libnwam/common/libnwam_backend.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 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <assert.h>
#include <auth_attr.h>
#include <auth_list.h>
#include <bsm/adt.h>
#include <bsm/adt_event.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <pwd.h>
#include <secdb.h>
#include <stdlib.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <strings.h>
#include <unistd.h>

#include "libnwam_impl.h"
#include <libnwam_priv.h>
#include <libnwam.h>

/*
 * Communicate with and implement library backend (running in netcfgd) to
 * retrieve or change NWAM configuration.
 */

static int backend_door_client_fd = -1;

/*
 * Check if uid has proper auths.  flags is used to check auths for
 * enable/disable of profiles and manipulation of Known WLANs.
 */
static nwam_error_t
nwam_check_auths(uid_t uid, boolean_t write, uint64_t flags)
{
    struct passwd *pwd;
    nwam_error_t err = NWAM_SUCCESS;

    if ((pwd = getpwuid(uid)) == NULL) {
        endpwent();
        return (NWAM_PERMISSION_DENIED);
    }

    if (flags & NWAM_FLAG_ENTITY_ENABLE) {
        /* Enabling/disabling profile - need SELECT auth */
        if (chkauthattr(AUTOCONF_SELECT_AUTH, pwd->pw_name) == 0)
            err = NWAM_PERMISSION_DENIED;

    } else if (flags & NWAM_FLAG_ENTITY_KNOWN_WLAN) {
        /* Known WLAN activity - need WLAN auth */
        if (chkauthattr(AUTOCONF_WLAN_AUTH, pwd->pw_name) == 0)
            err = NWAM_PERMISSION_DENIED;

    } else {
        /*
         * First, check for WRITE, since it implies READ.  If this
         * auth is not present, and write is true, fail, otherwise
         * check for READ.
         */
        if (chkauthattr(AUTOCONF_WRITE_AUTH, pwd->pw_name) == 0) {
            if (write) {
                err = NWAM_PERMISSION_DENIED;
            } else {
                if (chkauthattr(AUTOCONF_READ_AUTH,
                    pwd->pw_name) == 0)
                    err = NWAM_PERMISSION_DENIED;
            }
        }
    }

    endpwent();
    return (err);
}

static nwam_error_t
nwam_create_backend_door_arg(nwam_backend_door_cmd_t cmd,
    const char *dbname, const char *objname, uint64_t flags,
    void *obj, nwam_backend_door_arg_t *arg)
{
    nwam_error_t err;
    size_t datalen = 0;
    caddr_t dataptr;

    switch (cmd) {
    case NWAM_BACKEND_DOOR_CMD_READ_REQ:
        /*
         * For a read request,  we want the full buffer to be
         * available for the backend door to write to.
         */
        datalen = NWAM_BACKEND_DOOR_ARG_SIZE;
        break;

    case NWAM_BACKEND_DOOR_CMD_UPDATE_REQ:
        /*
         * An update request may either specify an object list
         * (which we pack into the buffer immediately after the
         * backend door request) or may not specify an object
         * (signifying a request to create the container of the
         * object).
         */
        if (obj == NULL) {
            datalen = 0;
            break;
        }
        /* Data immediately follows the descriptor */
        dataptr = (caddr_t)arg + sizeof (nwam_backend_door_arg_t);
        datalen = NWAM_BACKEND_DOOR_ARG_SIZE;
        /* pack object list for update request,  adjusting datalen */
        if ((err = nwam_pack_object_list(obj, (char **)&dataptr,
            &datalen)) != NWAM_SUCCESS)
            return (err);
        break;

    case NWAM_BACKEND_DOOR_CMD_REMOVE_REQ:
        /* A remove request has no associated object list. */
        datalen = 0;
        break;

    default:
        return (NWAM_INVALID_ARG);
    }

    arg->nwbda_cmd = cmd;
    arg->nwbda_flags = flags;
    arg->nwbda_datalen = datalen;
    arg->nwbda_result = NWAM_SUCCESS;

