* nonlocal-passwd.c
* passwd database for nss_nonlocal proxy.
*
- * Copyright © 2007 Anders Kaseorg <andersk@mit.edu> and Tim Abbott
- * <tabbott@mit.edu>
+ * Copyright © 2007–2010 Anders Kaseorg <andersk@mit.edu> and Tim
+ * Abbott <tabbott@mit.edu>
*
- * Permission is hereby granted, free of charge, to any person
- * obtaining a copy of this software and associated documentation
- * files (the "Software"), to deal in the Software without
- * restriction, including without limitation the rights to use, copy,
- * modify, merge, publish, distribute, sublicense, and/or sell copies
- * of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
+ * This file is part of nss_nonlocal.
*
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
+ * nss_nonlocal is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
*
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
- * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
- * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
+ * nss_nonlocal is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with nss_nonlocal; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
*/
#define _GNU_SOURCE
+
#include <sys/types.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <string.h>
#include <dlfcn.h>
-#include <stdio.h>
-#include <syslog.h>
#include <errno.h>
-#include <pwd.h>
-#include <grp.h>
#include <nss.h>
+#include <pwd.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include <unistd.h>
+
#include "nsswitch-internal.h"
#include "nonlocal.h"
char *buffer, size_t buflen, int *errnop);
-static service_user *
-nss_passwd_nonlocal_database(void)
+static service_user *__nss_passwd_nonlocal_database;
+
+static int
+internal_function
+__nss_passwd_nonlocal_lookup(service_user **ni, const char *fct_name,
+ void **fctp)
{
- static service_user *nip = NULL;
- if (nip == NULL)
- __nss_database_lookup("passwd_nonlocal", NULL, "", &nip);
+ if (__nss_passwd_nonlocal_database == NULL
+ && __nss_database_lookup("passwd_nonlocal", NULL, NULL,
+ &__nss_passwd_nonlocal_database) < 0)
+ return -1;
+
+ *ni = __nss_passwd_nonlocal_database;
- return nip;
+ *fctp = __nss_lookup_function(*ni, fct_name);
+ return 0;
}
enum nss_status
check_nonlocal_uid(const char *user, uid_t uid, int *errnop)
{
- static const char *fct_name = "getpwuid_r";
- static service_user *startp = NULL;
- static void *fct_start = NULL;
enum nss_status status;
- service_user *nip;
- union {
- enum nss_status (*l)(uid_t uid, struct passwd *pwd,
- char *buffer, size_t buflen, int *errnop);
- void *ptr;
- } fct;
struct passwd pwbuf;
- int old_errno = errno;
-
- int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
- char *buf = malloc(buflen);
- if (buf == NULL) {
- *errnop = ENOMEM;
- errno = old_errno;
- return NSS_STATUS_TRYAGAIN;
- }
-
- if (fct_start == NULL &&
- __nss_passwd_lookup(&startp, fct_name, &fct_start) != 0) {
- free(buf);
- return NSS_STATUS_UNAVAIL;
- }
- nip = startp;
- fct.ptr = fct_start;
- do {
- morebuf:
- if (fct.l == _nss_nonlocal_getpwuid_r)
- status = NSS_STATUS_NOTFOUND;
- else
- status = DL_CALL_FCT(fct.l, (uid, &pwbuf, buf, buflen, errnop));
- if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) {
- free(buf);
- buflen *= 2;
- buf = malloc(buflen);
- if (buf == NULL) {
- *errnop = ENOMEM;
- errno = old_errno;
- return NSS_STATUS_TRYAGAIN;
- }
- goto morebuf;
- }
- } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
+ char *buf;
+ size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ const struct walk_nss w = {
+ .lookup = &__nss_passwd_lookup, .fct_name = "getpwuid_r",
+ .status = &status, .errnop = errnop, .buf = &buf, .buflen = &buflen
+ };
+ const __typeof__(&_nss_nonlocal_getpwuid_r) self = &_nss_nonlocal_getpwuid_r;
+#define args (uid, &pwbuf, buf, buflen, errnop)
+#include "walk_nss.h"
+#undef args
if (status == NSS_STATUS_SUCCESS) {
syslog(LOG_ERR, "nss_nonlocal: possible spoofing attack: non-local user %s has same UID as local user %s!\n", user, pwbuf.pw_name);
+ free(buf);
status = NSS_STATUS_NOTFOUND;
} else if (status != NSS_STATUS_TRYAGAIN) {
status = NSS_STATUS_SUCCESS;
}
- free(buf);
return status;
}
enum nss_status
-check_nonlocal_user(const char *user, int *errnop)
+check_nonlocal_passwd(const char *user, struct passwd *pwd, int *errnop)
{
- static const char *fct_name = "getpwnam_r";
- static service_user *startp = NULL;
- static void *fct_start = NULL;
- enum nss_status status;
- service_user *nip;
- union {
- enum nss_status (*l)(const char *name, struct passwd *pwd,
- char *buffer, size_t buflen, int *errnop);
- void *ptr;
- } fct;
- struct passwd pwbuf;
+ enum nss_status status = NSS_STATUS_SUCCESS;
int old_errno = errno;
+ char *end;
+ unsigned long uid;
- int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
- char *buf = malloc(buflen);
- if (buf == NULL) {
- *errnop = ENOMEM;
+ errno = 0;
+ uid = strtoul(pwd->pw_name, &end, 10);
+ if (errno == 0 && *end == '\0' && (uid_t)uid == uid) {
+ errno = old_errno;
+ status = check_nonlocal_uid(user, uid, errnop);
+ } else {
errno = old_errno;
- return NSS_STATUS_TRYAGAIN;
}
+ if (status != NSS_STATUS_SUCCESS)
+ return status;
- if (fct_start == NULL &&
- __nss_passwd_lookup(&startp, fct_name, &fct_start) != 0) {
- free(buf);
- return NSS_STATUS_UNAVAIL;
- }
- nip = startp;
- fct.ptr = fct_start;
- do {
- morebuf:
- if (fct.l == _nss_nonlocal_getpwnam_r)
- status = NSS_STATUS_NOTFOUND;
- else
- status = DL_CALL_FCT(fct.l, (user, &pwbuf, buf, buflen, errnop));
- if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) {
- free(buf);
- buflen *= 2;
- buf = malloc(buflen);
- if (buf == NULL) {
- *errnop = ENOMEM;
- errno = old_errno;
- return NSS_STATUS_TRYAGAIN;
- }
- goto morebuf;
- }
- } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
+ return check_nonlocal_uid(user, pwd->pw_uid, errnop);
+}
- if (status == NSS_STATUS_SUCCESS)
+enum nss_status
+check_nonlocal_user(const char *user, int *errnop)
+{
+ enum nss_status status;
+ struct passwd pwbuf;
+ char *buf;
+ size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ const struct walk_nss w = {
+ .lookup = __nss_passwd_lookup, .fct_name = "getpwnam_r",
+ .status = &status, .errnop = errnop, .buf = &buf, .buflen = &buflen
+ };
+ const __typeof__(&_nss_nonlocal_getpwnam_r) self = &_nss_nonlocal_getpwnam_r;
+#define args (user, &pwbuf, buf, buflen, errnop)
+#include "walk_nss.h"
+#undef args
+
+ if (status == NSS_STATUS_SUCCESS) {
+ free(buf);
status = NSS_STATUS_NOTFOUND;
- else if (status != NSS_STATUS_TRYAGAIN)
+ } else if (status != NSS_STATUS_TRYAGAIN) {
status = NSS_STATUS_SUCCESS;
+ }
- free(buf);
return status;
}
+enum nss_status
+get_nonlocal_passwd(const char *name, struct passwd *pwd, char **buffer,
+ int *errnop)
+{
+ enum nss_status status;
