kernel-ark/net/sunrpc/pmap_clnt.c
Chuck Lever 71bdcf8056 [PATCH] SUNRPC: fix race in in-kernel RPC portmapper client
When submitting a request to a fast portmapper (such as the local rpcbind
daemon), the request can complete before the parent task is even queued up on
xprt->binding.  Fix this by queuing before submitting the rpcbind request.

Test plan:
Connectathon locking test with UDP.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20 10:26:39 -07:00

379 lines
9.2 KiB
C

/*
* linux/net/sunrpc/pmap_clnt.c
*
* In-kernel RPC portmapper client.
*
* Portmapper supports version 2 of the rpcbind protocol (RFC 1833).
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/uio.h>
#include <linux/in.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/sched.h>
#ifdef RPC_DEBUG
# define RPCDBG_FACILITY RPCDBG_PMAP
#endif
#define PMAP_SET 1
#define PMAP_UNSET 2
#define PMAP_GETPORT 3
struct portmap_args {
u32 pm_prog;
u32 pm_vers;
u32 pm_prot;
unsigned short pm_port;
struct rpc_xprt * pm_xprt;
};
static struct rpc_procinfo pmap_procedures[];
static struct rpc_clnt * pmap_create(char *, struct sockaddr_in *, int, int);
static void pmap_getport_done(struct rpc_task *, void *);
static struct rpc_program pmap_program;
static void pmap_getport_prepare(struct rpc_task *task, void *calldata)
{
struct portmap_args *map = calldata;
struct rpc_message msg = {
.rpc_proc = &pmap_procedures[PMAP_GETPORT],
.rpc_argp = map,
.rpc_resp = &map->pm_port,
};
rpc_call_setup(task, &msg, 0);
}
static inline struct portmap_args *pmap_map_alloc(void)
{
return kmalloc(sizeof(struct portmap_args), GFP_NOFS);
}
static inline void pmap_map_free(struct portmap_args *map)
{
kfree(map);
}
static void pmap_map_release(void *data)
{
pmap_map_free(data);
}
static const struct rpc_call_ops pmap_getport_ops = {
.rpc_call_prepare = pmap_getport_prepare,
.rpc_call_done = pmap_getport_done,
.rpc_release = pmap_map_release,
};
static inline void pmap_wake_portmap_waiters(struct rpc_xprt *xprt, int status)
{
xprt_clear_binding(xprt);
rpc_wake_up_status(&xprt->binding, status);
}
/**
* rpc_getport - obtain the port for a given RPC service on a given host
* @task: task that is waiting for portmapper request
*
* This one can be called for an ongoing RPC request, and can be used in
* an async (rpciod) context.
*/
void rpc_getport(struct rpc_task *task)
{
struct rpc_clnt *clnt = task->tk_client;
struct rpc_xprt *xprt = task->tk_xprt;
struct sockaddr_in addr;
struct portmap_args *map;
struct rpc_clnt *pmap_clnt;
struct rpc_task *child;
int status;
dprintk("RPC: %4d rpc_getport(%s, %u, %u, %d)\n",
task->tk_pid, clnt->cl_server,
clnt->cl_prog, clnt->cl_vers, xprt->prot);
/* Autobind on cloned rpc clients is discouraged */
BUG_ON(clnt->cl_parent != clnt);
/* Put self on queue before sending rpcbind request, in case
* pmap_getport_done completes before we return from rpc_run_task */
rpc_sleep_on(&xprt->binding, task, NULL, NULL);
status = -EACCES; /* tell caller to check again */
if (xprt_test_and_set_binding(xprt))
goto bailout_nofree;
/* Someone else may have bound if we slept */
status = 0;
if (xprt_bound(xprt))
goto bailout_nofree;
status = -ENOMEM;
map = pmap_map_alloc();
if (!map)
goto bailout_nofree;
map->pm_prog = clnt->cl_prog;
map->pm_vers = clnt->cl_vers;
map->pm_prot = xprt->prot;
map->pm_port = 0;
map->pm_xprt = xprt_get(xprt);
rpc_peeraddr(clnt, (struct sockaddr *) &addr, sizeof(addr));
pmap_clnt = pmap_create(clnt->cl_server, &addr, map->pm_prot, 0);
status = PTR_ERR(pmap_clnt);
if (IS_ERR(pmap_clnt))
goto bailout;
status = -EIO;
child = rpc_run_task(pmap_clnt, RPC_TASK_ASYNC, &pmap_getport_ops, map);
if (IS_ERR(child))
goto bailout;
rpc_release_task(child);
task->tk_xprt->stat.bind_count++;
return;
bailout:
pmap_map_free(map);
xprt_put(xprt);
bailout_nofree:
task->tk_status = status;
pmap_wake_portmap_waiters(xprt, status);
}
#ifdef CONFIG_ROOT_NFS
/**
* rpc_getport_external - obtain the port for a given RPC service on a given host
* @sin: address of remote peer
* @prog: RPC program number to bind
* @vers: RPC version number to bind
* @prot: transport protocol to use to make this request
*
* This one is called from outside the RPC client in a synchronous task context.
