM_LOG_ERROR, "%s: %s caught signal %d%s",
+ func, argv[0], WTERMSIG(status),
WCOREDUMP(status) ? " (core dumped)" : "");
- return (PAM_SYSTEM_ERR);
+ return (PAM_SERVICE_ERR);
}
if (!WIFEXITED(status)) {
- openpam_log(PAM_LOG_ERROR, "unknown status 0x%x", status);
- return (PAM_SYSTEM_ERR);
+ openpam_log(PAM_LOG_ERROR, "%s: unknown status 0x%x",
+ func, status);
+ return (PAM_SERVICE_ERR);
}
- if (WEXITSTATUS(status) != 0) {
- openpam_log(PAM_LOG_ERROR, "%s returned code %d",
- argv[0], WEXITSTATUS(status));
- return (PAM_SYSTEM_ERR);
+
+ if (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);
}
- return (PAM_SUCCESS);
}
PAM_EXTERN int
pam_sm_authenticate(pam_handle_t *pamh, int flags,
int argc, const char *argv[])
{
+ int ret;
+
+ ret = _pam_exec(pamh, __func__, flags, argc, argv);
- return (_pam_exec(pamh, flags, argc, argv));
+ /*
+ * 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;
- return (_pam_exec(pamh, flags, argc, argv));
+ ret = _pam_exec(pamh, __func__, flags, argc, argv);
+
+ /*
+ * 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;
+
+ ret = _pam_exec(pamh, __func__, flags, argc, argv);
- return (_pam_exec(pamh, flags, argc, argv));
+ /*
+ * 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;
+
+ ret = _pam_exec(pamh, __func__, flags, argc, argv);
- return (_pam_exec(pamh, flags, argc, argv));
+ /*
+ * 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;
+
+ ret = _pam_exec(pamh, __func__, flags, argc, argv);
+
+ /*
+ * 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 (_pam_exec(pamh, flags, argc, argv));
+ return (ret);
}
PAM_EXTERN int
pam_sm_chauthtok(pam_handle_t *pamh, int flags,
int argc, const char *argv[])
{
+ int ret;
+
+ ret = _pam_exec(pamh, __func__, flags, argc, argv);
+
+ /*
+ * 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 (_pam_exec(pamh, flags, argc, argv));
+ return (ret);
}
PAM_MODULE_ENTRY("pam_exec");
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