+ size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ const struct walk_nss w = {
+ .lookup = __nss_passwd_nonlocal_lookup, .fct_name = "getpwnam_r",
+ .status = &status, .errnop = errnop, .buf = buffer, .buflen = &buflen
+ };
+ const __typeof__(&_nss_nonlocal_getpwnam_r) self = NULL;
+#define args (name, pwd, *buffer, buflen, errnop)
+#include "walk_nss.h"
+#undef args
+ return status;
+}
-static service_user *pwent_nip = NULL;
+
+static bool pwent_initialized = false;
+static service_user *pwent_startp, *pwent_nip;
static void *pwent_fct_start;
static union {
enum nss_status (*l)(struct passwd *pwd, char *buffer, size_t buflen,
enum nss_status
_nss_nonlocal_setpwent(int stayopen)
{
- static const char *fct_name = "setpwent";
- static void *fct_start = NULL;
enum nss_status status;
- service_user *nip;
- union {
- enum nss_status (*l)(int stayopen);
- void *ptr;
- } fct;
-
- nip = nss_passwd_nonlocal_database();
- if (nip == NULL)
- return NSS_STATUS_UNAVAIL;
- if (fct_start == NULL)
- fct_start = __nss_lookup_function(nip, fct_name);
- fct.ptr = fct_start;
- do {
- if (fct.ptr == NULL)
- status = NSS_STATUS_UNAVAIL;
- else
- status = DL_CALL_FCT(fct.l, (stayopen));
- } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
+ const struct walk_nss w = {
+ .lookup = &__nss_passwd_nonlocal_lookup, .fct_name = "setpwent",
+ .status = &status
+ };
+ const __typeof__(&_nss_nonlocal_setpwent) self = NULL;
+#define args (stayopen)
+#include "walk_nss.h"
+#undef args
if (status != NSS_STATUS_SUCCESS)
return status;
- pwent_nip = nip;
- if (pwent_fct_start == NULL)
- pwent_fct_start = __nss_lookup_function(nip, pwent_fct_name);
+ if (!pwent_initialized) {
+ __nss_passwd_nonlocal_lookup(&pwent_startp, pwent_fct_name,
+ &pwent_fct_start);
+ __sync_synchronize();
+ pwent_initialized = true;
+ }
+ pwent_nip = pwent_startp;
pwent_fct.ptr = pwent_fct_start;
return NSS_STATUS_SUCCESS;
}
enum nss_status
_nss_nonlocal_endpwent(void)
{
- static const char *fct_name = "endpwent";
- static void *fct_start = NULL;
enum nss_status status;
- service_user *nip;
- union {
- enum nss_status (*l)(void);
- void *ptr;
- } fct;
+ const struct walk_nss w = {
+ .lookup = &__nss_passwd_nonlocal_lookup, .fct_name = "endpwent",
+ .status = &status
+ };
+ const __typeof__(&_nss_nonlocal_endpwent) self = NULL;
pwent_nip = NULL;
- nip = nss_passwd_nonlocal_database();
- if (nip == NULL)
- return NSS_STATUS_UNAVAIL;
- if (fct_start == NULL)
- fct_start = __nss_lookup_function(nip, fct_name);
- fct.ptr = fct_start;
- do {
- if (fct.ptr == NULL)
- status = NSS_STATUS_UNAVAIL;
- else
- status = DL_CALL_FCT(fct.l, ());
- } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
+#define args ()
+#include "walk_nss.h"
+#undef args
return status;
}
do
status = DL_CALL_FCT(pwent_fct.l, (pwd, buffer, buflen, errnop));
while (status == NSS_STATUS_SUCCESS &&
- check_nonlocal_uid(pwd->pw_name, pwd->pw_uid, &nonlocal_errno) != NSS_STATUS_SUCCESS);
+ check_nonlocal_passwd(pwd->pw_name, pwd, &nonlocal_errno) != NSS_STATUS_SUCCESS);
}
if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
return status;
_nss_nonlocal_getpwnam_r(const char *name, struct passwd *pwd,
char *buffer, size_t buflen, int *errnop)
{
- static const char *fct_name = "getpwnam_r";
- static void *fct_start = NULL;
enum nss_status status;
- service_user *nip;
- union {
