svcauth_unix.c

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#include <linux/types.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/sunrpc/gss_api.h>
#include <linux/err.h>
#include <linux/seq_file.h>
#include <linux/hash.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <linux/kernel.h>
#include <linux/user_namespace.h>
#define RPCDBG_FACILITY RPCDBG_AUTH

#include <linux/sunrpc/clnt.h>

#include "netns.h"

/*
 * AUTHUNIX and AUTHNULL credentials are both handled here.
 * AUTHNULL is treated just like AUTHUNIX except that the uid/gid
 * are always nobody (-2).  i.e. we do the same IP address checks for
 * AUTHNULL as for AUTHUNIX, and that is done here.
 */


struct unix_domain {
    struct auth_domain  h;
    /* other stuff later */
};

extern struct auth_ops svcauth_null;
extern struct auth_ops svcauth_unix;

static void svcauth_unix_domain_release(struct auth_domain *dom)
{
    struct unix_domain *ud = container_of(dom, struct unix_domain, h);

    kfree(dom->name);
    kfree(ud);
}

struct auth_domain *unix_domain_find(char *name)
{
    struct auth_domain *rv;
    struct unix_domain *new = NULL;

    rv = auth_domain_lookup(name, NULL);
    while(1) {
        if (rv) {
            if (new && rv != &new->h)
                svcauth_unix_domain_release(&new->h);

            if (rv->flavour != &svcauth_unix) {
                auth_domain_put(rv);
                return NULL;
            }
            return rv;
        }

        new = kmalloc(sizeof(*new), GFP_KERNEL);
        if (new == NULL)
            return NULL;
        kref_init(&new->h.ref);
        new->h.name = kstrdup(name, GFP_KERNEL);
        if (new->h.name == NULL) {
            kfree(new);
            return NULL;
        }
        new->h.flavour = &svcauth_unix;
        rv = auth_domain_lookup(name, &new->h);
    }
}
EXPORT_SYMBOL_GPL(unix_domain_find);


/**************************************************
 * cache for IP address to unix_domain
 * as needed by AUTH_UNIX
 */
#define IP_HASHBITS 8
#define IP_HASHMAX  (1<<IP_HASHBITS)

struct ip_map {
    struct cache_head   h;
    char            m_class[8]; /* e.g. "nfsd" */
    struct in6_addr     m_addr;
    struct unix_domain  *m_client;
};

static void ip_map_put(struct kref *kref)
{
    struct cache_head *item = container_of(kref, struct cache_head, ref);
    struct ip_map *im = container_of(item, struct ip_map,h);

    if (test_bit(CACHE_VALID, &item->flags) &&
        !test_bit(CACHE_NEGATIVE, &item->flags))
        auth_domain_put(&im->m_client->h);
    kfree(im);
}

static inline int hash_ip6(const struct in6_addr *ip)
{
    return hash_32(ipv6_addr_hash(ip), IP_HASHBITS);
}
static int ip_map_match(struct cache_head *corig, struct cache_head *cnew)
{
    struct ip_map *orig = container_of(corig, struct ip_map, h);
    struct ip_map *new = container_of(cnew, struct ip_map, h);
    return strcmp(orig->m_class, new->m_class) == 0 &&
           ipv6_addr_equal(&orig->m_addr, &new->m_addr);
}
static void ip_map_init(struct cache_head *cnew, struct cache_head *citem)
{
    struct ip_map *new = container_of(cnew, struct ip_map, h);
    struct ip_map *item = container_of(citem, struct ip_map, h);

    strcpy(new->m_class, item->m_class);
    new->m_addr = item->m_addr;
}
static void update(struct cache_head *cnew, struct cache_head *citem)
{
    struct ip_map *new = container_of(cnew, struct ip_map, h);
    struct ip_map *item = container_of(citem, struct ip_map, h);

    kref_get(&item->m_client->h.ref);
    new->m_client = item->m_client;
}
static struct cache_head *ip_map_alloc(void)
{
    struct ip_map *i = kmalloc(sizeof(*i), GFP_KERNEL);
    if (i)
        return &i->h;
    else
        return NULL;
}

