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-rw-r--r--modules/pam_wheel/pam_wheel.c300
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diff --git a/modules/pam_wheel/pam_wheel.c b/modules/pam_wheel/pam_wheel.c
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+/*
+ * pam_wheel module
+ *
+ * Written by Cristian Gafton <gafton@redhat.com> 1996/09/10
+ * See the end of the file for Copyright Information
+ *
+ *
+ * 1.2 - added 'deny' and 'group=' options
+ * 1.1 - added 'trust' option
+ * 1.0 - the code is working for at least another person, so... :-)
+ * 0.1 - use vsyslog instead of vfprintf/syslog in _pam_log
+ * - return PAM_IGNORE on success (take care of sloppy sysadmins..)
+ * - use pam_get_user instead of pam_get_item(...,PAM_USER,...)
+ * - a new arg use_uid to auth the current uid instead of the
+ * initial (logged in) one.
+ * 0.0 - first release
+ *
+ * TODO:
+ * - try to use make_remark from pam_unix/support.c
+ * - consider returning on failure PAM_FAIL_NOW if the user is not
+ * a wheel member.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <syslog.h>
+#include <stdarg.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <grp.h>
+
+/*
+ * here, we make a definition for the externally accessible function
+ * in this file (this definition is required for static a module
+ * but strongly encouraged generally) it is used to instruct the
+ * modules include file to define the function prototypes.
+ */
+
+#include <security/pam_modules.h>
+#include <security/pam_modutil.h>
+#include <security/pam_ext.h>
+#include "pam_inline.h"
+
+/* checks if a user is on a list of members of the GID 0 group */
+static int is_on_list(char * const *list, const char *member)
+{
+ while (list && *list) {
+ if (strcmp(*list, member) == 0)
+ return 1;
+ list++;
+ }
+ return 0;
+}
+
+/* argument parsing */
+
+#define PAM_DEBUG_ARG 0x0001
+#define PAM_USE_UID_ARG 0x0002
+#define PAM_TRUST_ARG 0x0004
+#define PAM_DENY_ARG 0x0010
+#define PAM_ROOT_ONLY_ARG 0x0020
+
+static int
+_pam_parse (const pam_handle_t *pamh, int argc, const char **argv,
+ char *use_group, size_t group_length)
+{
+ int ctrl=0;
+
+ memset(use_group, '\0', group_length);
+
+ /* step through arguments */
+ for (ctrl=0; argc-- > 0; ++argv) {
+ const char *str;
+
+ /* generic options */
+
+ if (!strcmp(*argv,"debug"))
+ ctrl |= PAM_DEBUG_ARG;
+ else if (!strcmp(*argv,"use_uid"))
+ ctrl |= PAM_USE_UID_ARG;
+ else if (!strcmp(*argv,"trust"))
+ ctrl |= PAM_TRUST_ARG;
+ else if (!strcmp(*argv,"deny"))
+ ctrl |= PAM_DENY_ARG;
+ else if (!strcmp(*argv,"root_only"))
+ ctrl |= PAM_ROOT_ONLY_ARG;
+ else if ((str = pam_str_skip_prefix(*argv, "group=")) != NULL)
+ strncpy(use_group, str, group_length - 1);
+ else {
+ pam_syslog(pamh, LOG_ERR, "unknown option: %s", *argv);
+ }
+ }
+
+ return ctrl;
+}
+
+static int
+perform_check (pam_handle_t *pamh, int ctrl, const char *use_group)
+{
+ const char *username = NULL;
+ const char *fromsu;
+ struct passwd *pwd, *tpwd = NULL;
+ struct group *grp;
+ int retval = PAM_AUTH_ERR;
+
+ retval = pam_get_user(pamh, &username, NULL);
+ if (retval != PAM_SUCCESS) {
+ if (ctrl & PAM_DEBUG_ARG) {
+ pam_syslog(pamh, LOG_DEBUG, "cannot determine user name: %s",
+ pam_strerror(pamh, retval));
+ }
+ return PAM_SERVICE_ERR;
+ }
+
+ pwd = pam_modutil_getpwnam (pamh, username);
+ if (!pwd) {
+ if (ctrl & PAM_DEBUG_ARG) {
+ pam_syslog(pamh, LOG_NOTICE, "unknown user %s", username);
+ }
+ return PAM_USER_UNKNOWN;
+ }
+ if (ctrl & PAM_ROOT_ONLY_ARG) {
+ /* su to a non uid 0 account ? */
+ if (pwd->pw_uid != 0) {
+ return PAM_IGNORE;
+ }
+ }
+
+ if (ctrl & PAM_USE_UID_ARG) {
+ tpwd = pam_modutil_getpwuid (pamh, getuid());
+ if (!tpwd) {
