kernel-fxtec-pro1x/fs/nfsd/nfs4callback.c
J. Bruce Fields 886e3b7fe6 nfsd4: fix null dereference creating nfsv4 callback client
On setting up the callback to the client, we attempt to use the same
authentication flavor the client did.  We find an rpc cred to use by
calling rpcauth_lookup_credcache(), which assumes that the given
authentication flavor has a credentials cache.  However, this is not
required to be true--in particular, auth_null does not use one.
Instead, we should call the auth's lookup_cred() method.

Without this, a client attempting to mount using nfsv4 and auth_null
triggers a null dereference.

Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-09-15 20:49:33 -04:00

564 lines
15 KiB
C

/*
* linux/fs/nfsd/nfs4callback.c
*
* Copyright (c) 2001 The Regents of the University of Michigan.
* All rights reserved.
*
* Kendrick Smith <kmsmith@umich.edu>
* Andy Adamson <andros@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/list.h>
#include <linux/inet.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/kthread.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/state.h>
#include <linux/sunrpc/sched.h>
#include <linux/nfs4.h>
#define NFSDDBG_FACILITY NFSDDBG_PROC
#define NFSPROC4_CB_NULL 0
#define NFSPROC4_CB_COMPOUND 1
/* Index of predefined Linux callback client operations */
enum {
NFSPROC4_CLNT_CB_NULL = 0,
NFSPROC4_CLNT_CB_RECALL,
};
enum nfs_cb_opnum4 {
OP_CB_RECALL = 4,
};
#define NFS4_MAXTAGLEN 20
#define NFS4_enc_cb_null_sz 0
#define NFS4_dec_cb_null_sz 0
#define cb_compound_enc_hdr_sz 4
#define cb_compound_dec_hdr_sz (3 + (NFS4_MAXTAGLEN >> 2))
#define op_enc_sz 1
#define op_dec_sz 2
#define enc_nfs4_fh_sz (1 + (NFS4_FHSIZE >> 2))
#define enc_stateid_sz (NFS4_STATEID_SIZE >> 2)
#define NFS4_enc_cb_recall_sz (cb_compound_enc_hdr_sz + \
1 + enc_stateid_sz + \
enc_nfs4_fh_sz)
#define NFS4_dec_cb_recall_sz (cb_compound_dec_hdr_sz + \
op_dec_sz)
/*
* Generic encode routines from fs/nfs/nfs4xdr.c
*/
static inline __be32 *
xdr_writemem(__be32 *p, const void *ptr, int nbytes)
{
int tmp = XDR_QUADLEN(nbytes);
if (!tmp)
return p;
p[tmp-1] = 0;
memcpy(p, ptr, nbytes);
return p + tmp;
}
#define WRITE32(n) *p++ = htonl(n)
#define WRITEMEM(ptr,nbytes) do { \
p = xdr_writemem(p, ptr, nbytes); \
} while (0)
#define RESERVE_SPACE(nbytes) do { \
p = xdr_reserve_space(xdr, nbytes); \
if (!p) dprintk("NFSD: RESERVE_SPACE(%d) failed in function %s\n", (int) (nbytes), __func__); \
BUG_ON(!p); \
} while (0)
/*
* Generic decode routines from fs/nfs/nfs4xdr.c
*/
#define DECODE_TAIL \
status = 0; \
out: \
return status; \
xdr_error: \
dprintk("NFSD: xdr error! (%s:%d)\n", __FILE__, __LINE__); \
status = -EIO; \
goto out
#define READ32(x) (x) = ntohl(*p++)
