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gnupg/dirmngr/dirmngr_ldap.c
Werner Koch 6300035ba1
dirmngr: New server flag "areconly" (A-record-only) 
* dirmngr/dirmngr.h (struct ldap_server_s): Add field areconly.
* dirmngr/ldapserver.c (ldapserver_parse_one): Parse "areconly"
* dirmngr/ks-engine-ldap.c (my_ldap_connect): Implement this flag.
* dirmngr/dirmngr_ldap.c: Add option --areconly
(connect_ldap): Implement option.
* dirmngr/ldap.c (run_ldap_wrapper): Add and pass that option.
--

This flag is used to pass the Windows specific option
LDAP_OPT_AREC_EXCLUSIVE.  It is ignored on other systems.

Signed-off-by: Werner Koch <wk@gnupg.org>
2022-09-28 09:43:25 +02:00

855 lines
22 KiB
C
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/* dirmngr-ldap.c - The LDAP helper for dirmngr.
* Copyright (C) 2004, 2021 g10 Code GmbH
* Copyright (C) 2010 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses/>.
* SPDX-License-Identifier: GPL-3.0-or-later
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdarg.h>
#include <string.h>
#ifdef HAVE_SIGNAL_H
# include <signal.h>
#endif
#include <errno.h>
#include <sys/time.h>
#include <unistd.h>
#ifdef HAVE_W32_SYSTEM
# include <winsock2.h>
# include <winldap.h>
# include <winber.h>
# include <fcntl.h>
# include "ldap-url.h"
#else
/* For OpenLDAP, to enable the API that we're using. */
# define LDAP_DEPRECATED 1
# include <ldap.h>
#endif
#include <gpg-error.h>
#include "../common/logging.h"
#include "../common/argparse.h"
#include "../common/stringhelp.h"
#include "../common/mischelp.h"
#include "../common/strlist.h"
#include "../common/util.h"
#include "../common/init.h"
#include "ldap-misc.h"
/* There is no need for the npth_unprotect and leave functions here;
* thus we redefine them to nops. We keep them in the code just for
* the case we ever want to reuse parts of the code in npth programs. */
static void npth_unprotect (void) { }
static void npth_protect (void) { }
#ifdef HAVE_W32_SYSTEM
typedef LDAP_TIMEVAL my_ldap_timeval_t;
#else
typedef struct timeval my_ldap_timeval_t;
#endif
#define DEFAULT_LDAP_TIMEOUT 15 /* Arbitrary long timeout. */
/* Constants for the options. */
enum
{
oQuiet = 'q',
oVerbose = 'v',
oTimeout = 500,
oMulti,
oProxy,
oHost,
oPort,
oUser,
oPass,
oEnvPass,
oBase,
oAttr,
oStartTLS,
oLdapTLS,
oNtds,
oARecOnly,
oOnlySearchTimeout,
oLogWithPID
};
/* The list of options as used by the argparse.c code. */
static ARGPARSE_OPTS opts[] = {
{ oVerbose, "verbose", 0, "verbose" },
{ oQuiet, "quiet", 0, "be somewhat more quiet" },
{ oTimeout, "timeout", 1, "|N|set LDAP timeout to N seconds"},
{ oMulti, "multi", 0, "return all values in"
" a record oriented format"},
{ oProxy, "proxy", 2,
"|NAME|ignore host part and connect through NAME"},
{ oStartTLS, "starttls", 0, "use STARTLS for the conenction"},
{ oLdapTLS, "ldaptls", 0, "use a TLS for the connection"},
{ oNtds, "ntds", 0, "authenticate using AD"},
{ oARecOnly, "areconly", 0, "do only an A record lookup"},
{ oHost, "host", 2, "|NAME|connect to host NAME"},
