// 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,
};