Adding upstream version 1.9.13p3.upstream/1.9.13p3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2154 insertions, 0 deletions

diff --git a/plugins/sudoers/ldap.c b/plugins/sudoers/ldap.c
new file mode 100644
index 0000000..90aa35e
--- /dev/null
+++ b/plugins/sudoers/ldap.c
@@ -0,0 +1,2154 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2003-2022 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * This code is derived from software contributed by Aaron Spangler.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif /* HAVE_STRINGS_H */
+#include <unistd.h>
+#include <time.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <grp.h>
+#ifdef HAVE_LBER_H
+# include <lber.h>
+#endif
+#include <ldap.h>
+#if defined(HAVE_LDAPSSL_H)
+# include <ldapssl.h>
+#elif defined(HAVE_LDAP_SSL_H)
+# include <ldap_ssl.h>
+#elif defined(HAVE_MPS_LDAP_SSL_H)
+# include <mps/ldap_ssl.h>
+#endif
+#ifdef HAVE_LDAP_SASL_INTERACTIVE_BIND_S
+# ifdef HAVE_SASL_SASL_H
+#  include <sasl/sasl.h>
+# else
+#  include <sasl.h>
+# endif
+#endif /* HAVE_LDAP_SASL_INTERACTIVE_BIND_S */
+
+#include "sudoers.h"
+#include "sudo_lbuf.h"
+#include "sudo_ldap.h"
+#include "sudo_ldap_conf.h"
+#include "sudo_dso.h"
+
+#ifndef LDAP_OPT_RESULT_CODE
+# define LDAP_OPT_RESULT_CODE LDAP_OPT_ERROR_NUMBER
+#endif
+
+#ifndef LDAP_OPT_SUCCESS
+# define LDAP_OPT_SUCCESS LDAP_SUCCESS
+#endif
+
+#if defined(HAVE_LDAP_SASL_INTERACTIVE_BIND_S) && !defined(LDAP_SASL_QUIET)
+# define LDAP_SASL_QUIET	0
+#endif
+
+#ifndef HAVE_LDAP_UNBIND_EXT_S
+#define ldap_unbind_ext_s(a, b, c)	ldap_unbind_s(a)
+#endif
+
+#ifndef HAVE_LDAP_SEARCH_EXT_S
+# ifdef HAVE_LDAP_SEARCH_ST
+#  define ldap_search_ext_s(a, b, c, d, e, f, g, h, i, j, k)		\
+	ldap_search_st(a, b, c, d, e, f, i, k)
+# else
+#  define ldap_search_ext_s(a, b, c, d, e, f, g, h, i, j, k)		\
+	ldap_search_s(a, b, c, d, e, f, k)
+# endif
+#endif
+
+#define LDAP_FOREACH(var, ld, res)					\
+    for ((var) = ldap_first_entry((ld), (res));				\
+	(var) != NULL;							\
+	(var) = ldap_next_entry((ld), (var)))
+
+/* The TIMEFILTER_LENGTH is the length of the filter when timed entries
+   are used. The length is computed as follows:
+       81       for the filter itself
+       + 2 * 17 for the now timestamp
+*/
+#define TIMEFILTER_LENGTH	115
+
+/*
+ * The ldap_search structure implements a linked list of ldap and
+ * search result pointers, which allows us to remove them after
+ * all search results have been combined in memory.
+ */
+struct ldap_search_result {
+    STAILQ_ENTRY(ldap_search_result) entries;
+    LDAP *ldap;
+    LDAPMessage *searchresult;
+};
+STAILQ_HEAD(ldap_search_list, ldap_search_result);
+
+/*
+ * The ldap_entry_wrapper structure is used to implement sorted result entries.
+ * A double is used for the order to allow for insertion of new entries
+ * without having to renumber everything.
+ * Note: there is no standard floating point type in LDAP.
+ *       As a result, some LDAP servers will only allow an integer.
+ */
+struct ldap_entry_wrapper {
+    LDAPMessage	*entry;
+    double order;
+};
+
+/*
+ * The ldap_result structure contains the list of matching searches as
+ * well as an array of all result entries sorted by the sudoOrder attribute.
+ */
+struct ldap_result {
+    struct ldap_search_list searches;
+    struct ldap_entry_wrapper *entries;
+    unsigned int allocated_entries;
+    unsigned int nentries;
+};
+#define	ALLOCATION_INCREMENT	100
+
+/*
+ * The ldap_netgroup structure implements a singly-linked tail queue of
+ * netgroups a user is a member of when querying netgroups directly.
+ */
+struct ldap_netgroup {
+    STAILQ_ENTRY(ldap_netgroup) entries;
+    char *name;
+};
+STAILQ_HEAD(ldap_netgroup_list, ldap_netgroup);
+
+/*
+ * LDAP sudo_nss handle.
+ * We store the connection to the LDAP server and the passwd struct of the
+ * user the last query was performed for.
+ */
+struct sudo_ldap_handle {
+    LDAP *ld;
+    struct passwd *pw;
+    struct sudoers_parse_tree parse_tree;
+};
+
+#ifdef HAVE_LDAP_INITIALIZE
+static char *
+sudo_ldap_join_uri(struct ldap_config_str_list *uri_list)
+{
+    struct ldap_config_str *uri;
+    size_t len = 0;
+    char *buf = NULL;
+    debug_decl(sudo_ldap_join_uri, SUDOERS_DEBUG_LDAP);
+
+    STAILQ_FOREACH(uri, uri_list, entries) {
+	if (ldap_conf.ssl_mode == SUDO_LDAP_STARTTLS) {
+	    if (strncasecmp(uri->val, "ldaps://", 8) == 0) {
+		sudo_warnx("%s", U_("starttls not supported when using ldaps"));
+		ldap_conf.ssl_mode = SUDO_LDAP_SSL;
+	    }
+	}
+	len += strlen(uri->val) + 1;
+    }
+    if (len == 0 || (buf = malloc(len)) == NULL) {
+	sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+    } else {
+	char *cp = buf;
+
+	STAILQ_FOREACH(uri, uri_list, entries) {
+	    cp += strlcpy(cp, uri->val, len - (cp - buf));
+	    *cp++ = ' ';
+	}
+	cp[-1] = '\0';
+    }
+    debug_return_str(buf);
+}
+#endif /* HAVE_LDAP_INITIALIZE */
+
+/*
+ * Wrapper for ldap_create() or ldap_init() that handles
+ * SSL/TLS initialization as well.
+ * Returns LDAP_SUCCESS on success, else non-zero.
+ */
+static int
+sudo_ldap_init(LDAP **ldp, const char *host, int port)
+{
+    LDAP *ld;
+    int ret;
+    debug_decl(sudo_ldap_init, SUDOERS_DEBUG_LDAP);
+
+#ifdef HAVE_LDAPSSL_INIT
+    if (ldap_conf.ssl_mode != SUDO_LDAP_CLEAR) {
+	const int defsecure = ldap_conf.ssl_mode == SUDO_LDAP_SSL;
+	DPRINTF2("ldapssl_clientauth_init(%s, %s)",
+	    ldap_conf.tls_certfile ? ldap_conf.tls_certfile : "NULL",
+	    ldap_conf.tls_keyfile ? ldap_conf.tls_keyfile : "NULL");
+	ret = ldapssl_clientauth_init(ldap_conf.tls_certfile, NULL,
+	    ldap_conf.tls_keyfile != NULL, ldap_conf.tls_keyfile, NULL);
+	/*
+	 * Starting with version 5.0, Mozilla-derived LDAP SDKs require
+	 * the cert and key paths to be a directory, not a file.
+	 * If the user specified a file and it fails, try the parent dir.
+	 */
+	if (ret != LDAP_SUCCESS) {
+	    bool retry = false;
+	    if (ldap_conf.tls_certfile != NULL) {
+		char *cp = strrchr(ldap_conf.tls_certfile, '/');
+		if (cp != NULL && strncmp(cp + 1, "cert", 4) == 0) {
+		    *cp = '\0';
+		    retry = true;
+		}
+	    }
+	    if (ldap_conf.tls_keyfile != NULL) {
+		char *cp = strrchr(ldap_conf.tls_keyfile, '/');
+		if (cp != NULL && strncmp(cp + 1, "key", 3) == 0) {
+		    *cp = '\0';
+		    retry = true;
+		}
+	    }
+	    if (retry) {
+		DPRINTF2("retry ldapssl_clientauth_init(%s, %s)",
+		    ldap_conf.tls_certfile ? ldap_conf.tls_certfile : "NULL",
+		    ldap_conf.tls_keyfile ? ldap_conf.tls_keyfile : "NULL");
+		ret = ldapssl_clientauth_init(ldap_conf.tls_certfile, NULL,
+		    ldap_conf.tls_keyfile != NULL, ldap_conf.tls_keyfile, NULL);
+	    }
+	}
+	if (ret != LDAP_SUCCESS) {
+	    sudo_warnx(U_("unable to initialize SSL cert and key db: %s"),
+		ldapssl_err2string(ret));
+	    if (ldap_conf.tls_certfile == NULL)
+		sudo_warnx(U_("you must set TLS_CERT in %s to use SSL"),
+		    path_ldap_conf);
+	    goto done;
+	}
+
+	DPRINTF2("ldapssl_init(%s, %d, %d)", host, port, defsecure);
+	if ((ld = ldapssl_init(host, port, defsecure)) != NULL)
+	    ret = LDAP_SUCCESS;
+    } else
+#elif defined(HAVE_LDAP_SSL_INIT) && defined(HAVE_LDAP_SSL_CLIENT_INIT)
+    if (ldap_conf.ssl_mode == SUDO_LDAP_SSL) {
+	int sslrc;
+	ret = ldap_ssl_client_init(ldap_conf.tls_keyfile, ldap_conf.tls_keypw,
+	    0, &sslrc);
+	if (ret != LDAP_SUCCESS) {
+	    sudo_warnx("ldap_ssl_client_init(): %s: %s",
+		ldap_err2string(ret), ssl_err2string(sslrc));
+	    goto done;
+	}
+	DPRINTF2("ldap_ssl_init(%s, %d, NULL)", host, port);
+	if ((ld = ldap_ssl_init((char *)host, port, NULL)) != NULL)
+	    ret = LDAP_SUCCESS;
+    } else
+#endif
+    {
+#ifdef HAVE_LDAP_CREATE
+	DPRINTF2("ldap_create()");
+	if ((ret = ldap_create(&ld)) != LDAP_SUCCESS)
+	    goto done;
+	DPRINTF2("ldap_set_option(LDAP_OPT_HOST_NAME, %s)", host);
+	ret = ldap_set_option(ld, LDAP_OPT_HOST_NAME, host);
+#else
+	DPRINTF2("ldap_init(%s, %d)", host, port);
+	if ((ld = ldap_init((char *)host, port)) == NULL) {
+	    ret = LDAP_LOCAL_ERROR;
+	    goto done;
+	}
+	ret = LDAP_SUCCESS;
+#endif
+    }
+
+    *ldp = ld;
+done:
+    debug_return_int(ret);
+}
+
+/*
+ * Wrapper for ldap_get_values_len() that fills in the response code
+ * on error.