{ oPort, "port", 1, "|N|connect to port N"},
{ oUser, "user", 2, "|NAME|use NAME for authentication"},
{ oPass, "pass", 2, "|PASS|use password PASS"
" for authentication"},
{ oEnvPass, "env-pass", 0, "take password from $DIRMNGR_LDAP_PASS"},
{ oBase, "base", 2, "|DN|Start query at DN"},
{ oAttr, "attr", 2, "|STRING|return the attribute STRING"},
{ oOnlySearchTimeout, "only-search-timeout", 0, "@"},
{ oLogWithPID,"log-with-pid", 0, "@"},
ARGPARSE_end ()
};
/* A structure with module options. */
static struct
{
int quiet;
int verbose;
my_ldap_timeval_t timeout;/* Timeout for the LDAP search functions. */
unsigned int alarm_timeout; /* And for the alarm based timeout. */
int multi;
int starttls;
int ldaptls;
int ntds;
int areconly;
estream_t outstream; /* Send output to this stream. */
/* Note that we can't use const for the strings because ldap_* are
not defined that way. */
char *proxy; /* Host and Port override. */
char *user; /* Authentication user. */
char *pass; /* Authentication password. */
char *host; /* Override host. */
int port; /* Override port. */
char *base; /* Override DN. */
char *attr; /* Override attribute. */
} opt;
/* Prototypes. */
#ifndef HAVE_W32_SYSTEM
static void catch_alarm (int dummy);
#endif
static gpg_error_t connect_ldap (LDAP **r_ld);
static gpg_error_t process_filter (LDAP *ld, const char *string);
/* Function called by argparse.c to display information. */
static const char *
my_strusage (int level)
{
const char *p;
switch(level)
{
case 9: p = "GPL-3.0-or-later"; break;
case 11: p = "dirmngr_ldap (@GNUPG@)";
break;
case 13: p = VERSION; break;
case 14: p = GNUPG_DEF_COPYRIGHT_LINE; break;
case 17: p = PRINTABLE_OS_NAME; break;
case 19: p = "Please report bugs to <@EMAIL@>.\n"; break;
case 49: p = PACKAGE_BUGREPORT; break;
case 1:
case 40: p =
"Usage: dirmngr_ldap [options] filters (-h for help)\n";
break;
case 41: p =
("Syntax: dirmngr_ldap [options] filters\n"
"Internal LDAP helper for Dirmngr\n"
"Interface and options may change without notice\n");
break;
default: p = NULL;
}
return p;
}
int
main (int argc, char **argv)
{
ARGPARSE_ARGS pargs;
int any_err = 0;
char *p;
int only_search_timeout = 0;
char *malloced_buffer1 = NULL;
LDAP *ld;
early_system_init ();
set_strusage (my_strusage);
log_set_prefix ("dirmngr_ldap", GPGRT_LOG_WITH_PREFIX);
init_common_subsystems (&argc, &argv);
es_set_binary (es_stdout);
opt.outstream = es_stdout;
/* LDAP defaults */
opt.timeout.tv_sec = DEFAULT_LDAP_TIMEOUT;
opt.timeout.tv_usec = 0;
opt.alarm_timeout = 0;
/* Parse the command line. */
pargs.argc = &argc;
pargs.argv = &argv;
pargs.flags= ARGPARSE_FLAG_KEEP;
while (gnupg_argparse (NULL, &pargs, opts))
{
switch (pargs.r_opt)
{
case oVerbose: opt.verbose++; break;
case oQuiet: opt.quiet++; break;
case oTimeout:
opt.timeout.tv_sec = pargs.r.ret_int;
opt.timeout.tv_usec = 0;
opt.alarm_timeout = pargs.r.ret_int;
break;
case oOnlySearchTimeout: only_search_timeout = 1; break;
case oStartTLS: opt.starttls = 1; opt.ldaptls = 0; break;
