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: a66913ce637742e487bb83adf444be9da014964f $
 * @file rlm_unix.c
 * @brief Unixy things
 *
 * @copyright 2000,2006 The FreeRADIUS server project
 * @copyright 2000 Jeff Carneal (jeff@apex.net)
 * @copyright 2000 Alan Curry (pacman@world.std.com)
 */
RCSID("$Id: a66913ce637742e487bb83adf444be9da014964f $")
USES_APPLE_DEPRECATED_API
 
#define LOG_PREFIX mctx->mi->name
 
#include <freeradius-devel/radius/radius.h>
#include <freeradius-devel/server/base.h>
#include <freeradius-devel/server/module_rlm.h>
#include <freeradius-devel/server/sysutmp.h>
#include <freeradius-devel/util/perm.h>
#include <freeradius-devel/unlang/xlat_func.h>
 
#include <grp.h>
#include <pwd.h>
#include <sys/stat.h>
 
#include "config.h"
 
#ifdef HAVE_SHADOW_H
#  include <shadow.h>
#endif
 
static char trans[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
#define ENC(c) trans[c]
 
typedef struct {
        char const *radwtmp;
} rlm_unix_t;
 
static const conf_parser_t module_config[] = {
        { FR_CONF_OFFSET_FLAGS("radwtmp", CONF_FLAG_FILE_INPUT, rlm_unix_t, radwtmp) },
        CONF_PARSER_TERMINATOR
};
 
static fr_dict_t const *dict_freeradius;
static fr_dict_t const *dict_radius;
 
extern fr_dict_autoload_t rlm_unix_dict[];
fr_dict_autoload_t rlm_unix_dict[] = {
        { .out = &dict_freeradius, .proto = "freeradius" },
        { .out = &dict_radius, .proto = "radius" },
        { NULL }
};
 
static fr_dict_attr_t const *attr_auth_type;
static fr_dict_attr_t const *attr_crypt_password;
static fr_dict_attr_t const *attr_user_name;
static fr_dict_attr_t const *attr_login_ip_host;
static fr_dict_attr_t const *attr_framed_ip_address;
static fr_dict_attr_t const *attr_framed_protocol;
static fr_dict_attr_t const *attr_nas_ip_address;
static fr_dict_attr_t const *attr_nas_port;
static fr_dict_attr_t const *attr_acct_status_type;
static fr_dict_attr_t const *attr_acct_delay_time;
static fr_dict_attr_t const *attr_expr_bool_enum;
 
extern fr_dict_attr_autoload_t rlm_unix_dict_attr[];
fr_dict_attr_autoload_t rlm_unix_dict_attr[] = {
        { .out = &attr_auth_type, .name = "Auth-Type", .type = FR_TYPE_UINT32, .dict = &dict_freeradius },
        { .out = &attr_crypt_password, .name = "Password.Crypt", .type = FR_TYPE_STRING, .dict = &dict_freeradius },
        { .out = &attr_user_name, .name = "User-Name", .type = FR_TYPE_STRING, .dict = &dict_radius },
        { .out = &attr_login_ip_host, .name = "Login-IP-Host", .type = FR_TYPE_IPV4_ADDR, .dict = &dict_radius },
        { .out = &attr_framed_ip_address, .name = "Framed-IP-Address", .type = FR_TYPE_IPV4_ADDR, .dict = &dict_radius },
        { .out = &attr_framed_protocol, .name = "Framed-Protocol", .type = FR_TYPE_UINT32, .dict = &dict_radius },
        { .out = &attr_nas_ip_address, .name = "NAS-IP-Address", .type = FR_TYPE_IPV4_ADDR, .dict = &dict_radius },
        { .out = &attr_nas_port, .name = "NAS-Port", .type = FR_TYPE_UINT32, .dict = &dict_radius },
        { .out = &attr_acct_status_type, .name = "Acct-Status-Type", .type = FR_TYPE_UINT32, .dict = &dict_radius },
        { .out = &attr_acct_delay_time, .name = "Acct-Delay-Time", .type = FR_TYPE_UINT32, .dict = &dict_radius },
        { .out = &attr_expr_bool_enum, .name = "Expr-Bool-Enum", .type = FR_TYPE_BOOL, .dict = &dict_freeradius },
        { NULL }
};
 