+ */
+static struct berval **
+sudo_ldap_get_values_len(LDAP *ld, LDAPMessage *entry, const char *attr, int *rc)
+{
+    struct berval **bval;
+
+    bval = ldap_get_values_len(ld, entry, attr);
+    if (bval == NULL) {
+	int optrc = ldap_get_option(ld, LDAP_OPT_RESULT_CODE, rc);
+	if (optrc != LDAP_OPT_SUCCESS)
+	    *rc = optrc;
+    } else {
+	*rc = LDAP_SUCCESS;
+    }
+    return bval;
+}
+
+/*
+ * Walk through search results and return true if we have a matching
+ * non-Unix group (including netgroups), else false.
+ * A matching entry that is negated will always return false.
+ */
+static int
+sudo_ldap_check_non_unix_group(LDAP *ld, LDAPMessage *entry, struct passwd *pw)
+{
+    struct berval **bv, **p;
+    bool ret = false;
+    int rc;
+    debug_decl(sudo_ldap_check_non_unix_group, SUDOERS_DEBUG_LDAP);
+
+    if (!entry)
+	debug_return_bool(false);
+
+    /* get the values from the entry */
+    bv = sudo_ldap_get_values_len(ld, entry, "sudoUser", &rc);
+    if (bv == NULL) {
+	if (rc == LDAP_NO_MEMORY)
+	    debug_return_int(-1);
+	debug_return_bool(false);
+    }
+
+    /* walk through values */
+    for (p = bv; *p != NULL && !ret; p++) {
+	bool negated = false;
+	char *val = (*p)->bv_val;
+
+	if (*val == '!') {
+	    val++;
+	    negated = true;
+	}
+	if (*val == '+') {
+	    if (netgr_matches(val, def_netgroup_tuple ? user_runhost : NULL,
+		def_netgroup_tuple ? user_srunhost : NULL, pw->pw_name))
+		ret = true;
+	    DPRINTF2("ldap sudoUser netgroup '%s%s' ... %s",
+		negated ? "!" : "", val, ret ? "MATCH!" : "not");
+	} else {
+	    if (group_plugin_query(pw->pw_name, val + 2, pw))
+		ret = true;
+	    DPRINTF2("ldap sudoUser non-Unix group '%s%s' ... %s",
+		negated ? "!" : "", val, ret ? "MATCH!" : "not");
+	}
+	/* A negated match overrides all other entries. */
+	if (ret && negated) {
+	    ret = false;
+	    break;
+	}
+    }
+
+    ldap_value_free_len(bv);	/* cleanup */
+
+    debug_return_bool(ret);
+}
+
+/*
+ * Extract the dn from an entry and return the first rdn from it.
+ */
+static char *
+sudo_ldap_get_first_rdn(LDAP *ld, LDAPMessage *entry, int *rc)
+{
+#ifdef HAVE_LDAP_STR2DN
+    char *dn, *rdn = NULL;
+    LDAPDN tmpDN;
+    debug_decl(sudo_ldap_get_first_rdn, SUDOERS_DEBUG_LDAP);
+
+    if ((dn = ldap_get_dn(ld, entry)) == NULL) {
+	int optrc = ldap_get_option(ld, LDAP_OPT_RESULT_CODE, rc);
+	if (optrc != LDAP_OPT_SUCCESS)
+	    *rc = optrc;
+	debug_return_str(NULL);
+    }
+    *rc = ldap_str2dn(dn, &tmpDN, LDAP_DN_FORMAT_LDAP);
+    if (*rc == LDAP_SUCCESS) {
+	ldap_rdn2str(tmpDN[0], &rdn, LDAP_DN_FORMAT_UFN);
+	ldap_dnfree(tmpDN);
+    }
+    ldap_memfree(dn);
+    debug_return_str(rdn);
+#else
+    char *dn, **edn;
+    debug_decl(sudo_ldap_get_first_rdn, SUDOERS_DEBUG_LDAP);
+
+    if ((dn = ldap_get_dn(ld, entry)) == NULL) {
+	int optrc = ldap_get_option(ld, LDAP_OPT_RESULT_CODE, rc);
+	if (optrc != LDAP_OPT_SUCCESS)
+	    *rc = optrc;
+	debug_return_str(NULL);
+    }
+    edn = ldap_explode_dn(dn, 1);
+    ldap_memfree(dn);
+    if (edn == NULL) {
+	*rc = LDAP_NO_MEMORY;
+	debug_return_str(NULL);
+    }
+    *rc = LDAP_SUCCESS;
+    debug_return_str(edn[0]);
+#endif
+}
+
+/*
+ * Read sudoOption and fill in the defaults list.
+ * This is used to parse the cn=defaults entry.
+ */
+static bool
+sudo_ldap_parse_options(LDAP *ld, LDAPMessage *entry, struct defaults_list *defs)
+{
+    struct berval **p, **bv = NULL;
+    char *cp, *cn = NULL, *source = NULL;
+    bool ret = false;
+    int rc;
+    debug_decl(sudo_ldap_parse_options, SUDOERS_DEBUG_LDAP);
+
+    bv = sudo_ldap_get_values_len(ld, entry, "sudoOption", &rc);
+    if (bv == NULL) {
+	if (rc == LDAP_NO_MEMORY)
+	    goto oom;
+	debug_return_bool(true);
+    }
+
+    /* Use sudoRole in place of file name in defaults. */
+    cn = sudo_ldap_get_first_rdn(ld, entry, &rc);
+    if (cn == NULL) {
+	if (rc == LDAP_NO_MEMORY)
+	    goto oom;
+    }
+    if (asprintf(&cp, "sudoRole %s", cn ? cn : "UNKNOWN") == -1)
+	goto oom;
+    source = sudo_rcstr_dup(cp);
+    free(cp);
+    if (source == NULL)
+	goto oom;
+
+    /* Walk through options, appending to defs. */
+    for (p = bv; *p != NULL; p++) {
+	char *var, *val;
+	int op;
+
+	op = sudo_ldap_parse_option((*p)->bv_val, &var, &val);
+	if (!append_default(var, val, op, source, defs))
+	    goto oom;
+    }
+
+    ret = true;
+    goto done;
+
+oom:
+    sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+
+done:
+    sudo_rcstr_delref(source);
+    if (cn)
+	ldap_memfree(cn);
+    ldap_value_free_len(bv);
+
+    debug_return_bool(ret);
+}
+
+/*
+ * Build an LDAP timefilter.
+ *
+ * Stores a filter in the buffer that makes sure only entries
+ * are selected that have a sudoNotBefore in the past and a
+ * sudoNotAfter in the future, i.e. a filter of the following
+ * structure (spaced out a little more for better readability:
+ *
+ * (&
+ *   (|
+ *	(!(sudoNotAfter=*))
+ *	(sudoNotAfter>__now__)
+ *   )
+ *   (|
+ *	(!(sudoNotBefore=*))
+ *	(sudoNotBefore<__now__)
+ *   )
+ * )
+ *
+ * If either the sudoNotAfter or sudoNotBefore attributes are missing,
+ * no time restriction shall be imposed.
+ */
+static bool
+sudo_ldap_timefilter(char *buffer, size_t buffersize)
+{
+    char timebuffer[sizeof("20120727121554.0Z")];
+    bool ret = false;
+    struct tm gmt;
+    time_t now;
+    int len;
+    debug_decl(sudo_ldap_timefilter, SUDOERS_DEBUG_LDAP);
+
+    /* Make sure we have a formatted timestamp for __now__. */
+    time(&now);
+    if (gmtime_r(&now, &gmt) == NULL) {
+	sudo_warn("%s", U_("unable to get GMT time"));
+	goto done;
+    }
+
+    /* Format the timestamp according to the RFC. */
+    timebuffer[sizeof(timebuffer) - 1] = '\0';
+    len = strftime(timebuffer, sizeof(timebuffer), "%Y%m%d%H%M%S.0Z", &gmt);
+    if (len == 0 || timebuffer[sizeof(timebuffer) - 1] != '\0') {
+	sudo_warnx("%s", U_("unable to format timestamp"));
+	goto done;
+    }
+
+    /* Build filter. */
+    len = snprintf(buffer, buffersize, "(&(|(!(sudoNotAfter=*))(sudoNotAfter>=%s))(|(!(sudoNotBefore=*))(sudoNotBefore<=%s)))",
+	timebuffer, timebuffer);
+    if (len < 0 || (size_t)len >= buffersize) {
+	sudo_warnx(U_("internal error, %s overflow"), __func__);
+	errno = EOVERFLOW;
+	goto done;
+    }
+
+    ret = true;
+
+done:
+    debug_return_bool(ret);
+}
+
+/*
+ * Builds up a filter to search for default settings
+ */
+static char *
+sudo_ldap_build_default_filter(void)
+{
+    char *filt;
+    debug_decl(sudo_ldap_build_default_filter, SUDOERS_DEBUG_LDAP);
+
+    if (!ldap_conf.search_filter)
+	debug_return_str(strdup("cn=defaults"));
+
+    if (asprintf(&filt, "(&%s(cn=defaults))", ldap_conf.search_filter) == -1)
+	debug_return_str(NULL);
+
+    debug_return_str(filt);
+}
+
+/*
+ * Determine length of query value after escaping characters
+ * as per RFC 4515.
+ */
+static size_t
+sudo_ldap_value_len(const char *value)
+{
+    const char *s;
+    size_t len = 0;
+
+    for (s = value; *s != '\0'; s++) {
+	switch (*s) {
+	case '\\':
+	case '(':
+	case ')':
+	case '*':
+	    len += 2;
+	    break;
+	}
+    }
+    len += (size_t)(s - value);
+    return len;
+}
+
+/*
+ * Like strlcat() but escapes characters as per RFC 4515.