    if (dbname != NULL)
        (void) strlcpy(arg->nwbda_dbname, dbname, MAXPATHLEN);
    else
        arg->nwbda_dbname[0] = '\0';

    if (objname != NULL)
        (void) strlcpy(arg->nwbda_object, objname, NWAM_MAX_NAME_LEN);
    else
        arg->nwbda_object[0] = '\0';

    return (NWAM_SUCCESS);
}

/*
 * If the arg datalen is non-zero,  unpack the object list associated with
 * the backend door argument.
 */
static nwam_error_t
nwam_read_object_from_backend_door_arg(nwam_backend_door_arg_t *arg,
    char *dbname, char *name, void *objp)
{
    nwam_error_t err;
    caddr_t dataptr = (caddr_t)arg + sizeof (nwam_backend_door_arg_t);

    if (arg->nwbda_result != NWAM_SUCCESS)
        return (arg->nwbda_result);

    if (arg->nwbda_datalen > 0) {
        if ((err = nwam_unpack_object_list((char *)dataptr,
            arg->nwbda_datalen, objp)) != NWAM_SUCCESS)
            return (err);
    } else {
        *((char **)objp) = NULL;
    }

    /*
     * If "dbname" and "name" are non-NULL, copy in the actual dbname
     * and name values from the door arg since both may have been changed
     * from case-insensitive to case-sensitive matches.  They will be the
     * same length as they only differ in case.
     */
    if (dbname != NULL && strcmp(dbname, arg->nwbda_dbname) != 0)
        (void) strlcpy(dbname, arg->nwbda_dbname, strlen(dbname) + 1);
    if (name != NULL && strcmp(name, arg->nwbda_object) != 0)
        (void) strlcpy(name, arg->nwbda_object, strlen(name) + 1);

    return (NWAM_SUCCESS);
}

/* ARGSUSED */
void
nwam_backend_door_server(void *cookie, char *arg, size_t arg_size,
    door_desc_t *dp, uint_t ndesc)
{
    /* LINTED: alignment */
    nwam_backend_door_arg_t *req = (nwam_backend_door_arg_t *)arg;
    nwam_error_t err;
    void *obj, *newobj = NULL;
    ucred_t *ucr = NULL;
    uid_t uid;
    boolean_t write = B_TRUE;

    /* Check arg size */
    if (arg_size < sizeof (nwam_backend_door_arg_t)) {
        req->nwbda_result = NWAM_INVALID_ARG;
        (void) door_return((char *)req,
            sizeof (nwam_backend_door_arg_t), NULL, 0);
    }

    if (door_ucred(&ucr) != 0) {
        req->nwbda_result = NWAM_ERROR_INTERNAL;
        (void) door_return((char *)req, arg_size, NULL, 0);
    }

    /* Check auths */
    uid = ucred_getruid(ucr);

    if (req->nwbda_cmd == NWAM_BACKEND_DOOR_CMD_READ_REQ)
        write = B_FALSE;
    if ((err = nwam_check_auths(uid, write, req->nwbda_flags))
        != NWAM_SUCCESS) {
        if (write) {
            nwam_record_audit_event(ucr,
                req->nwbda_cmd == NWAM_BACKEND_DOOR_CMD_UPDATE_REQ ?
                ADT_netcfg_update : ADT_netcfg_remove,
                (char *)req->nwbda_object,
                (char *)req->nwbda_dbname, ADT_FAILURE,
                ADT_FAIL_VALUE_AUTH);
        }
        req->nwbda_result = err;
        goto door_return;
    }

