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remarkable-linux/include/linux/sunrpc/auth.h
Andy Adamson 4de6caa270 SUNRPC new rpc_credops to test credential expiry 
This patch provides the RPC layer helper functions to allow NFS to manage
data in the face of expired credentials - such as avoiding buffered WRITEs
and COMMITs when the gss context will expire before the WRITEs are flushed
and COMMITs are sent.

These helper functions enable checking the expiration of an underlying
credential key for a generic rpc credential, e.g. the gss_cred gss context
gc_expiry which for Kerberos is set to the remaining TGT lifetime.

A new rpc_authops key_timeout is only defined for the generic auth.
A new rpc_credops crkey_to_expire is only defined for the generic cred.
A new rpc_credops crkey_timeout is only defined for the gss cred.

Set a credential key expiry watermark, RPC_KEY_EXPIRE_TIMEO set to 240 seconds
as a default and can be set via a module parameter as we need to ensure there
is time for any dirty data to be flushed.

If key_timeout is called on a credential with an underlying credential key that
will expire within watermark seconds, we set the RPC_CRED_KEY_EXPIRE_SOON
flag in the generic_cred acred so that the NFS layer can clean up prior to
key expiration.

Checking a generic credential's underlying credential involves a cred lookup.
To avoid this lookup in the normal case when the underlying credential has
a key that is valid (before the watermark), a notify flag is set in
the generic credential the first time the key_timeout is called. The
generic credential then stops checking the underlying credential key expiry, and
the underlying credential (gss_cred) match routine then checks the key
expiration upon each normal use and sets a flag in the associated generic
credential only when the key expiration is within the watermark.
This in turn signals the generic credential key_timeout to perform the extra
credential lookup thereafter.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-09-03 15:25:08 -04:00

