libnsl/rpc/netnamer.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
 */
/* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
 * Portions of this source code were derived from Berkeley
 * 4.3 BSD under license from the Regents of the University of
 * California.
 */
/*
 * ==== hack-attack:  possibly MT-safe but definitely not MT-hot.
 * ==== turn this into a real switch frontend and backends
 *
 * Well, at least the API doesn't involve pointers-to-static.
 */

/*
 * netname utility routines convert from netnames to unix names (uid, gid)
 *
 * This module is operating system dependent!
 * What we define here will work with any unix system that has adopted
 * the Sun NIS domain architecture.
 */

#undef NIS
#include "mt.h"
#include "rpc_mt.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <alloca.h>
#include <sys/types.h>
#include <ctype.h>
#include <grp.h>
#include <pwd.h>
#include <string.h>
#include <syslog.h>
#include <sys/param.h>
#include <nsswitch.h>
#include <rpc/rpc.h>
#include <rpcsvc/nis.h>
#include <rpcsvc/ypclnt.h>
#include <nss_dbdefs.h>

static const char    OPSYS[]    = "unix";
static const char    NETIDFILE[] = "/etc/netid";
static const char    NETID[]    = "netid.byname";
#define OPSYS_LEN 4

extern int _getgroupsbymember(const char *, gid_t[], int, int);

/*
 * the value for NOBODY_UID is set by the SVID. The following define also
 * appears in netname.c
 */

#define NOBODY_UID 60001

/*
 *  default publickey policy:
 *      publickey: nis [NOTFOUND = return] files
 */


/*      NSW_NOTSUCCESS  NSW_NOTFOUND   NSW_UNAVAIL    NSW_TRYAGAIN */
#define DEF_ACTION {__NSW_RETURN, __NSW_RETURN, __NSW_CONTINUE, __NSW_CONTINUE}

static struct __nsw_lookup lookup_files = {"files", DEF_ACTION, NULL, NULL},
        lookup_nis = {"nis", DEF_ACTION, NULL, &lookup_files};
static struct __nsw_switchconfig publickey_default =
            {0, "publickey", 2, &lookup_nis};

static mutex_t serialize_netname_r = DEFAULTMUTEX;

struct netid_userdata {
    uid_t   *uidp;
    gid_t   *gidp;
    int *gidlenp;
    gid_t   *gidlist;
};

static int
parse_uid(char *s, struct netid_userdata *argp)
{
    uid_t   u;

    if (!s || !isdigit(*s)) {
        syslog(LOG_ERR,
            "netname2user: expecting uid '%s'", s);
        return (__NSW_NOTFOUND); /* xxx need a better error */
    }

    /* Fetch the uid */
    u = (uid_t)(atoi(s));

    if (u == 0) {
        syslog(LOG_ERR, "netname2user: should not have uid 0");
        return (__NSW_NOTFOUND);
    }
    *(argp->uidp) = u;
    return (__NSW_SUCCESS);
}


/* parse a comma separated gid list */
static int
parse_gidlist(char *p, struct netid_userdata *argp)
{
    int len;
    gid_t   g;

    if (!p || (!isdigit(*p))) {
        syslog(LOG_ERR,
            "netname2user: missing group id list in '%s'.",
            p);
        return (__NSW_NOTFOUND);
    }

    g = (gid_t)(atoi(p));
    *(argp->gidp) = g;

    len = 0;
    while (p = strchr(p, ','))
        argp->gidlist[len++] = (gid_t)atoi(++p);
    *(argp->gidlenp) = len;
    return (__NSW_SUCCESS);
}


/*
 * parse_netid_str()
 *
 * Parse uid and group information from the passed string.
 *
 * The format of the string passed is
 *  uid:gid,grp,grp, ...
 *
 */
static int
parse_netid_str(char *s, struct netid_userdata *argp)
{
    char    *p;
    int err;

    /* get uid */
    err = parse_uid(s, argp);
    if (err != __NSW_SUCCESS)
        return (err);

    /* Now get the group list */
    p = strchr(s, ':');
    if (!p) {
        syslog(LOG_ERR,
            "netname2user: missing group id list in '%s'", s);
        return (__NSW_NOTFOUND);
    }
    ++p;            /* skip ':' */
    err = parse_gidlist(p, argp);
    return (err);
}

/*
 * netname2user_files()
 *
 * This routine fetches the netid information from the "files" nameservice.
 * ie /etc/netid.
 */
static int
netname2user_files(int *err, char *netname, struct netid_userdata *argp)
{
    char    buf[512];   /* one line from the file */
    char    *name;
    char    *value;
    char    *res;
    FILE    *fd;

    fd = fopen(NETIDFILE, "rF");
    if (fd == NULL) {
        *err = __NSW_UNAVAIL;
        return (0);
    }
    /*
     * for each line in the file parse it appropriately
     * file format is :
     *  netid   uid:grp,grp,grp # for users
     *  netid   0:hostname  # for hosts
     */
    while (!feof(fd)) {
        res = fgets(buf, 512, fd);
        if (res == NULL)
            break;