+ */
+static size_t
+sudo_ldap_value_cat(char *dst, const char *src, size_t size)
+{
+    char *d = dst;
+    const char *s = src;
+    size_t n = size;
+    size_t dlen;
+
+    /* Find the end of dst and adjust bytes left but don't go past end */
+    while (n-- != 0 && *d != '\0')
+	d++;
+    dlen = d - dst;
+    n = size - dlen;
+
+    if (n == 0)
+	return dlen + strlen(s);
+    while (*s != '\0') {
+	switch (*s) {
+	case '\\':
+	    if (n < 3)
+		goto done;
+	    *d++ = '\\';
+	    *d++ = '5';
+	    *d++ = 'c';
+	    n -= 3;
+	    break;
+	case '(':
+	    if (n < 3)
+		goto done;
+	    *d++ = '\\';
+	    *d++ = '2';
+	    *d++ = '8';
+	    n -= 3;
+	    break;
+	case ')':
+	    if (n < 3)
+		goto done;
+	    *d++ = '\\';
+	    *d++ = '2';
+	    *d++ = '9';
+	    n -= 3;
+	    break;
+	case '*':
+	    if (n < 3)
+		goto done;
+	    *d++ = '\\';
+	    *d++ = '2';
+	    *d++ = 'a';
+	    n -= 3;
+	    break;
+	default:
+	    if (n < 1)
+		goto done;
+	    *d++ = *s;
+	    n--;
+	    break;
+	}
+	s++;
+    }
+done:
+    *d = '\0';
+    while (*s != '\0')
+	s++;
+    return dlen + (s - src);	/* count does not include NUL */
+}
+
+/*
+ * Like strdup() but escapes characters as per RFC 4515.
+ */
+static char *
+sudo_ldap_value_dup(const char *src)
+{
+    char *dst;
+    size_t size;
+
+    size = sudo_ldap_value_len(src) + 1;
+    dst = malloc(size);
+    if (dst == NULL)
+	return NULL;
+
+    *dst = '\0';
+    if (sudo_ldap_value_cat(dst, src, size) >= size) {
+	/* Should not be possible... */
+	free(dst);
+	dst = NULL;
+    }
+    return dst;
+}
+
+/*
+ * Check the netgroups list beginning at "start" for nesting.
+ * Parent nodes with a memberNisNetgroup that match one of the
+ * netgroups are added to the list and checked for further nesting.
+ * Return true on success or false if there was an internal overflow.
+ */
+static bool
+sudo_netgroup_lookup_nested(LDAP *ld, char *base, struct timeval *timeout,
+    struct ldap_netgroup_list *netgroups, struct ldap_netgroup *start)
+{
+    LDAPMessage *entry, *result;
+    size_t filt_len;
+    char *filt;
+    int rc;
+    debug_decl(sudo_netgroup_lookup_nested, SUDOERS_DEBUG_LDAP);
+
+    DPRINTF1("Checking for nested netgroups from netgroup_base '%s'", base);
+    do {
+	struct ldap_netgroup *ng, *old_tail;
+
+	result = NULL;
+	old_tail = STAILQ_LAST(netgroups, ldap_netgroup, entries);
+	filt_len = strlen(ldap_conf.netgroup_search_filter) + 7;
+	for (ng = start; ng != NULL; ng = STAILQ_NEXT(ng, entries)) {
+	    filt_len += sudo_ldap_value_len(ng->name) + 20;
+	}
+	if ((filt = malloc(filt_len)) == NULL)
+	    goto oom;
+	CHECK_STRLCPY(filt, "(&", filt_len);
+	CHECK_STRLCAT(filt, ldap_conf.netgroup_search_filter, filt_len);
+	CHECK_STRLCAT(filt, "(|", filt_len);
+	for (ng = start; ng != NULL; ng = STAILQ_NEXT(ng, entries)) {
+	    CHECK_STRLCAT(filt, "(memberNisNetgroup=", filt_len);
+	    CHECK_LDAP_VCAT(filt, ng->name, filt_len);
+	    CHECK_STRLCAT(filt, ")", filt_len);
+	}
+	CHECK_STRLCAT(filt, "))", filt_len);
+	DPRINTF1("ldap netgroup search filter: '%s'", filt);
+	rc = ldap_search_ext_s(ld, base, LDAP_SCOPE_SUBTREE, filt,
+	    NULL, 0, NULL, NULL, timeout, 0, &result);
+	free(filt);
+	if (rc == LDAP_SUCCESS) {
+	    LDAP_FOREACH(entry, ld, result) {
+		struct berval **bv;
+
+		bv = sudo_ldap_get_values_len(ld, entry, "cn", &rc);
+		if (bv == NULL) {
+		    if (rc == LDAP_NO_MEMORY)
+			goto oom;
+		} else {
+		    /* Don't add a netgroup twice. */
+		    STAILQ_FOREACH(ng, netgroups, entries) {
+			/* Assumes only one cn per entry. */
+			if (strcasecmp(ng->name, (*bv)->bv_val) == 0)
+			    break;
+		    }
+		    if (ng == NULL) {
+			ng = malloc(sizeof(*ng));
+			if (ng == NULL ||
+			    (ng->name = strdup((*bv)->bv_val)) == NULL) {
+			    free(ng);
+			    ldap_value_free_len(bv);
+			    goto oom;
+			}
+#ifdef __clang_analyzer__
+			/* clang analyzer false positive */
+			if (__builtin_expect(netgroups->stqh_last == NULL, 0))
+			    __builtin_trap();
+#endif
+			STAILQ_INSERT_TAIL(netgroups, ng, entries);
+			DPRINTF1("Found new netgroup %s for %s", ng->name, base);
+		    }
+		    ldap_value_free_len(bv);
+		}
+	    }
+	}
+	ldap_msgfree(result);
+
+	/* Check for nested netgroups in what we added. */
+	start = old_tail ? STAILQ_NEXT(old_tail, entries) : STAILQ_FIRST(netgroups);
+    } while (start != NULL);
+
+    debug_return_bool(true);
+oom:
+    sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+    ldap_msgfree(result);
+    debug_return_bool(false);
+overflow:
+    sudo_warnx(U_("internal error, %s overflow"), __func__);
+    free(filt);
+    debug_return_bool(false);
+}
+
+/*
+ * Look up netgroups that the specified user is a member of.
+ * Appends new entries to the netgroups list.
+ * Return true on success or false if there was an internal overflow.
+ */
+static bool
+sudo_netgroup_lookup(LDAP *ld, struct passwd *pw,
+    struct ldap_netgroup_list *netgroups)
+{
+    struct ldap_config_str *base;
+    struct ldap_netgroup *ng, *old_tail;
+    struct timeval tv, *tvp = NULL;
+    LDAPMessage *entry, *result = NULL;
+    const char *domain;
+    char *escaped_domain = NULL, *escaped_user = NULL;
+    char *escaped_host = NULL, *escaped_shost = NULL, *filt = NULL;
+    int filt_len, rc;
+    bool ret = false;
+    debug_decl(sudo_netgroup_lookup, SUDOERS_DEBUG_LDAP);
+
+    if (ldap_conf.timeout > 0) {
+	tv.tv_sec = ldap_conf.timeout;
+	tv.tv_usec = 0;
+	tvp = &tv;
+    }
+
+    /* Use NIS domain if set, else wildcard match. */
+    domain = sudo_getdomainname();
+
+    /* Escape the domain, host names, and user name per RFC 4515. */
+    if (domain != NULL) {
+	if ((escaped_domain = sudo_ldap_value_dup(domain)) == NULL)
+	    goto oom;
+    }
+    if ((escaped_user = sudo_ldap_value_dup(pw->pw_name)) == NULL)
+	    goto oom;
+    if (def_netgroup_tuple) {
+	escaped_host = sudo_ldap_value_dup(user_runhost);
+	if (user_runhost == user_srunhost)
+	    escaped_shost = escaped_host;
+	else
+	    escaped_shost = sudo_ldap_value_dup(user_srunhost);
+	if (escaped_host == NULL || escaped_shost == NULL)
+	    goto oom;
+    }
+
+    /* Build query, using NIS domain if it is set. */
+    if (domain != NULL) {
+	if (escaped_host != escaped_shost) {
+	    filt_len = asprintf(&filt, "(&%s(|"
+		"(nisNetgroupTriple=\\28,%s,%s\\29)"
+		"(nisNetgroupTriple=\\28%s,%s,%s\\29)"
+		"(nisNetgroupTriple=\\28%s,%s,%s\\29)"
+		"(nisNetgroupTriple=\\28,%s,\\29)"
+		"(nisNetgroupTriple=\\28%s,%s,\\29)"
