nfs4idmap.c

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/*
 *  Mapping of UID/GIDs to name and vice versa.
 *
 *  Copyright (c) 2002, 2003 The Regents of the University of
 *  Michigan.  All rights reserved.
 *
 *  Marius Aamodt Eriksen <[email protected]>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/sunrpc/svc_xprt.h>
#include <net/net_namespace.h>
#include "idmap.h"
#include "nfsd.h"
#include "netns.h"

/*
 * Turn off idmapping when using AUTH_SYS.
 */
static bool nfs4_disable_idmapping = true;
module_param(nfs4_disable_idmapping, bool, 0644);
MODULE_PARM_DESC(nfs4_disable_idmapping,
        "Turn off server's NFSv4 idmapping when using 'sec=sys'");

/*
 * Cache entry
 */

/*
 * XXX we know that IDMAP_NAMESZ < PAGE_SIZE, but it's ugly to rely on
 * that.
 */

#define IDMAP_TYPE_USER  0
#define IDMAP_TYPE_GROUP 1

struct ent {
    struct cache_head h;
    int               type;            /* User / Group */
    uid_t             id;
    char              name[IDMAP_NAMESZ];
    char              authname[IDMAP_NAMESZ];
};

/* Common entry handling */

#define ENT_HASHBITS          8
#define ENT_HASHMAX           (1 << ENT_HASHBITS)

static void
ent_init(struct cache_head *cnew, struct cache_head *citm)
{
    struct ent *new = container_of(cnew, struct ent, h);
    struct ent *itm = container_of(citm, struct ent, h);

    new->id = itm->id;
    new->type = itm->type;

    strlcpy(new->name, itm->name, sizeof(new->name));
    strlcpy(new->authname, itm->authname, sizeof(new->name));
}

static void
ent_put(struct kref *ref)
{
    struct ent *map = container_of(ref, struct ent, h.ref);
    kfree(map);
}

static struct cache_head *
ent_alloc(void)
{
    struct ent *e = kmalloc(sizeof(*e), GFP_KERNEL);
    if (e)
        return &e->h;
    else
        return NULL;
}

/*
 * ID -> Name cache
 */

static uint32_t
idtoname_hash(struct ent *ent)
{
    uint32_t hash;

    hash = hash_str(ent->authname, ENT_HASHBITS);
    hash = hash_long(hash ^ ent->id, ENT_HASHBITS);

    /* Flip LSB for user/group */
    if (ent->type == IDMAP_TYPE_GROUP)
        hash ^= 1;

    return hash;
}

static void
idtoname_request(struct cache_detail *cd, struct cache_head *ch, char **bpp,
    int *blen)
{
    struct ent *ent = container_of(ch, struct ent, h);
    char idstr[11];

    qword_add(bpp, blen, ent->authname);
    snprintf(idstr, sizeof(idstr), "%u", ent->id);
    qword_add(bpp, blen, ent->type == IDMAP_TYPE_GROUP ? "group" : "user");
    qword_add(bpp, blen, idstr);

    (*bpp)[-1] = '\n';
}

static int
idtoname_upcall(struct cache_detail *cd, struct cache_head *ch)
{
    return sunrpc_cache_pipe_upcall(cd, ch, idtoname_request);
}

static int
idtoname_match(struct cache_head *ca, struct cache_head *cb)
{
    struct ent *a = container_of(ca, struct ent, h);
    struct ent *b = container_of(cb, struct ent, h);

    return (a->id == b->id && a->type == b->type &&
        strcmp(a->authname, b->authname) == 0);
}

static int
idtoname_show(struct seq_file *m, struct cache_detail *cd, struct cache_head *h)
{
    struct ent *ent;

    if (h == NULL) {
        seq_puts(m, "#domain type id [name]\n");
        return 0;
    }
    ent = container_of(h, struct ent, h);
    seq_printf(m, "%s %s %u", ent->authname,
            ent->type == IDMAP_TYPE_GROUP ? "group" : "user",
            ent->id);
    if (test_bit(CACHE_VALID, &h->flags))
        seq_printf(m, " %s", ent->name);
    seq_printf(m, "\n");
    return 0;
}

static void
warn_no_idmapd(struct cache_detail *detail, int has_died)
{
    printk("nfsd: nfsv4 idmapping failing: has idmapd %s?\n",
            has_died ? "died" : "not been started");
}


static int         idtoname_parse(struct cache_detail *, char *, int);
static struct ent *idtoname_lookup(struct cache_detail *, struct ent *);
static struct ent *idtoname_update(struct cache_detail *, struct ent *,
                   struct ent *);

