mac802154: add llsec structures and mutators

This patch adds containers and mutators for the major ieee802154_llsec
structures to mac802154. Most of the (rather simple) ieee802154_llsec
structs are wrapped only to provide an rcu_head for orderly disposal,
but some structs - llsec keys notably - require more complex
bookkeeping.

Since each llsec key may be referenced by a number of llsec key table
entries (with differing key ids, but the same actual key), we want to
save memory and not allocate crypto transforms for each entry in the
table. Thus, the mac802154 llsec key is reference-counted instead.
Further, each key will have four associated crypto transforms - three
CCM transforms for the authsizes 4/8/16 and one CTR transform for
unauthenticated encryption. If we had a CCM* transform that allowed
authsize 0, and authsize as part of requests instead of transforms, this
would not be necessary.

Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 637 insertions, 1 deletions

diff --git a/net/mac802154/Makefile b/net/mac802154/Makefile
index 15d62df5..9723d6f 100644
--- a/net/mac802154/Makefile
+++ b/net/mac802154/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_MAC802154)	+= mac802154.o
-mac802154-objs		:= ieee802154_dev.o rx.o tx.o mac_cmd.o mib.o monitor.o wpan.o
+mac802154-objs		:= ieee802154_dev.o rx.o tx.o mac_cmd.o mib.o \
+			   monitor.o wpan.o llsec.o
 
 ccflags-y += -D__CHECK_ENDIAN__
diff --git a/net/mac802154/llsec.c b/net/mac802154/llsec.c
new file mode 100644
index 0000000..a210d1e
--- /dev/null
+++ b/net/mac802154/llsec.c
@@ -0,0 +1,529 @@
+/*
+ * Copyright (C) 2014 Fraunhofer ITWM
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by:
+ * Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
+ */
+
+#include <linux/err.h>
+#include <linux/bug.h>
+#include <linux/completion.h>
+#include <net/ieee802154.h>
+
+#include "mac802154.h"
+#include "llsec.h"
+
+static void llsec_key_put(struct mac802154_llsec_key *key);
+static bool llsec_key_id_equal(const struct ieee802154_llsec_key_id *a,
+			       const struct ieee802154_llsec_key_id *b);
+
+static void llsec_dev_free(struct mac802154_llsec_device *dev);
+
+void mac802154_llsec_init(struct mac802154_llsec *sec)
+{
+	memset(sec, 0, sizeof(*sec));
+
+	memset(&sec->params.default_key_source, 0xFF, IEEE802154_ADDR_LEN);
+
+	INIT_LIST_HEAD(&sec->table.security_levels);
+	INIT_LIST_HEAD(&sec->table.devices);
+	INIT_LIST_HEAD(&sec->table.keys);
+	hash_init(sec->devices_short);
+	hash_init(sec->devices_hw);
+	rwlock_init(&sec->lock);
+}
+
+void mac802154_llsec_destroy(struct mac802154_llsec *sec)
+{
+	struct ieee802154_llsec_seclevel *sl, *sn;
+	struct ieee802154_llsec_device *dev, *dn;
+	struct ieee802154_llsec_key_entry *key, *kn;
+
+	list_for_each_entry_safe(sl, sn, &sec->table.security_levels, list) {
+		struct mac802154_llsec_seclevel *msl;
+
+		msl = container_of(sl, struct mac802154_llsec_seclevel, level);
+		list_del(&sl->list);
+		kfree(msl);
+	}
+
+	list_for_each_entry_safe(dev, dn, &sec->table.devices, list) {
+		struct mac802154_llsec_device *mdev;
+
+		mdev = container_of(dev, struct mac802154_llsec_device, dev);
+		list_del(&dev->list);
+		llsec_dev_free(mdev);
+	}
+
+	list_for_each_entry_safe(key, kn, &sec->table.keys, list) {
+		struct mac802154_llsec_key *mkey;
+
+		mkey = container_of(key->key, struct mac802154_llsec_key, key);
+		list_del(&key->list);
+		llsec_key_put(mkey);
+		kfree(key);
+	}
+}
+
+
+
+int mac802154_llsec_get_params(struct mac802154_llsec *sec,
+			       struct ieee802154_llsec_params *params)
+{
+	read_lock_bh(&sec->lock);
+	*params = sec->params;
+	read_unlock_bh(&sec->lock);
+
+	return 0;
+}
+
+int mac802154_llsec_set_params(struct mac802154_llsec *sec,
+			       const struct ieee802154_llsec_params *params,
+			       int changed)
+{
+	write_lock_bh(&sec->lock);
+
+	if (changed & IEEE802154_LLSEC_PARAM_ENABLED)
+		sec->params.enabled = params->enabled;