    switch (req->nwbda_cmd) {
    case NWAM_BACKEND_DOOR_CMD_READ_REQ:
        if ((req->nwbda_result = nwam_read_object_from_files_backend
            (strlen(req->nwbda_dbname) > 0 ? req->nwbda_dbname : NULL,
            strlen(req->nwbda_object) > 0 ? req->nwbda_object : NULL,
            req->nwbda_flags, &newobj)) != NWAM_SUCCESS) {
            break;
        }
        if (newobj != NULL) {
            size_t datalen = arg_size -
                sizeof (nwam_backend_door_arg_t);
            caddr_t dataptr = (caddr_t)req +
                sizeof (nwam_backend_door_arg_t);

            if ((req->nwbda_result = nwam_pack_object_list(newobj,
                (char **)&dataptr, &datalen)) != NWAM_SUCCESS)
                req->nwbda_datalen = 0;
            else
                req->nwbda_datalen = datalen;
            nwam_free_object_list(newobj);
        } else {
            req->nwbda_datalen = 0;
        }
        break;

    case NWAM_BACKEND_DOOR_CMD_UPDATE_REQ:
        if (req->nwbda_datalen == 0) {
            obj = NULL;
        } else {
            if ((req->nwbda_result =
                nwam_read_object_from_backend_door_arg
                (req, NULL, NULL, &obj)) != NWAM_SUCCESS)
                break;
        }
        req->nwbda_result = nwam_update_object_in_files_backend(
            req->nwbda_dbname[0] == 0 ? NULL : req->nwbda_dbname,
            req->nwbda_object[0] == 0 ? NULL : req->nwbda_object,
            req->nwbda_flags, obj);
        nwam_free_object_list(obj);
        if (req->nwbda_result == NWAM_SUCCESS) {
            req->nwbda_datalen = 0;
            nwam_record_audit_event(ucr, ADT_netcfg_update,
                (char *)req->nwbda_object,
                (char *)req->nwbda_dbname, ADT_SUCCESS,
                ADT_SUCCESS);
        }
        break;

    case NWAM_BACKEND_DOOR_CMD_REMOVE_REQ:
        req->nwbda_result = nwam_remove_object_from_files_backend
            (strlen(req->nwbda_dbname) > 0 ? req->nwbda_dbname : NULL,
            strlen(req->nwbda_object) > 0 ? req->nwbda_object : NULL,
            req->nwbda_flags);
        if (req->nwbda_result == NWAM_SUCCESS) {
            nwam_record_audit_event(ucr, ADT_netcfg_update,
                (char *)req->nwbda_object,
                (char *)req->nwbda_dbname, ADT_SUCCESS,
                ADT_SUCCESS);
        }
        break;

    default:
        req->nwbda_result = NWAM_INVALID_ARG;
        break;
    }

door_return:
    ucred_free(ucr);

    (void) door_return((char *)req, arg_size, NULL, 0);
}

static int backend_door_fd = -1;

void
nwam_backend_fini(void)
{
    if (backend_door_fd != -1) {
        (void) door_revoke(backend_door_fd);
        backend_door_fd = -1;
    }
    (void) unlink(NWAM_BACKEND_DOOR_FILE);
}

nwam_error_t
nwam_backend_init(void)
{
    int did;
    struct stat statbuf;

    /* Create the door directory if it doesn't already exist */
    if (stat(NWAM_DOOR_DIR, &statbuf) < 0) {
        if (mkdir(NWAM_DOOR_DIR, (mode_t)0755) < 0)
            return (NWAM_ERROR_BACKEND_INIT);
    } else {
        if ((statbuf.st_mode & S_IFMT) != S_IFDIR)
            return (NWAM_ERROR_BACKEND_INIT);
    }

    if (chmod(NWAM_DOOR_DIR, 0755) < 0 ||
        chown(NWAM_DOOR_DIR, UID_NETADM, GID_NETADM) < 0)
        return (NWAM_ERROR_BACKEND_INIT);

    /* Do a low-overhead "touch" on the file that will be the door node. */
    did = open(NWAM_BACKEND_DOOR_FILE,
        O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW | O_NONBLOCK,
        S_IRUSR | S_IRGRP | S_IROTH);

    if (did != -1)
        (void) close(did);
    else if (errno != EEXIST)
        return (NWAM_ERROR_BACKEND_INIT);

