rlm_unix.c

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/*
 *   This program is 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 2 of the License, or (at
 *   your option) any later version.
 *
 *   This program 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, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

/**
 * $Id: 329ed2916ae82a2a17f60377f26d5a21d7777f3d $
 * @file rlm_unix.c
 * @brief Unixy things
 *
 * authentication: Unix user authentication
 * accounting:     Functions to write radwtmp file.
 * Also contains handler for "Group".
 *
 * @copyright 2000,2006  The FreeRADIUS server project
 * @copyright 2000  Jeff Carneal <jeff@apex.net>
 * @copyright 2000  Alan Curry <pacman@world.std.com>
 */
RCSID("$Id: 329ed2916ae82a2a17f60377f26d5a21d7777f3d $")
USES_APPLE_DEPRECATED_API

#include        <freeradius-devel/radiusd.h>

#include        <grp.h>
#include        <pwd.h>
#include        <sys/stat.h>

#include "config.h"

#ifdef HAVE_SHADOW_H
#  include      <shadow.h>
#endif

#ifdef OSFC2
#  include      <sys/security.h>
#  include      <prot.h>
#endif

#ifdef OSFSIA
#  include      <sia.h>
#  include      <siad.h>
#endif

#include        <freeradius-devel/modules.h>
#include        <freeradius-devel/sysutmp.h>

static char trans[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
#define ENC(c) trans[c]

typedef struct rlm_unix {
        char const *name;       //!< Instance name.
        char const *radwtmp;
} rlm_unix_t;

static const CONF_PARSER module_config[] = {
        { FR_CONF_OFFSET("radwtmp", PW_TYPE_FILE_OUTPUT | PW_TYPE_REQUIRED, rlm_unix_t, radwtmp), .dflt = "NULL" },
        CONF_PARSER_TERMINATOR
};

/*
 *      The Group = handler.
 */
static int groupcmp(UNUSED void *instance, REQUEST *request, UNUSED VALUE_PAIR *req_vp,
                    VALUE_PAIR *check, UNUSED VALUE_PAIR *check_pairs,
                    UNUSED VALUE_PAIR **reply_pairs)
{
        struct passwd   *pwd;
        struct group    *grp;
        char            **member;
        int             retval = -1;

        /*
         *      No user name, can't compare.
         */
        if (!request->username) return -1;

        if (rad_getpwnam(request, &pwd, request->username->vp_strvalue) < 0) {
                RDEBUG("%s", fr_strerror());
                return -1;
        }

        if (rad_getgrnam(request, &grp, check->vp_strvalue) < 0) {
                RDEBUG("%s", fr_strerror());
                talloc_free(pwd);
                return -1;
        }

        /*
         *      The users default group isn't the one we're looking for,
         *      look through the list of group members.
         */
        if (pwd->pw_gid == grp->gr_gid) {
                retval = 0;

        } else {
                for (member = grp->gr_mem; *member && retval; member++) {
                        if (strcmp(*member, pwd->pw_name) == 0) {
                                retval = 0;
                                break;
                        }
                }
        }

        /* lifo */
        talloc_free(grp);
        talloc_free(pwd);

        return retval;
}


/*
 *      Read the config
 */
static int mod_bootstrap(CONF_SECTION *conf, void *instance)
{
        rlm_unix_t *inst = instance;

        fr_dict_attr_t const *group_da, *user_name_da;

        inst->name = cf_section_name2(conf);
        if (!inst->name) {
                inst->name = cf_section_name1(conf);
        }

        group_da = fr_dict_attr_by_num(NULL, 0, PW_GROUP);
        if (!group_da) {
                ERROR("rlm_unix (%s): 'Group' attribute not found in dictionary", inst->name);
                return -1;
        }

        user_name_da = fr_dict_attr_by_num(NULL, 0, PW_USER_NAME);
        if (!user_name_da) {
                ERROR("rlm_unix (%s): 'User-Name' attribute not found in dictionary", inst->name);
                return -1;
        }

        /* FIXME - delay these until a group file has been read so we know
         * groupcmp can actually do something */
        paircompare_register(group_da, user_name_da, false, groupcmp, inst);