- enum nss_status (*l)(const char *name, struct passwd *pwd,
- char *buffer, size_t buflen, int *errnop);
- void *ptr;
- } fct;
int group_errno;
+ const struct walk_nss w = {
+ .lookup = __nss_passwd_nonlocal_lookup, .fct_name = "getpwnam_r",
+ .status = &status, .errnop = errnop
+ };
+ const __typeof__(&_nss_nonlocal_getpwnam_r) self = NULL;
char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
return NSS_STATUS_UNAVAIL;
- nip = nss_passwd_nonlocal_database();
- if (nip == NULL)
- return NSS_STATUS_UNAVAIL;
- if (fct_start == NULL)
- fct_start = __nss_lookup_function(nip, fct_name);
- fct.ptr = fct_start;
- do {
- if (fct.ptr == NULL)
- status = NSS_STATUS_UNAVAIL;
- else
- status = DL_CALL_FCT(fct.l, (name, pwd, buffer, buflen, errnop));
- if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
- break;
- } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
+#define args (name, pwd, buffer, buflen, errnop)
+#include "walk_nss.h"
+#undef args
if (status != NSS_STATUS_SUCCESS)
return status;
- status = check_nonlocal_uid(name, pwd->pw_uid, errnop);
+ if (strcmp(name, pwd->pw_name) != 0) {
+ syslog(LOG_ERR, "nss_nonlocal: discarding user %s from lookup for user %s\n", pwd->pw_name, name);
+ return NSS_STATUS_NOTFOUND;
+ }
+
+ status = check_nonlocal_passwd(name, pwd, errnop);
if (status != NSS_STATUS_SUCCESS)
return status;
- if (check_nonlocal_gid(name, pwd->pw_gid, &group_errno) !=
+ if (check_nonlocal_gid(name, NULL, pwd->pw_gid, &group_errno) !=
NSS_STATUS_SUCCESS)
pwd->pw_gid = 65534 /* nogroup */;
return NSS_STATUS_SUCCESS;
_nss_nonlocal_getpwuid_r(uid_t uid, struct passwd *pwd,
char *buffer, size_t buflen, int *errnop)
{
- static const char *fct_name = "getpwuid_r";
- static void *fct_start = NULL;
enum nss_status status;
- service_user *nip;
- union {
- enum nss_status (*l)(uid_t uid, struct passwd *pwd,
- char *buffer, size_t buflen, int *errnop);
- void *ptr;
- } fct;
int group_errno;
+ const struct walk_nss w = {
+ .lookup = &__nss_passwd_nonlocal_lookup, .fct_name = "getpwuid_r",
+ .status = &status, .errnop = errnop
+ };
+ const __typeof__(&_nss_nonlocal_getpwuid_r) self = NULL;
char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
return NSS_STATUS_UNAVAIL;
- nip = nss_passwd_nonlocal_database();
- if (nip == NULL)
- return NSS_STATUS_UNAVAIL;
- if (fct_start == NULL)
- fct_start = __nss_lookup_function(nip, fct_name);
- fct.ptr = fct_start;
- do {
- if (fct.ptr == NULL)
- status = NSS_STATUS_UNAVAIL;
- else
- status = DL_CALL_FCT(fct.l, (uid, pwd, buffer, buflen, errnop));
- if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
- break;
- } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
+#define args (uid, pwd, buffer, buflen, errnop)
+#include "walk_nss.h"
+#undef args
if (status != NSS_STATUS_SUCCESS)
return status;
- status = check_nonlocal_uid(pwd->pw_name, pwd->pw_uid, errnop);
+ if (uid != pwd->pw_uid) {
+ syslog(LOG_ERR, "nss_nonlocal: discarding uid %d from lookup for uid %d\n", pwd->pw_uid, uid);
+ return NSS_STATUS_NOTFOUND;
+ }
+
+ status = check_nonlocal_passwd(pwd->pw_name, pwd, errnop);
if (status != NSS_STATUS_SUCCESS)
return status;
- if (check_nonlocal_gid(pwd->pw_name, pwd->pw_gid, &group_errno) !=
+ if (check_nonlocal_gid(pwd->pw_name, NULL, pwd->pw_gid, &group_errno) !=
NSS_STATUS_SUCCESS)
pwd->pw_gid = 65534 /* nogroup */;
return NSS_STATUS_SUCCESS;
andersk / nss_nonlocal.git / blobdiff