Commit 62346217 authored by Benjamin Coddington's avatar Benjamin Coddington Committed by Chuck Lever
Browse files

NFSD: Add a key for signing filehandles 

A future patch will enable NFSD to sign filehandles by appending a Message
Authentication Code(MAC).  To do this, NFSD requires a secret 128-bit key
that can persist across reboots.  A persisted key allows the server to
accept filehandles after a restart.  Enable NFSD to be configured with this
key via the netlink interface.

Link: https://lore.kernel.org/linux-nfs/cover.1772022373.git.bcodding@hammerspace.com


Signed-off-by: default avatarBenjamin Coddington <bcodding@hammerspace.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 116b6b7a

Documentation/netlink/specs/nfsd.yaml

+6 −0
Original line number Diff line number Diff line
@@ -81,6 +81,11 @@ attribute-sets: 
      -

        name: min-threads

        type: u32

      -

        name: fh-key

        type: binary

        checks:

            exact-len: 16

  -

    name: version

    attributes:
@@ -163,6 +168,7 @@ operations: 
            - leasetime

            - scope

            - min-threads

            - fh-key

    -

      name: threads-get

      doc: get the maximum number of running threads

fs/nfsd/netlink.c

+3 −2
Original line number Diff line number Diff line
@@ -24,12 +24,13 @@ const struct nla_policy nfsd_version_nl_policy[NFSD_A_VERSION_ENABLED + 1] = { 
};



/* NFSD_CMD_THREADS_SET - do */

static const struct nla_policy nfsd_threads_set_nl_policy[NFSD_A_SERVER_MIN_THREADS + 1] = {

static const struct nla_policy nfsd_threads_set_nl_policy[NFSD_A_SERVER_FH_KEY + 1] = {

	[NFSD_A_SERVER_THREADS] = { .type = NLA_U32, },

	[NFSD_A_SERVER_GRACETIME] = { .type = NLA_U32, },

	[NFSD_A_SERVER_LEASETIME] = { .type = NLA_U32, },

	[NFSD_A_SERVER_SCOPE] = { .type = NLA_NUL_STRING, },

	[NFSD_A_SERVER_MIN_THREADS] = { .type = NLA_U32, },

	[NFSD_A_SERVER_FH_KEY] = NLA_POLICY_EXACT_LEN(16),

};



/* NFSD_CMD_VERSION_SET - do */
@@ -58,7 +59,7 @@ static const struct genl_split_ops nfsd_nl_ops[] = { 
		.cmd		= NFSD_CMD_THREADS_SET,

		.doit		= nfsd_nl_threads_set_doit,

		.policy		= nfsd_threads_set_nl_policy,

		.maxattr	= NFSD_A_SERVER_MIN_THREADS,

		.maxattr	= NFSD_A_SERVER_FH_KEY,

		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,

	},

	{

fs/nfsd/netns.h

+1 −0
Original line number Diff line number Diff line
@@ -227,6 +227,7 @@ struct nfsd_net { 
	spinlock_t              local_clients_lock;

	struct list_head	local_clients;

#endif

	siphash_key_t		*fh_key;

};



/* Simple check to find out if a given net was properly initialized */

fs/nfsd/nfsctl.c

+37 −1
Original line number Diff line number Diff line
@@ -1581,6 +1581,32 @@ int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb, 
	return ret;

}



/**

 * nfsd_nl_fh_key_set - helper to copy fh_key from userspace

 * @attr: nlattr NFSD_A_SERVER_FH_KEY

 * @nn: nfsd_net

 *

 * Callers should hold nfsd_mutex, returns 0 on success or negative errno.

 * Callers must ensure the server is shut down (sv_nrthreads == 0),

 * userspace documentation asserts the key may only be set when the server

 * is not running.

 */

static int nfsd_nl_fh_key_set(const struct nlattr *attr, struct nfsd_net *nn)

{

	siphash_key_t *fh_key = nn->fh_key;



	if (!fh_key) {

		fh_key = kmalloc(sizeof(siphash_key_t), GFP_KERNEL);

		if (!fh_key)

			return -ENOMEM;

		nn->fh_key = fh_key;

	}



	fh_key->key[0] = get_unaligned_le64(nla_data(attr));

	fh_key->key[1] = get_unaligned_le64(nla_data(attr) + 8);

	return 0;

}



/**

 * nfsd_nl_threads_set_doit - set the number of running threads

 * @skb: reply buffer
@@ -1622,7 +1648,8 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info) 


	if (info->attrs[NFSD_A_SERVER_GRACETIME] ||

	    info->attrs[NFSD_A_SERVER_LEASETIME] ||

	    info->attrs[NFSD_A_SERVER_SCOPE]) {

	    info->attrs[NFSD_A_SERVER_SCOPE] ||

	    info->attrs[NFSD_A_SERVER_FH_KEY]) {

		ret = -EBUSY;

		if (nn->nfsd_serv && nn->nfsd_serv->sv_nrthreads)

			goto out_unlock;
@@ -1651,6 +1678,14 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info) 
		attr = info->attrs[NFSD_A_SERVER_SCOPE];

		if (attr)

			scope = nla_data(attr);



		attr = info->attrs[NFSD_A_SERVER_FH_KEY];

		if (attr) {

			ret = nfsd_nl_fh_key_set(attr, nn);

			trace_nfsd_ctl_fh_key_set((const char *)nn->fh_key, ret);

			if (ret)

				goto out_unlock;

		}

	}



	attr = info->attrs[NFSD_A_SERVER_MIN_THREADS];
@@ -2237,6 +2272,7 @@ static __net_exit void nfsd_net_exit(struct net *net) 
{

	struct nfsd_net *nn = net_generic(net, nfsd_net_id);



	kfree_sensitive(nn->fh_key);

	nfsd_proc_stat_shutdown(net);

	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);

	nfsd_idmap_shutdown(net);

fs/nfsd/trace.h

+22 −0
Original line number Diff line number Diff line
@@ -2240,6 +2240,28 @@ TRACE_EVENT(nfsd_end_grace, 
	)

);



TRACE_EVENT(nfsd_ctl_fh_key_set,

	TP_PROTO(

		const char *key,

		int result

	),

	TP_ARGS(key, result),

	TP_STRUCT__entry(

		__field(u32, key_hash)

		__field(int, result)

	),

	TP_fast_assign(

		if (key)

			__entry->key_hash = ~crc32_le(0xFFFFFFFF, key, 16);

		else

			__entry->key_hash = 0;

		__entry->result = result;

	),

	TP_printk("key=0x%08x result=%d",

		__entry->key_hash, __entry->result

	)

);



DECLARE_EVENT_CLASS(nfsd_copy_class,

	TP_PROTO(

		const struct nfsd4_copy *copy