static void ip_map_request(struct cache_detail *cd,
                  struct cache_head *h,
                  char **bpp, int *blen)
{
    char text_addr[40];
    struct ip_map *im = container_of(h, struct ip_map, h);

    if (ipv6_addr_v4mapped(&(im->m_addr))) {
        snprintf(text_addr, 20, "%pI4", &im->m_addr.s6_addr32[3]);
    } else {
        snprintf(text_addr, 40, "%pI6", &im->m_addr);
    }
    qword_add(bpp, blen, im->m_class);
    qword_add(bpp, blen, text_addr);
    (*bpp)[-1] = '\n';
}

static int ip_map_upcall(struct cache_detail *cd, struct cache_head *h)
{
    return sunrpc_cache_pipe_upcall(cd, h, ip_map_request);
}

static struct ip_map *__ip_map_lookup(struct cache_detail *cd, char *class, struct in6_addr *addr);
static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm, struct unix_domain *udom, time_t expiry);

static int ip_map_parse(struct cache_detail *cd,
              char *mesg, int mlen)
{
    /* class ipaddress [domainname] */
    /* should be safe just to use the start of the input buffer
     * for scratch: */
    char *buf = mesg;
    int len;
    char class[8];
    union {
        struct sockaddr     sa;
        struct sockaddr_in  s4;
        struct sockaddr_in6 s6;
    } address;
    struct sockaddr_in6 sin6;
    int err;

    struct ip_map *ipmp;
    struct auth_domain *dom;
    time_t expiry;

    if (mesg[mlen-1] != '\n')
        return -EINVAL;
    mesg[mlen-1] = 0;

    /* class */
    len = qword_get(&mesg, class, sizeof(class));
    if (len <= 0) return -EINVAL;

    /* ip address */
    len = qword_get(&mesg, buf, mlen);
    if (len <= 0) return -EINVAL;

    if (rpc_pton(cd->net, buf, len, &address.sa, sizeof(address)) == 0)
        return -EINVAL;
    switch (address.sa.sa_family) {
    case AF_INET:
        /* Form a mapped IPv4 address in sin6 */
        sin6.sin6_family = AF_INET6;
        ipv6_addr_set_v4mapped(address.s4.sin_addr.s_addr,
                &sin6.sin6_addr);
        break;
#if IS_ENABLED(CONFIG_IPV6)
    case AF_INET6:
        memcpy(&sin6, &address.s6, sizeof(sin6));
        break;
#endif
    default:
        return -EINVAL;
    }

    expiry = get_expiry(&mesg);
    if (expiry ==0)
        return -EINVAL;

    /* domainname, or empty for NEGATIVE */
    len = qword_get(&mesg, buf, mlen);
    if (len < 0) return -EINVAL;

    if (len) {
        dom = unix_domain_find(buf);
        if (dom == NULL)
            return -ENOENT;
    } else
        dom = NULL;

    /* IPv6 scope IDs are ignored for now */
    ipmp = __ip_map_lookup(cd, class, &sin6.sin6_addr);
    if (ipmp) {
        err = __ip_map_update(cd, ipmp,
                 container_of(dom, struct unix_domain, h),
                 expiry);
    } else
        err = -ENOMEM;

    if (dom)
        auth_domain_put(dom);

    cache_flush();
    return err;
}

static int ip_map_show(struct seq_file *m,
               struct cache_detail *cd,
               struct cache_head *h)
{
    struct ip_map *im;
    struct in6_addr addr;
    char *dom = "-no-domain-";

    if (h == NULL) {
        seq_puts(m, "#class IP domain\n");
        return 0;
    }
    im = container_of(h, struct ip_map, h);
    /* class addr domain */
    addr = im->m_addr;

    if (test_bit(CACHE_VALID, &h->flags) &&
        !test_bit(CACHE_NEGATIVE, &h->flags))
        dom = im->m_client->h.name;