/** Check if the user is in the given group
 *
 */
static bool CC_HINT(nonnull) unix_check_group(UNUSED rlm_unix_t const *inst, request_t *request, char const *name)
{
        bool            rcode = false;
        struct passwd   *pwd;
        struct group    *grp;
        fr_pair_t       *username;
 
        /*
         *      No user name, can't compare.
         */
        username = fr_pair_find_by_da(&request->request_pairs, NULL, attr_user_name);
        if (!username) return false;
 
        if (fr_perm_getpwnam(request, &pwd, username->vp_strvalue) < 0) {
                RPEDEBUG("Failed resolving user name");
                return false;
        }
 
        if (fr_perm_getgrnam(request, &grp, name) < 0) {
                RPEDEBUG("Failed resolving group name");
                talloc_free(pwd);
                return false;
        }
 
        /*
         *      The users default group may be the one we're looking
         *      for, in which case we use that.
         *
         *      Otherwise, we go through the list of groups to see if the group name matches.
         */
        if (pwd->pw_gid == grp->gr_gid) {
                rcode = true;
 
        } else {
                char **member;
 
                for (member = grp->gr_mem; *member; member++) {
                        if (strcmp(*member, pwd->pw_name) == 0) {
                                rcode = true;
                                break;
                        }
                }
        }
 
        /* lifo */
        talloc_free(grp);
        talloc_free(pwd);
 
        return rcode;
}
 
 
/** Check if the user is a member of a particular unix group
 *
@verbatim
%unix.group(<name>)
@endverbatim
 *
 * @ingroup xlat_functions
 */
static xlat_action_t unix_group_xlat(TALLOC_CTX *ctx, fr_dcursor_t *out,
                                     xlat_ctx_t const *xctx,
                                     request_t *request, fr_value_box_list_t *in)
{
        rlm_unix_t const        *inst = talloc_get_type_abort(xctx->mctx->mi->data, rlm_unix_t);
        fr_value_box_t          *arg = fr_value_box_list_head(in);
        char const              *p = arg->vb_strvalue;
        fr_value_box_t          *vb;
 
        fr_skip_whitespace(p);
 
        MEM(vb = fr_value_box_alloc(ctx, FR_TYPE_BOOL, attr_expr_bool_enum));
        vb->vb_bool = unix_check_group(inst, request, p);
        fr_dcursor_append(out, vb);
 
        return XLAT_ACTION_DONE;
}
 
 
/*
 *      Read the config
 */
static int mod_bootstrap(module_inst_ctx_t const *mctx)
{
        xlat_t                  *xlat;
        xlat_arg_parser_t       *xlat_arg;
 
        /*
         *      Define the new %unix.group(name) xlat.  The register
         *      function automatically adds the module instance name
         *      as a prefix.
         */
        xlat = module_rlm_xlat_register(mctx->mi->boot, mctx, "group", unix_group_xlat, FR_TYPE_BOOL);
        if (!xlat) {
                PERROR("Failed registering group expansion");
                return -1;
        }
 
        /*
         *      The xlat escape function needs access to inst - so
         *      argument parser details need to be defined here
         */
        xlat_arg = talloc_zero_array(xlat, xlat_arg_parser_t, 2);
        xlat_arg[0] = (xlat_arg_parser_t) {
                .type = FR_TYPE_STRING,
                .required = true,
                .concat = true
        };
        xlat_arg[1] = (xlat_arg_parser_t)XLAT_ARG_PARSER_TERMINATOR;
 
        xlat_func_args_set(xlat, xlat_arg);
 
        return 0;
}
 
 
/*
 *      Pull the users password from where-ever, and add it to
 *      the given vp list.
 */
static unlang_action_t CC_HINT(nonnull) mod_authorize(rlm_rcode_t *p_result, UNUSED module_ctx_t const *mctx, request_t *request)
{
        char const      *name;
        char const      *encrypted_pass;
#ifdef HAVE_GETSPNAM
        struct spwd     *spwd = NULL;
#endif
        struct passwd   *pwd;
#ifdef HAVE_GETUSERSHELL
        char            *shell;
#endif
        fr_pair_t       *vp;
        fr_pair_t       *username;
 