#define READ64(x) do { \
(x) = (u64)ntohl(*p++) << 32; \
(x) |= ntohl(*p++); \
} while (0)
#define READTIME(x) do { \
p++; \
(x.tv_sec) = ntohl(*p++); \
(x.tv_nsec) = ntohl(*p++); \
} while (0)
#define READ_BUF(nbytes) do { \
p = xdr_inline_decode(xdr, nbytes); \
if (!p) { \
dprintk("NFSD: %s: reply buffer overflowed in line %d.\n", \
__func__, __LINE__); \
return -EIO; \
} \
} while (0)
struct nfs4_cb_compound_hdr {
int status;
u32 ident;
u32 nops;
__be32 *nops_p;
u32 minorversion;
u32 taglen;
char *tag;
};
static struct {
int stat;
int errno;
} nfs_cb_errtbl[] = {
{ NFS4_OK, 0 },
{ NFS4ERR_PERM, EPERM },
{ NFS4ERR_NOENT, ENOENT },
{ NFS4ERR_IO, EIO },
{ NFS4ERR_NXIO, ENXIO },
{ NFS4ERR_ACCESS, EACCES },
{ NFS4ERR_EXIST, EEXIST },
{ NFS4ERR_XDEV, EXDEV },
{ NFS4ERR_NOTDIR, ENOTDIR },
{ NFS4ERR_ISDIR, EISDIR },
{ NFS4ERR_INVAL, EINVAL },
{ NFS4ERR_FBIG, EFBIG },
{ NFS4ERR_NOSPC, ENOSPC },
{ NFS4ERR_ROFS, EROFS },
{ NFS4ERR_MLINK, EMLINK },
{ NFS4ERR_NAMETOOLONG, ENAMETOOLONG },
{ NFS4ERR_NOTEMPTY, ENOTEMPTY },
{ NFS4ERR_DQUOT, EDQUOT },
{ NFS4ERR_STALE, ESTALE },
{ NFS4ERR_BADHANDLE, EBADHANDLE },
{ NFS4ERR_BAD_COOKIE, EBADCOOKIE },
{ NFS4ERR_NOTSUPP, ENOTSUPP },
{ NFS4ERR_TOOSMALL, ETOOSMALL },
{ NFS4ERR_SERVERFAULT, ESERVERFAULT },
{ NFS4ERR_BADTYPE, EBADTYPE },
{ NFS4ERR_LOCKED, EAGAIN },
{ NFS4ERR_RESOURCE, EREMOTEIO },
{ NFS4ERR_SYMLINK, ELOOP },
{ NFS4ERR_OP_ILLEGAL, EOPNOTSUPP },
{ NFS4ERR_DEADLOCK, EDEADLK },
{ -1, EIO }
};
static int
nfs_cb_stat_to_errno(int stat)
{
int i;
for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
if (nfs_cb_errtbl[i].stat == stat)
return nfs_cb_errtbl[i].errno;
}
/* If we cannot translate the error, the recovery routines should
* handle it.
* Note: remaining NFSv4 error codes have values > 10000, so should
* not conflict with native Linux error codes.
*/
return stat;
}
/*
* XDR encode
*/
static void
encode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr)
{
__be32 * p;
RESERVE_SPACE(16);
WRITE32(0); /* tag length is always 0 */
WRITE32(hdr->minorversion);
WRITE32(hdr->ident);
hdr->nops_p = p;
WRITE32(hdr->nops);
}
static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
{
*hdr->nops_p = htonl(hdr->nops);
}
static void
encode_cb_recall(struct xdr_stream *xdr, struct nfs4_delegation *dp,
struct nfs4_cb_compound_hdr *hdr)
{
__be32 *p;
int len = dp->dl_fh.fh_size;
RESERVE_SPACE(12+sizeof(dp->dl_stateid) + len);
WRITE32(OP_CB_RECALL);
WRITE32(dp->dl_stateid.si_generation);
WRITEMEM(&dp->dl_stateid.si_opaque, sizeof(stateid_opaque_t));
WRITE32(0); /* truncate optimization not implemented */
WRITE32(len);
WRITEMEM(&dp->dl_fh.fh_base, len);
hdr->nops++;
}
static int
nfs4_xdr_enc_cb_null(struct rpc_rqst *req, __be32 *p)
{
