/*
passwd.c - password entry lookup routines
Parts of this file were part of the nss_ldap library (as ldap-pwd.c)
which has been forked into the nss-pam-ldapd library.
Copyright (C) 1997-2005 Luke Howard
Copyright (C) 2006 West Consulting
Copyright (C) 2006-2017 Arthur de Jong
This library 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.
This library 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 this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
#include "common.h"
#include "log.h"
#include "myldap.h"
#include "cfg.h"
#include "attmap.h"
#include "common/dict.h"
#include "compat/strndup.h"
/* ( nisSchema.2.0 NAME 'posixAccount' SUP top AUXILIARY
* DESC 'Abstraction of an account with POSIX attributes'
* MUST ( cn $ uid $ uidNumber $ gidNumber $ homeDirectory )
* MAY ( userPassword $ loginShell $ gecos $ description ) )
*/
/* the search base for searches */
const char *passwd_bases[NSS_LDAP_CONFIG_MAX_BASES] = { NULL };
/* the search scope for searches */
int passwd_scope = LDAP_SCOPE_DEFAULT;
/* the basic search filter for searches */
const char *passwd_filter = "(objectClass=posixAccount)";
/* the attributes used in searches */
const char *attmap_passwd_uid = "uid";
const char *attmap_passwd_userPassword = "\"*\"";
const char *attmap_passwd_uidNumber = "uidNumber";
const char *attmap_passwd_gidNumber = "gidNumber";
const char *attmap_passwd_gecos = "\"${gecos:-$cn}\"";
const char *attmap_passwd_homeDirectory = "homeDirectory";
const char *attmap_passwd_loginShell = "loginShell";
/* special properties for objectSid-based searches
(these are already LDAP-escaped strings) */
static char *uidSid = NULL;
static char *gidSid = NULL;
/* default values for attributes */
static const char *default_passwd_userPassword = "*"; /* unmatchable */
/* Note that the resulting password value should be one of:
<empty> - no password set, allow login without password
* - often used to prevent logins
x - "valid" encrypted password that does not match any valid password
often used to indicate that the password is defined elsewhere
other - encrypted password, usually in crypt(3) format */
/* the attribute list to request with searches */
static const char **passwd_attrs = NULL;
/* create a search filter for searching a passwd entry
by name, return -1 on errors */
static int mkfilter_passwd_byname(const char *name,
char *buffer, size_t buflen)
{
char safename[BUFLEN_SAFENAME];
/* escape attribute */
if (myldap_escape(name, safename, sizeof(safename)))
{
log_log(LOG_ERR, "mkfilter_passwd_byname(): safename buffer too small");
return -1;
}
/* build filter */
return mysnprintf(buffer, buflen, "(&%s(%s=%s))",
passwd_filter, attmap_passwd_uid, safename);
}
/* create a search filter for searching a passwd entry
by uid, return -1 on errors */
static int mkfilter_passwd_byuid(uid_t uid, char *buffer, size_t buflen)
{
uid -= nslcd_cfg->nss_uid_offset;
if (uidSid != NULL)
{
return mysnprintf(buffer, buflen, "(&%s(%s=%s\\%02x\\%02x\\%02x\\%02x))",
passwd_filter, attmap_passwd_uidNumber, uidSid,
(int)(uid & 0xff), (int)((uid >> 8) & 0xff),
(int)((uid >> 16) & 0xff), (int)((uid >> 24) & 0xff));
}
else
{
return mysnprintf(buffer, buflen, "(&%s(%s=%lu))",
passwd_filter, attmap_passwd_uidNumber, (unsigned long int)uid);
}
}
void passwd_init(void)
{
int i;
SET *set;
/* set up search bases */
if (passwd_bases[0] == NULL)
