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authorAndy Adamson <andros@netapp.com>2013-08-14 11:59:15 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2013-09-03 15:25:08 -0400
commit4de6caa270afaa381dd3373e9e6d148b1090e0ec (patch)
tree2b212167c872f2038ed3480df872766bbd7b67e3 /net/sunrpc/auth_gss
parentf1ff0c27fd9987c59d707cd1a6b6c1fc3ae0a250 (diff)
downloadop-kernel-dev-4de6caa270afaa381dd3373e9e6d148b1090e0ec.zip
op-kernel-dev-4de6caa270afaa381dd3373e9e6d148b1090e0ec.tar.gz
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>
Diffstat (limited to 'net/sunrpc/auth_gss')
-rw-r--r--net/sunrpc/auth_gss/auth_gss.c52
1 files changed, 50 insertions, 2 deletions
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index dc4b449..a9b1edc 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -63,6 +63,9 @@ static const struct rpc_credops gss_nullops;
#define GSS_RETRY_EXPIRED 5
static unsigned int gss_expired_cred_retry_delay = GSS_RETRY_EXPIRED;
+#define GSS_KEY_EXPIRE_TIMEO 240
+static unsigned int gss_key_expire_timeo = GSS_KEY_EXPIRE_TIMEO;
+
#ifdef RPC_DEBUG
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
@@ -1295,10 +1298,32 @@ gss_cred_init(struct rpc_auth *auth, struct rpc_cred *cred)
return err;
}
+/*
+ * Returns -EACCES if GSS context is NULL or will expire within the
+ * timeout (miliseconds)
+ */
+static int
+gss_key_timeout(struct rpc_cred *rc)
+{
+ struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
+ unsigned long now = jiffies;
+ unsigned long expire;
+
+ if (gss_cred->gc_ctx == NULL)
+ return -EACCES;
+
+ expire = gss_cred->gc_ctx->gc_expiry - (gss_key_expire_timeo * HZ);
+
+ if (time_after(now, expire))
+ return -EACCES;
+ return 0;
+}
+
static int
gss_match(struct auth_cred *acred, struct rpc_cred *rc, int flags)
{
struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
+ int ret;
if (test_bit(RPCAUTH_CRED_NEW, &rc->cr_flags))
goto out;
@@ -1311,11 +1336,26 @@ out:
if (acred->principal != NULL) {
if (gss_cred->gc_principal == NULL)
return 0;
- return strcmp(acred->principal, gss_cred->gc_principal) == 0;
+ ret = strcmp(acred->principal, gss_cred->gc_principal) == 0;
+ goto check_expire;
}
if (gss_cred->gc_principal != NULL)
return 0;
- return uid_eq(rc->cr_uid, acred->uid);
+ ret = uid_eq(rc->cr_uid, acred->uid);
+
+check_expire:
+ if (ret == 0)
+ return ret;
+
+ /* Notify acred users of GSS context expiration timeout */
+ if (test_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags) &&
+ (gss_key_timeout(rc) != 0)) {
+ /* test will now be done from generic cred */
+ test_and_clear_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags);
+ /* tell NFS layer that key will expire soon */
+ set_bit(RPC_CRED_KEY_EXPIRE_SOON, &acred->ac_flags);
+ }
+ return ret;
}
/*
@@ -1842,6 +1882,7 @@ static const struct rpc_credops gss_credops = {
.crvalidate = gss_validate,
.crwrap_req = gss_wrap_req,
.crunwrap_resp = gss_unwrap_resp,
+ .crkey_timeout = gss_key_timeout,
};
static const struct rpc_credops gss_nullops = {
@@ -1929,5 +1970,12 @@ module_param_named(expired_cred_retry_delay,
MODULE_PARM_DESC(expired_cred_retry_delay, "Timeout (in seconds) until "
"the RPC engine retries an expired credential");
+module_param_named(key_expire_timeo,
+ gss_key_expire_timeo,
+ uint, 0644);
+MODULE_PARM_DESC(key_expire_timeo, "Time (in seconds) at the end of a "
+ "credential keys lifetime where the NFS layer cleans up "
+ "prior to key expiration");
+
module_init(init_rpcsec_gss)
module_exit(exit_rpcsec_gss)
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