case oLdapTLS: opt.starttls = 0; opt.ldaptls = 1; break;
case oNtds: opt.ntds = 1; break;
case oARecOnly: opt.areconly = 1; break;
case oMulti: opt.multi = 1; break;
case oUser: opt.user = pargs.r.ret_str; break;
case oPass: opt.pass = pargs.r.ret_str; break;
case oEnvPass:
opt.pass = getenv ("DIRMNGR_LDAP_PASS");
break;
case oProxy: opt.proxy = pargs.r.ret_str; break;
case oHost: opt.host = pargs.r.ret_str; break;
case oPort: opt.port = pargs.r.ret_int; break;
case oBase: opt.base = pargs.r.ret_str; break;
case oAttr: opt.attr = pargs.r.ret_str; break;
case oLogWithPID:
{
unsigned int oldflags;
log_get_prefix (&oldflags);
log_set_prefix (NULL, oldflags | GPGRT_LOG_WITH_PID);
}
break;
default :
pargs.err = ARGPARSE_PRINT_ERROR;
break;
}
}
gnupg_argparse (NULL, &pargs, NULL); /* Release internal state. */
if (only_search_timeout)
opt.alarm_timeout = 0;
if (opt.proxy)
{
malloced_buffer1 = xtrystrdup (opt.proxy);
if (!malloced_buffer1)
{
log_error ("error copying string: %s\n", strerror (errno));
return 1;
}
opt.host = malloced_buffer1;
p = strchr (opt.host, ':');
if (p)
{
*p++ = 0;
opt.port = atoi (p);
}
if (!opt.port)
opt.port = 389; /* make sure ports gets overridden. */
}
if (opt.port < 0 || opt.port > 65535)
log_error ("invalid port number %d\n", opt.port);
if (!opt.port)
opt.port = opt.ldaptls? 636 : 389;
#ifndef HAVE_W32_SYSTEM
if (!opt.host)
opt.host = "localhost";
#endif
if (log_get_errorcount (0))
exit (2);
if (opt.alarm_timeout)
{
#ifndef HAVE_W32_SYSTEM
# if defined(HAVE_SIGACTION) && defined(HAVE_STRUCT_SIGACTION)
struct sigaction act;
act.sa_handler = catch_alarm;
sigemptyset (&act.sa_mask);
act.sa_flags = 0;
if (sigaction (SIGALRM,&act,NULL))
# else
if (signal (SIGALRM, catch_alarm) == SIG_ERR)
# endif
log_fatal ("unable to register timeout handler\n");
#endif
}
if (connect_ldap (&ld))
any_err = 1;
else
{
if (!argc)
{
if (process_filter (ld, "(objectClass=*)"))
any_err = 1;
}
else
{
for (; argc; argc--, argv++)
if (process_filter (ld, *argv))
any_err = 1;
}
ldap_unbind (ld);
}
xfree (malloced_buffer1);
return any_err;
}
#ifndef HAVE_W32_SYSTEM
static void
catch_alarm (int dummy)
{
(void)dummy;
_exit (10);
}
#endif
#ifdef HAVE_W32_SYSTEM
static DWORD CALLBACK
alarm_thread (void *arg)
{
HANDLE timer = arg;
WaitForSingleObject (timer, INFINITE);
_exit (10);
return 0;
}
#endif
static void
set_timeout (void)
{
if (opt.alarm_timeout)
{
#ifdef HAVE_W32_SYSTEM
static HANDLE timer;
LARGE_INTEGER due_time;
/* A negative value is a relative time. */
due_time.QuadPart = (unsigned long long)-10000000 * opt.alarm_timeout;
if (!timer)
{
SECURITY_ATTRIBUTES sec_attr;
DWORD tid;
memset (&sec_attr, 0, sizeof sec_attr);
sec_attr.nLength = sizeof sec_attr;
sec_attr.bInheritHandle = FALSE;
/* Create a manual resetable timer. */
timer = CreateWaitableTimer (NULL, TRUE, NULL);
/* Initially set the timer. */
SetWaitableTimer (timer, &due_time, 0, NULL, NULL, 0);
if (CreateThread (&sec_attr, 0, alarm_thread, timer, 0, &tid))
log_error ("failed to create alarm thread\n");
}
else /* Retrigger the timer. */