#ifdef PW_GROUP_NAME /* compat */
        {
                fr_dict_attr_t const *group_name_da;

                group_name_da = fr_dict_attr_by_num(NULL, 0, PW_GROUP_NAME);
                if (!group_name_da) {
                        ERROR("rlm_unix (%s): 'Group-Name' attribute not found in dictionary", inst->name);
                        return -1;
                }
                paircompare_register(group_name_da, user_name_da, true, groupcmp, inst);
        }
#endif

        if (paircompare_register_byname("Unix-Group", user_name_da, false, groupcmp, inst) < 0) {
                ERROR("rlm_unix (%s): Failed registering Unix-Group: %s", inst->name,
                      fr_strerror());
                return -1;
        }

        return 0;
}


/*
 *      Pull the users password from where-ever, and add it to
 *      the given vp list.
 */
static rlm_rcode_t CC_HINT(nonnull) mod_authorize(UNUSED void *instance, REQUEST *request)
{
        char const      *name;
        char const      *encrypted_pass;
#ifdef HAVE_GETSPNAM
        struct spwd     *spwd = NULL;
#endif
#ifdef OSFC2
        struct pr_passwd *pr_pw;
#else
        struct passwd   *pwd;
#endif
#ifdef HAVE_GETUSERSHELL
        char            *shell;
#endif
        VALUE_PAIR      *vp;

        /*
         *      We can only authenticate user requests which HAVE
         *      a User-Name attribute.
         */
        if (!request->username) {
                return RLM_MODULE_NOOP;
        }

        name = request->username->vp_strvalue;
        encrypted_pass = NULL;

#ifdef OSFC2
        if ((pr_pw = getprpwnam(name)) == NULL)
                return RLM_MODULE_NOTFOUND;
        encrypted_pass = pr_pw->ufld.fd_encrypt;

        /*
         *      Check if account is locked.
         */
        if (pr_pw->uflg.fg_lock!=1) {
                AUTH("rlm_unix: [%s]: account locked", name);
                return RLM_MODULE_USERLOCK;
        }
#else /* OSFC2 */
        if ((pwd = getpwnam(name)) == NULL) {
                return RLM_MODULE_NOTFOUND;
        }
        encrypted_pass = pwd->pw_passwd;
#endif /* OSFC2 */

#ifdef HAVE_GETSPNAM
        /*
         *      See if there is a shadow password.
         *
         *      Only query the _system_ shadow file if the encrypted
         *      password from the passwd file is < 10 characters (i.e.
         *      a valid password would never crypt() to it).  This will
         *      prevents users from using NULL password fields as things
         *      stand right now.
         */
        if ((!encrypted_pass) || (strlen(encrypted_pass) < 10)) {
                if ((spwd = getspnam(name)) == NULL) {
                        return RLM_MODULE_NOTFOUND;
                }
                encrypted_pass = spwd->sp_pwdp;
        }
#endif  /* HAVE_GETSPNAM */

/*
 *      These require 'pwd != NULL', which isn't true on OSFC2
 */
#ifndef OSFC2
#ifdef DENY_SHELL
        /*
         *      Users with a particular shell are denied access
         */
        if (strcmp(pwd->pw_shell, DENY_SHELL) == 0) {
                RAUTH("rlm_unix: [%s]: invalid shell", name);
                return RLM_MODULE_REJECT;
        }
#endif

#ifdef HAVE_GETUSERSHELL
        /*
         *      Check /etc/shells for a valid shell. If that file
         *      contains /RADIUSD/ANY/SHELL then any shell will do.
         */
        while ((shell = getusershell()) != NULL) {
                if (strcmp(shell, pwd->pw_shell) == 0 ||
                    strcmp(shell, "/RADIUSD/ANY/SHELL") == 0) {
                        break;
                }
        }
        endusershell();
        if (!shell) {
                RAUTH("[%s]: invalid shell [%s]",
                       name, pwd->pw_shell);
                return RLM_MODULE_REJECT;
        }
#endif
#endif /* OSFC2 */

#if defined(HAVE_GETSPNAM) && !defined(M_UNIX)
        /*
         *      Check if password has expired.
         */
        if (spwd && spwd->sp_lstchg > 0 && spwd->sp_max >= 0 &&
            (request->timestamp.tv_sec / 86400) > (spwd->sp_lstchg + spwd->sp_max)) {
                RAUTH("[%s]: password has expired", name);
                return RLM_MODULE_REJECT;
        }
        /*
         *      Check if account has expired.
         */
        if (spwd && spwd->sp_expire > 0 &&
            (request->timestamp.tv_sec / 86400) > spwd->sp_expire) {
                RAUTH("[%s]: account has expired", name);
                return RLM_MODULE_REJECT;
        }
#endif

