linux/fs/nfsd/nfs4idmap.c
Bruce Allan f35279d3f7 [PATCH] sunrpc: cache_register can use wrong module reference
When registering an RPC cache, cache_register() always sets the owner as the
sunrpc module.  However, there are RPC caches owned by other modules.  With
the incorrect owner setting, the real owning module can be removed potentially
with an open reference to the cache from userspace.

For example, if one were to stop the nfs server and unmount the nfsd
filesystem, the nfsd module could be removed eventhough rpc.idmapd had
references to the idtoname and nametoid caches (i.e.
/proc/net/rpc/nfs4.<cachename>/channel is still open).  This resulted in a
system panic on one of our machines when attempting to restart the nfs
services after reloading the nfsd module.

The following patch adds a 'struct module *owner' field in struct
cache_detail.  The owner is further assigned to the struct proc_dir_entry
in cache_register() so that the module cannot be unloaded while user-space
daemons have an open reference on the associated file under /proc.

Signed-off-by: Bruce Allan <bwa@us.ibm.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:25 -07:00

593 lines
14 KiB
C

/*
* fs/nfsd/nfs4idmap.c
*
* 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 <marius@umich.edu>
*
* 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/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/utsname.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/smp_lock.h>
#include <linux/sunrpc/cache.h>
#include <linux/nfsd_idmap.h>
#include <linux/list.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/seq_file.h>
#include <linux/sunrpc/svcauth.h>
/*
* 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];
};
#define DefineSimpleCacheLookupMap(STRUCT, FUNC) \
DefineCacheLookup(struct STRUCT, h, FUNC##_lookup, \
(struct STRUCT *item, int set), /*no setup */, \
& FUNC##_cache, FUNC##_hash(item), FUNC##_match(item, tmp), \
STRUCT##_init(new, item), STRUCT##_update(tmp, item), 0)
/* Common entry handling */
#define ENT_HASHBITS 8
#define ENT_HASHMAX (1 << ENT_HASHBITS)
#define ENT_HASHMASK (ENT_HASHMAX - 1)
static inline void
ent_init(struct ent *new, struct ent *itm)
{
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 inline void
ent_update(struct ent *new, struct ent *itm)
{
ent_init(new, itm);
}
static void
ent_put(struct cache_head *ch, struct cache_detail *cd)
{
if (cache_put(ch, cd)) {
struct ent *map = container_of(ch, struct ent, h);
kfree(map);
}
}
/*
* ID -> Name cache
*/
static struct cache_head *idtoname_table[ENT_HASHMAX];
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), "%d", ent->id);
qword_add(bpp, blen, ent->type == IDMAP_TYPE_GROUP ? "group" : "user");
qword_add(bpp, blen, idstr);
(*bpp)[-1] = '\n';
}
static inline int
idtoname_match(struct ent *a, struct ent *b)
{
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 %d", 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)
{
printk("nfsd: nfsv4 idmapping failing: has idmapd %s?\n",
detail->last_close? "died" : "not been started");
}
static int idtoname_parse(struct cache_detail *, char *, int);
static struct ent *idtoname_lookup(struct ent *, int);
static struct cache_detail idtoname_cache = {
.owner = THIS_MODULE,
.hash_size = ENT_HASHMAX,
.hash_table = idtoname_table,
.name = "nfs4.idtoname",
.cache_put = ent_put,
.cache_request = idtoname_request,
.cache_parse = idtoname_parse,
.cache_show = idtoname_show,
.warn_no_listener = warn_no_idmapd,
};
int
idtoname_parse(struct cache_detail *cd, char *buf, int buflen)
{
struct ent ent, *res;
char *buf1, *bp;
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;
/* Name */
error = qword_get(&buf, buf1, PAGE_SIZE);
if (error == -EINVAL)
goto out;
if (error == -ENOENT)
set_bit(CACHE_NEGATIVE, &ent.h.flags);
else {
if (error >= IDMAP_NAMESZ) {
error = -EINVAL;
goto out;
}
memcpy(ent.name, buf1, sizeof(ent.name));
}
error = -ENOMEM;
if ((res = idtoname_lookup(&ent, 1)) == NULL)
goto out;
ent_put(&res->h, &idtoname_cache);
error = 0;
out:
kfree(buf1);
return error;
}
static DefineSimpleCacheLookupMap(ent, idtoname);
/*
* Name -> ID cache
*/
static struct cache_head *nametoid_table[ENT_HASHMAX];
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 inline int
nametoid_match(struct ent *a, struct ent *b)
{
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, " %d", ent->id);
seq_printf(m, "\n");
return 0;
}
static struct ent *nametoid_lookup(struct ent *, int);
