fmd/common/fmd_rpc.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 (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/types.h>
#include <sys/fm/util.h>

#include <netdir.h>
#include <strings.h>
#include <alloca.h>
#include <limits.h>
#include <unistd.h>
#include <ucred.h>
#include <priv.h>

#include <fmd_rpc_api.h>
#include <fmd_rpc_adm.h>
#include <rpc/svc_mt.h>

#include <fmd_subr.h>
#include <fmd_error.h>
#include <fmd_thread.h>
#include <fmd_conf.h>
#include <fmd_api.h>
#include <fmd.h>

/*
 * Define range of transient RPC program numbers to use for transient bindings.
 * These are defined in the Solaris ONC+ Developer's Guide, Appendix B, but
 * are cleverly not defined in any ONC+ standard system header file.
 */
#define RPC_TRANS_MIN   0x40000000
#define RPC_TRANS_MAX   0x5fffffff

/*
 * We use our own private version of svc_create() which registers our services
 * only on loopback transports and enables an option whereby Solaris ucreds
 * are associated with each connection, permitting us to check privilege bits.
 */
static int
fmd_rpc_svc_create_local(void (*disp)(struct svc_req *, SVCXPRT *),
    rpcprog_t prog, rpcvers_t vers, uint_t ssz, uint_t rsz, int force)
{
    struct netconfig *ncp;
    struct netbuf buf;
    SVCXPRT *xprt;
    void *hdl;
    int fd, n = 0;

    char door[PATH_MAX];
    time_t tm;

    if ((hdl = setnetconfig()) == NULL) {
        fmd_error(EFMD_RPC_REG, "failed to iterate over "
            "netconfig database: %s\n", nc_sperror());
        return (fmd_set_errno(EFMD_RPC_REG));
    }

    if (force)
        svc_unreg(prog, vers); /* clear stale rpcbind registrations */

    buf.buf = alloca(_SS_MAXSIZE);
    buf.maxlen = _SS_MAXSIZE;
    buf.len = 0;

    while ((ncp = getnetconfig(hdl)) != NULL) {
        if (strcmp(ncp->nc_protofmly, NC_LOOPBACK) != 0)
            continue;

        if (!force && rpcb_getaddr(prog, vers, ncp, &buf, HOST_SELF)) {
            (void) endnetconfig(hdl);
            return (fmd_set_errno(EFMD_RPC_BOUND));
        }

        if ((fd = t_open(ncp->nc_device, O_RDWR, NULL)) == -1) {
            fmd_error(EFMD_RPC_REG, "failed to open %s: %s\n",
                ncp->nc_device, t_strerror(t_errno));
            continue;
        }

        svc_fd_negotiate_ucred(fd); /* enable ucred option on xprt */

        if ((xprt = svc_tli_create(fd, ncp, NULL, ssz, rsz)) == NULL) {
            (void) t_close(fd);
            continue;
        }

        if (svc_reg(xprt, prog, vers, disp, ncp) == FALSE) {
            fmd_error(EFMD_RPC_REG, "failed to register "
                "rpc service on %s\n", ncp->nc_netid);
            svc_destroy(xprt);
            continue;
        }

        n++;
    }

    (void) endnetconfig(hdl);

    /*
     * If we failed to register services (n == 0) because rpcbind is down,
     * then check to see if the RPC door file exists before attempting an
     * svc_door_create(), which cleverly destroys any existing door file.
     * The RPC APIs have no stable errnos, so we use rpcb_gettime() as a
     * hack to determine if rpcbind itself is down.
     */
    if (!force && n == 0 && rpcb_gettime(HOST_SELF, &tm) == FALSE &&
        snprintf(door, sizeof (door), RPC_DOOR_RENDEZVOUS,
        prog, vers) > 0 && access(door, F_OK) == 0)
        return (fmd_set_errno(EFMD_RPC_BOUND));

    /*
     * Attempt to create a door server for the RPC program as well.  Limit
     * the maximum request size for the door transport to the receive size.
     */
    if ((xprt = svc_door_create(disp, prog, vers, ssz)) == NULL) {
        fmd_error(EFMD_RPC_REG, "failed to create door for "
            "rpc service 0x%lx/0x%lx\n", prog, vers);
    } else {
        (void) svc_control(xprt, SVCSET_CONNMAXREC, &rsz);
        n++;
    }

    return (n);
}

static int
fmd_rpc_svc_init(void (*disp)(struct svc_req *, SVCXPRT *),
    const char *name, const char *path, const char *prop,
    rpcprog_t pmin, rpcprog_t pmax, rpcvers_t vers,
    uint_t sndsize, uint_t rcvsize, int force)
{
    rpcprog_t prog;
    char buf[16];
    FILE *fp;

    for (prog = pmin; prog <= pmax; prog++) {
        if (fmd_rpc_svc_create_local(disp, prog, vers,
            sndsize, rcvsize, force) > 0) {
            fmd_dprintf(FMD_DBG_RPC, "registered %s rpc service "
                "as 0x%lx.%lx\n", name, prog, vers);

