* 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
*/
#include "nsswitch-internal.h"
#include "nonlocal.h"
-#define MAGIC_LOCAL_PW_BUFLEN (sysconf(_SC_GETPW_R_SIZE_MAX) + 7)
+
+enum nss_status
+_nss_nonlocal_getpwuid_r(uid_t uid, struct passwd *pwd,
+ char *buffer, size_t buflen, int *errnop);
+enum nss_status
+_nss_nonlocal_getpwnam_r(const char *name, struct passwd *pwd,
+ char *buffer, size_t buflen, int *errnop);
static service_user *
enum nss_status
check_nonlocal_uid(const char *user, uid_t uid, int *errnop)
{
- enum nss_status status = NSS_STATUS_SUCCESS;
+ 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;
- struct passwd *pwbufp = &pwbuf;
- int ret;
int old_errno = errno;
- int buflen = MAGIC_LOCAL_PW_BUFLEN;
+
+ size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
char *buf = malloc(buflen);
if (buf == NULL) {
*errnop = ENOMEM;
errno = old_errno;
return NSS_STATUS_TRYAGAIN;
}
- errno = 0;
- ret = getpwuid_r(uid, pwbufp, buf, buflen, &pwbufp);
- if (ret != 0) {
- *errnop = errno;
- status = NSS_STATUS_TRYAGAIN;
- } else if (pwbufp != NULL) {
+
+ 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);
+
+ 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);
status = NSS_STATUS_NOTFOUND;
+ } else if (status != NSS_STATUS_TRYAGAIN) {
+ status = NSS_STATUS_SUCCESS;
}
+
free(buf);
- errno = old_errno;
return status;
}
enum nss_status
-check_nonlocal_user(const char *user, int *errnop)
+check_nonlocal_passwd(const char *user, struct passwd *pwd, int *errnop)
{
enum nss_status status = NSS_STATUS_SUCCESS;
+ int old_errno = errno;
+ char *end;
+ unsigned long uid;
+
+ errno = 0;
+ uid = strtoul(pwd->pw_name, &end, 10);
+ if (errno == 0 && *end == '\0' && (uid_t)uid == uid)
+ status = check_nonlocal_uid(user, uid, errnop);
+ errno = old_errno;
+ if (status != NSS_STATUS_SUCCESS)
+ return status;
+
+ return check_nonlocal_uid(user, pwd->pw_uid, errnop);
+}
+
+enum nss_status
+check_nonlocal_user(const char *user, 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;
- struct passwd *pwbufp = &pwbuf;
- int ret;
int old_errno = errno;
- int buflen = MAGIC_LOCAL_PW_BUFLEN;
+
+ size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
char *buf = malloc(buflen);
if (buf == NULL) {
*errnop = ENOMEM;
errno = old_errno;
return NSS_STATUS_TRYAGAIN;
}
- errno = 0;
- ret = getpwnam_r(user, pwbufp, buf, buflen, &pwbufp);
- if (ret != 0) {
- *errnop = errno;
- status = NSS_STATUS_TRYAGAIN;
- } else if (pwbufp != NULL) {
- status = NSS_STATUS_NOTFOUND;
+
+ 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);
+
+ if (status == NSS_STATUS_SUCCESS)
+ status = NSS_STATUS_NOTFOUND;
+ else if (status != NSS_STATUS_TRYAGAIN)
+ status = NSS_STATUS_SUCCESS;
+
free(buf);
- errno = old_errno;
return status;
}
enum nss_status status;
char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
- if (buflen == MAGIC_LOCAL_PW_BUFLEN ||
- (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0'))
+ if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
return NSS_STATUS_UNAVAIL;
if (pwent_nip == NULL) {
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;
int group_errno;
char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
- if (buflen == MAGIC_LOCAL_PW_BUFLEN ||
- (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0'))
+ if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
return NSS_STATUS_UNAVAIL;
nip = nss_passwd_nonlocal_database();
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;
int group_errno;
char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
- if (buflen == MAGIC_LOCAL_PW_BUFLEN ||
- (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0'))
+ if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
return NSS_STATUS_UNAVAIL;
nip = nss_passwd_nonlocal_database();
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;
andersk / nss_nonlocal.git / blobdiff