        /*
         *      We can only authenticate user requests which HAVE
         *      a User-Name attribute.
         */
        username = fr_pair_find_by_da(&request->request_pairs, NULL, attr_user_name);
        if (!username) RETURN_MODULE_NOOP;
 
        name = username->vp_strvalue;
        encrypted_pass = NULL;
 
        if ((pwd = getpwnam(name)) == NULL) {
                RETURN_MODULE_NOTFOUND;
        }
        encrypted_pass = pwd->pw_passwd;
 
#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_MODULE_NOTFOUND;
                }
                encrypted_pass = spwd->sp_pwdp;
        }
#endif  /* HAVE_GETSPNAM */
 
#ifdef DENY_SHELL
        /*
         *      Users with a particular shell are denied access
         */
        if (strcmp(pwd->pw_shell, DENY_SHELL) == 0) {
                REDEBUG("Invalid shell", name);
                RETURN_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) {
                REDEBUG("[%s]: invalid shell [%s]", name, pwd->pw_shell);
                RETURN_MODULE_REJECT;
        }
#endif
 
#if defined(HAVE_GETSPNAM) && !defined(M_UNIX)
        /*
         *      Check if password has expired.
         */
        if (spwd && spwd->sp_lstchg > 0 && spwd->sp_max >= 0 &&
            (fr_time_to_sec(request->packet->timestamp) / 86400) > (spwd->sp_lstchg + spwd->sp_max)) {
                REDEBUG("[%s]: password has expired", name);
                RETURN_MODULE_REJECT;
        }
        /*
         *      Check if account has expired.
         */
        if (spwd && spwd->sp_expire > 0 &&
            (fr_time_to_sec(request->packet->timestamp) / 86400) > spwd->sp_expire) {
                REDEBUG("[%s]: account has expired", name);
                RETURN_MODULE_REJECT;
        }
#endif
 
#if defined(__FreeBSD__) || defined(bsdi) || defined(_PWF_EXPIRE)
        /*
         *      Check if password has expired.
         */
        if ((pwd->pw_expire > 0) &&
            (fr_time_to_sec(request->packet->timestamp) > pwd->pw_expire)) {
                REDEBUG("[%s]: password has expired", name);
                RETURN_MODULE_REJECT;
        }
#endif
 
        /*
         *      We might have a passwordless account.
         *
         *      FIXME: Maybe add Auth-Type := Accept?
         */
        if (encrypted_pass[0] == 0)
                RETURN_MODULE_NOOP;
 
        MEM(pair_update_control(&vp, attr_crypt_password) >= 0);
        fr_pair_value_strdup(vp, encrypted_pass, false);
 
        RETURN_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 unlang_action_t CC_HINT(nonnull) mod_accounting(rlm_rcode_t *p_result, module_ctx_t const *mctx, request_t *request)
{
        rlm_unix_t const        *inst = talloc_get_type_abort_const(mctx->mi->data, rlm_unix_t);
        fr_pair_t               *vp;
        FILE                    *fp;
        struct utmp             ut;
        uint64_t                t;
        char                    buf[64];
        char const              *s = NULL;
        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;
        fr_client_t             *client;
 
        /*
         *      No radwtmp.  Don't do anything.
         */
        if (!inst->radwtmp) {
                RDEBUG2("No radwtmp file configured.  Ignoring accounting request");
                RETURN_MODULE_NOOP;
        }
 
        if (request->packet->socket.inet.src_ipaddr.af != AF_INET) {
                RDEBUG2("IPv6 is not supported!");
                RETURN_MODULE_NOOP;
        }
 