static struct cache_detail idtoname_cache_template = {
    .owner      = THIS_MODULE,
    .hash_size  = ENT_HASHMAX,
    .name       = "nfs4.idtoname",
    .cache_put  = ent_put,
    .cache_upcall   = idtoname_upcall,
    .cache_parse    = idtoname_parse,
    .cache_show = idtoname_show,
    .warn_no_listener = warn_no_idmapd,
    .match      = idtoname_match,
    .init       = ent_init,
    .update     = ent_init,
    .alloc      = ent_alloc,
};

static int
idtoname_parse(struct cache_detail *cd, char *buf, int buflen)
{
    struct ent ent, *res;
    char *buf1, *bp;
    int len;
    int error = -EINVAL;

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

    buf1 = kmalloc(PAGE_SIZE, GFP_KERNEL);
    if (buf1 == NULL)
        return (-ENOMEM);

    memset(&ent, 0, sizeof(ent));

    /* Authentication name */
    if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
        goto out;
    memcpy(ent.authname, buf1, sizeof(ent.authname));

    /* Type */
    if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
        goto out;
    ent.type = strcmp(buf1, "user") == 0 ?
        IDMAP_TYPE_USER : IDMAP_TYPE_GROUP;

    /* ID */
    if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
        goto out;
    ent.id = simple_strtoul(buf1, &bp, 10);
    if (bp == buf1)
        goto out;

    /* expiry */
    ent.h.expiry_time = get_expiry(&buf);
    if (ent.h.expiry_time == 0)
        goto out;

    error = -ENOMEM;
    res = idtoname_lookup(cd, &ent);
    if (!res)
        goto out;

    /* Name */
    error = -EINVAL;
    len = qword_get(&buf, buf1, PAGE_SIZE);
    if (len < 0)
        goto out;
    if (len == 0)
        set_bit(CACHE_NEGATIVE, &ent.h.flags);
    else if (len >= IDMAP_NAMESZ)
        goto out;
    else
        memcpy(ent.name, buf1, sizeof(ent.name));
    error = -ENOMEM;
    res = idtoname_update(cd, &ent, res);
    if (res == NULL)
        goto out;

    cache_put(&res->h, cd);

    error = 0;
out:
    kfree(buf1);

    return error;
}


static struct ent *
idtoname_lookup(struct cache_detail *cd, struct ent *item)
{
    struct cache_head *ch = sunrpc_cache_lookup(cd, &item->h,
                            idtoname_hash(item));
    if (ch)
        return container_of(ch, struct ent, h);
    else
        return NULL;
}

static struct ent *
idtoname_update(struct cache_detail *cd, struct ent *new, struct ent *old)
{
    struct cache_head *ch = sunrpc_cache_update(cd, &new->h, &old->h,
                            idtoname_hash(new));
    if (ch)
        return container_of(ch, struct ent, h);
    else
        return NULL;
}


/*
 * Name -> ID cache
 */

static inline int
nametoid_hash(struct ent *ent)
{
    return hash_str(ent->name, ENT_HASHBITS);
}

static void
nametoid_request(struct cache_detail *cd, struct cache_head *ch, char **bpp,
    int *blen)
{
    struct ent *ent = container_of(ch, struct ent, h);

    qword_add(bpp, blen, ent->authname);
    qword_add(bpp, blen, ent->type == IDMAP_TYPE_GROUP ? "group" : "user");
    qword_add(bpp, blen, ent->name);

    (*bpp)[-1] = '\n';
}

static int
nametoid_upcall(struct cache_detail *cd, struct cache_head *ch)
{
    return sunrpc_cache_pipe_upcall(cd, ch, nametoid_request);
}

static int
nametoid_match(struct cache_head *ca, struct cache_head *cb)
{
    struct ent *a = container_of(ca, struct ent, h);
    struct ent *b = container_of(cb, struct ent, h);

    return (a->type == b->type && strcmp(a->name, b->name) == 0 &&
        strcmp(a->authname, b->authname) == 0);
}

static int
nametoid_show(struct seq_file *m, struct cache_detail *cd, struct cache_head *h)
{
    struct ent *ent;

    if (h == NULL) {
        seq_puts(m, "#domain type name [id]\n");
        return 0;
    }
    ent = container_of(h, struct ent, h);
    seq_printf(m, "%s %s %s", ent->authname,
            ent->type == IDMAP_TYPE_GROUP ? "group" : "user",
            ent->name);
    if (test_bit(CACHE_VALID, &h->flags))
        seq_printf(m, " %u", ent->id);
    seq_printf(m, "\n");
    return 0;
}