+		"(nisNetgroupTriple=\\28%s,%s,\\29)))",
+		ldap_conf.netgroup_search_filter, escaped_user, escaped_domain,
+		escaped_shost, escaped_user, escaped_domain,
+		escaped_host, escaped_user, escaped_domain, escaped_user,
+		escaped_shost, escaped_user, escaped_host, escaped_user);
+	} else if (escaped_shost != NULL) {
+	    filt_len = asprintf(&filt, "(&%s(|"
+		"(nisNetgroupTriple=\\28,%s,%s\\29)"
+		"(nisNetgroupTriple=\\28%s,%s,%s\\29)"
+		"(nisNetgroupTriple=\\28,%s,\\29)"
+		"(nisNetgroupTriple=\\28%s,%s,\\29)))",
+		ldap_conf.netgroup_search_filter, escaped_user, escaped_domain,
+		escaped_shost, escaped_user, escaped_domain,
+		escaped_user, escaped_shost, escaped_user);
+	} else {
+	    filt_len = asprintf(&filt, "(&%s(|"
+		"(nisNetgroupTriple=\\28*,%s,%s\\29)"
+		"(nisNetgroupTriple=\\28*,%s,\\29)))",
+		ldap_conf.netgroup_search_filter, escaped_user, escaped_domain,
+		escaped_user);
+	}
+    } else {
+	if (escaped_host != escaped_shost) {
+	    filt_len = asprintf(&filt, "(&%s(|"
+		"(nisNetgroupTriple=\\28,%s,*\\29)"
+		"(nisNetgroupTriple=\\28%s,%s,*\\29)"
+		"(nisNetgroupTriple=\\28%s,%s,*\\29)))",
+		ldap_conf.netgroup_search_filter, escaped_user,
+		escaped_shost, escaped_user, escaped_host, escaped_user);
+	} else if (escaped_shost != NULL) {
+	    filt_len = asprintf(&filt, "(&%s(|"
+		"(nisNetgroupTriple=\\28,%s,*\\29)"
+		"(nisNetgroupTriple=\\28%s,%s,*\\29)))",
+		ldap_conf.netgroup_search_filter, escaped_user,
+		escaped_shost, escaped_user);
+	} else {
+	    filt_len = asprintf(&filt,
+		"(&%s(|(nisNetgroupTriple=\\28*,%s,*\\29)))",
+		ldap_conf.netgroup_search_filter, escaped_user);
+	}
+    }
+    if (filt_len == -1)
+	goto oom;
+    DPRINTF1("ldap netgroup search filter: '%s'", filt);
+
+    STAILQ_FOREACH(base, &ldap_conf.netgroup_base, entries) {
+	DPRINTF1("searching from netgroup_base '%s'", base->val);
+	rc = ldap_search_ext_s(ld, base->val, LDAP_SCOPE_SUBTREE, filt,
+	    NULL, 0, NULL, NULL, tvp, 0, &result);
+	if (rc != LDAP_SUCCESS) {
+	    DPRINTF1("ldap netgroup search failed: %s", ldap_err2string(rc));
+	    ldap_msgfree(result);
+	    result = NULL;
+	    continue;
+	}
+
+	old_tail = STAILQ_LAST(netgroups, ldap_netgroup, entries);
+	LDAP_FOREACH(entry, ld, result) {
+	    struct berval **bv;
+
+	    bv = sudo_ldap_get_values_len(ld, entry, "cn", &rc);
+	    if (bv == NULL) {
+		if (rc == LDAP_NO_MEMORY)
+		    goto oom;
+	    } else {
+		/* Don't add a netgroup twice. */
+		STAILQ_FOREACH(ng, netgroups, entries) {
+		    /* Assumes only one cn per entry. */
+		    if (strcasecmp(ng->name, (*bv)->bv_val) == 0)
+			break;
+		}
+		if (ng == NULL) {
+		    ng = malloc(sizeof(*ng));
+		    if (ng == NULL ||
+			(ng->name = strdup((*bv)->bv_val)) == NULL) {
+			free(ng);
+			ldap_value_free_len(bv);
+			goto oom;
+		    }
+		    STAILQ_INSERT_TAIL(netgroups, ng, entries);
+		    DPRINTF1("Found new netgroup %s for %s", ng->name,
+			base->val);
+		}
+		ldap_value_free_len(bv);
+	    }
+	}
+	ldap_msgfree(result);
+	result = NULL;
+
+	/* Check for nested netgroups in what we added. */
+	ng = old_tail ? STAILQ_NEXT(old_tail, entries) : STAILQ_FIRST(netgroups);
+	if (ng != NULL) {
+	    if (!sudo_netgroup_lookup_nested(ld, base->val, tvp, netgroups, ng))
+		goto done;
+	}
+    }
+    ret = true;
+    goto done;
+
+oom:
+    sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+done:
+    free(escaped_domain);
+    free(escaped_user);
+    free(escaped_host);
+    if (escaped_host != escaped_shost)
+	free(escaped_shost);
+    free(filt);
+    ldap_msgfree(result);
+    debug_return_bool(ret);
+}
+
+/*
+ * Builds up a filter to check against LDAP.
+ */
+static char *
+sudo_ldap_build_pass1(LDAP *ld, struct passwd *pw)
+{
+    char timebuffer[TIMEFILTER_LENGTH + 1], idbuf[MAX_UID_T_LEN + 1];
+    char *buf, *notbuf;
+    struct ldap_netgroup_list netgroups;
+    struct ldap_netgroup *ng = NULL;
+    struct gid_list *gidlist;
+    struct group_list *grlist;
+    struct group *grp;
+    size_t sz = 0;
+    int i;
+    debug_decl(sudo_ldap_build_pass1, SUDOERS_DEBUG_LDAP);
+
+    STAILQ_INIT(&netgroups);
+
+    if (ldap_conf.timed || ldap_conf.search_filter) {
+	/* Allocate space for the global AND. */
+	sz += 3;
+
+	/* Add LDAP search filter if present. */
+	if (ldap_conf.search_filter)
+	    sz += strlen(ldap_conf.search_filter);
+
+	/* If timed, add space for time limits. */
+	if (ldap_conf.timed)
+	    sz += TIMEFILTER_LENGTH;
+    }
+
+    /* Add space for the global OR clause + (sudoUser=ALL) + NOT + NUL. */
+    sz += sizeof("(|(sudoUser=ALL)(!(|)))");
+
+    /* Add space for username and uid, including the negated versions. */
+    sz += ((sizeof("(sudoUser=)(sudoUser=#)") - 1 +
+	sudo_ldap_value_len(pw->pw_name) + MAX_UID_T_LEN) * 2) + 2;
+
+    /* Add space for primary and supplementary groups and gids */
+    if ((grp = sudo_getgrgid(pw->pw_gid)) != NULL) {
+	sz += ((sizeof("(sudoUser=%)") - 1 +
+	    sudo_ldap_value_len(grp->gr_name)) * 2) + 1;
+    }
+    sz += ((sizeof("(sudoUser=%#)") - 1 + MAX_UID_T_LEN) * 2) + 1;
+    if ((grlist = sudo_get_grlist(pw)) != NULL) {
+	for (i = 0; i < grlist->ngroups; i++) {
+	    if (grp != NULL && strcasecmp(grlist->groups[i], grp->gr_name) == 0)
+		continue;
+	    sz += ((sizeof("(sudoUser=%)") - 1 +
+		sudo_ldap_value_len(grlist->groups[i])) * 2) + 1;
+	}
+    }
+    if ((gidlist = sudo_get_gidlist(pw, ENTRY_TYPE_ANY)) != NULL) {
+	for (i = 0; i < gidlist->ngids; i++) {
+	    if (pw->pw_gid == gidlist->gids[i])
+		continue;
+	    sz += ((sizeof("(sudoUser=%#)") - 1 + MAX_UID_T_LEN) * 2) + 1;
+	}
+    }
+
+    /* Add space for user netgroups if netgroup_base specified. */
+    if (!STAILQ_EMPTY(&ldap_conf.netgroup_base)) {
+	DPRINTF1("Looking up netgroups for %s", pw->pw_name);
+	if (sudo_netgroup_lookup(ld, pw, &netgroups)) {
+	    STAILQ_FOREACH(ng, &netgroups, entries) {
+		sz += ((sizeof("(sudoUser=+)") - 1 + strlen(ng->name)) * 2) + 1;
+	    }
+	} else {
+	    /* sudo_netgroup_lookup() failed, clean up. */
+	    while ((ng = STAILQ_FIRST(&netgroups)) != NULL) {
+		STAILQ_REMOVE_HEAD(&netgroups, entries);
+		free(ng->name);
+		free(ng);
+	    }
+	}
+    }
+
+    buf = malloc(sz);
+    notbuf = malloc(sz);
+    if (buf == NULL || notbuf == NULL)
+	goto bad;
+    *buf = '\0';
+    *notbuf = '\0';
+
+    /*
+     * If timed or using a search filter, start a global AND clause to
+     * contain the search filter, search criteria, and time restriction.