SetWaitableTimer (timer, &due_time, 0, NULL, NULL, 0);
#else
alarm (opt.alarm_timeout);
#endif
}
}
/* Connect to the ldap server. On success the connection handle is
* stored at R_LD. */
static gpg_error_t
connect_ldap (LDAP **r_ld)
{
gpg_error_t err = 0;
int lerr;
LDAP *ld = NULL;
#ifndef HAVE_W32_SYSTEM
char *tmpstr;
#endif
*r_ld = NULL;
if (opt.starttls || opt.ldaptls)
{
#ifndef HAVE_LDAP_START_TLS_S
log_error ("ldap: can't connect to the server: no TLS support.");
err = GPG_ERR_LDAP_NOT_SUPPORTED;
goto leave;
#endif
}
set_timeout ();
#ifdef HAVE_W32_SYSTEM
npth_unprotect ();
ld = ldap_sslinit (opt.host, opt.port, opt.ldaptls);
npth_protect ();
if (!ld)
{
lerr = LdapGetLastError ();
err = ldap_err_to_gpg_err (lerr);
log_error ("error initializing LDAP '%s:%d': %s\n",
opt.host, opt.port, ldap_err2string (lerr));
goto leave;
}
if (opt.areconly)
{
lerr = ldap_set_option (ld, LDAP_OPT_AREC_EXCLUSIVE, LDAP_OPT_ON);
if (lerr != LDAP_SUCCESS)
{
log_error ("ldap: unable to set AREC_EXLUSIVE: %s\n",
ldap_err2string (lerr));
err = ldap_err_to_gpg_err (lerr);
goto leave;
}
}
#else /* Unix */
tmpstr = xtryasprintf ("%s://%s:%d",
opt.ldaptls? "ldaps" : "ldap",
opt.host, opt.port);
if (!tmpstr)
{
err = gpg_error_from_syserror ();
goto leave;
}
npth_unprotect ();
lerr = ldap_initialize (&ld, tmpstr);
npth_protect ();
if (lerr || !ld)
{
err = ldap_err_to_gpg_err (lerr);
log_error ("error initializing LDAP '%s': %s\n",
tmpstr, ldap_err2string (lerr));
xfree (tmpstr);
goto leave;
}
xfree (tmpstr);
#endif /* Unix */
if (opt.verbose)
log_info ("LDAP connected to '%s:%d'%s\n",
opt.host, opt.port,
opt.starttls? " using STARTTLS" :
opt.ldaptls? " using LDAP-over-TLS" : "");
#ifdef HAVE_LDAP_SET_OPTION
{
int ver = LDAP_VERSION3;
lerr = ldap_set_option (ld, LDAP_OPT_PROTOCOL_VERSION, &ver);
if (lerr != LDAP_SUCCESS)
{
log_error ("unable to go to LDAP 3: %s\n", ldap_err2string (lerr));
err = ldap_err_to_gpg_err (lerr);
goto leave;
}
}
#endif
#ifdef HAVE_LDAP_START_TLS_S
if (opt.starttls)
{
#ifndef HAVE_W32_SYSTEM
int check_cert = LDAP_OPT_X_TLS_HARD; /* LDAP_OPT_X_TLS_NEVER */
lerr = ldap_set_option (ld, LDAP_OPT_X_TLS_REQUIRE_CERT, &check_cert);
if (lerr)
{
log_error ("ldap: error setting an TLS option: %s\n",
ldap_err2string (lerr));
err = ldap_err_to_gpg_err (lerr);
goto leave;
}
#else
/* On Windows, the certificates are checked by default. If the
option to disable checking mentioned above is ever
implemented, the way to do that on Windows is to install a
callback routine using ldap_set_option (..,
LDAP_OPT_SERVER_CERTIFICATE, ..); */
#endif
npth_unprotect ();
lerr = ldap_start_tls_s (ld,
#ifdef HAVE_W32_SYSTEM
/* ServerReturnValue, result */
NULL, NULL,
#endif
/* ServerControls, ClientControls */
NULL, NULL);
npth_protect ();
if (lerr)
{
log_error ("ldap: error switching to STARTTLS mode: %s\n",
ldap_err2string (lerr));
err = ldap_err_to_gpg_err (lerr);
goto leave;
}
}
#endif
if (opt.ntds)
{
if (opt.verbose)
log_info ("binding to current user via AD\n");
#ifdef HAVE_W32_SYSTEM
npth_unprotect ();