for (i = 0; i < NSS_LDAP_CONFIG_MAX_BASES; i++)
passwd_bases[i] = nslcd_cfg->bases[i];
/* set up scope */
if (passwd_scope == LDAP_SCOPE_DEFAULT)
passwd_scope = nslcd_cfg->scope;
/* special case when uidNumber or gidNumber reference objectSid */
if (strncasecmp(attmap_passwd_uidNumber, "objectSid:", 10) == 0)
{
uidSid = sid2search(attmap_passwd_uidNumber + 10);
attmap_passwd_uidNumber = strndup(attmap_passwd_uidNumber, 9);
}
if (strncasecmp(attmap_passwd_gidNumber, "objectSid:", 10) == 0)
{
gidSid = sid2search(attmap_passwd_gidNumber + 10);
attmap_passwd_gidNumber = strndup(attmap_passwd_gidNumber, 9);
}
/* set up attribute list */
set = set_new();
attmap_add_attributes(set, "objectClass"); /* for testing shadowAccount */
attmap_add_attributes(set, attmap_passwd_uid);
attmap_add_attributes(set, attmap_passwd_userPassword);
attmap_add_attributes(set, attmap_passwd_uidNumber);
attmap_add_attributes(set, attmap_passwd_gidNumber);
attmap_add_attributes(set, attmap_passwd_gecos);
attmap_add_attributes(set, attmap_passwd_homeDirectory);
attmap_add_attributes(set, attmap_passwd_loginShell);
passwd_attrs = set_tolist(set);
if (passwd_attrs == NULL)
{
log_log(LOG_CRIT, "malloc() failed to allocate memory");
exit(EXIT_FAILURE);
}
set_free(set);
}
/* the cache that is used in dn2uid() */
static pthread_mutex_t dn2uid_cache_mutex = PTHREAD_MUTEX_INITIALIZER;
static DICT *dn2uid_cache = NULL;
struct dn2uid_cache_entry {
time_t timestamp;
char *uid;
};
/* checks whether the entry has a valid uidNumber attribute
(>= nss_min_uid) */
static int entry_has_valid_uid(MYLDAP_ENTRY *entry)
{
int i;
const char **values;
char *tmp;
uid_t uid;
/* if min_uid is not set any entry should do */
if (nslcd_cfg->nss_min_uid == 0)
return 1;
/* get all uidNumber attributes */
values = myldap_get_values_len(entry, attmap_passwd_uidNumber);
if ((values == NULL) || (values[0] == NULL))
{
log_log(LOG_WARNING, "%s: %s: missing",
myldap_get_dn(entry), attmap_passwd_uidNumber);
return 0;
}
/* check if there is a uidNumber attributes >= min_uid */
for (i = 0; values[i] != NULL; i++)
{
if (uidSid != NULL)
uid = (uid_t)binsid2id(values[i]);
else
{
errno = 0;
uid = strtouid(values[i], &tmp, 10);
if ((*(values[i]) == '\0') || (*tmp != '\0'))
{
log_log(LOG_WARNING, "%s: %s: non-numeric",
myldap_get_dn(entry), attmap_passwd_uidNumber);
continue;
}
else if ((errno != 0) || (strchr(values[i], '-') != NULL))
{
log_log(LOG_WARNING, "%s: %s: out of range",
myldap_get_dn(entry), attmap_passwd_uidNumber);
continue;
}
}
if (uid < nslcd_cfg->nss_min_uid)
{
log_log(LOG_DEBUG, "%s: %s: less than nss_min_uid",
myldap_get_dn(entry), attmap_passwd_uidNumber);
}
else
return 1;
}
/* nothing found */
return 0;
}
/* Perform an LDAP lookup to translate the DN into a uid.
This function either returns NULL or a strdup()ed string. */
char *lookup_dn2uid(MYLDAP_SESSION *session, const char *dn, int *rcp,
char *buf, size_t buflen)
{
MYLDAP_SEARCH *search;
MYLDAP_ENTRY *entry;
static const char *attrs[3];
int rc = LDAP_SUCCESS;
const char **values;
char *uid = NULL;
if (rcp == NULL)
rcp = &rc;
/* we have to look up the entry */
attrs[0] = attmap_passwd_uid;
attrs[1] = attmap_passwd_uidNumber;
attrs[2] = NULL;
search = myldap_search(session, dn, LDAP_SCOPE_BASE, passwd_filter, attrs, rcp);
if (search == NULL)
{
log_log(LOG_WARNING, "%s: lookup error: %s", dn, ldap_err2string(*rcp));
return NULL;
}