+     */
+    if (ldap_conf.timed || ldap_conf.search_filter)
+	CHECK_STRLCPY(buf, "(&", sz);
+
+    if (ldap_conf.search_filter)
+	CHECK_STRLCAT(buf, ldap_conf.search_filter, sz);
+
+    /* Global OR + sudoUser=user_name filter */
+    CHECK_STRLCAT(buf, "(|(sudoUser=", sz);
+    CHECK_LDAP_VCAT(buf, pw->pw_name, sz);
+    CHECK_STRLCAT(buf, ")", sz);
+    CHECK_STRLCAT(notbuf, "(sudoUser=!", sz);
+    CHECK_LDAP_VCAT(notbuf, pw->pw_name, sz);
+    CHECK_STRLCAT(notbuf, ")", sz);
+
+    /* Append user-ID */
+    (void) snprintf(idbuf, sizeof(idbuf), "%u", (unsigned int)pw->pw_uid);
+    CHECK_STRLCAT(buf, "(sudoUser=#", sz);
+    CHECK_STRLCAT(buf, idbuf, sz);
+    CHECK_STRLCAT(buf, ")", sz);
+    CHECK_STRLCAT(notbuf, "(sudoUser=!#", sz);
+    CHECK_STRLCAT(notbuf, idbuf, sz);
+    CHECK_STRLCAT(notbuf, ")", sz);
+
+    /* Append primary group and group-ID */
+    if (grp != NULL) {
+	CHECK_STRLCAT(buf, "(sudoUser=%", sz);
+	CHECK_LDAP_VCAT(buf, grp->gr_name, sz);
+	CHECK_STRLCAT(buf, ")", sz);
+	CHECK_STRLCAT(notbuf, "(sudoUser=!%", sz);
+	CHECK_LDAP_VCAT(notbuf, grp->gr_name, sz);
+	CHECK_STRLCAT(notbuf, ")", sz);
+    }
+    (void) snprintf(idbuf, sizeof(idbuf), "%u", (unsigned int)pw->pw_gid);
+    CHECK_STRLCAT(buf, "(sudoUser=%#", sz);
+    CHECK_STRLCAT(buf, idbuf, sz);
+    CHECK_STRLCAT(buf, ")", sz);
+    CHECK_STRLCAT(notbuf, "(sudoUser=!%#", sz);
+    CHECK_STRLCAT(notbuf, idbuf, sz);
+    CHECK_STRLCAT(notbuf, ")", sz);
+
+    /* Append supplementary groups and group-IDs */
+    if (grlist != NULL) {
+	for (i = 0; i < grlist->ngroups; i++) {
+	    if (grp != NULL && strcasecmp(grlist->groups[i], grp->gr_name) == 0)
+		continue;
+	    CHECK_STRLCAT(buf, "(sudoUser=%", sz);
+	    CHECK_LDAP_VCAT(buf, grlist->groups[i], sz);
+	    CHECK_STRLCAT(buf, ")", sz);
+	    CHECK_STRLCAT(notbuf, "(sudoUser=!%", sz);
+	    CHECK_LDAP_VCAT(notbuf, grlist->groups[i], sz);
+	    CHECK_STRLCAT(notbuf, ")", sz);
+	}
+    }
+    if (gidlist != NULL) {
+	for (i = 0; i < gidlist->ngids; i++) {
+	    if (pw->pw_gid == gidlist->gids[i])
+		continue;
+	    (void) snprintf(idbuf, sizeof(idbuf), "%u",
+		(unsigned int)gidlist->gids[i]);
+	    CHECK_STRLCAT(buf, "(sudoUser=%#", sz);
+	    CHECK_STRLCAT(buf, idbuf, sz);
+	    CHECK_STRLCAT(buf, ")", sz);
+	    CHECK_STRLCAT(notbuf, "(sudoUser=!%#", sz);
+	    CHECK_STRLCAT(notbuf, idbuf, sz);
+	    CHECK_STRLCAT(notbuf, ")", sz);
+	}
+    }
+
+    /* Done with groups. */
+    if (gidlist != NULL)
+	sudo_gidlist_delref(gidlist);
+    if (grlist != NULL)
+	sudo_grlist_delref(grlist);
+    if (grp != NULL)
+	sudo_gr_delref(grp);
+
+    /* Add netgroups (if any), freeing the list as we go. */
+    while ((ng = STAILQ_FIRST(&netgroups)) != NULL) {
+	STAILQ_REMOVE_HEAD(&netgroups, entries);
+	CHECK_STRLCAT(buf, "(sudoUser=+", sz);
+	CHECK_LDAP_VCAT(buf, ng->name, sz);
+	CHECK_STRLCAT(buf, ")", sz);
+	CHECK_STRLCAT(notbuf, "(sudoUser=!+", sz);
+	CHECK_LDAP_VCAT(notbuf, ng->name, sz);
+	CHECK_STRLCAT(notbuf, ")", sz);
+	free(ng->name);
+	free(ng);
+    }
+
+    /* Add ALL to list. */
+    CHECK_STRLCAT(buf, "(sudoUser=ALL))", sz);
+
+    /* Add filter for negated entries. */
+    CHECK_STRLCAT(buf, "(!(|", sz);
+    CHECK_STRLCAT(buf, notbuf, sz);
+    CHECK_STRLCAT(buf, ")", sz);
+
+    /* Add the time restriction, or simply end the global OR. */
+    if (ldap_conf.timed) {
+	CHECK_STRLCAT(buf, ")", sz); /* closes the global OR */
+	if (!sudo_ldap_timefilter(timebuffer, sizeof(timebuffer)))
+	    goto bad;
+	CHECK_STRLCAT(buf, timebuffer, sz);
+    } else if (ldap_conf.search_filter) {
+	CHECK_STRLCAT(buf, ")", sz); /* closes the global OR */
+    }
+
+    CHECK_STRLCAT(buf, ")", sz); /* closes the global OR or the global AND */
+
+    free(notbuf);
+    debug_return_str(buf);
+overflow:
+    sudo_warnx(U_("internal error, %s overflow"), __func__);
+    if (ng != NULL) {
+	/* Overflow while traversing netgroups. */
+	free(ng->name);
+	free(ng);
+    }
+    errno = EOVERFLOW;
+bad:
+    while ((ng = STAILQ_FIRST(&netgroups)) != NULL) {
+	STAILQ_REMOVE_HEAD(&netgroups, entries);
+	free(ng->name);
+	free(ng);
+    }
+    free(buf);
+    free(notbuf);
+    debug_return_str(NULL);
+}
+
+/*
+ * Builds up a filter to check against non-Unix group
+ * entries in LDAP, including netgroups.
+ */
+static char *
+sudo_ldap_build_pass2(void)
+{
+    char *filt, timebuffer[TIMEFILTER_LENGTH + 1];
+    bool query_netgroups = def_use_netgroups;
+    int len;
+    debug_decl(sudo_ldap_build_pass2, SUDOERS_DEBUG_LDAP);
+
+    /* No need to query netgroups if using netgroup_base. */
+    if (!STAILQ_EMPTY(&ldap_conf.netgroup_base))
+	query_netgroups = false;
+
+    /* Short circuit if no netgroups and no non-Unix groups. */
+    if (!query_netgroups && !def_group_plugin) {
+	errno = ENOENT;
+	debug_return_str(NULL);
+    }
+
+    if (ldap_conf.timed) {
+	if (!sudo_ldap_timefilter(timebuffer, sizeof(timebuffer)))
+	    debug_return_str(NULL);
+    }
+
+    /*
+     * Match all sudoUsers beginning with '+' or '%:'.
+     * If a search filter or time restriction is specified,
+     * those get ANDed in to the expression.
+     */
+    if (query_netgroups && def_group_plugin) {
+	len = asprintf(&filt, "%s%s(|(sudoUser=+*)(sudoUser=!+*)(sudoUser=%%:*)(sudoUser=!%%:*))%s%s",
+	    (ldap_conf.timed || ldap_conf.search_filter) ? "(&" : "",
+	    ldap_conf.search_filter ? ldap_conf.search_filter : "",
+	    ldap_conf.timed ? timebuffer : "",
+	    (ldap_conf.timed || ldap_conf.search_filter) ? ")" : "");
+    } else {
+	len = asprintf(&filt, "%s%s(|(sudoUser=%s*)(sudoUser=!%s*))%s%s",
+	    (ldap_conf.timed || ldap_conf.search_filter) ? "(&" : "",
+	    ldap_conf.search_filter ? ldap_conf.search_filter : "",
+	    query_netgroups ? "+" : "%:", query_netgroups ? "+" : "%:",
+	    ldap_conf.timed ? timebuffer : "",
+	    (ldap_conf.timed || ldap_conf.search_filter) ? ")" : "");
+    }
+    if (len == -1)
+	filt = NULL;
+
+    debug_return_str(filt);
+}
+
+static char *
+berval_iter(void **vp)
+{
+    struct berval **bv = *vp;
+
+    *vp = bv + 1;
+    return *bv ? (*bv)->bv_val : NULL;
+}
+
+/*
+ * Wrapper for sudo_ldap_role_to_priv() that takes an LDAPMessage.
+ * Returns a struct privilege on success or NULL on failure.
+ */
+static struct privilege *
+ldap_entry_to_priv(LDAP *ld, LDAPMessage *entry, int *rc_out)
+{
+    struct berval **cmnds = NULL, **hosts = NULL;
+    struct berval **runasusers = NULL, **runasgroups = NULL;
+    struct berval **opts = NULL, **notbefore = NULL, **notafter = NULL;
+    struct privilege *priv = NULL;
+    char *cn = NULL;
+    int rc;
+    debug_decl(ldap_entry_to_priv, SUDOERS_DEBUG_LDAP);
+
+    /* Ignore sudoRole without sudoCommand or sudoHost. */
+    cmnds = sudo_ldap_get_values_len(ld, entry, "sudoCommand", &rc);
+    if (cmnds == NULL)
+	goto cleanup;
+    hosts = sudo_ldap_get_values_len(ld, entry, "sudoHost", &rc);
+    if (hosts == NULL)
+	goto cleanup;
+
+    /* Get the entry's dn for long format printing. */
+    if ((cn = sudo_ldap_get_first_rdn(ld, entry, &rc)) == NULL)
+	goto cleanup;
+
+    /* Get sudoRunAsUser / sudoRunAsGroup */
+    runasusers = sudo_ldap_get_values_len(ld, entry, "sudoRunAsUser", &rc);
+    if (runasusers == NULL) {
+	if (rc != LDAP_NO_MEMORY)
+	    runasusers = sudo_ldap_get_values_len(ld, entry, "sudoRunAs", &rc);
+	if (rc == LDAP_NO_MEMORY)
+	    goto cleanup;
+    }
+    runasgroups = sudo_ldap_get_values_len(ld, entry, "sudoRunAsGroup", &rc);
+    if (rc == LDAP_NO_MEMORY)
+	goto cleanup;
+
+    /* Get sudoNotBefore / sudoNotAfter */
+    if (ldap_conf.timed) {
+	notbefore = sudo_ldap_get_values_len(ld, entry, "sudoNotBefore", &rc);
+	if (rc == LDAP_NO_MEMORY)
+	    goto cleanup;
+	notafter = sudo_ldap_get_values_len(ld, entry, "sudoNotAfter", &rc);
+	if (rc == LDAP_NO_MEMORY)
+	    goto cleanup;
+    }
+
+    /* Parse sudoOptions. */
+    opts = sudo_ldap_get_values_len(ld, entry, "sudoOption", &rc);
+    if (rc == LDAP_NO_MEMORY)
+	goto cleanup;
+
+    priv = sudo_ldap_role_to_priv(cn, hosts, runasusers, runasgroups,
+	cmnds, opts, notbefore ? notbefore[0]->bv_val : NULL,
+	notafter ? notafter[0]->bv_val : NULL, false, true, berval_iter);
+    if (priv == NULL) {
+	rc = LDAP_NO_MEMORY;
+	goto cleanup;
+    }
+
+cleanup:
+    if (cn != NULL)
+	ldap_memfree(cn);
+    if (cmnds != NULL)
+	ldap_value_free_len(cmnds);
+    if (hosts != NULL)
+	ldap_value_free_len(hosts);
+    if (runasusers != NULL)
+	ldap_value_free_len(runasusers);
+    if (runasgroups != NULL)
+	ldap_value_free_len(runasgroups);
+    if (opts != NULL)
+	ldap_value_free_len(opts);
+    if (notbefore != NULL)
+	ldap_value_free_len(notbefore);
+    if (notafter != NULL)
+	ldap_value_free_len(notafter);
+
+    *rc_out = rc;
+    debug_return_ptr(priv);
+}
+
+static bool
+ldap_to_sudoers(LDAP *ld, struct ldap_result *lres,
+    struct userspec_list *ldap_userspecs)
+{
+    struct userspec *us;
+    struct member *m;
+    unsigned int i;
+    int rc;
+    debug_decl(ldap_to_sudoers, SUDOERS_DEBUG_LDAP);
+
+    /* We only have a single userspec */
+    if ((us = calloc(1, sizeof(*us))) == NULL)
+	goto oom;
+    us->file = sudo_rcstr_dup("LDAP");
+    TAILQ_INIT(&us->users);
+    TAILQ_INIT(&us->privileges);
+    STAILQ_INIT(&us->comments);
+    TAILQ_INSERT_TAIL(ldap_userspecs, us, entries);
+
+    /* The user has already matched, use ALL as wildcard. */
+    if ((m = sudo_ldap_new_member_all()) == NULL)
+	goto oom;
+    TAILQ_INSERT_TAIL(&us->users, m, entries);
+
+    /* Treat each entry as a separate privilege. */
+    for (i = 0; i < lres->nentries; i++) {
+	struct privilege *priv;
+
+	priv = ldap_entry_to_priv(ld, lres->entries[i].entry, &rc);
+	if (priv == NULL) {
+	    if (rc == LDAP_NO_MEMORY)
+		goto oom;
+	    continue;
+	}
+	TAILQ_INSERT_TAIL(&us->privileges, priv, entries);
+    }
+
+    debug_return_bool(true);
+
+oom:
+    sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+    free_userspecs(ldap_userspecs);
+    debug_return_bool(false);
+}
+
+#ifdef HAVE_LDAP_SASL_INTERACTIVE_BIND_S
+typedef unsigned int (*sudo_gss_krb5_ccache_name_t)(unsigned int *minor_status, const char *name, const char **old_name);
+static sudo_gss_krb5_ccache_name_t sudo_gss_krb5_ccache_name;
+
+static int
+sudo_set_krb5_ccache_name(const char *name, const char **old_name)
+{
+    int ret = 0;
+    unsigned int junk;
+    static bool initialized;
+    debug_decl(sudo_set_krb5_ccache_name, SUDOERS_DEBUG_LDAP);
+
+    if (!initialized) {
+	sudo_gss_krb5_ccache_name = (sudo_gss_krb5_ccache_name_t)
+	    sudo_dso_findsym(SUDO_DSO_DEFAULT, "gss_krb5_ccache_name");
+	initialized = true;
+    }
+
+    /*
+     * Try to use gss_krb5_ccache_name() if possible.