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/*
* linux/include/linux/sunrpc/auth.h
*
* Declarations for the RPC client authentication machinery.
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#ifndef _LINUX_SUNRPC_AUTH_H
#define _LINUX_SUNRPC_AUTH_H
#ifdef __KERNEL__
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/msg_prot.h>
#include <linux/sunrpc/xdr.h>
#include <linux/atomic.h>
#include <linux/rcupdate.h>
#include <linux/uidgid.h>
/* size of the nodename buffer */
#define UNX_MAXNODENAME 32
struct rpcsec_gss_info;
/* auth_cred ac_flags bits */
enum {
RPC_CRED_NO_CRKEY_TIMEOUT = 0, /* underlying cred has no key timeout */
RPC_CRED_KEY_EXPIRE_SOON = 1, /* underlying cred key will expire soon */
RPC_CRED_NOTIFY_TIMEOUT = 2, /* nofity generic cred when underlying
key will expire soon */
};
/* Work around the lack of a VFS credential */
struct auth_cred {
kuid_t uid;
kgid_t gid;
struct group_info *group_info;
const char *principal;
unsigned long ac_flags;
unsigned char machine_cred : 1;
};
/*
* Client user credentials
*/
struct rpc_auth;
struct rpc_credops;
struct rpc_cred {
struct hlist_node cr_hash; /* hash chain */
struct list_head cr_lru; /* lru garbage collection */
struct rcu_head cr_rcu;
struct rpc_auth * cr_auth;
const struct rpc_credops *cr_ops;
#ifdef RPC_DEBUG
unsigned long cr_magic; /* 0x0f4aa4f0 */
#endif
unsigned long cr_expire; /* when to gc */
unsigned long cr_flags; /* various flags */
atomic_t cr_count; /* ref count */
kuid_t cr_uid;
/* per-flavor data */
};
#define RPCAUTH_CRED_NEW 0
#define RPCAUTH_CRED_UPTODATE 1
#define RPCAUTH_CRED_HASHED 2
#define RPCAUTH_CRED_NEGATIVE 3
#define RPCAUTH_CRED_MAGIC 0x0f4aa4f0
/*
* Client authentication handle
*/
struct rpc_cred_cache;
struct rpc_authops;
struct rpc_auth {
unsigned int au_cslack; /* call cred size estimate */
/* guess at number of u32's auth adds before
* reply data; normally the verifier size: */
unsigned int au_rslack;
/* for gss, used to calculate au_rslack: */
unsigned int au_verfsize;
unsigned int au_flags; /* various flags */
const struct rpc_authops *au_ops; /* operations */
rpc_authflavor_t au_flavor; /* pseudoflavor (note may
* differ from the flavor in
* au_ops->au_flavor in gss
* case) */
atomic_t au_count; /* Reference counter */
struct rpc_cred_cache * au_credcache;
/* per-flavor data */
};
struct rpc_auth_create_args {
rpc_authflavor_t pseudoflavor;
const char *target_name;
};
/* Flags for rpcauth_lookupcred() */
#define RPCAUTH_LOOKUP_NEW 0x01 /* Accept an uninitialised cred */
/*
* Client authentication ops
*/
struct rpc_authops {
struct module *owner;
rpc_authflavor_t au_flavor; /* flavor (RPC_AUTH_*) */
char * au_name;
struct rpc_auth * (*create)(struct rpc_auth_create_args *, struct rpc_clnt *);
void (*destroy)(struct rpc_auth *);
struct rpc_cred * (*lookup_cred)(struct rpc_auth *, struct auth_cred *, int);
struct rpc_cred * (*crcreate)(struct rpc_auth*, struct auth_cred *, int);
int (*list_pseudoflavors)(rpc_authflavor_t *, int);
rpc_authflavor_t (*info2flavor)(struct rpcsec_gss_info *);
int (*flavor2info)(rpc_authflavor_t,
struct rpcsec_gss_info *);
int (*key_timeout)(struct rpc_auth *,
struct rpc_cred *);
};
struct rpc_credops {
const char * cr_name; /* Name of the auth flavour */
int (*cr_init)(struct rpc_auth *, struct rpc_cred *);
void (*crdestroy)(struct rpc_cred *);
int (*crmatch)(struct auth_cred *, struct rpc_cred *, int);
struct rpc_cred * (*crbind)(struct rpc_task *, struct rpc_cred *, int);
__be32 * (*crmarshal)(struct rpc_task *, __be32 *);
int (*crrefresh)(struct rpc_task *);
__be32 * (*crvalidate)(struct rpc_task *, __be32 *);
int (*crwrap_req)(struct rpc_task *, kxdreproc_t,
void *, __be32 *, void *);
int (*crunwrap_resp)(struct rpc_task *, kxdrdproc_t,
void *, __be32 *, void *);
int (*crkey_timeout)(struct rpc_cred *);
bool (*crkey_to_expire)(struct rpc_cred *);
};
extern const struct rpc_authops authunix_ops;
extern const struct rpc_authops authnull_ops;
int __init rpc_init_authunix(void);
int __init rpc_init_generic_auth(void);
int __init rpcauth_init_module(void);
void rpcauth_remove_module(void);
void rpc_destroy_generic_auth(void);
void rpc_destroy_authunix(void);
struct rpc_cred * rpc_lookup_cred(void);
struct rpc_cred * rpc_lookup_machine_cred(const char *service_name);
int rpcauth_register(const struct rpc_authops *);
int rpcauth_unregister(const struct rpc_authops *);
struct rpc_auth * rpcauth_create(struct rpc_auth_create_args *,
struct rpc_clnt *);
void rpcauth_release(struct rpc_auth *);
rpc_authflavor_t rpcauth_get_pseudoflavor(rpc_authflavor_t,
struct rpcsec_gss_info *);
int rpcauth_get_gssinfo(rpc_authflavor_t,
struct rpcsec_gss_info *);
int rpcauth_list_flavors(rpc_authflavor_t *, int);
struct rpc_cred * rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *, int);
void rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
struct rpc_cred * rpcauth_lookupcred(struct rpc_auth *, int);
struct rpc_cred * rpcauth_generic_bind_cred(struct rpc_task *, struct rpc_cred *, int);
void put_rpccred(struct rpc_cred *);
__be32 * rpcauth_marshcred(struct rpc_task *, __be32 *);
__be32 * rpcauth_checkverf(struct rpc_task *, __be32 *);
int rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp, __be32 *data, void *obj);
int rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp, __be32 *data, void *obj);
int rpcauth_refreshcred(struct rpc_task *);
void rpcauth_invalcred(struct rpc_task *);
int rpcauth_uptodatecred(struct rpc_task *);
int rpcauth_init_credcache(struct rpc_auth *);
void rpcauth_destroy_credcache(struct rpc_auth *);
void rpcauth_clear_credcache(struct rpc_cred_cache *);
int rpcauth_key_timeout_notify(struct rpc_auth *,
struct rpc_cred *);
bool rpcauth_cred_key_to_expire(struct rpc_cred *);
static inline
struct rpc_cred * get_rpccred(struct rpc_cred *cred)
{
atomic_inc(&cred->cr_count);
return cred;
}
#endif /* __KERNEL__ */
#endif /* _LINUX_SUNRPC_AUTH_H */
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