entry = myldap_get_entry(search, rcp);
if (entry == NULL)
{
if (*rcp != LDAP_SUCCESS)
log_log(LOG_WARNING, "%s: lookup error: %s", dn, ldap_err2string(*rcp));
return NULL;
}
/* check the uidNumber attribute if min_uid is set */
if (entry_has_valid_uid(entry))
{
/* get uid (just use first one) */
values = myldap_get_values(entry, attmap_passwd_uid);
/* check the result for presence and validity */
if ((values != NULL) && (values[0] != NULL) &&
isvalidname(values[0]) && (strlen(values[0]) < buflen))
{
strcpy(buf, values[0]);
uid = buf;
}
}
/* clean up and return */
myldap_search_close(search);
return uid;
}
/* Translate the DN into a user name. This function tries several aproaches
at getting the user name, including looking in the DN for a uid attribute,
looking in the cache and falling back to looking up a uid attribute in a
LDAP query. */
char *dn2uid(MYLDAP_SESSION *session, const char *dn, char *buf, size_t buflen)
{
struct dn2uid_cache_entry *cacheentry = NULL;
char *uid;
/* check for empty string */
if ((dn == NULL) || (*dn == '\0'))
return NULL;
/* try to look up uid within DN string */
if (myldap_cpy_rdn_value(dn, attmap_passwd_uid, buf, buflen) != NULL)
{
/* check if it is valid */
if (!isvalidname(buf))
return NULL;
return buf;
}
/* if we don't use the cache, just lookup and return */
if ((nslcd_cfg->cache_dn2uid_positive == 0) && (nslcd_cfg->cache_dn2uid_negative == 0))
return lookup_dn2uid(session, dn, NULL, buf, buflen);
/* see if we have a cached entry */
pthread_mutex_lock(&dn2uid_cache_mutex);
if (dn2uid_cache == NULL)
dn2uid_cache = dict_new();
if ((dn2uid_cache != NULL) && ((cacheentry = dict_get(dn2uid_cache, dn)) != NULL))
{
if ((cacheentry->uid != NULL) && (strlen(cacheentry->uid) < buflen))
{
/* positive hit: if the cached entry is still valid, return that */
if ((nslcd_cfg->cache_dn2uid_positive > 0) &&
(time(NULL) < (cacheentry->timestamp + nslcd_cfg->cache_dn2uid_positive)))
{
strcpy(buf, cacheentry->uid);
pthread_mutex_unlock(&dn2uid_cache_mutex);
return buf;
}
}
else
{
/* negative hit: if the cached entry is still valid, return that */
if ((nslcd_cfg->cache_dn2uid_negative > 0) &&
(time(NULL) < (cacheentry->timestamp + nslcd_cfg->cache_dn2uid_negative)))
{
pthread_mutex_unlock(&dn2uid_cache_mutex);
return NULL;
}
}
}
pthread_mutex_unlock(&dn2uid_cache_mutex);
/* look up the uid using an LDAP query */
uid = lookup_dn2uid(session, dn, NULL, buf, buflen);
/* store the result in the cache */
pthread_mutex_lock(&dn2uid_cache_mutex);
/* try to get the entry from the cache here again because it could have
changed in the meantime */
cacheentry = dict_get(dn2uid_cache, dn);
if (cacheentry == NULL)
{
/* allocate a new entry in the cache */
cacheentry = (struct dn2uid_cache_entry *)malloc(sizeof(struct dn2uid_cache_entry));
if (cacheentry != NULL)
{
cacheentry->uid = NULL;
dict_put(dn2uid_cache, dn, cacheentry);
}
}
/* update the cache entry */
if (cacheentry != NULL)
{
cacheentry->timestamp = time(NULL);
/* copy the uid if needed */
if (cacheentry->uid == NULL)
cacheentry->uid = uid != NULL ? strdup(uid) : NULL;
else if ((uid == NULL) || (strcmp(cacheentry->uid, uid) != 0))
{
free(cacheentry->uid);
cacheentry->uid = uid != NULL ? strdup(uid) : NULL;
}
}
pthread_mutex_unlock(&dn2uid_cache_mutex);
/* copy the result into the buffer */
return uid;
}
MYLDAP_ENTRY *uid2entry(MYLDAP_SESSION *session, const char *uid, int *rcp)