+	if (changed & IEEE802154_LLSEC_PARAM_FRAME_COUNTER)
+		sec->params.frame_counter = params->frame_counter;
+	if (changed & IEEE802154_LLSEC_PARAM_OUT_LEVEL)
+		sec->params.out_level = params->out_level;
+	if (changed & IEEE802154_LLSEC_PARAM_OUT_KEY)
+		sec->params.out_key = params->out_key;
+	if (changed & IEEE802154_LLSEC_PARAM_KEY_SOURCE)
+		sec->params.default_key_source = params->default_key_source;
+	if (changed & IEEE802154_LLSEC_PARAM_PAN_ID)
+		sec->params.pan_id = params->pan_id;
+	if (changed & IEEE802154_LLSEC_PARAM_HWADDR)
+		sec->params.hwaddr = params->hwaddr;
+	if (changed & IEEE802154_LLSEC_PARAM_COORD_HWADDR)
+		sec->params.coord_hwaddr = params->coord_hwaddr;
+	if (changed & IEEE802154_LLSEC_PARAM_COORD_SHORTADDR)
+		sec->params.coord_shortaddr = params->coord_shortaddr;
+
+	write_unlock_bh(&sec->lock);
+
+	return 0;
+}
+
+
+
+static struct mac802154_llsec_key*
+llsec_key_alloc(const struct ieee802154_llsec_key *template)
+{
+	const int authsizes[3] = { 4, 8, 16 };
+	struct mac802154_llsec_key *key;
+	int i;
+
+	key = kzalloc(sizeof(*key), GFP_KERNEL);
+	if (!key)
+		return NULL;
+
+	kref_init(&key->ref);
+	key->key = *template;
+
+	BUILD_BUG_ON(ARRAY_SIZE(authsizes) != ARRAY_SIZE(key->tfm));
+
+	for (i = 0; i < ARRAY_SIZE(key->tfm); i++) {
+		key->tfm[i] = crypto_alloc_aead("ccm(aes)", 0,
+						CRYPTO_ALG_ASYNC);
+		if (!key->tfm[i])
+			goto err_tfm;
+		if (crypto_aead_setkey(key->tfm[i], template->key,
+				       IEEE802154_LLSEC_KEY_SIZE))
+			goto err_tfm;
+		if (crypto_aead_setauthsize(key->tfm[i], authsizes[i]))
+			goto err_tfm;
+	}
+
+	key->tfm0 = crypto_alloc_blkcipher("ctr(aes)", 0, CRYPTO_ALG_ASYNC);
+	if (!key->tfm0)
+		goto err_tfm;
+
+	if (crypto_blkcipher_setkey(key->tfm0, template->key,
+				    IEEE802154_LLSEC_KEY_SIZE))
+		goto err_tfm0;
+
+	return key;
+
+err_tfm0:
+	crypto_free_blkcipher(key->tfm0);
+err_tfm:
+	for (i = 0; i < ARRAY_SIZE(key->tfm); i++)
+		if (key->tfm[i])
+			crypto_free_aead(key->tfm[i]);
+
+	kfree(key);
+	return NULL;
+}
+
+static void llsec_key_release(struct kref *ref)
+{
+	struct mac802154_llsec_key *key;
+	int i;
+
+	key = container_of(ref, struct mac802154_llsec_key, ref);
+
+	for (i = 0; i < ARRAY_SIZE(key->tfm); i++)
+		crypto_free_aead(key->tfm[i]);
+
+	crypto_free_blkcipher(key->tfm0);
+	kfree(key);
+}
+
+static struct mac802154_llsec_key*
+llsec_key_get(struct mac802154_llsec_key *key)
+{
+	kref_get(&key->ref);
+	return key;
+}
+
+static void llsec_key_put(struct mac802154_llsec_key *key)
+{
+	kref_put(&key->ref, llsec_key_release);
+}
+
+static bool llsec_key_id_equal(const struct ieee802154_llsec_key_id *a,
+			       const struct ieee802154_llsec_key_id *b)
+{
+	if (a->mode != b->mode)
+		return false;
+
+	if (a->mode == IEEE802154_SCF_KEY_IMPLICIT)
+		return ieee802154_addr_equal(&a->device_addr, &b->device_addr);
+
+	if (a->id != b->id)
+		return false;
+
+	switch (a->mode) {
+	case IEEE802154_SCF_KEY_SHORT_INDEX:
+		return a->short_source == b->short_source;
+	case IEEE802154_SCF_KEY_HW_INDEX:
+		return a->extended_source == b->extended_source;
+	}
+
+	return false;
+}
+
+int mac802154_llsec_key_add(struct mac802154_llsec *sec,
+			    const struct ieee802154_llsec_key_id *id,
+			    const struct ieee802154_llsec_key *key)
+{
+	struct mac802154_llsec_key *mkey = NULL;
+	struct ieee802154_llsec_key_entry *pos, *new;
+
+	if (!(key->frame_types & (1 << IEEE802154_FC_TYPE_MAC_CMD)) &&
+	    key->cmd_frame_ids)
+		return -EINVAL;
+
+	list_for_each_entry(pos, &sec->table.keys, list) {
+		if (llsec_key_id_equal(&pos->id, id))
+			return -EEXIST;
+
+		if (memcmp(pos->key->key, key->key,
+			   IEEE802154_LLSEC_KEY_SIZE))
+			continue;
+
+		mkey = container_of(pos->key, struct mac802154_llsec_key, key);
+
+		/* Don't allow multiple instances of the same AES key to have
+		 * different allowed frame types/command frame ids, as this is
+		 * not possible in the 802.15.4 PIB.
