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c5f8dc95c6f73274dcd213176d7429bbbd98bd7d
sudo/plugins/sudoers/auth/sudo_auth.c
Todd C. Miller c5f8dc95c6 Fix a PAM_USER mismatch in session open/close. We update PAM_USER 
to the target user immediately before setting resource limits, which
is after the monitor process has forked (so it has the old value).
Also, if the user did not authenticate, there is no pamh in the
monitor so we need to init pam here too.  This means we end up
calling pam_start() twice, which should be fixed, but at least the
session is always properly closed now.
2011-09-27 11:13:44 -04:00

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/*
* Copyright (c) 1999-2005, 2008-2010 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 <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
# 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 <time.h>
#include <signal.h>
#include "sudoers.h"
#include "sudo_auth.h"
#include "insults.h"
static sudo_auth auth_switch[] = {
/* Standalone entries first */
#ifdef HAVE_PAM
AUTH_ENTRY("pam", FLAG_STANDALONE, pam_init, NULL, pam_verify, pam_cleanup, pam_begin_session, pam_end_session)
#endif
#ifdef HAVE_SECURID
AUTH_ENTRY("SecurId", FLAG_STANDALONE, securid_init, securid_setup, securid_verify, NULL, NULL, NULL)
#endif
#ifdef HAVE_SIA_SES_INIT
AUTH_ENTRY("sia", FLAG_STANDALONE, NULL, sia_setup, sia_verify, sia_cleanup, NULL, NULL)
#endif
#ifdef HAVE_AIXAUTH
AUTH_ENTRY("aixauth", FLAG_STANDALONE, NULL, NULL, aixauth_verify, aixauth_cleanup, NULL, NULL)
#endif
#ifdef HAVE_FWTK
AUTH_ENTRY("fwtk", FLAG_STANDALONE, fwtk_init, NULL, fwtk_verify, fwtk_cleanup, NULL, NULL)
#endif
#ifdef HAVE_BSD_AUTH_H
AUTH_ENTRY("bsdauth", FLAG_STANDALONE, bsdauth_init, NULL, bsdauth_verify, bsdauth_cleanup, NULL, NULL)
#endif
/* Non-standalone entries */
#ifndef WITHOUT_PASSWD
AUTH_ENTRY("passwd", 0, passwd_init, NULL, passwd_verify, passwd_cleanup, NULL, NULL)
#endif
#if defined(HAVE_GETPRPWNAM) && !defined(WITHOUT_PASSWD)
AUTH_ENTRY("secureware", 0, secureware_init, NULL, secureware_verify, secureware_cleanup, NULL, NULL)
#endif
#ifdef HAVE_AFS
AUTH_ENTRY("afs", 0, NULL, NULL, afs_verify, NULL, NULL, NULL)
#endif
#ifdef HAVE_DCE
AUTH_ENTRY("dce", 0, NULL, NULL, dce_verify, NULL, NULL, NULL)
#endif
#ifdef HAVE_KERB4
AUTH_ENTRY("kerb4", 0, kerb4_init, NULL, kerb4_verify, NULL, NULL, NULL)
#endif
#ifdef HAVE_KERB5
AUTH_ENTRY("kerb5", 0, kerb5_init, NULL, kerb5_verify, kerb5_cleanup, NULL, NULL)
#endif
#ifdef HAVE_SKEY
AUTH_ENTRY("S/Key", 0, NULL, rfc1938_setup, rfc1938_verify, NULL, NULL, NULL)
#endif
#ifdef HAVE_OPIE
AUTH_ENTRY("OPIE", 0, NULL, rfc1938_setup, rfc1938_verify, NULL, NULL, NULL)
#endif
AUTH_ENTRY(NULL, 0, NULL, NULL, NULL, NULL, NULL, NULL)
};
extern char **NewArgv; /* XXX - for auditing */
static void pass_warn(void);
int
verify_user(struct passwd *pw, char *prompt)
{
int counter = def_passwd_tries + 1;
int success = AUTH_FAILURE;
int flags, status, standalone, rval;
char *p;
sudo_auth *auth;
sigaction_t sa, osa;
/* Enable suspend during password entry. */
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
sa.sa_handler = SIG_DFL;
(void) sigaction(SIGTSTP, &sa, &osa);
/* Make sure we have at least one auth method. */
if (auth_switch[0].name == NULL) {
audit_failure(NewArgv, "no authentication methods");
log_error(0,
_("There are no authentication methods compiled into sudo! "
"If you want to turn off authentication, use the "
"--disable-authentication configure option."));
return -1;
}
/* Make sure we haven't mixed standalone and shared auth methods. */
standalone = IS_STANDALONE(&auth_switch[0]);
if (standalone && auth_switch[1].name != NULL) {
audit_failure(NewArgv, "invalid authentication methods");
log_error(0, _("Invalid authentication methods compiled into sudo! "
"You may mix standalone and non-standalone authentication."));
return -1;
}
/* Set FLAG_ONEANDONLY if there is only one auth method. */
if (auth_switch[1].name == NULL)
SET(auth_switch[0].flags, FLAG_ONEANDONLY);
/* Initialize auth methods and unconfigure the method if necessary. */
for (auth = auth_switch; auth->name; auth++) {
if (auth->init && !IS_DISABLED(auth)) {
if (NEEDS_USER(auth))