lerr = ldap_bind_s (ld, NULL, NULL, LDAP_AUTH_NEGOTIATE);
npth_protect ();
if (lerr != LDAP_SUCCESS)
{
log_error ("error binding to LDAP via AD: %s\n",
ldap_err2string (lerr));
err = ldap_err_to_gpg_err (lerr);
goto leave;
}
#else /* Unix */
err = gpg_error (GPG_ERR_NOT_SUPPORTED);
goto leave;
#endif /* Unix */
}
else if (opt.user)
{
if (opt.verbose)
log_info ("LDAP bind to '%s', password '%s'\n",
opt.user, opt.pass ? ">not_shown<" : ">none<");
npth_unprotect ();
lerr = ldap_simple_bind_s (ld, opt.user, opt.pass);
npth_protect ();
if (lerr != LDAP_SUCCESS)
{
log_error ("error binding to LDAP: %s\n", ldap_err2string (lerr));
err = ldap_err_to_gpg_err (lerr);
goto leave;
}
}
else
{
/* By default we don't bind as there is usually no need to. */
}
leave:
if (err)
{
if (ld)
ldap_unbind (ld);
}
else
*r_ld = ld;
return err;
}
/* Helper for fetch_ldap(). */
static int
print_ldap_entries (LDAP *ld, LDAPMessage *msg, char *want_attr)
{
LDAPMessage *item;
int any = 0;
for (npth_unprotect (), item = ldap_first_entry (ld, msg), npth_protect ();
item;
npth_unprotect (), item = ldap_next_entry (ld, item), npth_protect ())
{
BerElement *berctx;
char *attr;
if (opt.verbose > 1)
log_info ("scanning result for attribute '%s'\n",
want_attr? want_attr : "[all]");
if (opt.multi)
{ /* Write item marker. */
if (es_fwrite ("I\0\0\0\0", 5, 1, opt.outstream) != 1)
{
log_error ("error writing to stdout: %s\n",
strerror (errno));
return -1;
}
}
for (npth_unprotect (), attr = ldap_first_attribute (ld, item, &berctx),
npth_protect ();
attr;
npth_unprotect (), attr = ldap_next_attribute (ld, item, berctx),
npth_protect ())
{
struct berval **values;
int idx;
if (opt.verbose > 1)
log_info (" available attribute '%s'\n", attr);
set_timeout ();
/* I case we want only one attribute we do a case
insensitive compare without the optional extension
(i.e. ";binary"). Case insensitive is not really correct
but the best we can do. */
if (want_attr)
{
char *cp1, *cp2;
int cmpres;
cp1 = strchr (want_attr, ';');
if (cp1)
*cp1 = 0;
cp2 = strchr (attr, ';');
if (cp2)
*cp2 = 0;
cmpres = ascii_strcasecmp (want_attr, attr);
if (cp1)
*cp1 = ';';
if (cp2)
*cp2 = ';';
if (cmpres)
{
ldap_memfree (attr);
continue; /* Not found: Try next attribute. */
}
}
npth_unprotect ();
values = ldap_get_values_len (ld, item, attr);
npth_protect ();
if (!values)
{
if (opt.verbose)
log_info ("attribute '%s' not found\n", attr);
ldap_memfree (attr);
continue;
}
if (opt.verbose)
{
log_info ("found attribute '%s'\n", attr);
if (opt.verbose > 1)
for (idx=0; values[idx]; idx++)
log_info (" length[%d]=%d\n",
idx, (int)values[0]->bv_len);
}
if (opt.multi)
{ /* Write attribute marker. */
unsigned char tmp[5];
size_t n = strlen (attr);
tmp[0] = 'A';
tmp[1] = (n >> 24);
tmp[2] = (n >> 16);
tmp[3] = (n >> 8);
tmp[4] = (n);
if (es_fwrite (tmp, 5, 1, opt.outstream) != 1
|| es_fwrite (attr, n, 1, opt.outstream) != 1)
{
log_error ("error writing to stdout: %s\n",
strerror (errno));
ldap_value_free_len (values);
ldap_memfree (attr);
ber_free (berctx, 0);
