/*      $OpenBSD: getgrouplist.c,v 1.32 2026/03/10 00:06:39 deraadt Exp $ */
/*
 * Copyright (c) 2008 Ingo Schwarze <schwarze@usta.de>
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * get credential
 */
#include <sys/types.h>
#include <sys/limits.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <grp.h>
#include <pwd.h>
#include <errno.h>

#include <rpc/rpc.h>
#include <rpcsvc/yp.h>
#include <rpcsvc/ypclnt.h>

#ifdef YP
#define _PATH_NETID     "/etc/netid"
#define MAXLINELENGTH   1024

static int _parse_netid(char*, uid_t, gid_t*, int*, int);
static int _read_netid(const char *, uid_t, gid_t*, int*, int);

/*
 * Parse one string of the form "uid:gid[,gid[,...]]".
 * If the uid matches, add the groups to the group list and return 1.
 * If the uid does not match, return 0.
 */
static int
_parse_netid(char *netid, uid_t uid, gid_t *groups, int *ngroups,
             int maxgroups)
{
        const char *errstr = NULL;
        char *start, *p;
        uid_t tuid;
        gid_t gid;
        int i;

        /* Check the uid. */
        p = strchr(netid, ':');
        if (!p)
                return (0);
        *p++ = '\0';
        tuid = (uid_t)strtonum(netid, 0, UID_MAX, &errstr);
        if (errstr || tuid != uid)
                return (0);

        /* Loop over the gids. */
        while (p && *p) {
                start = p;
                p = strchr(start, ',');
                if (p)
                        *p++ = '\0';
                gid = (gid_t)strtonum(start, 0, GID_MAX, &errstr);
                if (errstr)
                        continue;

                /* Skip this group if it is already in the list. */
                for (i = 0; i < maxgroups && i < *ngroups; i++)
                        if (groups[i] == gid)
                                break;

                /* Try to add this new group to the list. */
                if (i == *ngroups) {
                        if (*ngroups >= maxgroups)
                                (*ngroups)++;
                        else
                                groups[(*ngroups)++] = gid;
                }
        }
        return (1);
}

/*
 * Search /etc/netid for a particular uid and process that line.
 * See _parse_netid for details, including return values.
 */
static int
_read_netid(const char *key, uid_t uid, gid_t *groups, int *ngroups,
            int maxgroups)
{
        FILE *fp;
        char line[MAXLINELENGTH], *p;
        int found = 0, fd;

        fd = __pledge_open(_PATH_NETID, O_RDONLY|O_CLOEXEC);
        if (fd == -1)
                return (0);
        fp = fdopen(fd, "r");
        if (!fp) {
                close(fd);
                return (0);
        }
        while (!found && fgets(line, sizeof(line), fp)) {
                p = strchr(line, '\n');
                if (p)
                        *p = '\0';
                else { /* Skip lines that are too long. */
                        int ch;
                        while ((ch = getc_unlocked(fp)) != '\n' && ch != EOF)
                                ;
                        continue;
                }
                p = strchr(line, ' ');
                if (!p)
                        continue;
                *p++ = '\0';
                if (strcmp(line, key))
                        continue;
                found = _parse_netid(p, uid, groups, ngroups, maxgroups);
        }
        (void)fclose(fp);
        return (found);
}
#endif /* YP */

int
getgrouplist(const char *uname, gid_t agroup, gid_t *groups, int *grpcnt)
{
        int i, ngroups = 0, maxgroups = *grpcnt, bail;
        int needyp = 0, foundyp = 0;
        int *skipyp = &foundyp;
        extern struct group *_getgrent_yp(int *);
        struct group *grp;

        /*
         * install primary group
         */
        if (ngroups >= maxgroups)
                ngroups++;
        else
                groups[ngroups++] = agroup;

        /*
         * Scan the group file to find additional groups.
         */
        setgrent();
        while ((grp = _getgrent_yp(skipyp)) || foundyp) {
                if (foundyp) {
                        if (foundyp > 0)
                                needyp = 1;
                        else
                                skipyp = NULL;
                        foundyp = 0;
                        continue;
                }
                if (grp->gr_gid == agroup)
                        continue;
                for (bail = 0, i = 0; bail == 0 && i < maxgroups &&
                    i < ngroups; i++) {
                        if (groups[i] == grp->gr_gid)
                                bail = 1;
                }
                if (bail)
                        continue;
                for (i = 0; grp->gr_mem[i]; i++) {
                        if (!strcmp(grp->gr_mem[i], uname)) {
                                if (ngroups >= maxgroups)
                                        ngroups++;
                                else
                                        groups[ngroups++] = grp->gr_gid;
                                break;
                        }
                }
        }

#ifdef YP
        /*
         * If we were told that there is a YP marker, look at netid data.
         */
        if (skipyp && needyp) {
                char buf[MAXLINELENGTH], *ypdata = NULL, *key;
                static char *__ypdomain;
                struct passwd pwstore;
                int ypdatalen;

                /* Construct the netid key to look up. */
                if (getpwnam_r(uname, &pwstore, buf, sizeof buf, NULL) ||
                    (!__ypdomain && yp_get_default_domain(&__ypdomain)))
                        goto out;
                i = asprintf(&key, "unix.%u@%s", pwstore.pw_uid, __ypdomain);
                if (i == -1)
                        goto out;

                /* First scan the static netid file. */
                if (_read_netid(key, pwstore.pw_uid, groups, &ngroups,
                    maxgroups)) {
                        free(key);
                        goto out;
                }

                /* Only access YP when there is no static entry. */
                if (!yp_match(__ypdomain, "netid.byname", key,
                    (int)strlen(key), &ypdata, &ypdatalen))
                        _parse_netid(ypdata, pwstore.pw_uid, groups, &ngroups,
                            maxgroups);

                free(key);
                free(ypdata);
        }
#endif /* YP */

out:
        endgrent();
        *grpcnt = ngroups;
        return (ngroups > maxgroups ? -1 : 0);
}
DEF_WEAK(getgrouplist);