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/*
* 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/sunrpc/clnt.h>
#include <linux/sunrpc/auth.h>
#include <linux/user_namespace.h>
#define NFS_NGROUPS 16
struct unx_cred {
struct rpc_cred uc_base;
kgid_t uc_gid;
kgid_t uc_gids[NFS_NGROUPS];
};
#define uc_uid uc_base.cr_uid
#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 struct rpc_auth *
unx_create(struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
{
dprintk("RPC: creating UNIX authenticator for client %p\n",
clnt);
atomic_inc(&unix_auth.au_count);
return &unix_auth;
}
static void
unx_destroy(struct rpc_auth *auth)
{
dprintk("RPC: destroying UNIX authenticator %p\n", auth);
rpcauth_clear_credcache(auth->au_credcache);
}
/*
* Lookup AUTH_UNIX creds for current process
*/
static struct rpc_cred *
unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
{
return rpcauth_lookup_credcache(auth, acred, flags, GFP_NOFS);
}
static struct rpc_cred *
unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
{
struct unx_cred *cred;
unsigned int groups = 0;
unsigned int i;
dprintk("RPC: allocating UNIX cred for uid %d gid %d\n",
from_kuid(&init_user_ns, acred->uid),
from_kgid(&init_user_ns, acred->gid));
if (!(cred = kmalloc(sizeof(*cred), gfp)))
return ERR_PTR(-ENOMEM);
rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
if (acred->group_info != NULL)
groups = acred->group_info->ngroups;
if (groups > NFS_NGROUPS)
groups = NFS_NGROUPS;
cred->uc_gid = acred->gid;
for (i = 0; i < groups; i++)
cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
if (i < NFS_NGROUPS)
cred->uc_gids[i] = INVALID_GID;
return &cred->uc_base;
}
static void
unx_free_cred(struct unx_cred *unx_cred)
{
dprintk("RPC: unx_free_cred %p\n", unx_cred);
kfree(unx_cred);
}
static void
unx_free_cred_callback(struct rcu_head *head)
{
struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
unx_free_cred(unx_cred);
}
static void
unx_destroy_cred(struct rpc_cred *cred)
{
call_rcu(&cred->cr_rcu, unx_free_cred_callback);
}
/*
* Match credentials against current process creds.
* The root_override argument takes care of cases where the caller may
* request root creds (e.g. for NFS swapping).
*/
static int
unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
{
struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
unsigned int groups = 0;
unsigned int i;
if (!uid_eq(cred->uc_uid, acred->uid) || !gid_eq(cred->uc_gid, acred->gid))
return 0;
if (acred->group_info != NULL)
groups = acred->group_info->ngroups;
if (groups > NFS_NGROUPS)
groups = NFS_NGROUPS;
for (i = 0; i < groups ; i++)
if (!gid_eq(cred->uc_gids[i], GROUP_AT(acred->group_info, i)))
return 0;
if (groups < NFS_NGROUPS && gid_valid(cred->uc_gids[groups]))
return 0;
return 1;
}
/*
* Marshal credentials.
* Maybe we should keep a cached credential for performance reasons.
*/
static __be32 *
unx_marshal(struct rpc_task *task, __be32 *p)
{
struct rpc_clnt *clnt = task->tk_client;
struct unx_cred *cred = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base);
__be32 *base, *hold;
int i;
*p++ = htonl(RPC_AUTH_UNIX);
base = p++;
*p++ = htonl(jiffies/HZ);
/*
* Copy the UTS nodename captured when the client was created.
*/
p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
*p++ = htonl((u32) from_kuid(&init_user_ns, cred->uc_uid));
*p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gid));
hold = p++;
for (i = 0; i < 16 && gid_valid(cred->uc_gids[i]); i++)
*p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gids[i]));
*hold = htonl(p - hold - 1); /* gid array length */
*base = htonl((p - base - 1) << 2); /* cred length */
*p++ = htonl(RPC_AUTH_NULL);
*p++ = htonl(0);
return p;
}
/*
* 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 __be32 *
unx_validate(struct rpc_task *task, __be32 *p)
{
rpc_authflavor_t flavor;
u32 size;
flavor = ntohl(*p++);
if (flavor != RPC_AUTH_NULL &&
flavor != RPC_AUTH_UNIX &&
flavor != RPC_AUTH_SHORT) {
printk("RPC: bad verf flavor: %u\n", flavor);
return ERR_PTR(-EIO);
}
size = ntohl(*p++);
if (size > RPC_MAX_AUTH_SIZE) {
printk("RPC: giant verf size: %u\n", size);
return ERR_PTR(-EIO);
}
task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
p += (size >> 2);
return p;
}
int __init rpc_init_authunix(void)
{
return rpcauth_init_credcache(&unix_auth);
}
void rpc_destroy_authunix(void)
{
rpcauth_destroy_credcache(&unix_auth);
}
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,
.crcreate = unx_create_cred,
};
static
struct rpc_auth unix_auth = {
.au_cslack = UNX_CALLSLACK,
.au_rslack = NUL_REPLYSLACK,
.au_ops = &authunix_ops,
.au_flavor = RPC_AUTH_UNIX,
.au_count = ATOMIC_INIT(0),
};
static
const struct rpc_credops unix_credops = {
.cr_name = "AUTH_UNIX",
.crdestroy = unx_destroy_cred,
.crbind = rpcauth_generic_bind_cred,
.crmatch = unx_match,
.crmarshal = unx_marshal,
.crrefresh = unx_refresh,
.crvalidate = unx_validate,
};
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