            /*
             * To aid simulator scripts, save our RPC "digits" in
             * the specified file for rendezvous with libfmd_adm.
             */
            if (path != NULL && (fp = fopen(path, "w")) != NULL) {
                (void) fprintf(fp, "%ld\n", prog);
                (void) fclose(fp);
            }

            (void) snprintf(buf, sizeof (buf), "%ld", prog);
            (void) fmd_conf_setprop(fmd.d_conf, prop, buf);

            return (0);
        }
    }

    return (-1); /* errno is set for us */
}

void
fmd_rpc_init(void)
{
    int err, prog, mode = RPC_SVC_MT_USER;
    uint64_t sndsize = 0, rcvsize = 0;
    const char *s;

    if (rpc_control(RPC_SVC_MTMODE_SET, &mode) == FALSE)
        fmd_panic("failed to enable user-MT rpc mode");

    (void) fmd_conf_getprop(fmd.d_conf, "rpc.sndsize", &sndsize);
    (void) fmd_conf_getprop(fmd.d_conf, "rpc.rcvsize", &rcvsize);

    /*
     * Infer whether we are the "default" fault manager or an alternate one
     * based on whether the initial setting of rpc.adm.prog is non-zero.
     */
    (void) fmd_conf_getprop(fmd.d_conf, "rpc.adm.prog", &prog);
    (void) fmd_conf_getprop(fmd.d_conf, "rpc.adm.path", &s);

    if (prog != 0) {
        err = fmd_rpc_svc_init(fmd_adm_1, "FMD_ADM", s, "rpc.adm.prog",
            FMD_ADM, FMD_ADM, FMD_ADM_VERSION_1,
            (uint_t)sndsize, (uint_t)rcvsize, TRUE);
    } else {
        err = fmd_rpc_svc_init(fmd_adm_1, "FMD_ADM", s, "rpc.adm.prog",
            RPC_TRANS_MIN, RPC_TRANS_MAX, FMD_ADM_VERSION_1,
            (uint_t)sndsize, (uint_t)rcvsize, FALSE);
    }

    if (err != 0)
        fmd_error(EFMD_EXIT, "failed to create rpc server bindings");

    if (fmd_thread_create(fmd.d_rmod, (fmd_thread_f *)svc_run, 0) == NULL)
        fmd_error(EFMD_EXIT, "failed to create rpc server thread");
}

void
fmd_rpc_fini(void)
{
    rpcprog_t prog;

    svc_exit(); /* force svc_run() threads to exit */

    (void) fmd_conf_getprop(fmd.d_conf, "rpc.adm.prog", &prog);
    svc_unreg(prog, FMD_ADM_VERSION_1);

    (void) fmd_conf_getprop(fmd.d_conf, "rpc.api.prog", &prog);
    svc_unreg(prog, FMD_API_VERSION_1);
}

/*
 * Utillity function to fetch the XPRT's ucred and determine if we should deny
 * the request.  For now, we implement a simple policy of rejecting any caller
 * who does not have the PRIV_SYS_ADMIN bit in their Effective privilege set,
 * unless the caller is loading a module, which requires all privileges.
 */
int
fmd_rpc_deny(struct svc_req *rqp)
{
    ucred_t *ucp = alloca(ucred_size());
    const priv_set_t *psp;

    if (!fmd.d_booted) {
        (void) pthread_mutex_lock(&fmd.d_fmd_lock);
        while (!fmd.d_booted)
            (void) pthread_cond_wait(&fmd.d_fmd_cv,
                &fmd.d_fmd_lock);
        (void) pthread_mutex_unlock(&fmd.d_fmd_lock);
    }

    if (svc_getcallerucred(rqp->rq_xprt, &ucp) != 0 ||
        (psp = ucred_getprivset(ucp, PRIV_EFFECTIVE)) == NULL)
        return (1); /* deny access if we can't get credentials */

#ifndef DEBUG
    /*
     * For convenience of testing, we only require all privileges for a
     * module load when running a non-DEBUG fault management daemon.
     */
    if (rqp->rq_proc == FMD_ADM_MODLOAD)
        return (!priv_isfullset(psp));
#endif
    return (!priv_ismember(psp, PRIV_SYS_ADMIN));
}