    if (ipv6_addr_v4mapped(&addr)) {
        seq_printf(m, "%s %pI4 %s\n",
            im->m_class, &addr.s6_addr32[3], dom);
    } else {
        seq_printf(m, "%s %pI6 %s\n", im->m_class, &addr, dom);
    }
    return 0;
}


static struct ip_map *__ip_map_lookup(struct cache_detail *cd, char *class,
        struct in6_addr *addr)
{
    struct ip_map ip;
    struct cache_head *ch;

    strcpy(ip.m_class, class);
    ip.m_addr = *addr;
    ch = sunrpc_cache_lookup(cd, &ip.h,
                 hash_str(class, IP_HASHBITS) ^
                 hash_ip6(addr));

    if (ch)
        return container_of(ch, struct ip_map, h);
    else
        return NULL;
}

static inline struct ip_map *ip_map_lookup(struct net *net, char *class,
        struct in6_addr *addr)
{
    struct sunrpc_net *sn;

    sn = net_generic(net, sunrpc_net_id);
    return __ip_map_lookup(sn->ip_map_cache, class, addr);
}

static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm,
        struct unix_domain *udom, time_t expiry)
{
    struct ip_map ip;
    struct cache_head *ch;

    ip.m_client = udom;
    ip.h.flags = 0;
    if (!udom)
        set_bit(CACHE_NEGATIVE, &ip.h.flags);
    ip.h.expiry_time = expiry;
    ch = sunrpc_cache_update(cd, &ip.h, &ipm->h,
                 hash_str(ipm->m_class, IP_HASHBITS) ^
                 hash_ip6(&ipm->m_addr));
    if (!ch)
        return -ENOMEM;
    cache_put(ch, cd);
    return 0;
}

static inline int ip_map_update(struct net *net, struct ip_map *ipm,
        struct unix_domain *udom, time_t expiry)
{
    struct sunrpc_net *sn;

    sn = net_generic(net, sunrpc_net_id);
    return __ip_map_update(sn->ip_map_cache, ipm, udom, expiry);
}

void svcauth_unix_purge(struct net *net)
{
    struct sunrpc_net *sn;

    sn = net_generic(net, sunrpc_net_id);
    cache_purge(sn->ip_map_cache);
}
EXPORT_SYMBOL_GPL(svcauth_unix_purge);

static inline struct ip_map *
ip_map_cached_get(struct svc_xprt *xprt)
{
    struct ip_map *ipm = NULL;
    struct sunrpc_net *sn;

    if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags)) {
        spin_lock(&xprt->xpt_lock);
        ipm = xprt->xpt_auth_cache;
        if (ipm != NULL) {
            if (!cache_valid(&ipm->h)) {
                /*
                 * The entry has been invalidated since it was
                 * remembered, e.g. by a second mount from the
                 * same IP address.
                 */
                sn = net_generic(xprt->xpt_net, sunrpc_net_id);
                xprt->xpt_auth_cache = NULL;
                spin_unlock(&xprt->xpt_lock);
                cache_put(&ipm->h, sn->ip_map_cache);
                return NULL;
            }
            cache_get(&ipm->h);
        }
        spin_unlock(&xprt->xpt_lock);
    }
    return ipm;
}

static inline void
ip_map_cached_put(struct svc_xprt *xprt, struct ip_map *ipm)
{
    if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags)) {
        spin_lock(&xprt->xpt_lock);
        if (xprt->xpt_auth_cache == NULL) {
            /* newly cached, keep the reference */
            xprt->xpt_auth_cache = ipm;
            ipm = NULL;
        }
        spin_unlock(&xprt->xpt_lock);
    }
    if (ipm) {
        struct sunrpc_net *sn;

        sn = net_generic(xprt->xpt_net, sunrpc_net_id);
        cache_put(&ipm->h, sn->ip_map_cache);
    }
}

void
svcauth_unix_info_release(struct svc_xprt *xpt)
{
    struct ip_map *ipm;

    ipm = xpt->xpt_auth_cache;
    if (ipm != NULL) {
        struct sunrpc_net *sn;

        sn = net_generic(xpt->xpt_net, sunrpc_net_id);
        cache_put(&ipm->h, sn->ip_map_cache);
    }
}

