swh:1:snp:c2847dfd741eae21606027cf29250d1ebcd63fb4
Tip revision: d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 authored by Linus Torvalds on 27 January 2020, 00:23:03 UTC
Linux 5.5
Linux 5.5
Tip revision: d5226fa
auth_unix.c
// SPDX-License-Identifier: GPL-2.0
/*
* linux/net/sunrpc/auth_unix.c
*
* UNIX-style authentication; no AUTH_SHORT support
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/mempool.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/auth.h>
#include <linux/user_namespace.h>
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
static struct rpc_auth unix_auth;
static const struct rpc_credops unix_credops;
static mempool_t *unix_pool;
static struct rpc_auth *
unx_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
{
refcount_inc(&unix_auth.au_count);
return &unix_auth;
}
static void
unx_destroy(struct rpc_auth *auth)
{
}
/*
* Lookup AUTH_UNIX creds for current process
*/
static struct rpc_cred *
unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
{
struct rpc_cred *ret = mempool_alloc(unix_pool, GFP_NOFS);
rpcauth_init_cred(ret, acred, auth, &unix_credops);
ret->cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
return ret;
}
static void
unx_free_cred_callback(struct rcu_head *head)
{
struct rpc_cred *rpc_cred = container_of(head, struct rpc_cred, cr_rcu);
put_cred(rpc_cred->cr_cred);
mempool_free(rpc_cred, unix_pool);
}
static void
unx_destroy_cred(struct rpc_cred *cred)
{
call_rcu(&cred->cr_rcu, unx_free_cred_callback);
}
/*
* Match credentials against current the auth_cred.
*/
static int
unx_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
{
unsigned int groups = 0;
unsigned int i;
if (cred->cr_cred == acred->cred)
return 1;
if (!uid_eq(cred->cr_cred->fsuid, acred->cred->fsuid) || !gid_eq(cred->cr_cred->fsgid, acred->cred->fsgid))
return 0;
if (acred->cred->group_info != NULL)
groups = acred->cred->group_info->ngroups;
if (groups > UNX_NGROUPS)
groups = UNX_NGROUPS;
if (cred->cr_cred->group_info == NULL)
return groups == 0;
if (groups != cred->cr_cred->group_info->ngroups)
return 0;
for (i = 0; i < groups ; i++)
if (!gid_eq(cred->cr_cred->group_info->gid[i], acred->cred->group_info->gid[i]))
return 0;
return 1;
}
/*
* Marshal credentials.
* Maybe we should keep a cached credential for performance reasons.
*/
static int
unx_marshal(struct rpc_task *task, struct xdr_stream *xdr)
{
struct rpc_clnt *clnt = task->tk_client;
struct rpc_cred *cred = task->tk_rqstp->rq_cred;
__be32 *p, *cred_len, *gidarr_len;
int i;
struct group_info *gi = cred->cr_cred->group_info;
struct user_namespace *userns = clnt->cl_cred ?
clnt->cl_cred->user_ns : &init_user_ns;
/* Credential */
p = xdr_reserve_space(xdr, 3 * sizeof(*p));
if (!p)
goto marshal_failed;
*p++ = rpc_auth_unix;
cred_len = p++;
*p++ = xdr_zero; /* stamp */
if (xdr_stream_encode_opaque(xdr, clnt->cl_nodename,
clnt->cl_nodelen) < 0)
goto marshal_failed;
p = xdr_reserve_space(xdr, 3 * sizeof(*p));
if (!p)
goto marshal_failed;
*p++ = cpu_to_be32(from_kuid_munged(userns, cred->cr_cred->fsuid));
*p++ = cpu_to_be32(from_kgid_munged(userns, cred->cr_cred->fsgid));
gidarr_len = p++;
if (gi)
for (i = 0; i < UNX_NGROUPS && i < gi->ngroups; i++)
*p++ = cpu_to_be32(from_kgid_munged(userns, gi->gid[i]));
*gidarr_len = cpu_to_be32(p - gidarr_len - 1);
*cred_len = cpu_to_be32((p - cred_len - 1) << 2);
p = xdr_reserve_space(xdr, (p - gidarr_len - 1) << 2);
if (!p)
goto marshal_failed;
/* Verifier */
p = xdr_reserve_space(xdr, 2 * sizeof(*p));
if (!p)
goto marshal_failed;
*p++ = rpc_auth_null;
*p = xdr_zero;
return 0;
marshal_failed:
return -EMSGSIZE;
}
/*
* Refresh credentials. This is a no-op for AUTH_UNIX
*/
static int
unx_refresh(struct rpc_task *task)
{
set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
return 0;
}
static int
unx_validate(struct rpc_task *task, struct xdr_stream *xdr)
{
struct rpc_auth *auth = task->tk_rqstp->rq_cred->cr_auth;
__be32 *p;
u32 size;
p = xdr_inline_decode(xdr, 2 * sizeof(*p));
if (!p)
return -EIO;
switch (*p++) {
case rpc_auth_null:
case rpc_auth_unix:
case rpc_auth_short:
break;
default:
return -EIO;
}
size = be32_to_cpup(p);
if (size > RPC_MAX_AUTH_SIZE)
return -EIO;
p = xdr_inline_decode(xdr, size);
if (!p)
return -EIO;
auth->au_verfsize = XDR_QUADLEN(size) + 2;
auth->au_rslack = XDR_QUADLEN(size) + 2;
auth->au_ralign = XDR_QUADLEN(size) + 2;
return 0;
}
int __init rpc_init_authunix(void)
{
unix_pool = mempool_create_kmalloc_pool(16, sizeof(struct rpc_cred));
return unix_pool ? 0 : -ENOMEM;
}
void rpc_destroy_authunix(void)
{
mempool_destroy(unix_pool);
}
const struct rpc_authops authunix_ops = {
.owner = THIS_MODULE,
.au_flavor = RPC_AUTH_UNIX,
.au_name = "UNIX",
.create = unx_create,
.destroy = unx_destroy,
.lookup_cred = unx_lookup_cred,
};
static
struct rpc_auth unix_auth = {
.au_cslack = UNX_CALLSLACK,
.au_rslack = NUL_REPLYSLACK,
.au_verfsize = NUL_REPLYSLACK,
.au_ops = &authunix_ops,
.au_flavor = RPC_AUTH_UNIX,
.au_count = REFCOUNT_INIT(1),
};
static
const struct rpc_credops unix_credops = {
.cr_name = "AUTH_UNIX",
.crdestroy = unx_destroy_cred,
.crmatch = unx_match,
.crmarshal = unx_marshal,
.crwrap_req = rpcauth_wrap_req_encode,
.crrefresh = unx_refresh,
.crvalidate = unx_validate,
.crunwrap_resp = rpcauth_unwrap_resp_decode,
};