{
MYLDAP_SEARCH *search = NULL;
MYLDAP_ENTRY *entry = NULL;
const char *base;
int i;
static const char *attrs[3];
char filter[BUFLEN_FILTER];
/* if it isn't a valid username, just bail out now */
if (!isvalidname(uid))
{
if (rcp != NULL)
*rcp = LDAP_INVALID_SYNTAX;
return NULL;
}
/* set up attributes (we don't need much) */
attrs[0] = attmap_passwd_uid;
attrs[1] = attmap_passwd_uidNumber;
attrs[2] = NULL;
/* we have to look up the entry */
mkfilter_passwd_byname(uid, filter, sizeof(filter));
for (i = 0; (i < NSS_LDAP_CONFIG_MAX_BASES) && ((base = passwd_bases[i]) != NULL); i++)
{
search = myldap_search(session, base, passwd_scope, filter, attrs, rcp);
if (search == NULL)
{
if ((rcp != NULL) && (*rcp == LDAP_SUCCESS))
*rcp = LDAP_NO_SUCH_OBJECT;
return NULL;
}
entry = myldap_get_entry(search, rcp);
if ((entry != NULL) && (entry_has_valid_uid(entry)))
return entry;
}
if ((rcp != NULL) && (*rcp == LDAP_SUCCESS))
*rcp = LDAP_NO_SUCH_OBJECT;
return NULL;
}
char *uid2dn(MYLDAP_SESSION *session, const char *uid, char *buf, size_t buflen)
{
MYLDAP_ENTRY *entry;
/* look up the entry */
entry = uid2entry(session, uid, NULL);
if (entry == NULL)
return NULL;
/* get DN */
return myldap_cpy_dn(entry, buf, buflen);
}
#ifndef NSS_FLAVOUR_GLIBC
/* only check nsswitch.conf for glibc */
#define check_nsswitch_reload()
#define shadow_uses_ldap() (1)
#endif /* NSS_FLAVOUR_GLIBC */
/* the maximum number of uidNumber attributes per entry */
#define MAXUIDS_PER_ENTRY 5
static int write_passwd(TFILE *fp, MYLDAP_ENTRY *entry, const char *requser,
const uid_t *requid, uid_t calleruid)
{
int32_t tmpint32;
const char **tmpvalues;
char *tmp;
const char **usernames;
const char *passwd;
uid_t uids[MAXUIDS_PER_ENTRY];
int numuids;
char gidbuf[32];
gid_t gid;
char gecos[1024];
char homedir[256];
char shell[64];
char passbuffer[BUFLEN_PASSWORDHASH];
int i, j;
/* get the usernames for this entry */
usernames = myldap_get_values(entry, attmap_passwd_uid);
if ((usernames == NULL) || (usernames[0] == NULL))
{
log_log(LOG_WARNING, "%s: %s: missing",
myldap_get_dn(entry), attmap_passwd_uid);
return 0;
}
/* if we are using shadow maps and this entry looks like it would return
shadow information, make the passwd entry indicate it */
if (myldap_has_objectclass(entry, "shadowAccount") && nsswitch_shadow_uses_ldap())
{
passwd = "x";
}
else
{
passwd = get_userpassword(entry, attmap_passwd_userPassword,
passbuffer, sizeof(passbuffer));
if ((passwd == NULL) || (calleruid != 0))
passwd = default_passwd_userPassword;
}
/* get the uids for this entry */
if (requid != NULL)
{
uids[0] = *requid;
numuids = 1;
}
else
{
tmpvalues = myldap_get_values_len(entry, attmap_passwd_uidNumber);
if ((tmpvalues == NULL) || (tmpvalues[0] == NULL))
{
log_log(LOG_WARNING, "%s: %s: missing",
myldap_get_dn(entry), attmap_passwd_uidNumber);
return 0;
}
for (numuids = 0; (numuids < MAXUIDS_PER_ENTRY) && (tmpvalues[numuids] != NULL); numuids++)
{
if (uidSid != NULL)
uids[numuids] = (uid_t)binsid2id(tmpvalues[numuids]);
else
{
errno = 0;
uids[numuids] = strtouid(tmpvalues[numuids], &tmp, 10);
if ((*(tmpvalues[numuids]) == '\0') || (*tmp != '\0'))
{
log_log(LOG_WARNING, "%s: %s: non-numeric",
myldap_get_dn(entry), attmap_passwd_uidNumber);
return 0;
}
else if ((errno != 0) || (strchr(tmpvalues[numuids], '-') != NULL))
{
log_log(LOG_WARNING, "%s: %s: out of range",