/****************************************************************************
 * auth.unix.gid cache
 * simple cache to map a UID to a list of GIDs
 * because AUTH_UNIX aka AUTH_SYS has a max of 16
 */
#define GID_HASHBITS    8
#define GID_HASHMAX (1<<GID_HASHBITS)

struct unix_gid {
    struct cache_head   h;
    uid_t           uid;
    struct group_info   *gi;
};

static void unix_gid_put(struct kref *kref)
{
    struct cache_head *item = container_of(kref, struct cache_head, ref);
    struct unix_gid *ug = container_of(item, struct unix_gid, h);
    if (test_bit(CACHE_VALID, &item->flags) &&
        !test_bit(CACHE_NEGATIVE, &item->flags))
        put_group_info(ug->gi);
    kfree(ug);
}

static int unix_gid_match(struct cache_head *corig, struct cache_head *cnew)
{
    struct unix_gid *orig = container_of(corig, struct unix_gid, h);
    struct unix_gid *new = container_of(cnew, struct unix_gid, h);
    return orig->uid == new->uid;
}
static void unix_gid_init(struct cache_head *cnew, struct cache_head *citem)
{
    struct unix_gid *new = container_of(cnew, struct unix_gid, h);
    struct unix_gid *item = container_of(citem, struct unix_gid, h);
    new->uid = item->uid;
}
static void unix_gid_update(struct cache_head *cnew, struct cache_head *citem)
{
    struct unix_gid *new = container_of(cnew, struct unix_gid, h);
    struct unix_gid *item = container_of(citem, struct unix_gid, h);

    get_group_info(item->gi);
    new->gi = item->gi;
}
static struct cache_head *unix_gid_alloc(void)
{
    struct unix_gid *g = kmalloc(sizeof(*g), GFP_KERNEL);
    if (g)
        return &g->h;
    else
        return NULL;
}

static void unix_gid_request(struct cache_detail *cd,
                 struct cache_head *h,
                 char **bpp, int *blen)
{
    char tuid[20];
    struct unix_gid *ug = container_of(h, struct unix_gid, h);

    snprintf(tuid, 20, "%u", ug->uid);
    qword_add(bpp, blen, tuid);
    (*bpp)[-1] = '\n';
}

static int unix_gid_upcall(struct cache_detail *cd, struct cache_head *h)
{
    return sunrpc_cache_pipe_upcall(cd, h, unix_gid_request);
}

static struct unix_gid *unix_gid_lookup(struct cache_detail *cd, uid_t uid);

static int unix_gid_parse(struct cache_detail *cd,
            char *mesg, int mlen)
{
    /* uid expiry Ngid gid0 gid1 ... gidN-1 */
    int uid;
    int gids;
    int rv;
    int i;
    int err;
    time_t expiry;
    struct unix_gid ug, *ugp;

    if (mesg[mlen - 1] != '\n')
        return -EINVAL;
    mesg[mlen-1] = 0;

    rv = get_int(&mesg, &uid);
    if (rv)
        return -EINVAL;
    ug.uid = uid;

    expiry = get_expiry(&mesg);
    if (expiry == 0)
        return -EINVAL;

    rv = get_int(&mesg, &gids);
    if (rv || gids < 0 || gids > 8192)
        return -EINVAL;

    ug.gi = groups_alloc(gids);
    if (!ug.gi)
        return -ENOMEM;

    for (i = 0 ; i < gids ; i++) {
        int gid;
        kgid_t kgid;
        rv = get_int(&mesg, &gid);
        err = -EINVAL;
        if (rv)
            goto out;
        kgid = make_kgid(&init_user_ns, gid);
        if (!gid_valid(kgid))
            goto out;
        GROUP_AT(ug.gi, i) = kgid;
    }

    ugp = unix_gid_lookup(cd, uid);
    if (ugp) {
        struct cache_head *ch;
        ug.h.flags = 0;
        ug.h.expiry_time = expiry;
        ch = sunrpc_cache_update(cd,
                     &ug.h, &ugp->h,
                     hash_long(uid, GID_HASHBITS));
        if (!ch)
            err = -ENOMEM;
        else {
            err = 0;
            cache_put(ch, cd);
        }
    } else
        err = -ENOMEM;
 out:
    if (ug.gi)
        put_group_info(ug.gi);
    return err;
}