+ if (ctrl & PAM_DEBUG_ARG) {
+ pam_syslog(pamh, LOG_NOTICE, "who is running me ?!");
+ }
+ return PAM_SERVICE_ERR;
+ }
+ fromsu = tpwd->pw_name;
+ } else {
+ fromsu = pam_modutil_getlogin(pamh);
+ if (fromsu) {
+ tpwd = pam_modutil_getpwnam (pamh, fromsu);
+ }
+ if (!fromsu || !tpwd) {
+ if (ctrl & PAM_DEBUG_ARG) {
+ pam_syslog(pamh, LOG_NOTICE, "who is running me ?!");
+ }
+ return PAM_SERVICE_ERR;
+ }
+ }
+
+ /*
+ * At this point fromsu = username-of-invoker; tpwd = pwd ptr for fromsu
+ */
+
+ if (!use_group[0]) {
+ if ((grp = pam_modutil_getgrnam (pamh, "wheel")) == NULL) {
+ grp = pam_modutil_getgrgid (pamh, 0);
+ }
+ } else {
+ grp = pam_modutil_getgrnam (pamh, use_group);
+ }
+
+ if (!grp || (!grp->gr_mem && (tpwd->pw_gid != grp->gr_gid))) {
+ if (ctrl & PAM_DEBUG_ARG) {
+ if (!use_group[0]) {
+ pam_syslog(pamh, LOG_NOTICE, "no members in a GID 0 group");
+ } else {
+ pam_syslog(pamh, LOG_NOTICE,
+ "no members in '%s' group", use_group);
+ }
+ }
+ if (ctrl & PAM_DENY_ARG) {
+ /* if this was meant to deny access to the members
+ * of this group and the group does not exist, allow
+ * access
+ */
+ return PAM_IGNORE;
+ } else {
+ return PAM_AUTH_ERR;
+ }
+ }
+
+ /*
+ * test if the user is a member of the group, or if the
+ * user has the "wheel" (sic) group as its primary group.
+ */
+
+ if (is_on_list(grp->gr_mem, fromsu) || (tpwd->pw_gid == grp->gr_gid)) {
+
+ if (ctrl & PAM_DENY_ARG) {
+ retval = PAM_PERM_DENIED;
+
+ } else if (ctrl & PAM_TRUST_ARG) {
+ retval = PAM_SUCCESS; /* this can be a sufficient check */
+
+ } else {
+ retval = PAM_IGNORE;
+ }
+
+ } else {
+
+ if (ctrl & PAM_DENY_ARG) {
+
+ if (ctrl & PAM_TRUST_ARG) {
+ retval = PAM_SUCCESS; /* this can be a sufficient check */
+ } else {
+ retval = PAM_IGNORE;
+ }
+
+ } else {
+ retval = PAM_PERM_DENIED;
+ }
+ }
+
+ if (ctrl & PAM_DEBUG_ARG) {
+ if (retval == PAM_IGNORE) {
+ pam_syslog(pamh, LOG_NOTICE,
+ "Ignoring access request '%s' for '%s'",
+ fromsu, username);
+ } else {
+ pam_syslog(pamh, LOG_NOTICE, "Access %s to '%s' for '%s'",
+ (retval != PAM_SUCCESS) ? "denied":"granted",
+ fromsu, username);
+ }
+ }
+
+ return retval;
+}
+
+/* --- authentication management functions --- */
+
+int
+pam_sm_authenticate (pam_handle_t *pamh, int flags UNUSED,
+ int argc, const char **argv)
+{
+ char use_group[BUFSIZ];
+ int ctrl;
+
+ ctrl = _pam_parse(pamh, argc, argv, use_group, sizeof(use_group));
+
+ return perform_check(pamh, ctrl, use_group);
+}
+
+int
+pam_sm_setcred (pam_handle_t *pamh UNUSED, int flags UNUSED,
+ int argc UNUSED, const char **argv UNUSED)
+{
+ return PAM_SUCCESS;
+}
+
+int
+pam_sm_acct_mgmt (pam_handle_t *pamh, int flags UNUSED,
+ int argc, const char **argv)
+{
+ char use_group[BUFSIZ];
+ int ctrl;
+
+ ctrl = _pam_parse(pamh, argc, argv, use_group, sizeof(use_group));
+
+ return perform_check(pamh, ctrl, use_group);
+}
+
+/*
+ * Copyright (c) Cristian Gafton <gafton@redhat.com>, 1996, 1997
+ * All rights reserved
+ *
+ * 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, and the entire permission notice in its entirety,
+ * including the disclaimer of warranties.
+ * 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.
+ *
+ * ALTERNATIVELY, this product may be distributed under the terms of
+ * the GNU Public License, in which case the provisions of the GPL are
+ * required INSTEAD OF the above restrictions. (This clause is
+ * necessary due to a potential bad interaction between the GPL and
+ * the restrictions contained in a BSD-style copyright.)
+ *
+ * THIS SOFTWARE IS PROVIDED `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 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.
+ */
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