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Commit 9568c5e9 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

SUNRPC: Introduce rpcauth_get_pseudoflavor() 



A SECINFO reply may contain flavors whose kernel module is not
yet loaded by the client's kernel.  A new RPC client API, called
rpcauth_get_pseudoflavor(), is introduced to do proper checking
for support of a security flavor.

When this API is invoked, the RPC client now tries to load the
module for each flavor first before performing the "is this
supported?" check.  This means if a module is available on the
client, but has not been loaded yet, it will be loaded and
registered automatically when the SECINFO reply is processed.

The new API can take a full GSS tuple (OID, QoP, and service).
Previously only the OID and service were considered.

nfs_find_best_sec() is updated to verify all flavors requested in a
SECINFO reply, including AUTH_NULL and AUTH_UNIX.  Previously these
two flavors were simply assumed to be supported without consulting
the RPC client.

Note that the replaced version of nfs_find_best_sec() can return
RPC_AUTH_MAXFLAVOR if the server returns a recognized OID but an
unsupported "service" value.  nfs_find_best_sec() now returns
RPC_AUTH_UNIX in this case.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent fb15b26f

fs/nfs/nfs4namespace.c

+23 −18
Original line number Diff line number Diff line
@@ -134,33 +134,38 @@ static size_t nfs_parse_server_name(char *string, size_t len, 
	return ret;

}



/**

 * nfs_find_best_sec - Find a security mechanism supported locally

 * @flavors: List of security tuples returned by SECINFO procedure

 *

 * Return the pseudoflavor of the first security mechanism in

 * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if

 * no matching flavor is found in the array.  The "flavors" array

 * is searched in the order returned from the server, per RFC 3530

 * recommendation.

 */

rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)

{

	struct gss_api_mech *mech;

	struct xdr_netobj oid;

	rpc_authflavor_t pseudoflavor;

	struct nfs4_secinfo4 *secinfo;

	unsigned int i;

	rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX;



	for (i = 0; i < flavors->num_flavors; i++) {

		struct nfs4_secinfo4 *flavor = &flavors->flavors[i];



		if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) {

			pseudoflavor = flavor->flavor;

			break;

		} else if (flavor->flavor == RPC_AUTH_GSS) {

			oid.len  = flavor->flavor_info.oid.len;

			oid.data = flavor->flavor_info.oid.data;

			mech = gss_mech_get_by_OID(&oid);

			if (!mech)

				continue;

			pseudoflavor = gss_svc_to_pseudoflavor(mech,

						flavor->flavor_info.service);

			gss_mech_put(mech);

		secinfo = &flavors->flavors[i];



		switch (secinfo->flavor) {

		case RPC_AUTH_NULL:

		case RPC_AUTH_UNIX:

		case RPC_AUTH_GSS:

			pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,

							&secinfo->flavor_info);

			if (pseudoflavor != RPC_AUTH_MAXFLAVOR)

				return pseudoflavor;

			break;

		}

	}



	return pseudoflavor;

	return RPC_AUTH_UNIX;

}



static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name)

include/linux/sunrpc/auth.h

+5 −0
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ 
/* size of the nodename buffer */

#define UNX_MAXNODENAME	32



struct rpcsec_gss_info;



/* Work around the lack of a VFS credential */

struct auth_cred {

	kuid_t	uid;
@@ -103,6 +105,7 @@ struct rpc_authops { 
	int			(*pipes_create)(struct rpc_auth *);

	void			(*pipes_destroy)(struct rpc_auth *);

	int			(*list_pseudoflavors)(rpc_authflavor_t *, int);

	rpc_authflavor_t	(*info2flavor)(struct rpcsec_gss_info *);

};



struct rpc_credops {
@@ -137,6 +140,8 @@ int rpcauth_register(const struct rpc_authops *); 
int			rpcauth_unregister(const struct rpc_authops *);

struct rpc_auth *	rpcauth_create(rpc_authflavor_t, struct rpc_clnt *);

void			rpcauth_release(struct rpc_auth *);

rpc_authflavor_t	rpcauth_get_pseudoflavor(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 *);

include/linux/sunrpc/gss_api.h

+2 −3
Original line number Diff line number Diff line
@@ -127,9 +127,8 @@ struct gss_api_ops { 
int gss_mech_register(struct gss_api_mech *);

void gss_mech_unregister(struct gss_api_mech *);



/* returns a mechanism descriptor given an OID, and increments the mechanism's

 * reference count. */

struct gss_api_mech * gss_mech_get_by_OID(struct xdr_netobj *);

/* Given a GSS security tuple, look up a pseudoflavor */

rpc_authflavor_t gss_mech_info2flavor(struct rpcsec_gss_info *);



/* Returns a reference to a mechanism, given a name like "krb5" etc. */

struct gss_api_mech *gss_mech_get_by_name(const char *);

net/sunrpc/auth.c

+35 −0
Original line number Diff line number Diff line
@@ -123,6 +123,41 @@ rpcauth_unregister(const struct rpc_authops *ops) 
}

EXPORT_SYMBOL_GPL(rpcauth_unregister);



/**

 * rpcauth_get_pseudoflavor - check if security flavor is supported

 * @flavor: a security flavor

 * @info: a GSS mech OID, quality of protection, and service value

 *

 * Verifies that an appropriate kernel module is available or already loaded.

 * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is

 * not supported locally.

 */

rpc_authflavor_t

rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)

{

	const struct rpc_authops *ops;

	rpc_authflavor_t pseudoflavor;



	ops = auth_flavors[flavor];

	if (ops == NULL)

		request_module("rpc-auth-%u", flavor);

	spin_lock(&rpc_authflavor_lock);

	ops = auth_flavors[flavor];

	if (ops == NULL || !try_module_get(ops->owner)) {

		spin_unlock(&rpc_authflavor_lock);

		return RPC_AUTH_MAXFLAVOR;

	}

	spin_unlock(&rpc_authflavor_lock);



	pseudoflavor = flavor;

	if (ops->info2flavor != NULL)

		pseudoflavor = ops->info2flavor(info);



	module_put(ops->owner);

	return pseudoflavor;

}

EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);



/**

 * rpcauth_list_flavors - discover registered flavors and pseudoflavors

 * @array: array to fill in

net/sunrpc/auth_gss/auth_gss.c

+1 −0
Original line number Diff line number Diff line
@@ -1641,6 +1641,7 @@ static const struct rpc_authops authgss_ops = { 
	.pipes_create	= gss_pipes_dentries_create,

	.pipes_destroy	= gss_pipes_dentries_destroy,

	.list_pseudoflavors = gss_mech_list_pseudoflavors,

	.info2flavor	= gss_mech_info2flavor,

};



static const struct rpc_credops gss_credops = {