static int unix_gid_show(struct seq_file *m,
             struct cache_detail *cd,
             struct cache_head *h)
{
    struct user_namespace *user_ns = current_user_ns();
    struct unix_gid *ug;
    int i;
    int glen;

    if (h == NULL) {
        seq_puts(m, "#uid cnt: gids...\n");
        return 0;
    }
    ug = container_of(h, struct unix_gid, h);
    if (test_bit(CACHE_VALID, &h->flags) &&
        !test_bit(CACHE_NEGATIVE, &h->flags))
        glen = ug->gi->ngroups;
    else
        glen = 0;

    seq_printf(m, "%u %d:", ug->uid, glen);
    for (i = 0; i < glen; i++)
        seq_printf(m, " %d", from_kgid_munged(user_ns, GROUP_AT(ug->gi, i)));
    seq_printf(m, "\n");
    return 0;
}

static struct cache_detail unix_gid_cache_template = {
    .owner      = THIS_MODULE,
    .hash_size  = GID_HASHMAX,
    .name       = "auth.unix.gid",
    .cache_put  = unix_gid_put,
    .cache_upcall   = unix_gid_upcall,
    .cache_parse    = unix_gid_parse,
    .cache_show = unix_gid_show,
    .match      = unix_gid_match,
    .init       = unix_gid_init,
    .update     = unix_gid_update,
    .alloc      = unix_gid_alloc,
};

int unix_gid_cache_create(struct net *net)
{
    struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
    struct cache_detail *cd;
    int err;

    cd = cache_create_net(&unix_gid_cache_template, net);
    if (IS_ERR(cd))
        return PTR_ERR(cd);
    err = cache_register_net(cd, net);
    if (err) {
        cache_destroy_net(cd, net);
        return err;
    }
    sn->unix_gid_cache = cd;
    return 0;
}

void unix_gid_cache_destroy(struct net *net)
{
    struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
    struct cache_detail *cd = sn->unix_gid_cache;

    sn->unix_gid_cache = NULL;
    cache_purge(cd);
    cache_unregister_net(cd, net);
    cache_destroy_net(cd, net);
}

static struct unix_gid *unix_gid_lookup(struct cache_detail *cd, uid_t uid)
{
    struct unix_gid ug;
    struct cache_head *ch;

    ug.uid = uid;
    ch = sunrpc_cache_lookup(cd, &ug.h, hash_long(uid, GID_HASHBITS));
    if (ch)
        return container_of(ch, struct unix_gid, h);
    else
        return NULL;
}

static struct group_info *unix_gid_find(uid_t uid, struct svc_rqst *rqstp)
{
    struct unix_gid *ug;
    struct group_info *gi;
    int ret;
    struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net,
                        sunrpc_net_id);

    ug = unix_gid_lookup(sn->unix_gid_cache, uid);
    if (!ug)
        return ERR_PTR(-EAGAIN);
    ret = cache_check(sn->unix_gid_cache, &ug->h, &rqstp->rq_chandle);
    switch (ret) {
    case -ENOENT:
        return ERR_PTR(-ENOENT);
    case -ETIMEDOUT:
        return ERR_PTR(-ESHUTDOWN);
    case 0:
        gi = get_group_info(ug->gi);
        cache_put(&ug->h, sn->unix_gid_cache);
        return gi;
    default:
        return ERR_PTR(-EAGAIN);
    }
}

int
svcauth_unix_set_client(struct svc_rqst *rqstp)
{
    struct sockaddr_in *sin;
    struct sockaddr_in6 *sin6, sin6_storage;
    struct ip_map *ipm;
    struct group_info *gi;
    struct svc_cred *cred = &rqstp->rq_cred;
    struct svc_xprt *xprt = rqstp->rq_xprt;
    struct net *net = xprt->xpt_net;
    struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);