static struct ent *nametoid_lookup(struct cache_detail *, struct ent *);
static struct ent *nametoid_update(struct cache_detail *, struct ent *,
                   struct ent *);
static int         nametoid_parse(struct cache_detail *, char *, int);

static struct cache_detail nametoid_cache_template = {
    .owner      = THIS_MODULE,
    .hash_size  = ENT_HASHMAX,
    .name       = "nfs4.nametoid",
    .cache_put  = ent_put,
    .cache_upcall   = nametoid_upcall,
    .cache_parse    = nametoid_parse,
    .cache_show = nametoid_show,
    .warn_no_listener = warn_no_idmapd,
    .match      = nametoid_match,
    .init       = ent_init,
    .update     = ent_init,
    .alloc      = ent_alloc,
};

static int
nametoid_parse(struct cache_detail *cd, char *buf, int buflen)
{
    struct ent ent, *res;
    char *buf1;
    int error = -EINVAL;

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

    buf1 = kmalloc(PAGE_SIZE, GFP_KERNEL);
    if (buf1 == NULL)
        return (-ENOMEM);

    memset(&ent, 0, sizeof(ent));

    /* Authentication name */
    if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
        goto out;
    memcpy(ent.authname, buf1, sizeof(ent.authname));

    /* Type */
    if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
        goto out;
    ent.type = strcmp(buf1, "user") == 0 ?
        IDMAP_TYPE_USER : IDMAP_TYPE_GROUP;

    /* Name */
    error = qword_get(&buf, buf1, PAGE_SIZE);
    if (error <= 0 || error >= IDMAP_NAMESZ)
        goto out;
    memcpy(ent.name, buf1, sizeof(ent.name));

    /* expiry */
    ent.h.expiry_time = get_expiry(&buf);
    if (ent.h.expiry_time == 0)
        goto out;

    /* ID */
    error = get_int(&buf, &ent.id);
    if (error == -EINVAL)
        goto out;
    if (error == -ENOENT)
        set_bit(CACHE_NEGATIVE, &ent.h.flags);

    error = -ENOMEM;
    res = nametoid_lookup(cd, &ent);
    if (res == NULL)
        goto out;
    res = nametoid_update(cd, &ent, res);
    if (res == NULL)
        goto out;

    cache_put(&res->h, cd);
    error = 0;
out:
    kfree(buf1);

    return (error);
}


static struct ent *
nametoid_lookup(struct cache_detail *cd, struct ent *item)
{
    struct cache_head *ch = sunrpc_cache_lookup(cd, &item->h,
                            nametoid_hash(item));
    if (ch)
        return container_of(ch, struct ent, h);
    else
        return NULL;
}

static struct ent *
nametoid_update(struct cache_detail *cd, struct ent *new, struct ent *old)
{
    struct cache_head *ch = sunrpc_cache_update(cd, &new->h, &old->h,
                            nametoid_hash(new));
    if (ch)
        return container_of(ch, struct ent, h);
    else
        return NULL;
}

/*
 * Exported API
 */

int
nfsd_idmap_init(struct net *net)
{
    int rv;
    struct nfsd_net *nn = net_generic(net, nfsd_net_id);

    nn->idtoname_cache = cache_create_net(&idtoname_cache_template, net);
    if (IS_ERR(nn->idtoname_cache))
        return PTR_ERR(nn->idtoname_cache);
    rv = cache_register_net(nn->idtoname_cache, net);
    if (rv)
        goto destroy_idtoname_cache;
    nn->nametoid_cache = cache_create_net(&nametoid_cache_template, net);
    if (IS_ERR(nn->nametoid_cache)) {
        rv = PTR_ERR(nn->nametoid_cache);
        goto unregister_idtoname_cache;
    }
    rv = cache_register_net(nn->nametoid_cache, net);
    if (rv)
        goto destroy_nametoid_cache;
    return 0;

destroy_nametoid_cache:
    cache_destroy_net(nn->nametoid_cache, net);
unregister_idtoname_cache:
    cache_unregister_net(nn->idtoname_cache, net);
destroy_idtoname_cache:
    cache_destroy_net(nn->idtoname_cache, net);
    return rv;
}

void
nfsd_idmap_shutdown(struct net *net)
{
    struct nfsd_net *nn = net_generic(net, nfsd_net_id);

    cache_unregister_net(nn->idtoname_cache, net);
    cache_unregister_net(nn->nametoid_cache, net);
    cache_destroy_net(nn->idtoname_cache, net);
    cache_destroy_net(nn->nametoid_cache, net);
}

static int
idmap_lookup(struct svc_rqst *rqstp,
        struct ent *(*lookup_fn)(struct cache_detail *, struct ent *),
        struct ent *key, struct cache_detail *detail, struct ent **item)
{
    int ret;