+		 */
+		if (pos->key->frame_types != key->frame_types ||
+		    pos->key->cmd_frame_ids != key->cmd_frame_ids)
+			return -EEXIST;
+
+		break;
+	}
+
+	new = kzalloc(sizeof(*new), GFP_KERNEL);
+	if (!new)
+		return -ENOMEM;
+
+	if (!mkey)
+		mkey = llsec_key_alloc(key);
+	else
+		mkey = llsec_key_get(mkey);
+
+	if (!mkey)
+		goto fail;
+
+	new->id = *id;
+	new->key = &mkey->key;
+
+	list_add_rcu(&new->list, &sec->table.keys);
+
+	return 0;
+
+fail:
+	kfree(new);
+	return -ENOMEM;
+}
+
+int mac802154_llsec_key_del(struct mac802154_llsec *sec,
+			    const struct ieee802154_llsec_key_id *key)
+{
+	struct ieee802154_llsec_key_entry *pos;
+
+	list_for_each_entry(pos, &sec->table.keys, list) {
+		struct mac802154_llsec_key *mkey;
+
+		mkey = container_of(pos->key, struct mac802154_llsec_key, key);
+
+		if (llsec_key_id_equal(&pos->id, key)) {
+			llsec_key_put(mkey);
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+
+
+static bool llsec_dev_use_shortaddr(__le16 short_addr)
+{
+	return short_addr != cpu_to_le16(IEEE802154_ADDR_UNDEF) &&
+		short_addr != cpu_to_le16(0xffff);
+}
+
+static u32 llsec_dev_hash_short(__le16 short_addr, __le16 pan_id)
+{
+	return ((__force u16) short_addr) << 16 | (__force u16) pan_id;
+}
+
+static u64 llsec_dev_hash_long(__le64 hwaddr)
+{
+	return (__force u64) hwaddr;
+}
+
+static struct mac802154_llsec_device*
+llsec_dev_find_short(struct mac802154_llsec *sec, __le16 short_addr,
+		     __le16 pan_id)
+{
+	struct mac802154_llsec_device *dev;
+	u32 key = llsec_dev_hash_short(short_addr, pan_id);
+
+	hash_for_each_possible_rcu(sec->devices_short, dev, bucket_s, key) {
+		if (dev->dev.short_addr == short_addr &&
+		    dev->dev.pan_id == pan_id)
+			return dev;
+	}
+
+	return NULL;
+}
+
+static struct mac802154_llsec_device*
+llsec_dev_find_long(struct mac802154_llsec *sec, __le64 hwaddr)
+{
+	struct mac802154_llsec_device *dev;
+	u64 key = llsec_dev_hash_long(hwaddr);
+
+	hash_for_each_possible_rcu(sec->devices_hw, dev, bucket_hw, key) {
+		if (dev->dev.hwaddr == hwaddr)
+			return dev;
+	}
+
+	return NULL;
+}
+
+static void llsec_dev_free(struct mac802154_llsec_device *dev)
+{
+	struct ieee802154_llsec_device_key *pos, *pn;
+	struct mac802154_llsec_device_key *devkey;
+
+	list_for_each_entry_safe(pos, pn, &dev->dev.keys, list) {
+		devkey = container_of(pos, struct mac802154_llsec_device_key,
+				      devkey);
+
+		list_del(&pos->list);
+		kfree(devkey);
+	}
+
+	kfree(dev);
+}
+
+int mac802154_llsec_dev_add(struct mac802154_llsec *sec,
+			    const struct ieee802154_llsec_device *dev)
+{
+	struct mac802154_llsec_device *entry;
+	u32 skey = llsec_dev_hash_short(dev->short_addr, dev->pan_id);
+	u64 hwkey = llsec_dev_hash_long(dev->hwaddr);
+
+	BUILD_BUG_ON(sizeof(hwkey) != IEEE802154_ADDR_LEN);
+
+	if ((llsec_dev_use_shortaddr(dev->short_addr) &&
+	     llsec_dev_find_short(sec, dev->short_addr, dev->pan_id)) ||
+	     llsec_dev_find_long(sec, dev->hwaddr))
+		return -EEXIST;
+
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->dev = *dev;
+	spin_lock_init(&entry->lock);
+	INIT_LIST_HEAD(&entry->dev.keys);
+
+	if (llsec_dev_use_shortaddr(dev->short_addr))
