linux-stable/fs/nfsd/nfs4idmap.c
NeilBrown cf64b9bce9 SUNRPC: return proper error from get_expiry()
The get_expiry() function currently returns a timestamp, and uses the
special return value of 0 to indicate an error.

Unfortunately this causes a problem when 0 is the correct return value.

On a system with no RTC it is possible that the boot time will be seen
to be "3".  When exportfs probes to see if a particular filesystem
supports NFS export it tries to cache information with an expiry time of
"3".  The intention is for this to be "long in the past".  Even with no
RTC it will not be far in the future (at most a second or two) so this
is harmless.
But if the boot time happens to have been calculated to be "3", then
get_expiry will fail incorrectly as it converts the number to "seconds
since bootime" - 0.

To avoid this problem we change get_expiry() to report the error quite
separately from the expiry time.  The error is now the return value.
The expiry time is reported through a by-reference parameter.

Reported-by: Jerry Zhang <jerry@skydio.com>
Tested-by: Jerry Zhang <jerry@skydio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-04-26 09:05:00 -04:00

687 lines
17 KiB
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/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"
#include "vfs.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.
*/
struct ent {
struct cache_head h;
int type; /* User / Group */
u32 id;
char name[IDMAP_NAMESZ];
char authname[IDMAP_NAMESZ];
struct rcu_head rcu_head;
};
/* 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;
strscpy(new->name, itm->name, sizeof(new->name));
strscpy(new->authname, itm->authname, sizeof(new->authname));
}
static void
ent_put(struct kref *ref)
{
struct ent *map = container_of(ref, struct ent, h.ref);
kfree_rcu(map, rcu_head);
}
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 int
idtoname_upcall(struct cache_detail *cd, struct cache_head *h)
{
return sunrpc_cache_pipe_upcall_timeout(cd, h);
}
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_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_putc(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 const 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_request = idtoname_request,
.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 */
len = qword_get(&buf, buf1, PAGE_SIZE);
if (len <= 0 || len >= IDMAP_NAMESZ)
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 */
error = get_expiry(&buf, &ent.h.expiry_time);
if (error)
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 || len >= IDMAP_NAMESZ)
goto out;
if (len == 0)
set_bit(CACHE_NEGATIVE, &ent.h.flags);
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_rcu(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 int
nametoid_upcall(struct cache_detail *cd, struct cache_head *h)
{
return sunrpc_cache_pipe_upcall_timeout(cd, h);
}
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_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_putc(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 const 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_request = nametoid_request,
.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 len, 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 */
len = qword_get(&buf, buf1, PAGE_SIZE);
if (len <= 0 || len >= IDMAP_NAMESZ)
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 */
len = qword_get(&buf, buf1, PAGE_SIZE);
if (len <= 0 || len >= IDMAP_NAMESZ)
goto out;
memcpy(ent.name, buf1, sizeof(ent.name));
/* expiry */
error = get_expiry(&buf, &ent.h.expiry_time);
if (error)
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_rcu(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,
u32 *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';
strscpy(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 __be32 encode_ascii_id(struct xdr_stream *xdr, u32 id)
{
char buf[11];
int len;
__be32 *p;
len = sprintf(buf, "%u", id);
p = xdr_reserve_space(xdr, len + 4);
if (!p)
return nfserr_resource;
p = xdr_encode_opaque(p, buf, len);
return 0;
}
static __be32 idmap_id_to_name(struct xdr_stream *xdr,
struct svc_rqst *rqstp, int type, u32 id)
{
struct ent *item, key = {
.id = id,
.type = type,
};
__be32 *p;
int ret;
struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
strscpy(key.authname, rqst_authname(rqstp), sizeof(key.authname));
ret = idmap_lookup(rqstp, idtoname_lookup, &key, nn->idtoname_cache, &item);
if (ret == -ENOENT)
return encode_ascii_id(xdr, id);
if (ret)
return nfserrno(ret);
ret = strlen(item->name);
WARN_ON_ONCE(ret > IDMAP_NAMESZ);
p = xdr_reserve_space(xdr, ret + 4);
if (!p)
return nfserr_resource;
p = xdr_encode_opaque(p, item->name, ret);
cache_put(&item->h, nn->idtoname_cache);
return 0;
}
static bool
numeric_name_to_id(struct svc_rqst *rqstp, int type, const char *name, u32 namelen, u32 *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, u32 *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 __be32 encode_name_from_id(struct xdr_stream *xdr,
struct svc_rqst *rqstp, int type, u32 id)
{
if (nfs4_disable_idmapping && rqstp->rq_cred.cr_flavor < RPC_AUTH_GSS)
return encode_ascii_id(xdr, id);
return idmap_id_to_name(xdr, rqstp, type, id);
}
__be32
nfsd_map_name_to_uid(struct svc_rqst *rqstp, const char *name, size_t namelen,
kuid_t *uid)
{
__be32 status;
u32 id = -1;
if (name == NULL || namelen == 0)
return nfserr_inval;
status = do_name_to_id(rqstp, IDMAP_TYPE_USER, name, namelen, &id);
*uid = make_kuid(nfsd_user_namespace(rqstp), id);
if (!uid_valid(*uid))
status = nfserr_badowner;
return status;
}
__be32
nfsd_map_name_to_gid(struct svc_rqst *rqstp, const char *name, size_t namelen,
kgid_t *gid)
{
__be32 status;
u32 id = -1;
if (name == NULL || namelen == 0)
return nfserr_inval;
status = do_name_to_id(rqstp, IDMAP_TYPE_GROUP, name, namelen, &id);
*gid = make_kgid(nfsd_user_namespace(rqstp), id);
if (!gid_valid(*gid))
status = nfserr_badowner;
return status;
}
__be32 nfsd4_encode_user(struct xdr_stream *xdr, struct svc_rqst *rqstp,
kuid_t uid)
{
u32 id = from_kuid_munged(nfsd_user_namespace(rqstp), uid);
return encode_name_from_id(xdr, rqstp, IDMAP_TYPE_USER, id);
}
__be32 nfsd4_encode_group(struct xdr_stream *xdr, struct svc_rqst *rqstp,
kgid_t gid)
{
u32 id = from_kgid_munged(nfsd_user_namespace(rqstp), gid);
return encode_name_from_id(xdr, rqstp, IDMAP_TYPE_GROUP, id);
}