        /*
         *      Which type is this.
         */
        if ((vp = fr_pair_find_by_da(&request->request_pairs, NULL, attr_acct_status_type)) == NULL) {
                RDEBUG2("no Accounting-Status-Type attribute in request");
                RETURN_MODULE_NOOP;
        }
        status = vp->vp_uint32;
 
        /*
         *      Maybe handle ALIVE, too?
         */
        if (status != FR_STATUS_START &&
            status != FR_STATUS_STOP)
                RETURN_MODULE_NOOP;
 
        /*
         *      We're only interested in accounting messages
         *      with a username in it.
         */
        if (fr_pair_find_by_da(&request->request_pairs, NULL, attr_user_name) == NULL)
                RETURN_MODULE_NOOP;
 
        t = fr_time_to_sec(request->packet->timestamp);
        memset(&ut, 0, sizeof(ut));
 
        /*
         *      First, find the interesting attributes.
         */
        for (vp = fr_pair_list_head(&request->request_pairs);
             vp;
             vp = fr_pair_list_next(&request->request_pairs, vp)) {
                if (vp->da == attr_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));
                        }
 
                } else if (vp->da == attr_login_ip_host ||
                           vp->da == attr_framed_ip_address) {
                        framed_address = vp->vp_ipv4addr;
 
#ifdef USER_PROCESS
                } else if (vp->da == attr_framed_protocol) {
                        protocol = vp->vp_uint32;
#endif
                } else if (vp->da == attr_nas_ip_address) {
                        nas_address = vp->vp_ipv4addr;
 
                } else if (vp->da == attr_nas_port) {
                        nas_port = vp->vp_uint32;
                        port_seen = true;
 
                } else if (vp->da == attr_acct_delay_time) {
                        uint32_t delay;
 
                        delay = vp->vp_uint32;
 
                        if (t < delay) RETURN_MODULE_FAIL;
 
                        t -= delay;
                }
        }
        if (t > UINT32_MAX) RETURN_MODULE_FAIL;
 
        /*
         *      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_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->socket.inet.src_ipaddr.addr.v4.s_addr;
        }
 
        client = client_from_request(request);
        if (client) s = 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), "%03u:%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 USE_UTMPX
        ut.ut_xtime = t;
#else
        ut.ut_time = t;
#endif
#ifdef USER_PROCESS
        /*
         *      And we can use the ID field to store
         *      the protocol.
         */
        if (protocol == FR_PPP)
                strcpy(ut.ut_id, "P");
        else if (protocol == FR_SLIP)
                strcpy(ut.ut_id, "S");
        else
                strcpy(ut.ut_id, "T");
        ut.ut_type = status == FR_STATUS_STOP ? DEAD_PROCESS : USER_PROCESS;
#endif
        if (status == FR_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_MODULE_FAIL;
                }
                fclose(fp);
        } else
                RETURN_MODULE_FAIL;
 
        RETURN_MODULE_OK;
}
 
/* globally exported name */
extern module_rlm_t rlm_unix;
module_rlm_t rlm_unix = {
        .common = {
                .magic          = MODULE_MAGIC_INIT,
                .name           = "unix",
                .flags          = MODULE_TYPE_THREAD_UNSAFE,
                .inst_size      = sizeof(rlm_unix_t),
                .config         = module_config,
                .bootstrap      = mod_bootstrap
        },
        .method_group = {
                .bindings = (module_method_binding_t[]){
                        { .section = SECTION_NAME("accounting", CF_IDENT_ANY), .method = mod_accounting },
                        { .section = SECTION_NAME("recv", "Access-Request"), .method = mod_authorize },
                        { .section = SECTION_NAME("send", "Accounting-Response"), .method = mod_accounting },   /* Backwards compatibility */
                        MODULE_BINDING_TERMINATOR
                }
        }
};