+		hash_add_rcu(sec->devices_short, &entry->bucket_s, skey);
+	else
+		INIT_HLIST_NODE(&entry->bucket_s);
+
+	hash_add_rcu(sec->devices_hw, &entry->bucket_hw, hwkey);
+	list_add_tail_rcu(&entry->dev.list, &sec->table.devices);
+
+	return 0;
+}
+
+static void llsec_dev_free_rcu(struct rcu_head *rcu)
+{
+	llsec_dev_free(container_of(rcu, struct mac802154_llsec_device, rcu));
+}
+
+int mac802154_llsec_dev_del(struct mac802154_llsec *sec, __le64 device_addr)
+{
+	struct mac802154_llsec_device *pos;
+
+	pos = llsec_dev_find_long(sec, device_addr);
+	if (!pos)
+		return -ENOENT;
+
+	hash_del_rcu(&pos->bucket_s);
+	hash_del_rcu(&pos->bucket_hw);
+	call_rcu(&pos->rcu, llsec_dev_free_rcu);
+
+	return 0;
+}
+
+
+
+static struct mac802154_llsec_device_key*
+llsec_devkey_find(struct mac802154_llsec_device *dev,
+		  const struct ieee802154_llsec_key_id *key)
+{
+	struct ieee802154_llsec_device_key *devkey;
+
+	list_for_each_entry_rcu(devkey, &dev->dev.keys, list) {
+		if (!llsec_key_id_equal(key, &devkey->key_id))
+			continue;
+
+		return container_of(devkey, struct mac802154_llsec_device_key,
+				    devkey);
+	}
+
+	return NULL;
+}
+
+int mac802154_llsec_devkey_add(struct mac802154_llsec *sec,
+			       __le64 dev_addr,
+			       const struct ieee802154_llsec_device_key *key)
+{
+	struct mac802154_llsec_device *dev;
+	struct mac802154_llsec_device_key *devkey;
+
+	dev = llsec_dev_find_long(sec, dev_addr);
+
+	if (!dev)
+		return -ENOENT;
+
+	if (llsec_devkey_find(dev, &key->key_id))
+		return -EEXIST;
+
+	devkey = kmalloc(sizeof(*devkey), GFP_KERNEL);
+	if (!devkey)
+		return -ENOMEM;
+
+	devkey->devkey = *key;
+	list_add_tail_rcu(&devkey->devkey.list, &dev->dev.keys);
+	return 0;
+}
+
+int mac802154_llsec_devkey_del(struct mac802154_llsec *sec,
+			       __le64 dev_addr,
+			       const struct ieee802154_llsec_device_key *key)
+{
+	struct mac802154_llsec_device *dev;
+	struct mac802154_llsec_device_key *devkey;
+
+	dev = llsec_dev_find_long(sec, dev_addr);
+
+	if (!dev)
+		return -ENOENT;
+
+	devkey = llsec_devkey_find(dev, &key->key_id);
+	if (!devkey)
+		return -ENOENT;
+
+	list_del_rcu(&devkey->devkey.list);
+	kfree_rcu(devkey, rcu);
+	return 0;
+}
+
+
+
+static struct mac802154_llsec_seclevel*
+llsec_find_seclevel(const struct mac802154_llsec *sec,
+		    const struct ieee802154_llsec_seclevel *sl)
+{
+	struct ieee802154_llsec_seclevel *pos;
+
+	list_for_each_entry(pos, &sec->table.security_levels, list) {
+		if (pos->frame_type != sl->frame_type ||
+		    (pos->frame_type == IEEE802154_FC_TYPE_MAC_CMD &&
+		     pos->cmd_frame_id != sl->cmd_frame_id) ||
+		    pos->device_override != sl->device_override ||
+		    pos->sec_levels != sl->sec_levels)
+			continue;
+
+		return container_of(pos, struct mac802154_llsec_seclevel,
+				    level);
+	}
+
+	return NULL;
+}
+
+int mac802154_llsec_seclevel_add(struct mac802154_llsec *sec,
+				 const struct ieee802154_llsec_seclevel *sl)
+{
+	struct mac802154_llsec_seclevel *entry;
+
+	if (llsec_find_seclevel(sec, sl))
+		return -EEXIST;
+
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->level = *sl;
+
+	list_add_tail_rcu(&entry->level.list, &sec->table.security_levels);