*/
int rpc_getport_external(struct sockaddr_in *sin, __u32 prog, __u32 vers, int prot)
{
struct portmap_args map = {
.pm_prog = prog,
.pm_vers = vers,
.pm_prot = prot,
.pm_port = 0
};
struct rpc_message msg = {
.rpc_proc = &pmap_procedures[PMAP_GETPORT],
.rpc_argp = &map,
.rpc_resp = &map.pm_port,
};
struct rpc_clnt *pmap_clnt;
char hostname[32];
int status;
dprintk("RPC: rpc_getport_external(%u.%u.%u.%u, %u, %u, %d)\n",
NIPQUAD(sin->sin_addr.s_addr), prog, vers, prot);
sprintf(hostname, "%u.%u.%u.%u", NIPQUAD(sin->sin_addr.s_addr));
pmap_clnt = pmap_create(hostname, sin, prot, 0);
if (IS_ERR(pmap_clnt))
return PTR_ERR(pmap_clnt);
/* Setup the call info struct */
status = rpc_call_sync(pmap_clnt, &msg, 0);
if (status >= 0) {
if (map.pm_port != 0)
return map.pm_port;
status = -EACCES;
}
return status;
}
#endif
/*
* Portmapper child task invokes this callback via tk_exit.
*/
static void pmap_getport_done(struct rpc_task *child, void *data)
{
struct portmap_args *map = data;
struct rpc_xprt *xprt = map->pm_xprt;
int status = child->tk_status;
if (status < 0) {
/* Portmapper not available */
xprt->ops->set_port(xprt, 0);
} else if (map->pm_port == 0) {
/* Requested RPC service wasn't registered */
xprt->ops->set_port(xprt, 0);
status = -EACCES;
} else {
/* Succeeded */
xprt->ops->set_port(xprt, map->pm_port);
xprt_set_bound(xprt);
status = 0;
}
dprintk("RPC: %4d pmap_getport_done(status %d, port %u)\n",
child->tk_pid, status, map->pm_port);
pmap_wake_portmap_waiters(xprt, status);
xprt_put(xprt);
}
/**
* rpc_register - set or unset a port registration with the local portmapper
* @prog: RPC program number to bind
* @vers: RPC version number to bind
* @prot: transport protocol to use to make this request
* @port: port value to register
* @okay: result code
*
* port == 0 means unregister, port != 0 means register.