return -1;
}
}
for (idx=0; values[idx]; idx++)
{
if (opt.multi)
{ /* Write value marker. */
unsigned char tmp[5];
size_t n = values[0]->bv_len;
tmp[0] = 'V';
tmp[1] = (n >> 24);
tmp[2] = (n >> 16);
tmp[3] = (n >> 8);
tmp[4] = (n);
if (es_fwrite (tmp, 5, 1, opt.outstream) != 1)
{
log_error ("error writing to stdout: %s\n",
strerror (errno));
ldap_value_free_len (values);
ldap_memfree (attr);
ber_free (berctx, 0);
return -1;
}
}
if (es_fwrite (values[0]->bv_val, values[0]->bv_len,
1, opt.outstream) != 1)
{
log_error ("error writing to stdout: %s\n",
strerror (errno));
ldap_value_free_len (values);
ldap_memfree (attr);
ber_free (berctx, 0);
return -1;
}
any = 1;
if (!opt.multi)
break; /* Print only the first value. */
}
ldap_value_free_len (values);
ldap_memfree (attr);
if (want_attr || !opt.multi)
break; /* We only want to return the first attribute. */
}
ber_free (berctx, 0);
}
if (opt.verbose > 1 && any)
log_info ("result has been printed\n");
return any?0:-1;
}
/* Fetch data from the server at LD using FILTER. */
static int
fetch_ldap (LDAP *ld, char *base, int scope, char *filter)
{
gpg_error_t err;
int lerr;
LDAPMessage *msg;
char *attrs[2];
if (filter && !*filter)
filter = NULL;
if (opt.verbose)
{
log_info ("fetching using");
if (base)
log_printf (" base '%s'", base);
if (filter)
log_printf (" filter '%s'", filter);
log_printf ("\n");
}
attrs[0] = opt.attr;
attrs[1] = NULL;
set_timeout ();
npth_unprotect ();
lerr = ldap_search_st (ld, base, scope, filter,
attrs,
0,
&opt.timeout, &msg);
npth_protect ();
if (lerr == LDAP_SIZELIMIT_EXCEEDED && opt.multi)
{
if (es_fwrite ("E\0\0\0\x09truncated", 14, 1, opt.outstream) != 1)
{
log_error ("error writing to stdout: %s\n", strerror (errno));
return -1;
}
}
else if (lerr)
{
log_error ("searching '%s' failed: %s\n",
filter, ldap_err2string (lerr));
if (lerr != LDAP_NO_SUCH_OBJECT)
{
/* FIXME: Need deinit (ld)? */
/* Hmmm: Do we need to released MSG in case of an error? */
return -1;
}
}
err = print_ldap_entries (ld, msg, opt.multi? NULL:opt.attr);
ldap_msgfree (msg);
return err;
}
/* Main processing. Take the filter and run the LDAP query. The
* result is printed to stdout, errors are logged to the log stream.
* To allow searching with a different base it is possible to extend
* the filer. For example:
*
* ^CN=foo, OU=My Users&(objectClasses=*)
*
* Uses "CN=foo, OU=My Users" as base DN and "(objectClasses=*)" as
* filter. If the base prefix includes an ampersand, it needs to be
* doubled. The usual escaping rules for DNs (for the base) and
* filters apply. If no scope is given (see ldap_parse_extfilter for
* the syntax) subtree scope is used.
*/
static gpg_error_t
process_filter (LDAP *ld, const char *string)
{
gpg_error_t err;
char *base, *filter;
int scope = -1;
err = ldap_parse_extfilter (string, 0, &base, &scope, &filter);
if (!err)
err = fetch_ldap (ld,
base? base : opt.base,
scope == -1? LDAP_SCOPE_SUBTREE : scope,
filter);
xfree (base);
xfree (filter);
return err;
}
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