myldap_get_dn(entry), attmap_passwd_uidNumber);
return 0;
}
}
uids[numuids] += nslcd_cfg->nss_uid_offset;
if (uids[numuids] < nslcd_cfg->nss_min_uid)
{
log_log(LOG_DEBUG, "%s: %s: less than nss_min_uid",
myldap_get_dn(entry), attmap_passwd_uidNumber);
}
}
}
/* get the gid for this entry */
if (gidSid != NULL)
{
tmpvalues = myldap_get_values_len(entry, attmap_passwd_gidNumber);
if ((tmpvalues == NULL) || (tmpvalues[0] == NULL))
{
log_log(LOG_WARNING, "%s: %s: missing",
myldap_get_dn(entry), attmap_passwd_gidNumber);
return 0;
}
gid = (gid_t)binsid2id(tmpvalues[0]);
}
else
{
attmap_get_value(entry, attmap_passwd_gidNumber, gidbuf, sizeof(gidbuf));
if (gidbuf[0] == '\0')
{
log_log(LOG_WARNING, "%s: %s: missing",
myldap_get_dn(entry), attmap_passwd_gidNumber);
return 0;
}
errno = 0;
gid = strtogid(gidbuf, &tmp, 10);
if ((gidbuf[0] == '\0') || (*tmp != '\0'))
{
log_log(LOG_WARNING, "%s: %s: non-numeric",
myldap_get_dn(entry), attmap_passwd_gidNumber);
return 0;
}
else if ((errno != 0) || (strchr(gidbuf, '-') != NULL))
{
log_log(LOG_WARNING, "%s: %s: out of range",
myldap_get_dn(entry), attmap_passwd_gidNumber);
return 0;
}
}
gid += nslcd_cfg->nss_gid_offset;
/* get the gecos for this entry */
attmap_get_value(entry, attmap_passwd_gecos, gecos, sizeof(gecos));
/* get the home directory for this entry */
attmap_get_value(entry, attmap_passwd_homeDirectory, homedir, sizeof(homedir));
if (homedir[0] == '\0')
log_log(LOG_WARNING, "%s: %s: missing",
myldap_get_dn(entry), attmap_passwd_homeDirectory);
/* get the shell for this entry */
attmap_get_value(entry, attmap_passwd_loginShell, shell, sizeof(shell));
/* write the entries */
for (i = 0; usernames[i] != NULL; i++)
{
if ((requser == NULL) || (STR_CMP(requser, usernames[i]) == 0))
{
if (!isvalidname(usernames[i]))
{
log_log(LOG_WARNING, "%s: %s: denied by validnames option",
myldap_get_dn(entry), attmap_passwd_uid);
}
else
{
for (j = 0; j < numuids; j++)
{
if (uids[j] >= nslcd_cfg->nss_min_uid)
{
WRITE_INT32(fp, NSLCD_RESULT_BEGIN);
WRITE_STRING(fp, usernames[i]);
WRITE_STRING(fp, passwd);
WRITE_INT32(fp, uids[j]);
WRITE_INT32(fp, gid);
WRITE_STRING(fp, gecos);
WRITE_STRING(fp, homedir);
WRITE_STRING(fp, shell);
}
}
}
}
}
return 0;
}
NSLCD_HANDLE_UID(
passwd, byname, NSLCD_ACTION_PASSWD_BYNAME,
char name[BUFLEN_NAME];
char filter[BUFLEN_FILTER];
READ_STRING(fp, name);
log_setrequest("passwd=\"%s\"", name);
if (!isvalidname(name))
{
log_log(LOG_WARNING, "request denied by validnames option");
return -1;
}
nsswitch_check_reload();,
mkfilter_passwd_byname(name, filter, sizeof(filter)),
write_passwd(fp, entry, name, NULL, calleruid)
)
NSLCD_HANDLE_UID(
passwd, byuid, NSLCD_ACTION_PASSWD_BYUID,
uid_t uid;
char filter[BUFLEN_FILTER];
READ_INT32(fp, uid);
log_setrequest("passwd=%lu", (unsigned long int)uid);
if (uid < nslcd_cfg->nss_min_uid)
{
log_log(LOG_DEBUG, "request ignored by nss_min_uid option");
/* return an empty result */
WRITE_INT32(fp, NSLCD_VERSION);
WRITE_INT32(fp, NSLCD_ACTION_PASSWD_BYUID);
WRITE_INT32(fp, NSLCD_RESULT_END);
return 0;
}
nsswitch_check_reload();,
mkfilter_passwd_byuid(uid, filter, sizeof(filter)),
write_passwd(fp, entry, NULL, &uid, calleruid)
)
NSLCD_HANDLE_UID(
passwd, all, NSLCD_ACTION_PASSWD_ALL,
const char *filter;
log_setrequest("passwd(all)");
nsswitch_check_reload();,
(filter = passwd_filter, 0),
write_passwd(fp, entry, NULL, NULL, calleruid)
)