static int nametoid_parse(struct cache_detail *, char *, int);
static struct cache_detail nametoid_cache = {
.owner = THIS_MODULE,
.hash_size = ENT_HASHMAX,
.hash_table = nametoid_table,
.name = "nfs4.nametoid",
.cache_put = ent_put,
.cache_request = nametoid_request,
.cache_parse = nametoid_parse,
.cache_show = nametoid_show,
.warn_no_listener = warn_no_idmapd,
};
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;
if ((res = nametoid_lookup(&ent, 1)) == NULL)
goto out;
ent_put(&res->h, &nametoid_cache);
error = 0;
out:
kfree(buf1);
return (error);
}
static DefineSimpleCacheLookupMap(ent, nametoid);
/*
* Exported API
*/
void
nfsd_idmap_init(void)
{
cache_register(&idtoname_cache);
cache_register(&nametoid_cache);
}
void
nfsd_idmap_shutdown(void)
{
if (cache_unregister(&idtoname_cache))
printk(KERN_ERR "nfsd: failed to unregister idtoname cache\n");
if (cache_unregister(&nametoid_cache))
printk(KERN_ERR "nfsd: failed to unregister nametoid cache\n");
}
/*
* Deferred request handling
*/
struct idmap_defer_req {
struct cache_req req;
struct cache_deferred_req deferred_req;
wait_queue_head_t waitq;
atomic_t count;
};
static inline void
put_mdr(struct idmap_defer_req *mdr)
{
if (atomic_dec_and_test(&mdr->count))
kfree(mdr);
}
static inline void
get_mdr(struct idmap_defer_req *mdr)
{
atomic_inc(&mdr->count);
}
static void
idmap_revisit(struct cache_deferred_req *dreq, int toomany)
{
struct idmap_defer_req *mdr =
container_of(dreq, struct idmap_defer_req, deferred_req);
wake_up(&mdr->waitq);
put_mdr(mdr);
}
static struct cache_deferred_req *
idmap_defer(struct cache_req *req)
{
struct idmap_defer_req *mdr =
container_of(req, struct idmap_defer_req, req);
mdr->deferred_req.revisit = idmap_revisit;
get_mdr(mdr);
return (&mdr->deferred_req);
}
static inline int
do_idmap_lookup(struct ent *(*lookup_fn)(struct ent *, int), struct ent *key,
struct cache_detail *detail, struct ent **item,
struct idmap_defer_req *mdr)
{
*item = lookup_fn(key, 0);
if (!*item)
return -ENOMEM;
return cache_check(detail, &(*item)->h, &mdr->req);
}
static inline int
do_idmap_lookup_nowait(struct ent *(*lookup_fn)(struct ent *, int),
struct ent *key, struct cache_detail *detail,
struct ent **item)
{
int ret = -ENOMEM;
*item = lookup_fn(key, 0);
if (!*item)
goto out_err;
ret = -ETIMEDOUT;
if (!test_bit(CACHE_VALID, &(*item)->h.flags)
|| (*item)->h.expiry_time < get_seconds()
|| detail->flush_time > (*item)->h.last_refresh)
goto out_put;
ret = -ENOENT;
if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
goto out_put;
return 0;
out_put:
ent_put(&(*item)->h, detail);
out_err:
*item = NULL;
return ret;
}
static int
idmap_lookup(struct svc_rqst *rqstp,
struct ent *(*lookup_fn)(struct ent *, int), struct ent *key,
struct cache_detail *detail, struct ent **item)
{
struct idmap_defer_req *mdr;
int ret;
mdr = kmalloc(sizeof(*mdr), GFP_KERNEL);
if (!mdr)
return -ENOMEM;
memset(mdr, 0, sizeof(*mdr));
atomic_set(&mdr->count, 1);
init_waitqueue_head(&mdr->waitq);
mdr->req.defer = idmap_defer;
ret = do_idmap_lookup(lookup_fn, key, detail, item, mdr);
if (ret == -EAGAIN) {
wait_event_interruptible_timeout(mdr->waitq,
test_bit(CACHE_VALID, &(*item)->h.flags), 1 * HZ);
ret = do_idmap_lookup_nowait(lookup_fn, key, detail, item);
}
put_mdr(mdr);
return ret;
}
static int
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;
if (namelen + 1 > sizeof(key.name))
return -EINVAL;
memcpy(key.name, name, namelen);
key.name[namelen] = '\0';
strlcpy(key.authname, rqstp->rq_client->name, sizeof(key.authname));
ret = idmap_lookup(rqstp, nametoid_lookup, &key, &nametoid_cache, &item);
if (ret == -ENOENT)
ret = -ESRCH; /* nfserr_badname */
if (ret)
return ret;
*id = item->id;
ent_put(&item->h, &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;
strlcpy(key.authname, rqstp->rq_client->name, sizeof(key.authname));
ret = idmap_lookup(rqstp, idtoname_lookup, &key, &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);
ent_put(&item->h, &idtoname_cache);
return ret;
}
int
nfsd_map_name_to_uid(struct svc_rqst *rqstp, const char *name, size_t namelen,
__u32 *id)
{
return idmap_name_to_id(rqstp, IDMAP_TYPE_USER, name, namelen, id);
}
int
nfsd_map_name_to_gid(struct svc_rqst *rqstp, const char *name, size_t namelen,
__u32 *id)
{
return idmap_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 idmap_id_to_name(rqstp, IDMAP_TYPE_USER, id, name);
}
int
nfsd_map_gid_to_name(struct svc_rqst *rqstp, __u32 id, char *name)
{
return idmap_id_to_name(rqstp, IDMAP_TYPE_GROUP, id, name);
}