        /* Skip comments and blank lines */
        if ((*res == '#') || (*res == '\n'))
            continue;

        name = &(buf[0]);
        while (isspace(*name))
            name++;
        if (*name == '\0')  /* blank line continue */
            continue;
        value = name;       /* will contain the value eventually */
        while (!isspace(*value))
            value++;
        if (*value == '\0') {
            syslog(LOG_WARNING,
                "netname2user: badly formatted line in %s.",
                NETIDFILE);
            continue;
        }
        *value++ = '\0'; /* nul terminate the name */

        if (strcasecmp(name, netname) == 0) {
            (void) fclose(fd);
            while (isspace(*value))
                value++;
            *err = parse_netid_str(value, argp);
            return (*err == __NSW_SUCCESS);
        }
    }
    (void) fclose(fd);
    *err = __NSW_NOTFOUND;
    return (0);
}

/*
 * netname2user_nis()
 *
 * This function reads the netid from the NIS (YP) nameservice.
 */
static int
netname2user_nis(int *err, char *netname, struct netid_userdata *argp)
{
    char *domain;
    int yperr;
    char *lookup;
    int len;

    domain = strchr(netname, '@');
    if (!domain) {
        *err = __NSW_UNAVAIL;
        return (0);
    }

    /* Point past the '@' character */
    domain++;
    lookup = NULL;
    yperr = yp_match(domain, (char *)NETID, netname, strlen(netname),
        &lookup, &len);
    switch (yperr) {
        case 0:
            break; /* the successful case */

        default :
            /*
             *  XXX not sure about yp_match semantics.
             * should err be set to NOTFOUND here?
             */
            *err = __NSW_UNAVAIL;
            return (0);
    }
    if (lookup) {
        lookup[len] = '\0';
        *err = parse_netid_str(lookup, argp);
        free(lookup);
        return (*err == __NSW_SUCCESS);
    }
    *err = __NSW_NOTFOUND;
    return (0);
}

/*
 * Build the uid and gid from the netname for users in LDAP.
 * There is no netid container in LDAP. For this we build
 * the netname to user data dynamically from the passwd and
 * group data. This works only for users in a single domain.
 * This function is an interim solution until we support a
 * netid container in LDAP which enables us to do netname2user
 * resolution for multiple domains.
 */
static int
netname2user_ldap(int *err, char *netname, struct netid_userdata *argp)
{
    char buf[NSS_LINELEN_PASSWD];
    char *p2, *lasts;
    struct passwd pw;
    uid_t uidnu;
    int ngroups = 0;
    int count;
    char pwbuf[NSS_LINELEN_PASSWD];
    int maxgrp = sysconf(_SC_NGROUPS_MAX);
    gid_t *groups = alloca(maxgrp * sizeof (gid_t));

    if (strlcpy(buf, netname, NSS_LINELEN_PASSWD) >= NSS_LINELEN_PASSWD) {
        *err = __NSW_UNAVAIL;
        return (0);
    }

    /* get the uid from the netname */
    if (strtok_r(buf, ".", &lasts) == NULL) {
        *err = __NSW_UNAVAIL;
        return (0);
    }
    if ((p2 = strtok_r(NULL, "@", &lasts)) == NULL) {
        *err = __NSW_UNAVAIL;
        return (0);
    }
    uidnu = atoi(p2);

    /*
     * check out the primary group and crosscheck the uid
     * with the passwd data
     */
    if ((getpwuid_r(uidnu, &pw, pwbuf, sizeof (pwbuf))) == NULL) {
        *err = __NSW_UNAVAIL;
        return (0);
    }

    *(argp->uidp) = pw.pw_uid;
    *(argp->gidp) = pw.pw_gid;

    /* search through all groups for membership */

    groups[0] = pw.pw_gid;

    ngroups = _getgroupsbymember(pw.pw_name, groups, maxgrp,
        (pw.pw_gid <= MAXUID) ? 1 : 0);

    if (ngroups < 0) {
        *err = __NSW_UNAVAIL;
        return (0);
    }

    *(argp->gidlenp) = ngroups;

    for (count = 0; count < ngroups; count++) {
        (argp->gidlist[count]) = groups[count];
    }

    *err = __NSW_SUCCESS;
    return (1);