+     * We also need to set KRB5CCNAME since some LDAP libs may not use
+     * gss_krb5_ccache_name().
+     */
+    if (sudo_gss_krb5_ccache_name != NULL) {
+	ret = sudo_gss_krb5_ccache_name(&junk, name, old_name);
+    } else {
+	/* No gss_krb5_ccache_name(), fall back on KRB5CCNAME. */
+	if (old_name != NULL)
+	    *old_name = sudo_getenv("KRB5CCNAME");
+    }
+    if (name != NULL && *name != '\0') {
+	if (sudo_setenv("KRB5CCNAME", name, true) == -1)
+	    ret = -1;
+    } else {
+	if (sudo_unsetenv("KRB5CCNAME") == -1)
+	    ret = -1;
+    }
+
+    debug_return_int(ret);
+}
+
+/*
+ * Make a copy of the credential cache file specified by KRB5CCNAME
+ * which must be readable by the user.  The resulting cache file
+ * is root-owned and will be removed after authenticating via SASL.
+ */
+static char *
+sudo_krb5_copy_cc_file(const char *old_ccname)
+{
+    int nfd, ofd = -1;
+    ssize_t nread, nwritten = -1;
+    static char new_ccname[] = _PATH_TMP "sudocc_XXXXXXXX";
+    char buf[10240], *ret = NULL;
+    debug_decl(sudo_krb5_copy_cc_file, SUDOERS_DEBUG_LDAP);
+
+    old_ccname = sudo_krb5_ccname_path(old_ccname);
+    if (old_ccname != NULL) {
+	/* Open credential cache as user to prevent stolen creds. */
+	if (!set_perms(PERM_USER))
+	    goto done;
+	ofd = open(old_ccname, O_RDONLY|O_NONBLOCK);
+	if (!restore_perms())
+	    goto done;
+
+	if (ofd != -1) {
+	    (void) fcntl(ofd, F_SETFL, 0);
+	    if (sudo_lock_file(ofd, SUDO_LOCK)) {
+		nfd = mkstemp(new_ccname);
+		if (nfd != -1) {
+		    sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+			"copy ccache %s -> %s", old_ccname, new_ccname);
+		    while ((nread = read(ofd, buf, sizeof(buf))) > 0) {
+			ssize_t off = 0;
+			do {
+			    nwritten = write(nfd, buf + off, nread - off);
+			    if (nwritten == -1) {
+				sudo_warn("error writing to %s", new_ccname);
+				goto write_error;
+			    }
+			    off += nwritten;
+			} while (off < nread);
+		    }
+		    if (nread == -1)
+			sudo_warn("unable to read %s", new_ccname);
+write_error:
+		    close(nfd);
+		    if (nread != -1 && nwritten != -1) {
+			ret = new_ccname;	/* success! */
+		    } else {
+			unlink(new_ccname);	/* failed */
+		    }
+		} else {
+		    sudo_warn("unable to create temp file %s", new_ccname);
+		}
+	    }
+	} else {
+	    sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,
+		"unable to open %s", old_ccname);
+	}
+    }
+done:
+    if (ofd != -1)
+	close(ofd);
+    debug_return_str(ret);
+}
+
+static int
+sudo_ldap_sasl_interact(LDAP *ld, unsigned int flags, void *_auth_id,
+    void *_interact)
+{
+    char *auth_id = (char *)_auth_id;
+    sasl_interact_t *interact = (sasl_interact_t *)_interact;
+    int ret = LDAP_SUCCESS;
+    debug_decl(sudo_ldap_sasl_interact, SUDOERS_DEBUG_LDAP);
+
+    for (; interact->id != SASL_CB_LIST_END; interact++) {
+	if (interact->id != SASL_CB_USER) {
+	    sudo_warnx("sudo_ldap_sasl_interact: unexpected interact id %lu",
+		interact->id);
+	    ret = LDAP_PARAM_ERROR;
+	    break;
+	}
+
+	if (auth_id != NULL)
+	    interact->result = auth_id;
+	else if (interact->defresult != NULL)
+	    interact->result = interact->defresult;
+	else
+	    interact->result = "";
+
+	interact->len = strlen(interact->result);
+#if SASL_VERSION_MAJOR < 2
+	interact->result = strdup(interact->result);
+	if (interact->result == NULL) {
+	    ret = LDAP_NO_MEMORY;
+	    break;
+	}
+#endif /* SASL_VERSION_MAJOR < 2 */
+	DPRINTF2("sudo_ldap_sasl_interact: SASL_CB_USER %s",
+	    (const char *)interact->result);
+    }
+    debug_return_int(ret);
+}
+#endif /* HAVE_LDAP_SASL_INTERACTIVE_BIND_S */
+
+/*
+ * Create a new sudo_ldap_result structure.
+ */
+static struct ldap_result *
+sudo_ldap_result_alloc(void)
+{
+    struct ldap_result *result;
+    debug_decl(sudo_ldap_result_alloc, SUDOERS_DEBUG_LDAP);
+
+    result = calloc(1, sizeof(*result));
+    if (result != NULL)
+	STAILQ_INIT(&result->searches);
+
+    debug_return_ptr(result);
+}
+
+/*
+ * Free the ldap result structure
+ */
+static void
+sudo_ldap_result_free(struct ldap_result *lres)
+{
+    struct ldap_search_result *s;
+    debug_decl(sudo_ldap_result_free, SUDOERS_DEBUG_LDAP);
+
+    if (lres != NULL) {
+	if (lres->nentries) {
+	    free(lres->entries);
+	    lres->entries = NULL;
+	}
+	while ((s = STAILQ_FIRST(&lres->searches)) != NULL) {
+	    STAILQ_REMOVE_HEAD(&lres->searches, entries);
+	    ldap_msgfree(s->searchresult);
+	    free(s);
+	}
+	free(lres);
+    }
+    debug_return;
+}
+
+/*
+ * Add a search result to the ldap_result structure.
+ */
+static struct ldap_search_result *
+sudo_ldap_result_add_search(struct ldap_result *lres, LDAP *ldap,
+    LDAPMessage *searchresult)
+{
+    struct ldap_search_result *news;
+    debug_decl(sudo_ldap_result_add_search, SUDOERS_DEBUG_LDAP);
+
+    /* Create new entry and add it to the end of the chain. */
+    news = calloc(1, sizeof(*news));
+    if (news != NULL) {
+	news->ldap = ldap;
+	news->searchresult = searchresult;
+	STAILQ_INSERT_TAIL(&lres->searches, news, entries);
+    }
+
+    debug_return_ptr(news);
+}
+
+/*
+ * Connect to the LDAP server specified by ld.
+ * Returns LDAP_SUCCESS on success, else non-zero.
+ */
+static int
+sudo_ldap_bind_s(LDAP *ld)
+{
+    int ret;
+    debug_decl(sudo_ldap_bind_s, SUDOERS_DEBUG_LDAP);
+
+#ifdef HAVE_LDAP_SASL_INTERACTIVE_BIND_S
+    if (ldap_conf.rootuse_sasl == true ||
+	(ldap_conf.rootuse_sasl != false && ldap_conf.use_sasl == true)) {
+	const char *old_ccname = NULL;
+	const char *new_ccname = ldap_conf.krb5_ccname;
+	const char *tmp_ccname = NULL;
+	void *auth_id = ldap_conf.rootsasl_auth_id ?