    switch (rqstp->rq_addr.ss_family) {
    case AF_INET:
        sin = svc_addr_in(rqstp);
        sin6 = &sin6_storage;
        ipv6_addr_set_v4mapped(sin->sin_addr.s_addr, &sin6->sin6_addr);
        break;
    case AF_INET6:
        sin6 = svc_addr_in6(rqstp);
        break;
    default:
        BUG();
    }

    rqstp->rq_client = NULL;
    if (rqstp->rq_proc == 0)
        return SVC_OK;

    ipm = ip_map_cached_get(xprt);
    if (ipm == NULL)
        ipm = __ip_map_lookup(sn->ip_map_cache, rqstp->rq_server->sv_program->pg_class,
                    &sin6->sin6_addr);

    if (ipm == NULL)
        return SVC_DENIED;

    switch (cache_check(sn->ip_map_cache, &ipm->h, &rqstp->rq_chandle)) {
        default:
            BUG();
        case -ETIMEDOUT:
            return SVC_CLOSE;
        case -EAGAIN:
            return SVC_DROP;
        case -ENOENT:
            return SVC_DENIED;
        case 0:
            rqstp->rq_client = &ipm->m_client->h;
            kref_get(&rqstp->rq_client->ref);
            ip_map_cached_put(xprt, ipm);
            break;
    }

    gi = unix_gid_find(cred->cr_uid, rqstp);
    switch (PTR_ERR(gi)) {
    case -EAGAIN:
        return SVC_DROP;
    case -ESHUTDOWN:
        return SVC_CLOSE;
    case -ENOENT:
        break;
    default:
        put_group_info(cred->cr_group_info);
        cred->cr_group_info = gi;
    }
    return SVC_OK;
}

EXPORT_SYMBOL_GPL(svcauth_unix_set_client);

static int
svcauth_null_accept(struct svc_rqst *rqstp, __be32 *authp)
{
    struct kvec *argv = &rqstp->rq_arg.head[0];
    struct kvec *resv = &rqstp->rq_res.head[0];
    struct svc_cred *cred = &rqstp->rq_cred;

    cred->cr_group_info = NULL;
    cred->cr_principal = NULL;
    rqstp->rq_client = NULL;

    if (argv->iov_len < 3*4)
        return SVC_GARBAGE;

    if (svc_getu32(argv) != 0) {
        dprintk("svc: bad null cred\n");
        *authp = rpc_autherr_badcred;
        return SVC_DENIED;
    }
    if (svc_getu32(argv) != htonl(RPC_AUTH_NULL) || svc_getu32(argv) != 0) {
        dprintk("svc: bad null verf\n");
        *authp = rpc_autherr_badverf;
        return SVC_DENIED;
    }

    /* Signal that mapping to nobody uid/gid is required */
    cred->cr_uid = (uid_t) -1;
    cred->cr_gid = (gid_t) -1;
    cred->cr_group_info = groups_alloc(0);
    if (cred->cr_group_info == NULL)
        return SVC_CLOSE; /* kmalloc failure - client must retry */

    /* Put NULL verifier */
    svc_putnl(resv, RPC_AUTH_NULL);
    svc_putnl(resv, 0);

    rqstp->rq_cred.cr_flavor = RPC_AUTH_NULL;
    return SVC_OK;
}

static int
svcauth_null_release(struct svc_rqst *rqstp)
{
    if (rqstp->rq_client)
        auth_domain_put(rqstp->rq_client);
    rqstp->rq_client = NULL;
    if (rqstp->rq_cred.cr_group_info)
        put_group_info(rqstp->rq_cred.cr_group_info);
    rqstp->rq_cred.cr_group_info = NULL;

    return 0; /* don't drop */
}


struct auth_ops svcauth_null = {
    .name       = "null",
    .owner      = THIS_MODULE,
    .flavour    = RPC_AUTH_NULL,
    .accept     = svcauth_null_accept,
    .release    = svcauth_null_release,
    .set_client = svcauth_unix_set_client,
};