#if defined(__FreeBSD__) || defined(bsdi) || defined(_PWF_EXPIRE)
        /*
         *      Check if password has expired.
         */
        if ((pwd->pw_expire > 0) &&
            (request->timestamp.tv_sec > pwd->pw_expire)) {
                RAUTH("[%s]: password has expired", name);
                return RLM_MODULE_REJECT;
        }
#endif

        /*
         *      We might have a passwordless account.
         *
         *      FIXME: Maybe add Auth-Type := Accept?
         */
        if (encrypted_pass[0] == 0)
                return RLM_MODULE_NOOP;

        vp = pair_make_config("Crypt-Password", encrypted_pass, T_OP_SET);
        if (!vp) return RLM_MODULE_FAIL;

        return RLM_MODULE_UPDATED;
}


/*
 *      UUencode 4 bits base64. We use this to turn a 4 byte field
 *      (an IP address) into 6 bytes of ASCII. This is used for the
 *      wtmp file if we didn't find a short name in the naslist file.
 */
static char *uue(void *in)
{
        int i;
        static unsigned char res[7];
        unsigned char *data = (unsigned char *)in;

        res[0] = ENC( data[0] >> 2 );
        res[1] = ENC( ((data[0] << 4) & 060) + ((data[1] >> 4) & 017) );
        res[2] = ENC( ((data[1] << 2) & 074) + ((data[2] >> 6) & 03) );
        res[3] = ENC( data[2] & 077 );

        res[4] = ENC( data[3] >> 2 );
        res[5] = ENC( (data[3] << 4) & 060 );
        res[6] = 0;

        for(i = 0; i < 6; i++) {
                if (res[i] == ' ') res[i] = '`';
                if (res[i] < 32 || res[i] > 127)
                        printf("uue: protocol error ?!\n");
        }
        return (char *)res;
}


/*
 *      Unix accounting - write a wtmp file.
 */
static rlm_rcode_t CC_HINT(nonnull) mod_accounting(void *instance, REQUEST *request)
{
        VALUE_PAIR      *vp;
        vp_cursor_t     cursor;
        FILE            *fp;
        struct utmp     ut;
        time_t          t;
        char            buf[64];
        char const      *s;
        int             delay = 0;
        int             status = -1;
        int             nas_address = 0;
        int             framed_address = 0;
#ifdef USER_PROCESS
        int             protocol = -1;
#endif
        uint32_t        nas_port = 0;
        bool            port_seen = true;
        rlm_unix_t *inst = (rlm_unix_t *) instance;

        /*
         *      No radwtmp.  Don't do anything.
         */
        if (!inst->radwtmp) {
                RDEBUG2("No radwtmp file configured.  Ignoring accounting request");
                return RLM_MODULE_NOOP;
        }

        if (request->packet->src_ipaddr.af != AF_INET) {
                RDEBUG2("IPv6 is not supported!");
                return RLM_MODULE_NOOP;
        }

        /*
         *      Which type is this.
         */
        if ((vp = fr_pair_find_by_num(request->packet->vps, 0, PW_ACCT_STATUS_TYPE, TAG_ANY)) == NULL) {
                RDEBUG("no Accounting-Status-Type attribute in request");
                return RLM_MODULE_NOOP;
        }
        status = vp->vp_integer;

        /*
         *      FIXME: handle PW_STATUS_ALIVE like 1.5.4.3 did.
         */
        if (status != PW_STATUS_START &&
            status != PW_STATUS_STOP)
                return RLM_MODULE_NOOP;

        /*
         *      We're only interested in accounting messages
         *      with a username in it.
         */
        if (fr_pair_find_by_num(request->packet->vps, 0, PW_USER_NAME, TAG_ANY) == NULL)
                return RLM_MODULE_NOOP;

        t = request->timestamp.tv_sec;
        memset(&ut, 0, sizeof(ut));