    *item = lookup_fn(detail, key);
    if (!*item)
        return -ENOMEM;
 retry:
    ret = cache_check(detail, &(*item)->h, &rqstp->rq_chandle);

    if (ret == -ETIMEDOUT) {
        struct ent *prev_item = *item;
        *item = lookup_fn(detail, key);
        if (*item != prev_item)
            goto retry;
        cache_put(&(*item)->h, detail);
    }
    return ret;
}

static char *
rqst_authname(struct svc_rqst *rqstp)
{
    struct auth_domain *clp;

    clp = rqstp->rq_gssclient ? rqstp->rq_gssclient : rqstp->rq_client;
    return clp->name;
}

static __be32
idmap_name_to_id(struct svc_rqst *rqstp, int type, const char *name, u32 namelen,
        uid_t *id)
{
    struct ent *item, key = {
        .type = type,
    };
    int ret;
    struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

    if (namelen + 1 > sizeof(key.name))
        return nfserr_badowner;
    memcpy(key.name, name, namelen);
    key.name[namelen] = '\0';
    strlcpy(key.authname, rqst_authname(rqstp), sizeof(key.authname));
    ret = idmap_lookup(rqstp, nametoid_lookup, &key, nn->nametoid_cache, &item);
    if (ret == -ENOENT)
        return nfserr_badowner;
    if (ret)
        return nfserrno(ret);
    *id = item->id;
    cache_put(&item->h, nn->nametoid_cache);
    return 0;
}

static int
idmap_id_to_name(struct svc_rqst *rqstp, int type, uid_t id, char *name)
{
    struct ent *item, key = {
        .id = id,
        .type = type,
    };
    int ret;
    struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

    strlcpy(key.authname, rqst_authname(rqstp), sizeof(key.authname));
    ret = idmap_lookup(rqstp, idtoname_lookup, &key, nn->idtoname_cache, &item);
    if (ret == -ENOENT)
        return sprintf(name, "%u", id);
    if (ret)
        return ret;
    ret = strlen(item->name);
    BUG_ON(ret > IDMAP_NAMESZ);
    memcpy(name, item->name, ret);
    cache_put(&item->h, nn->idtoname_cache);
    return ret;
}

static bool
numeric_name_to_id(struct svc_rqst *rqstp, int type, const char *name, u32 namelen, uid_t *id)
{
    int ret;
    char buf[11];

    if (namelen + 1 > sizeof(buf))
        /* too long to represent a 32-bit id: */
        return false;
    /* Just to make sure it's null-terminated: */
    memcpy(buf, name, namelen);
    buf[namelen] = '\0';
    ret = kstrtouint(buf, 10, id);
    return ret == 0;
}

static __be32
do_name_to_id(struct svc_rqst *rqstp, int type, const char *name, u32 namelen, uid_t *id)
{
    if (nfs4_disable_idmapping && rqstp->rq_cred.cr_flavor < RPC_AUTH_GSS)
        if (numeric_name_to_id(rqstp, type, name, namelen, id))
            return 0;
        /*
         * otherwise, fall through and try idmapping, for
         * backwards compatibility with clients sending names:
         */
    return idmap_name_to_id(rqstp, type, name, namelen, id);
}

static int
do_id_to_name(struct svc_rqst *rqstp, int type, uid_t id, char *name)
{
    if (nfs4_disable_idmapping && rqstp->rq_cred.cr_flavor < RPC_AUTH_GSS)
        return sprintf(name, "%u", id);
    return idmap_id_to_name(rqstp, type, id, name);
}

__be32
nfsd_map_name_to_uid(struct svc_rqst *rqstp, const char *name, size_t namelen,
        __u32 *id)
{
    return do_name_to_id(rqstp, IDMAP_TYPE_USER, name, namelen, id);
}

__be32
nfsd_map_name_to_gid(struct svc_rqst *rqstp, const char *name, size_t namelen,
        __u32 *id)
{
    return do_name_to_id(rqstp, IDMAP_TYPE_GROUP, name, namelen, id);
}

int
nfsd_map_uid_to_name(struct svc_rqst *rqstp, __u32 id, char *name)
{
    return do_id_to_name(rqstp, IDMAP_TYPE_USER, id, name);
}

int
nfsd_map_gid_to_name(struct svc_rqst *rqstp, __u32 id, char *name)
{
    return do_id_to_name(rqstp, IDMAP_TYPE_GROUP, id, name);
}