+	    ldap_conf.rootsasl_auth_id : ldap_conf.sasl_auth_id;
+	int rc;
+
+	/* Make temp copy of the user's credential cache as needed. */
+	if (ldap_conf.krb5_ccname == NULL && user_ccname != NULL) {
+	    new_ccname = tmp_ccname = sudo_krb5_copy_cc_file(user_ccname);
+	    if (tmp_ccname == NULL) {
+		/* XXX - fatal error */
+		sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+		    "unable to copy user ccache %s", user_ccname);
+	    }
+	}
+
+	if (new_ccname != NULL) {
+	    rc = sudo_set_krb5_ccache_name(new_ccname, &old_ccname);
+	    if (rc == 0) {
+		sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+		    "set ccache name %s -> %s",
+		    old_ccname ? old_ccname : "(none)", new_ccname);
+	    } else {
+		sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO,
+		    "sudo_set_krb5_ccache_name() failed: %d", rc);
+	    }
+	}
+	ret = ldap_sasl_interactive_bind_s(ld, ldap_conf.binddn,
+	    ldap_conf.sasl_mech, NULL, NULL, LDAP_SASL_QUIET,
+	    sudo_ldap_sasl_interact, auth_id);
+	if (new_ccname != NULL) {
+	    rc = sudo_set_krb5_ccache_name(old_ccname ? old_ccname : "", NULL);
+	    if (rc == 0) {
+		sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+		    "restore ccache name %s -> %s", new_ccname,
+		    old_ccname ? old_ccname : "(none)");
+	    } else {
+		sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO,
+		    "sudo_set_krb5_ccache_name() failed: %d", rc);
+	    }
+	    /* Remove temporary copy of user's credential cache. */
+	    if (tmp_ccname != NULL)
+		unlink(tmp_ccname);
+	}
+	if (ret != LDAP_SUCCESS) {
+	    sudo_warnx("ldap_sasl_interactive_bind_s(): %s",
+		ldap_err2string(ret));
+	    goto done;
+	}
+	DPRINTF1("ldap_sasl_interactive_bind_s() ok");
+    } else
+#endif /* HAVE_LDAP_SASL_INTERACTIVE_BIND_S */
+#ifdef HAVE_LDAP_SASL_BIND_S
+    {
+	struct berval bv;
+
+	bv.bv_val = ldap_conf.bindpw ? ldap_conf.bindpw : (char *)"";
+	bv.bv_len = strlen(bv.bv_val);
+
+	ret = ldap_sasl_bind_s(ld, ldap_conf.binddn, LDAP_SASL_SIMPLE, &bv,
+	    NULL, NULL, NULL);
+	if (ret != LDAP_SUCCESS) {
+	    sudo_warnx("ldap_sasl_bind_s(): %s", ldap_err2string(ret));
+	    goto done;
+	}
+	DPRINTF1("ldap_sasl_bind_s() ok");
+    }
+#else
+    {
+	ret = ldap_simple_bind_s(ld, ldap_conf.binddn, ldap_conf.bindpw);
+	if (ret != LDAP_SUCCESS) {
+	    sudo_warnx("ldap_simple_bind_s(): %s", ldap_err2string(ret));
+	    goto done;
+	}
+	DPRINTF1("ldap_simple_bind_s() ok");
+    }
+#endif
+done:
+    debug_return_int(ret);
+}
+
+/*
+ * Shut down the LDAP connection.
+ */
+static int
+sudo_ldap_close(struct sudo_nss *nss)
+{
+    struct sudo_ldap_handle *handle = nss->handle;
+    debug_decl(sudo_ldap_close, SUDOERS_DEBUG_LDAP);
+
+    if (handle != NULL) {
+	/* Unbind and close the LDAP connection. */
+	if (handle->ld != NULL) {
+	    ldap_unbind_ext_s(handle->ld, NULL, NULL);
+	    handle->ld = NULL;
+	}
+
+	/* Free the handle container. */
+	if (handle->pw != NULL)
+	    sudo_pw_delref(handle->pw);
+	free_parse_tree(&handle->parse_tree);
+	free(handle);
+	nss->handle = NULL;
+    }
+    debug_return_int(0);
+}
+
+/*
+ * Open a connection to the LDAP server.
+ * Returns 0 on success and non-zero on failure.
+ */
+static int
+sudo_ldap_open(struct sudo_nss *nss)
+{
+    LDAP *ld;
+    int rc = -1;
+    bool ldapnoinit = false;
+    struct sudo_ldap_handle *handle;
+    debug_decl(sudo_ldap_open, SUDOERS_DEBUG_LDAP);
+
+    if (nss->handle != NULL) {
+	sudo_debug_printf(SUDO_DEBUG_ERROR,
+	    "%s: called with non-NULL handle %p", __func__, nss->handle);
+	sudo_ldap_close(nss);
+    }
+
+    if (!sudo_ldap_read_config())
+	goto done;
+
+    /* Prevent reading of user ldaprc and system defaults. */
+    if (sudo_getenv("LDAPNOINIT") == NULL) {
+	if (sudo_setenv("LDAPNOINIT", "1", true) == 0)
+	    ldapnoinit = true;
+    }
+
+    /* Set global LDAP options */
+    if (sudo_ldap_set_options_global() != LDAP_SUCCESS)
+	goto done;
+
+    /* Connect to LDAP server */
+#ifdef HAVE_LDAP_INITIALIZE
+    if (!STAILQ_EMPTY(&ldap_conf.uri)) {
+	char *buf = sudo_ldap_join_uri(&ldap_conf.uri);
+	if (buf == NULL)
+	    goto done;
+	DPRINTF2("ldap_initialize(ld, %s)", buf);
+	rc = ldap_initialize(&ld, buf);
+	free(buf);
+    } else
+#endif
+	rc = sudo_ldap_init(&ld, ldap_conf.host, ldap_conf.port);
+    if (rc != LDAP_SUCCESS) {
+	sudo_warnx(U_("unable to initialize LDAP: %s"), ldap_err2string(rc));
+	goto done;
+    }
+
+    /* Set LDAP per-connection options */
+    rc = sudo_ldap_set_options_conn(ld);
+    if (rc != LDAP_SUCCESS)
+	goto done;
+
+    if (ldapnoinit)
+	(void) sudo_unsetenv("LDAPNOINIT");
+
+    if (ldap_conf.ssl_mode == SUDO_LDAP_STARTTLS) {
+#if defined(HAVE_LDAP_START_TLS_S)
+	rc = ldap_start_tls_s(ld, NULL, NULL);
+	if (rc != LDAP_SUCCESS) {
+	    sudo_warnx("ldap_start_tls_s(): %s", ldap_err2string(rc));
+	    goto done;
+	}
+	DPRINTF1("ldap_start_tls_s() ok");
+#elif defined(HAVE_LDAP_SSL_CLIENT_INIT) && defined(HAVE_LDAP_START_TLS_S_NP)
+	int sslrc;
+	rc = ldap_ssl_client_init(ldap_conf.tls_keyfile, ldap_conf.tls_keypw,
+	    0, &sslrc);
+	if (rc != LDAP_SUCCESS) {
+	    sudo_warnx("ldap_ssl_client_init(): %s: %s",
+		ldap_err2string(rc), ssl_err2string(sslrc));
+	    goto done;
+	}
+	rc = ldap_start_tls_s_np(ld, NULL);
+	if (rc != LDAP_SUCCESS) {
+	    sudo_warnx("ldap_start_tls_s_np(): %s", ldap_err2string(rc));
+	    goto done;
+	}
+	DPRINTF1("ldap_start_tls_s_np() ok");
+#else
+	sudo_warnx("%s",
+	    U_("start_tls specified but LDAP libs do not support ldap_start_tls_s() or ldap_start_tls_s_np()"));
+#endif /* !HAVE_LDAP_START_TLS_S && !HAVE_LDAP_START_TLS_S_NP */
+    }
+
+    /* Actually connect */
+    rc = sudo_ldap_bind_s(ld);
+    if (rc != LDAP_SUCCESS)
+	goto done;
+
+    /* Create a handle container. */
+    handle = calloc(1, sizeof(struct sudo_ldap_handle));
+    if (handle == NULL) {
+	sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	rc = -1;
+	goto done;
+    }
+    handle->ld = ld;
+    /* handle->pw = NULL; */
+    init_parse_tree(&handle->parse_tree, NULL, NULL);
+    nss->handle = handle;
+
+done:
+    debug_return_int(rc == LDAP_SUCCESS ? 0 : -1);
+}
+
+static int
+sudo_ldap_getdefs(struct sudo_nss *nss)
+{
+    struct sudo_ldap_handle *handle = nss->handle;
+    struct timeval tv, *tvp = NULL;
+    struct ldap_config_str *base;
+    LDAPMessage *entry, *result = NULL;
+    char *filt = NULL;
+    int rc, ret = -1;
+    static bool cached;
+    debug_decl(sudo_ldap_getdefs, SUDOERS_DEBUG_LDAP);
+
+    if (handle == NULL) {
+	sudo_debug_printf(SUDO_DEBUG_ERROR,
+	    "%s: called with NULL handle", __func__);
+	debug_return_int(-1);
+    }
+
+    /* Use cached result if present. */
+    if (cached)
+	debug_return_int(0);
+
+    filt = sudo_ldap_build_default_filter();
+    if (filt == NULL) {
+	sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	debug_return_int(-1);
+    }
+    DPRINTF1("Looking for cn=defaults: %s", filt);
+
+    STAILQ_FOREACH(base, &ldap_conf.base, entries) {
+	LDAP *ld = handle->ld;
+
+	if (ldap_conf.timeout > 0) {
+	    tv.tv_sec = ldap_conf.timeout;
+	    tv.tv_usec = 0;
+	    tvp = &tv;
+	}
+	ldap_msgfree(result);
+	result = NULL;
+	rc = ldap_search_ext_s(ld, base->val, LDAP_SCOPE_SUBTREE,
+	    filt, NULL, 0, NULL, NULL, tvp, 0, &result);
+	if (rc == LDAP_SUCCESS && (entry = ldap_first_entry(ld, result))) {
+	    DPRINTF1("found:%s", ldap_get_dn(ld, entry));
+	    if (!sudo_ldap_parse_options(ld, entry, &handle->parse_tree.defaults))
+		goto done;
+	} else {
+	    DPRINTF1("no default options found in %s", base->val);
+	}
+    }
+    cached = true;
+    ret = 0;
+
+done:
+    ldap_msgfree(result);
+    free(filt);
+
+    debug_return_int(ret);
+}
+
+/*
+ * Comparison function for ldap_entry_wrapper structures, ascending order.
+ * This should match role_order_cmp() in parse_ldif.c.
+ */
+static int
+ldap_entry_compare(const void *a, const void *b)
+{
+    const struct ldap_entry_wrapper *aw = a;
+    const struct ldap_entry_wrapper *bw = b;
+    debug_decl(ldap_entry_compare, SUDOERS_DEBUG_LDAP);
+
+    debug_return_int(aw->order < bw->order ? -1 :
+	(aw->order > bw->order ? 1 : 0));
+}
+
+/*
+ * Return the last entry in the list of searches, usually the
+ * one currently being used to add entries.
+ */
+static struct ldap_search_result *
+sudo_ldap_result_last_search(struct ldap_result *lres)
+{
+    debug_decl(sudo_ldap_result_last_search, SUDOERS_DEBUG_LDAP);
+
+    debug_return_ptr(STAILQ_LAST(&lres->searches, ldap_search_result, entries));
+}
+
+/*
+ * Add an entry to the result structure.
