linux/net/sunrpc/auth_null.c
Chuck Lever 35e77d21ba SUNRPC: Add rpc_auth::au_ralign field
Currently rpc_inline_rcv_pages() uses au_rslack to estimate the
size of the upper layer reply header. This is fine for auth flavors
where au_verfsize == au_rslack.

However, some auth flavors have more going on. krb5i for example has
two more words after the verifier, and another blob following the
RPC message. The calculation involving au_rslack pushes the upper
layer reply header too far into the rcv_buf.

au_rslack is still valuable: it's the amount of buffer space needed
for the reply, and is used when allocating the reply buffer. We'll
keep that.

But, add a new field that can be used to properly estimate the
location of the upper layer header in each RPC reply, based on the
auth flavor in use.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-02-14 11:48:36 -05:00

144 lines
2.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* linux/net/sunrpc/auth_null.c
*
* AUTH_NULL authentication. Really :-)
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/types.h>
#include <linux/module.h>
#include <linux/sunrpc/clnt.h>
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
static struct rpc_auth null_auth;
static struct rpc_cred null_cred;
static struct rpc_auth *
nul_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
{
refcount_inc(&null_auth.au_count);
return &null_auth;
}
static void
nul_destroy(struct rpc_auth *auth)
{
}
/*
* Lookup NULL creds for current process
*/
static struct rpc_cred *
nul_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
{
return get_rpccred(&null_cred);
}
/*
* Destroy cred handle.
*/
static void
nul_destroy_cred(struct rpc_cred *cred)
{
}
/*
* Match cred handle against current process
*/
static int
nul_match(struct auth_cred *acred, struct rpc_cred *cred, int taskflags)
{
return 1;
}
/*
* Marshal credential.
*/
static int
nul_marshal(struct rpc_task *task, struct xdr_stream *xdr)
{
__be32 *p;
p = xdr_reserve_space(xdr, 4 * sizeof(*p));
if (!p)
return -EMSGSIZE;
/* Credential */
*p++ = rpc_auth_null;
*p++ = xdr_zero;
/* Verifier */
*p++ = rpc_auth_null;
*p = xdr_zero;
return 0;
}
/*
* Refresh credential. This is a no-op for AUTH_NULL
*/
static int
nul_refresh(struct rpc_task *task)
{
set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
return 0;
}
static int
nul_validate(struct rpc_task *task, struct xdr_stream *xdr)
{
__be32 *p;
p = xdr_inline_decode(xdr, 2 * sizeof(*p));
if (!p)
return -EIO;
if (*p++ != rpc_auth_null)
return -EIO;
if (*p != xdr_zero)
return -EIO;
return 0;
}
const struct rpc_authops authnull_ops = {
.owner = THIS_MODULE,
.au_flavor = RPC_AUTH_NULL,
.au_name = "NULL",
.create = nul_create,
.destroy = nul_destroy,
.lookup_cred = nul_lookup_cred,
};
static
struct rpc_auth null_auth = {
.au_cslack = NUL_CALLSLACK,
.au_rslack = NUL_REPLYSLACK,
.au_verfsize = NUL_REPLYSLACK,
.au_ralign = NUL_REPLYSLACK,
.au_ops = &authnull_ops,
.au_flavor = RPC_AUTH_NULL,
.au_count = REFCOUNT_INIT(1),
};
static
const struct rpc_credops null_credops = {
.cr_name = "AUTH_NULL",
.crdestroy = nul_destroy_cred,
.crmatch = nul_match,
.crmarshal = nul_marshal,
.crwrap_req = rpcauth_wrap_req_encode,
.crrefresh = nul_refresh,
.crvalidate = nul_validate,
.crunwrap_resp = rpcauth_unwrap_resp_decode,
};
static
struct rpc_cred null_cred = {
.cr_lru = LIST_HEAD_INIT(null_cred.cr_lru),
.cr_auth = &null_auth,
.cr_ops = &null_credops,
.cr_count = REFCOUNT_INIT(2),
.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE,
};