}

/*
 * Convert network-name into unix credential
 */
int
netname2user(const char netname[MAXNETNAMELEN + 1], uid_t *uidp, gid_t *gidp,
                        int *gidlenp, gid_t *gidlist)
{
    struct __nsw_switchconfig *conf;
    struct __nsw_lookup *look;
    enum __nsw_parse_err perr;
    int needfree = 1, res;
    struct netid_userdata argp;
    int err;

    /*
     * Take care of the special case of nobody. Compare the netname
     * to the string "nobody". If they are equal, return the SVID
     * standard value for nobody.
     */

    if (strcmp(netname, "nobody") == 0) {
        *uidp = NOBODY_UID;
        *gidp = NOBODY_UID;
        *gidlenp = 0;
        return (1);
    }

    /*
     * First we do some generic sanity checks on the name we were
     * passed. This lets us assume they are correct in the backends.
     *
     * NOTE: this code only recognizes names of the form :
     *      unix.UID@domainname
     */
    if (strncmp(netname, OPSYS, OPSYS_LEN) != 0)
        return (0);
    if (!isdigit(netname[OPSYS_LEN+1])) /* check for uid string */
        return (0);

    argp.uidp = uidp;
    argp.gidp = gidp;
    argp.gidlenp = gidlenp;
    argp.gidlist = gidlist;
    (void) mutex_lock(&serialize_netname_r);

    conf = __nsw_getconfig("publickey", &perr);
    if (!conf) {
        conf = &publickey_default;
        needfree = 0;
    } else
        needfree = 1; /* free the config structure */

    for (look = conf->lookups; look; look = look->next) {
        if (strcmp(look->service_name, "nis") == 0)
            res = netname2user_nis(&err, (char *)netname, &argp);
        else if (strcmp(look->service_name, "files") == 0)
            res = netname2user_files(&err, (char *)netname, &argp);
        else if (strcmp(look->service_name, "ldap") == 0)
            res = netname2user_ldap(&err, (char *)netname, &argp);
        else {
            syslog(LOG_INFO,
                "netname2user: unknown nameservice for publickey"
                "info '%s'\n", look->service_name);
            err = __NSW_UNAVAIL;
            res = 0;
        }
        switch (look->actions[err]) {
            case __NSW_CONTINUE :
                break;
            case __NSW_RETURN :
                if (needfree)
                    (void) __nsw_freeconfig(conf);
                (void) mutex_unlock(&serialize_netname_r);
                return (res);
            default :
                syslog(LOG_ERR,
                    "netname2user: Unknown action for "
                    "nameservice '%s'", look->service_name);
        }
    }
    if (needfree)
        (void) __nsw_freeconfig(conf);
    (void) mutex_unlock(&serialize_netname_r);
    return (0);
}

/*
 * Convert network-name to hostname (fully qualified)
 * NOTE: this code only recognizes names of the form :
 *      unix.HOST@domainname
 *
 * This is very simple.  Since the netname is of the form:
 *  unix.host@domainname
 * We just construct the hostname using information from the domainname.
 */
int
netname2host(const char netname[MAXNETNAMELEN + 1], char *hostname,
                            const int hostlen)
{
    char *p, *domainname;
    int len, dlen;

    if (!netname) {
        syslog(LOG_ERR, "netname2host: null netname");
        goto bad_exit;
    }

    if (strncmp(netname, OPSYS, OPSYS_LEN) != 0)
        goto bad_netname;
    p = (char *)netname + OPSYS_LEN;    /* skip OPSYS part */
    if (*p != '.')
        goto bad_netname;
    ++p;                /* skip '.' */

    domainname = strchr(p, '@');    /* get domain name */
    if (domainname == 0)
        goto bad_netname;

    len = domainname - p;       /* host sits between '.' and '@' */
    domainname++;           /* skip '@' sign */

    if (len <= 0)
        goto bad_netname;

    if (hostlen < len) {
        syslog(LOG_ERR,
            "netname2host: insufficient space for hostname");
        goto bad_exit;
    }

    if (isdigit(*p))        /* don't want uid here */
        goto bad_netname;

    if (*p == '\0')         /* check for null hostname */
        goto bad_netname;

    (void) strncpy(hostname, p, len);

    /* make into fully qualified hostname by concatenating domain part */
    dlen = strlen(domainname);
    if (hostlen < (len + dlen + 2)) {
        syslog(LOG_ERR,
            "netname2host: insufficient space for hostname");
        goto bad_exit;
    }

    hostname[len] = '.';
    (void) strncpy(hostname+len+1, domainname, dlen);
    hostname[len+dlen+1] = '\0';

    return (1);

bad_netname:
    syslog(LOG_ERR, "netname2host: invalid host netname %s", netname);

bad_exit:
    hostname[0] = '\0';
    return (0);
}