        /*
         *      First, find the interesting attributes.
         */
        for (vp = fr_cursor_init(&cursor, &request->packet->vps);
             vp;
             vp = fr_cursor_next(&cursor)) {
                if (!vp->da->vendor) switch (vp->da->attr) {
                case PW_USER_NAME:
                        if (vp->vp_length >= sizeof(ut.ut_name)) {
                                memcpy(ut.ut_name, vp->vp_strvalue, sizeof(ut.ut_name));
                        } else {
                                strlcpy(ut.ut_name, vp->vp_strvalue, sizeof(ut.ut_name));
                        }
                        break;

                case PW_LOGIN_IP_HOST:
                case PW_FRAMED_IP_ADDRESS:
                        framed_address = vp->vp_ipaddr;
                                break;
#ifdef USER_PROCESS
                case PW_FRAMED_PROTOCOL:
                        protocol = vp->vp_integer;
                        break;
#endif
                case PW_NAS_IP_ADDRESS:
                        nas_address = vp->vp_ipaddr;
                        break;

                case PW_NAS_PORT:
                        nas_port = vp->vp_integer;
                        port_seen = true;
                        break;

                case PW_ACCT_DELAY_TIME:
                        delay = vp->vp_ipaddr;
                        break;
                }
        }

        /*
         *      We don't store !root sessions, or sessions
         *      where we didn't see a NAS-Port attribute.
         */
        if (strncmp(ut.ut_name, "!root", sizeof(ut.ut_name)) == 0 || !port_seen)
                return RLM_MODULE_NOOP;

        /*
         *      If we didn't find out the NAS address, use the
         *      originator's IP address.
         */
        if (nas_address == 0) {
                nas_address = request->packet->src_ipaddr.ipaddr.ip4addr.s_addr;
        }
        s = request->client->shortname;
        if (!s || s[0] == 0) s = uue(&(nas_address));

#ifdef __linux__
        /*
         *      Linux has a field for the client address.
         */
        ut.ut_addr = framed_address;
#endif
        /*
         *      We use the tty field to store the terminal servers' port
         *      and address so that the tty field is unique.
         */
        snprintf(buf, sizeof(buf), "%03d:%s", nas_port, s);
        strlcpy(ut.ut_line, buf, sizeof(ut.ut_line));

        /*
         *      We store the dynamic IP address in the hostname field.
         */
#ifdef UT_HOSTSIZE
        if (framed_address) {
                inet_ntop(AF_INET, &framed_address, buf, sizeof(buf));
                strlcpy(ut.ut_host, buf, sizeof(ut.ut_host));
        }
#endif
#ifdef HAVE_UTMPX_H
        ut.ut_xtime = t- delay;
#else
        ut.ut_time = t - delay;
#endif
#ifdef USER_PROCESS
        /*
         *      And we can use the ID field to store
         *      the protocol.
         */
        if (protocol == PW_PPP)
                strcpy(ut.ut_id, "P");
        else if (protocol == PW_SLIP)
                strcpy(ut.ut_id, "S");
        else
                strcpy(ut.ut_id, "T");
        ut.ut_type = status == PW_STATUS_STOP ? DEAD_PROCESS : USER_PROCESS;
#endif
        if (status == PW_STATUS_STOP)
                ut.ut_name[0] = 0;

        /*
         *      Write a RADIUS wtmp log file.
         *
         *      Try to open the file if we can't, we don't write the
         *      wtmp file. If we can try to write. If we fail,
         *      return RLM_MODULE_FAIL ..
         */
        if ((fp = fopen(inst->radwtmp, "a")) != NULL) {
                if ((fwrite(&ut, sizeof(ut), 1, fp)) != 1) {
                        fclose(fp);
                        return RLM_MODULE_FAIL;
                }
                fclose(fp);
        } else
                return RLM_MODULE_FAIL;

        return RLM_MODULE_OK;
}

/* globally exported name */
extern module_t rlm_unix;
module_t rlm_unix = {
        .magic          = RLM_MODULE_INIT,
        .name           = "unix",
        .type           = RLM_TYPE_THREAD_UNSAFE,
        .inst_size      = sizeof(rlm_unix_t),
        .config         = module_config,
        .bootstrap      = mod_bootstrap,
        .methods = {
                [MOD_AUTHORIZE]         = mod_authorize,
                [MOD_ACCOUNTING]        = mod_accounting
        },
};