    /* Create the door. */
    backend_door_fd = door_create(nwam_backend_door_server, NULL,
        DOOR_REFUSE_DESC);
    if (backend_door_fd == -1)
        return (NWAM_ERROR_BACKEND_INIT);

    /* Attach the door to the file. */
    (void) fdetach(NWAM_BACKEND_DOOR_FILE);
    if (fattach(backend_door_fd, NWAM_BACKEND_DOOR_FILE) == -1) {
        (void) door_revoke(backend_door_fd);
        return (NWAM_ERROR_BACKEND_INIT);
    }

    return (NWAM_SUCCESS);
}

static nwam_error_t
nwam_backend_door_call(nwam_backend_door_cmd_t cmd, char *dbname,
    char *objname, uint64_t flags, void *obj)
{
    uchar_t reqbuf[NWAM_BACKEND_DOOR_ARG_SIZE];
    /* LINTED: alignment */
    nwam_backend_door_arg_t *req = (nwam_backend_door_arg_t *)&reqbuf;
    nwam_error_t err, reserr;

    if ((err = nwam_create_backend_door_arg(cmd, dbname, objname, flags,
        obj, req)) != NWAM_SUCCESS)
        return (err);

    if (nwam_make_door_call(NWAM_BACKEND_DOOR_FILE, &backend_door_client_fd,
        req, sizeof (reqbuf)) != 0)
        return (NWAM_ERROR_BIND);

    reserr = req->nwbda_result;

    if (cmd == NWAM_BACKEND_DOOR_CMD_READ_REQ) {
        err = nwam_read_object_from_backend_door_arg(req, dbname,
            objname, obj);
    }

    return (err == NWAM_SUCCESS ? reserr : err);
}

/*
 * Read object specified by objname from backend dbname, retrieving an object
 * list representation.
 *
 * If dbname is NULL, obj is a list of string arrays consisting of the list
 * of backend dbnames.
 *
 * If objname is NULL, read all objects in the specified dbname and create
 * an object list containing a string array which represents each object.
 *
 * Otherwise obj will point to a list of the properties for the object
 * specified by objname in the backend dbname.
 */
/* ARGSUSED2 */
nwam_error_t
nwam_read_object_from_backend(char *dbname, char *objname,
    uint64_t flags, void *obj)
{
    nwam_error_t err = nwam_check_auths(getuid(), B_FALSE, flags);

    if (err != NWAM_SUCCESS)
        return (err);

    return (nwam_backend_door_call(NWAM_BACKEND_DOOR_CMD_READ_REQ,
        dbname, objname, flags, obj));
}

/*
 * Read in all objects from backend dbname and update object corresponding
 * to objname with properties recorded in proplist, writing the results to
 * the backend dbname.
 */
nwam_error_t
nwam_update_object_in_backend(char *dbname, char *objname,
    uint64_t flags, void *obj)
{
    nwam_error_t err = nwam_check_auths(getuid(), B_TRUE, flags);

    if (err != NWAM_SUCCESS)
        return (err);

    return (nwam_backend_door_call(NWAM_BACKEND_DOOR_CMD_UPDATE_REQ,
        dbname, objname, flags, obj));
}

/*
 * Remove specified object from backend by reading in the list of objects,
 * removing objname and writing the remainder.
 *
 * If objname is NULL, remove the backend dbname.
 */
nwam_error_t
nwam_remove_object_from_backend(char *dbname, char *objname, uint64_t flags)
{
    nwam_error_t err = nwam_check_auths(getuid(), B_TRUE, flags);

    if (err != NWAM_SUCCESS)
        return (err);

    return (nwam_backend_door_call(NWAM_BACKEND_DOOR_CMD_REMOVE_REQ,
        dbname, objname, flags, NULL));
}