+ */
+static struct ldap_entry_wrapper *
+sudo_ldap_result_add_entry(struct ldap_result *lres, LDAPMessage *entry)
+{
+    struct ldap_search_result *last;
+    struct berval **bv;
+    double order = 0.0;
+    char *ep;
+    int rc;
+    debug_decl(sudo_ldap_result_add_entry, SUDOERS_DEBUG_LDAP);
+
+    /* Determine whether the entry has the sudoOrder attribute. */
+    last = sudo_ldap_result_last_search(lres);
+    if (last != NULL) {
+	bv = sudo_ldap_get_values_len(last->ldap, entry, "sudoOrder", &rc);
+	if (bv == NULL) {
+	    if (rc == LDAP_NO_MEMORY)
+		debug_return_ptr(NULL);
+	} else {
+	    if (ldap_count_values_len(bv) > 0) {
+		/* Get the value of this attribute, 0 if not present. */
+		DPRINTF2("order attribute raw: %s", (*bv)->bv_val);
+		order = strtod((*bv)->bv_val, &ep);
+		if (ep == (*bv)->bv_val || *ep != '\0') {
+		    sudo_warnx(U_("invalid sudoOrder attribute: %s"),
+			(*bv)->bv_val);
+		    order = 0.0;
+		}
+		DPRINTF2("order attribute: %f", order);
+	    }
+	    ldap_value_free_len(bv);
+	}
+    }
+
+    /*
+     * Enlarge the array of entry wrappers as needed, preallocating blocks
+     * of 100 entries to save on allocation time.
+     */
+    if (++lres->nentries > lres->allocated_entries) {
+	int allocated_entries = lres->allocated_entries + ALLOCATION_INCREMENT;
+	struct ldap_entry_wrapper *entries = reallocarray(lres->entries,
+	    allocated_entries, sizeof(lres->entries[0]));
+	if (entries == NULL)
+	    debug_return_ptr(NULL);
+	lres->allocated_entries = allocated_entries;
+	lres->entries = entries;
+    }
+
+    /* Fill in the new entry and return it. */
+    lres->entries[lres->nentries - 1].entry = entry;
+    lres->entries[lres->nentries - 1].order = order;
+
+    debug_return_ptr(&lres->entries[lres->nentries - 1]);
+}
+
+/*
+ * Perform the LDAP query for the user.  The caller is responsible for
+ * freeing the result with sudo_ldap_result_free().
+ */
+static struct ldap_result *
+sudo_ldap_result_get(struct sudo_nss *nss, struct passwd *pw)
+{
+    struct sudo_ldap_handle *handle = nss->handle;
+    struct ldap_config_str *base;
+    struct ldap_result *lres;
+    struct timeval tv, *tvp = NULL;
+    LDAPMessage *entry, *result;
+    LDAP *ld = handle->ld;
+    char *filt = NULL;
+    int pass, rc;
+    debug_decl(sudo_ldap_result_get, SUDOERS_DEBUG_LDAP);
+
+    /*
+     * Okay - time to search for anything that matches this user
+     * Lets limit it to only two queries of the LDAP server
+     *
+     * The first pass will look by the username, groups, and
+     * the keyword ALL.  We will then inspect the results that
+     * came back from the query.  We don't need to inspect the
+     * sudoUser in this pass since the LDAP server already scanned
+     * it for us.
+     *
+     * The second pass will return all the entries that contain non-
+     * Unix groups, including netgroups.  Then we take the non-Unix
+     * groups returned and try to match them against the username.
+     *
+     * Since we have to sort the possible entries before we make a
+     * decision, we perform the queries and store all of the results in
+     * an ldap_result object.  The results are then sorted by sudoOrder.
+     */
+    lres = sudo_ldap_result_alloc();
+    if (lres == NULL)
+	goto oom;
+    for (pass = 0; pass < 2; pass++) {
+	filt = pass ? sudo_ldap_build_pass2() : sudo_ldap_build_pass1(ld, pw);
+	if (filt != NULL) {
+	    DPRINTF1("ldap search '%s'", filt);
+	    STAILQ_FOREACH(base, &ldap_conf.base, entries) {
+		DPRINTF1("searching from base '%s'",
+		    base->val);
+		if (ldap_conf.timeout > 0) {
+		    tv.tv_sec = ldap_conf.timeout;
+		    tv.tv_usec = 0;
+		    tvp = &tv;
+		}
+		result = NULL;
+		rc = ldap_search_ext_s(ld, base->val, LDAP_SCOPE_SUBTREE, filt,
+		    NULL, 0, NULL, NULL, tvp, 0, &result);
+		if (rc != LDAP_SUCCESS) {
+		    DPRINTF1("ldap search pass %d failed: %s", pass + 1,
+			ldap_err2string(rc));
+		    continue;
+		}
+
+		/* Add the search result to list of search results. */
+		DPRINTF1("adding search result");
+		if (sudo_ldap_result_add_search(lres, ld, result) == NULL)
+		    goto oom;
+		LDAP_FOREACH(entry, ld, result) {
+		    if (pass != 0) {
+			/* Check non-unix group in 2nd pass. */
+			switch (sudo_ldap_check_non_unix_group(ld, entry, pw)) {
+			case -1:
+			    goto oom;
+			case false:
+			    continue;
+			default:
+			    break;
+			}
+		    }
+		    if (sudo_ldap_result_add_entry(lres, entry) == NULL)
+			goto oom;
+		}
+		DPRINTF1("result now has %d entries", lres->nentries);
+	    }
+	    free(filt);
+	    filt = NULL;
+	} else if (errno != ENOENT) {
+	    /* Out of memory? */
+	    goto oom;
+	}
+    }
+
+    /* Sort the entries by the sudoOrder attribute. */
+    if (lres->nentries != 0) {
+	DPRINTF1("sorting remaining %d entries", lres->nentries);
+	qsort(lres->entries, lres->nentries, sizeof(lres->entries[0]),
+	    ldap_entry_compare);
+    }
+
+    debug_return_ptr(lres);
+oom:
+    sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+    free(filt);
+    sudo_ldap_result_free(lres);
+    debug_return_ptr(NULL);
+}
+
+/*
+ * Perform LDAP query for user and host and convert to sudoers
+ * parse tree.
+ */
+static int
+sudo_ldap_query(struct sudo_nss *nss, struct passwd *pw)
+{
+    struct sudo_ldap_handle *handle = nss->handle;
+    struct ldap_result *lres = NULL;
+    int ret = -1;
+    debug_decl(sudo_ldap_query, SUDOERS_DEBUG_LDAP);
+
+    if (handle == NULL) {
+	sudo_debug_printf(SUDO_DEBUG_ERROR,
+	    "%s: called with NULL handle", __func__);
+	debug_return_int(-1);
+    }
+
+    /* Use cached result if it matches pw. */
+    if (handle->pw != NULL) {
+	if (pw == handle->pw) {
+	    ret = 0;
+	    goto done;
+	}
+	sudo_pw_delref(handle->pw);
+	handle->pw = NULL;
+    }
+
+    /* Free old userspecs, if any. */
+    free_userspecs(&handle->parse_tree.userspecs);
+
+    DPRINTF1("%s: ldap search user %s, host %s", __func__, pw->pw_name,
+	user_runhost);
+    if ((lres = sudo_ldap_result_get(nss, pw)) == NULL)
+	goto done;
+
+    /* Convert to sudoers parse tree. */
+    if (!ldap_to_sudoers(handle->ld, lres, &handle->parse_tree.userspecs))
+	goto done;
+
+    /* Stash a ref to the passwd struct in the handle. */
+    sudo_pw_addref(pw);
+    handle->pw = pw;
+
+    ret = 0;
+
+done:
+    /* Cleanup. */
+    sudo_ldap_result_free(lres);
+    if (ret == -1)
+	free_userspecs(&handle->parse_tree.userspecs);
+    debug_return_int(ret);
+}
+
+/*
+ * Return the initialized (but empty) sudoers parse tree.
+ * The contents will be populated by the getdefs() and query() functions.
+ */
+static struct sudoers_parse_tree *
+sudo_ldap_parse(struct sudo_nss *nss)
+{
+    struct sudo_ldap_handle *handle = nss->handle;
+    debug_decl(sudo_ldap_parse, SUDOERS_DEBUG_LDAP);
+
+    if (handle == NULL) {
+	sudo_debug_printf(SUDO_DEBUG_ERROR,
+	    "%s: called with NULL handle", __func__);
+	debug_return_ptr(NULL);
+    }
+
+    debug_return_ptr(&handle->parse_tree);
+}
+
+#if 0
+/*
+ * Create an ldap_result from an LDAP search result.
+ *
+ * This function is currently not used anywhere, it is left here as
+ * an example of how to use the cached searches.
+ */
+static struct ldap_result *
+sudo_ldap_result_from_search(LDAP *ldap, LDAPMessage *searchresult)
+{
+    struct ldap_search_result *last;
+    struct ldap_result *result;
+    LDAPMessage	*entry;
+
+    /*
+     * An ldap_result is built from several search results, which are
+     * organized in a list. The head of the list is maintained in the
+     * ldap_result structure, together with the wrappers that point
+     * to individual entries, this has to be initialized first.
+     */
+    result = sudo_ldap_result_alloc();
+    if (result == NULL) {
+	sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	debug_return_ptr(NULL);
+    }
+
+    /*
+     * Build a new list node for the search result, this creates the
+     * list node.
+     */
+    last = sudo_ldap_result_add_search(result, ldap, searchresult);
+
+    /*
+     * Now add each entry in the search result to the array of of entries
+     * in the ldap_result object.
+     */
+    LDAP_FOREACH(entry, last->ldap, last->searchresult) {
+	if (sudo_ldap_result_add_entry(result, entry) == NULL) {
+	    sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	    sudo_ldap_result_free(result);
+	    result = NULL;
+	    break;
+	}
+    }
+    DPRINTF1("sudo_ldap_result_from_search: %d entries found",
+	result ? result->nentries : -1);
+    return result;
+}
+#endif
+
+/* sudo_nss implementation */
+struct sudo_nss sudo_nss_ldap = {
+    { NULL, NULL },
+    "ldap",
+    sudo_ldap_open,
+    sudo_ldap_close,
+    sudo_ldap_parse,
+    sudo_ldap_query,
+    sudo_ldap_getdefs
+};