*/
int rpc_register(u32 prog, u32 vers, int prot, unsigned short port, int *okay)
{
struct sockaddr_in sin = {
.sin_family = AF_INET,
.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
};
struct portmap_args map = {
.pm_prog = prog,
.pm_vers = vers,
.pm_prot = prot,
.pm_port = port,
};
struct rpc_message msg = {
.rpc_proc = &pmap_procedures[port ? PMAP_SET : PMAP_UNSET],
.rpc_argp = &map,
.rpc_resp = okay,
};
struct rpc_clnt *pmap_clnt;
int error = 0;
dprintk("RPC: registering (%u, %u, %d, %u) with portmapper.\n",
prog, vers, prot, port);
pmap_clnt = pmap_create("localhost", &sin, IPPROTO_UDP, 1);
if (IS_ERR(pmap_clnt)) {
error = PTR_ERR(pmap_clnt);
dprintk("RPC: couldn't create pmap client. Error = %d\n", error);
return error;
}
error = rpc_call_sync(pmap_clnt, &msg, 0);
if (error < 0) {
printk(KERN_WARNING
"RPC: failed to contact portmap (errno %d).\n",
error);
}
dprintk("RPC: registration status %d/%d\n", error, *okay);
/* Client deleted automatically because cl_oneshot == 1 */
return error;
}
static struct rpc_clnt *pmap_create(char *hostname, struct sockaddr_in *srvaddr, int proto, int privileged)
{
struct rpc_create_args args = {
.protocol = proto,
.address = (struct sockaddr *)srvaddr,
.addrsize = sizeof(*srvaddr),
.servername = hostname,
.program = &pmap_program,
.version = RPC_PMAP_VERSION,
.authflavor = RPC_AUTH_UNIX,
.flags = (RPC_CLNT_CREATE_ONESHOT |
RPC_CLNT_CREATE_NOPING),
};
srvaddr->sin_port = htons(RPC_PMAP_PORT);
if (!privileged)
args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
return rpc_create(&args);
}
/*
* XDR encode/decode functions for PMAP
*/
static int xdr_encode_mapping(struct rpc_rqst *req, __be32 *p, struct portmap_args *map)
{
dprintk("RPC: xdr_encode_mapping(%u, %u, %u, %u)\n",
map->pm_prog, map->pm_vers, map->pm_prot, map->pm_port);
*p++ = htonl(map->pm_prog);
*p++ = htonl(map->pm_vers);
*p++ = htonl(map->pm_prot);
*p++ = htonl(map->pm_port);
req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
return 0;
}
static int xdr_decode_port(struct rpc_rqst *req, __be32 *p, unsigned short *portp)
{
*portp = (unsigned short) ntohl(*p++);
return 0;
}
static int xdr_decode_bool(struct rpc_rqst *req, __be32 *p, unsigned int *boolp)
{
*boolp = (unsigned int) ntohl(*p++);
return 0;
}
static struct rpc_procinfo pmap_procedures[] = {
[PMAP_SET] = {
.p_proc = PMAP_SET,
.p_encode = (kxdrproc_t) xdr_encode_mapping,
.p_decode = (kxdrproc_t) xdr_decode_bool,
.p_bufsiz = 4,
.p_count = 1,
.p_statidx = PMAP_SET,
.p_name = "SET",
},
[PMAP_UNSET] = {
.p_proc = PMAP_UNSET,
.p_encode = (kxdrproc_t) xdr_encode_mapping,
.p_decode = (kxdrproc_t) xdr_decode_bool,
.p_bufsiz = 4,
.p_count = 1,
.p_statidx = PMAP_UNSET,
.p_name = "UNSET",
},
[PMAP_GETPORT] = {
.p_proc = PMAP_GETPORT,
.p_encode = (kxdrproc_t) xdr_encode_mapping,
.p_decode = (kxdrproc_t) xdr_decode_port,
.p_bufsiz = 4,
.p_count = 1,
.p_statidx = PMAP_GETPORT,
.p_name = "GETPORT",
},
};
static struct rpc_version pmap_version2 = {
.number = 2,
.nrprocs = 4,
.procs = pmap_procedures
};
static struct rpc_version * pmap_version[] = {
NULL,
NULL,
&pmap_version2
};
static struct rpc_stat pmap_stats;
static struct rpc_program pmap_program = {
.name = "portmap",
.number = RPC_PMAP_PROGRAM,
.nrvers = ARRAY_SIZE(pmap_version),
.version = pmap_version,
.stats = &pmap_stats,
};