struct xdr_stream xdrs, *xdr = &xdrs;
xdr_init_encode(&xdrs, &req->rq_snd_buf, p);
RESERVE_SPACE(0);
return 0;
}
static int
nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p, struct nfs4_delegation *args)
{
struct xdr_stream xdr;
struct nfs4_cb_compound_hdr hdr = {
.ident = args->dl_ident,
};
xdr_init_encode(&xdr, &req->rq_snd_buf, p);
encode_cb_compound_hdr(&xdr, &hdr);
encode_cb_recall(&xdr, args, &hdr);
encode_cb_nops(&hdr);
return 0;
}
static int
decode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr){
__be32 *p;
READ_BUF(8);
READ32(hdr->status);
READ32(hdr->taglen);
READ_BUF(hdr->taglen + 4);
hdr->tag = (char *)p;
p += XDR_QUADLEN(hdr->taglen);
READ32(hdr->nops);
return 0;
}
static int
decode_cb_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
{
__be32 *p;
u32 op;
int32_t nfserr;
READ_BUF(8);
READ32(op);
if (op != expected) {
dprintk("NFSD: decode_cb_op_hdr: Callback server returned "
" operation %d but we issued a request for %d\n",
op, expected);
return -EIO;
}
READ32(nfserr);
if (nfserr != NFS_OK)
return -nfs_cb_stat_to_errno(nfserr);
return 0;
}
static int
nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
{
return 0;
}
static int
nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp, __be32 *p)
{
struct xdr_stream xdr;
struct nfs4_cb_compound_hdr hdr;
int status;
xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
status = decode_cb_compound_hdr(&xdr, &hdr);
if (status)
goto out;
status = decode_cb_op_hdr(&xdr, OP_CB_RECALL);
out:
return status;
}
/*
* RPC procedure tables
*/
#define PROC(proc, call, argtype, restype) \
[NFSPROC4_CLNT_##proc] = { \
.p_proc = NFSPROC4_CB_##call, \
.p_encode = (kxdrproc_t) nfs4_xdr_##argtype, \
.p_decode = (kxdrproc_t) nfs4_xdr_##restype, \
.p_arglen = NFS4_##argtype##_sz, \
.p_replen = NFS4_##restype##_sz, \
.p_statidx = NFSPROC4_CB_##call, \
.p_name = #proc, \
}
static struct rpc_procinfo nfs4_cb_procedures[] = {
PROC(CB_NULL, NULL, enc_cb_null, dec_cb_null),
PROC(CB_RECALL, COMPOUND, enc_cb_recall, dec_cb_recall),
};
static struct rpc_version nfs_cb_version4 = {
.number = 1,
.nrprocs = ARRAY_SIZE(nfs4_cb_procedures),
.procs = nfs4_cb_procedures
};
static struct rpc_version * nfs_cb_version[] = {
NULL,
&nfs_cb_version4,
};
static struct rpc_program cb_program;
static struct rpc_stat cb_stats = {
.program = &cb_program
};
#define NFS4_CALLBACK 0x40000000
static struct rpc_program cb_program = {
.name = "nfs4_cb",
.number = NFS4_CALLBACK,
.nrvers = ARRAY_SIZE(nfs_cb_version),
.version = nfs_cb_version,
.stats = &cb_stats,
.pipe_dir_name = "/nfsd4_cb",
};
static int max_cb_time(void)
{
return max(NFSD_LEASE_TIME/10, (time_t)1) * HZ;
}
/* Reference counting, callback cleanup, etc., all look racy as heck.