static int
svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
{
    struct kvec *argv = &rqstp->rq_arg.head[0];
    struct kvec *resv = &rqstp->rq_res.head[0];
    struct svc_cred *cred = &rqstp->rq_cred;
    u32     slen, i;
    int     len   = argv->iov_len;

    cred->cr_group_info = NULL;
    cred->cr_principal = NULL;
    rqstp->rq_client = NULL;

    if ((len -= 3*4) < 0)
        return SVC_GARBAGE;

    svc_getu32(argv);           /* length */
    svc_getu32(argv);           /* time stamp */
    slen = XDR_QUADLEN(svc_getnl(argv));    /* machname length */
    if (slen > 64 || (len -= (slen + 3)*4) < 0)
        goto badcred;
    argv->iov_base = (void*)((__be32*)argv->iov_base + slen);   /* skip machname */
    argv->iov_len -= slen*4;

    cred->cr_uid = svc_getnl(argv);     /* uid */
    cred->cr_gid = svc_getnl(argv);     /* gid */
    slen = svc_getnl(argv);         /* gids length */
    if (slen > 16 || (len -= (slen + 2)*4) < 0)
        goto badcred;
    cred->cr_group_info = groups_alloc(slen);
    if (cred->cr_group_info == NULL)
        return SVC_CLOSE;
    for (i = 0; i < slen; i++) {
        kgid_t kgid = make_kgid(&init_user_ns, svc_getnl(argv));
        if (!gid_valid(kgid))
            goto badcred;
        GROUP_AT(cred->cr_group_info, i) = kgid;
    }
    if (svc_getu32(argv) != htonl(RPC_AUTH_NULL) || svc_getu32(argv) != 0) {
        *authp = rpc_autherr_badverf;
        return SVC_DENIED;
    }

    /* Put NULL verifier */
    svc_putnl(resv, RPC_AUTH_NULL);
    svc_putnl(resv, 0);

    rqstp->rq_cred.cr_flavor = RPC_AUTH_UNIX;
    return SVC_OK;

badcred:
    *authp = rpc_autherr_badcred;
    return SVC_DENIED;
}

static int
svcauth_unix_release(struct svc_rqst *rqstp)
{
    /* Verifier (such as it is) is already in place.
     */
    if (rqstp->rq_client)
        auth_domain_put(rqstp->rq_client);
    rqstp->rq_client = NULL;
    if (rqstp->rq_cred.cr_group_info)
        put_group_info(rqstp->rq_cred.cr_group_info);
    rqstp->rq_cred.cr_group_info = NULL;

    return 0;
}


struct auth_ops svcauth_unix = {
    .name       = "unix",
    .owner      = THIS_MODULE,
    .flavour    = RPC_AUTH_UNIX,
    .accept     = svcauth_unix_accept,
    .release    = svcauth_unix_release,
    .domain_release = svcauth_unix_domain_release,
    .set_client = svcauth_unix_set_client,
};

static struct cache_detail ip_map_cache_template = {
    .owner      = THIS_MODULE,
    .hash_size  = IP_HASHMAX,
    .name       = "auth.unix.ip",
    .cache_put  = ip_map_put,
    .cache_upcall   = ip_map_upcall,
    .cache_parse    = ip_map_parse,
    .cache_show = ip_map_show,
    .match      = ip_map_match,
    .init       = ip_map_init,
    .update     = update,
    .alloc      = ip_map_alloc,
};

int ip_map_cache_create(struct net *net)
{
    struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
    struct cache_detail *cd;
    int err;

    cd = cache_create_net(&ip_map_cache_template, net);
    if (IS_ERR(cd))
        return PTR_ERR(cd);
    err = cache_register_net(cd, net);
    if (err) {
        cache_destroy_net(cd, net);
        return err;
    }
    sn->ip_map_cache = cd;
    return 0;
}

void ip_map_cache_destroy(struct net *net)
{
    struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
    struct cache_detail *cd = sn->ip_map_cache;

    sn->ip_map_cache = NULL;
    cache_purge(cd);
    cache_unregister_net(cd, net);
    cache_destroy_net(cd, net);
}