set_perms(PERM_USER);
status = (auth->init)(pw, &prompt, auth);
if (status == AUTH_FAILURE)
SET(auth->flags, FLAG_DISABLED);
else if (status == AUTH_FATAL) { /* XXX log */
audit_failure(NewArgv, "authentication failure");
return -1; /* assume error msg already printed */
}
if (NEEDS_USER(auth))
restore_perms();
}
}
while (--counter) {
/* Do any per-method setup and unconfigure the method if needed */
for (auth = auth_switch; auth->name; auth++) {
if (auth->setup && !IS_DISABLED(auth)) {
if (NEEDS_USER(auth))
set_perms(PERM_USER);
status = (auth->setup)(pw, &prompt, auth);
if (status == AUTH_FAILURE)
SET(auth->flags, FLAG_DISABLED);
else if (status == AUTH_FATAL) {/* XXX log */
audit_failure(NewArgv, "authentication failure");
return -1; /* assume error msg already printed */
}
if (NEEDS_USER(auth))
restore_perms();
}
}
/* Get the password unless the auth function will do it for us */
if (standalone) {
p = prompt;
} else {
p = auth_getpass(prompt, def_passwd_timeout * 60,
SUDO_CONV_PROMPT_ECHO_OFF);
if (p == NULL)
break;
}
/* Call authentication functions. */
for (auth = auth_switch; auth->name; auth++) {
if (IS_DISABLED(auth))
continue;
if (NEEDS_USER(auth))
set_perms(PERM_USER);
success = auth->status = (auth->verify)(pw, p, auth);
if (NEEDS_USER(auth))
restore_perms();
if (auth->status != AUTH_FAILURE)
goto cleanup;
}
if (!standalone)
zero_bytes(p, strlen(p));
pass_warn();
}
cleanup:
/* Call cleanup routines. */
for (auth = auth_switch; auth->name; auth++) {
if (auth->cleanup && !IS_DISABLED(auth)) {
if (NEEDS_USER(auth))
set_perms(PERM_USER);
status = (auth->cleanup)(pw, auth);
if (status == AUTH_FATAL) { /* XXX log */
audit_failure(NewArgv, "authentication failure");
return -1; /* assume error msg already printed */
}
if (NEEDS_USER(auth))
restore_perms();
}
}
switch (success) {
case AUTH_SUCCESS:
(void) sigaction(SIGTSTP, &osa, NULL);
rval = TRUE;
break;
case AUTH_INTR:
case AUTH_FAILURE:
if (counter != def_passwd_tries) {
if (def_mail_badpass || def_mail_always)
flags = 0;
else
flags = NO_MAIL;
log_error(flags, ngettext("%d incorrect password attempt",
"%d incorrect password attempts",
def_passwd_tries - counter), def_passwd_tries - counter);
}
audit_failure(NewArgv, "authentication failure");
rval = FALSE;
break;
case AUTH_FATAL:
default:
audit_failure(NewArgv, "authentication failure");
rval = -1;
break;
}
return rval;
}
int auth_begin_session(struct passwd *pw)
{
sudo_auth *auth;
int status;
for (auth = auth_switch; auth->name; auth++) {
if (auth->begin_session && !IS_DISABLED(auth)) {
status = (auth->begin_session)(pw, auth);
if (status == AUTH_FATAL) { /* XXX log */
audit_failure(NewArgv, "authentication failure");
return -1; /* assume error msg already printed */
}
}
}
return TRUE;
}
int auth_end_session(struct passwd *pw)
{
sudo_auth *auth;
int status;
for (auth = auth_switch; auth->name; auth++) {
if (auth->end_session && !IS_DISABLED(auth)) {
status = (auth->end_session)(pw, auth);
if (status == AUTH_FATAL) { /* XXX log */
return -1; /* assume error msg already printed */
}
}
}
return TRUE;
}
static void
pass_warn(void)
{
const char *warning = def_badpass_message;
#ifdef INSULT
if (def_insults)
warning = INSULT;
#endif
sudo_printf(SUDO_CONV_ERROR_MSG, "%s\n", warning);
}
char *
auth_getpass(const char *prompt, int timeout, int type)
{
struct sudo_conv_message msg;
struct sudo_conv_reply repl;
/* Mask user input if pwfeedback set and echo is off. */
if (type == SUDO_CONV_PROMPT_ECHO_OFF && def_pwfeedback)
type = SUDO_CONV_PROMPT_MASK;
/* If visiblepw set, do not error out if there is no tty. */
if (def_visiblepw)
type |= SUDO_CONV_PROMPT_ECHO_OK;
/* Call conversation function */
memset(&msg, 0, sizeof(msg));
msg.msg_type = type;
msg.timeout = def_passwd_timeout * 60;
msg.msg = prompt;
memset(&repl, 0, sizeof(repl));
sudo_conv(1, &msg, &repl);
/* XXX - check for ENOTTY? */
return repl.reply;
}
void
dump_auth_methods(void)
{
sudo_auth *auth;
sudo_printf(SUDO_CONV_INFO_MSG, _("Authentication methods:"));
for (auth = auth_switch; auth->name; auth++)
sudo_printf(SUDO_CONV_INFO_MSG, " '%s'", auth->name);
sudo_printf(SUDO_CONV_INFO_MSG, "\n");
}
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