* And why is cb_set an atomic? */
int setup_callback_client(struct nfs4_client *clp)
{
struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
struct rpc_timeout timeparms = {
.to_initval = max_cb_time(),
.to_retries = 0,
};
struct rpc_create_args args = {
.protocol = IPPROTO_TCP,
.address = (struct sockaddr *) &cb->cb_addr,
.addrsize = cb->cb_addrlen,
.timeout = &timeparms,
.program = &cb_program,
.prognumber = cb->cb_prog,
.version = nfs_cb_version[1]->number,
.authflavor = clp->cl_flavor,
.flags = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
.client_name = clp->cl_principal,
};
struct rpc_clnt *client;
if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
return -EINVAL;
/* Create RPC client */
client = rpc_create(&args);
if (IS_ERR(client)) {
dprintk("NFSD: couldn't create callback client: %ld\n",
PTR_ERR(client));
return PTR_ERR(client);
}
cb->cb_client = client;
return 0;
}
static void warn_no_callback_path(struct nfs4_client *clp, int reason)
{
dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
(int)clp->cl_name.len, clp->cl_name.data, reason);
}
static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
{
struct nfs4_client *clp = calldata;
if (task->tk_status)
warn_no_callback_path(clp, task->tk_status);
else
atomic_set(&clp->cl_cb_conn.cb_set, 1);
put_nfs4_client(clp);
}
static const struct rpc_call_ops nfsd4_cb_probe_ops = {
.rpc_call_done = nfsd4_cb_probe_done,
};
static struct rpc_cred *lookup_cb_cred(struct nfs4_cb_conn *cb)
{
struct auth_cred acred = {
.machine_cred = 1
};
struct rpc_auth *auth = cb->cb_client->cl_auth;
/*
* Note in the gss case this doesn't actually have to wait for a
* gss upcall (or any calls to the client); this just creates a
* non-uptodate cred which the rpc state machine will fill in with
* a refresh_upcall later.
*/
return auth->au_ops->lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
}
void do_probe_callback(struct nfs4_client *clp)
{
struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
struct rpc_message msg = {
.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
.rpc_argp = clp,
};
struct rpc_cred *cred;
int status;
cred = lookup_cb_cred(cb);
if (IS_ERR(cred)) {
status = PTR_ERR(cred);
goto out;
}
cb->cb_cred = cred;
msg.rpc_cred = cb->cb_cred;
status = rpc_call_async(cb->cb_client, &msg, RPC_TASK_SOFT,
&nfsd4_cb_probe_ops, (void *)clp);
out:
if (status) {
warn_no_callback_path(clp, status);
put_nfs4_client(clp);
}
}
/*
* Set up the callback client and put a NFSPROC4_CB_NULL on the wire...
*/
void
nfsd4_probe_callback(struct nfs4_client *clp)
{
int status;
BUG_ON(atomic_read(&clp->cl_cb_conn.cb_set));
status = setup_callback_client(clp);
if (status) {
warn_no_callback_path(clp, status);
return;
}
/* the task holds a reference to the nfs4_client struct */
atomic_inc(&clp->cl_count);
do_probe_callback(clp);
}
static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
{
struct nfs4_delegation *dp = calldata;
struct nfs4_client *clp = dp->dl_client;
switch (task->tk_status) {
case -EIO:
/* Network partition? */
atomic_set(&clp->cl_cb_conn.cb_set, 0);
warn_no_callback_path(clp, task->tk_status);
case -EBADHANDLE:
case -NFS4ERR_BAD_STATEID:
/* Race: client probably got cb_recall
* before open reply granting delegation */
break;
default:
/* success, or error we can't handle */
return;
}
if (dp->dl_retries--) {
rpc_delay(task, 2*HZ);
task->tk_status = 0;
rpc_restart_call(task);
} else {
atomic_set(&clp->cl_cb_conn.cb_set, 0);
warn_no_callback_path(clp, task->tk_status);
}
}
static void nfsd4_cb_recall_release(void *calldata)
{
struct nfs4_delegation *dp = calldata;
struct nfs4_client *clp = dp->dl_client;
nfs4_put_delegation(dp);
put_nfs4_client(clp);
}
static const struct rpc_call_ops nfsd4_cb_recall_ops = {
.rpc_call_done = nfsd4_cb_recall_done,
.rpc_release = nfsd4_cb_recall_release,
};
/*
* called with dp->dl_count inc'ed.
*/
void
nfsd4_cb_recall(struct nfs4_delegation *dp)
{
struct nfs4_client *clp = dp->dl_client;
struct rpc_clnt *clnt = clp->cl_cb_conn.cb_client;
struct rpc_message msg = {
.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL],
.rpc_argp = dp,
.rpc_cred = clp->cl_cb_conn.cb_cred
};
int status;
dp->dl_retries = 1;
status = rpc_call_async(clnt, &msg, RPC_TASK_SOFT,
&nfsd4_cb_recall_ops, dp);
if (status) {
put_nfs4_client(clp);
nfs4_put_delegation(dp);
}
}