+
+	return 0;
+}
+
+int mac802154_llsec_seclevel_del(struct mac802154_llsec *sec,
+				 const struct ieee802154_llsec_seclevel *sl)
+{
+	struct mac802154_llsec_seclevel *pos;
+
+	pos = llsec_find_seclevel(sec, sl);
+	if (!pos)
+		return -ENOENT;
+
+	list_del_rcu(&pos->level.list);
+	kfree_rcu(pos, rcu);
+
+	return 0;
+}
diff --git a/net/mac802154/llsec.h b/net/mac802154/llsec.h
new file mode 100644
index 0000000..65c1dd4
--- /dev/null
+++ b/net/mac802154/llsec.h
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2014 Fraunhofer ITWM
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by:
+ * Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
+ */
+
+#ifndef MAC802154_LLSEC_H
+#define MAC802154_LLSEC_H
+
+#include <linux/slab.h>
+#include <linux/hashtable.h>
+#include <linux/crypto.h>
+#include <linux/kref.h>
+#include <linux/spinlock.h>
+#include <net/af_ieee802154.h>
+#include <net/ieee802154_netdev.h>
+
+struct mac802154_llsec_key {
+	struct ieee802154_llsec_key key;
+
+	/* one tfm for each authsize (4/8/16) */
+	struct crypto_aead *tfm[3];
+	struct crypto_blkcipher *tfm0;
+
+	struct kref ref;
+};
+
+struct mac802154_llsec_device_key {
+	struct ieee802154_llsec_device_key devkey;
+
+	struct rcu_head rcu;
+};
+
+struct mac802154_llsec_device {
+	struct ieee802154_llsec_device dev;
+
+	struct hlist_node bucket_s;
+	struct hlist_node bucket_hw;
+
+	/* protects dev.frame_counter and the elements of dev.keys */
+	spinlock_t lock;
+
+	struct rcu_head rcu;
+};
+
+struct mac802154_llsec_seclevel {
+	struct ieee802154_llsec_seclevel level;
+
+	struct rcu_head rcu;
+};
+
+struct mac802154_llsec {
+	struct ieee802154_llsec_params params;
+	struct ieee802154_llsec_table table;
+
+	DECLARE_HASHTABLE(devices_short, 6);
+	DECLARE_HASHTABLE(devices_hw, 6);
+
+	/* protects params, all other fields are fine with RCU */
+	rwlock_t lock;
+};
+
+void mac802154_llsec_init(struct mac802154_llsec *sec);
+void mac802154_llsec_destroy(struct mac802154_llsec *sec);
+
+int mac802154_llsec_get_params(struct mac802154_llsec *sec,
+			       struct ieee802154_llsec_params *params);
+int mac802154_llsec_set_params(struct mac802154_llsec *sec,
+			       const struct ieee802154_llsec_params *params,
+			       int changed);
+
+int mac802154_llsec_key_add(struct mac802154_llsec *sec,
+			    const struct ieee802154_llsec_key_id *id,
+			    const struct ieee802154_llsec_key *key);
+int mac802154_llsec_key_del(struct mac802154_llsec *sec,
+			    const struct ieee802154_llsec_key_id *key);
+
+int mac802154_llsec_dev_add(struct mac802154_llsec *sec,
+			    const struct ieee802154_llsec_device *dev);
+int mac802154_llsec_dev_del(struct mac802154_llsec *sec,
+			    __le64 device_addr);
+
+int mac802154_llsec_devkey_add(struct mac802154_llsec *sec,
+			       __le64 dev_addr,
+			       const struct ieee802154_llsec_device_key *key);
+int mac802154_llsec_devkey_del(struct mac802154_llsec *sec,
+			       __le64 dev_addr,
+			       const struct ieee802154_llsec_device_key *key);
+
+int mac802154_llsec_seclevel_add(struct mac802154_llsec *sec,
+				 const struct ieee802154_llsec_seclevel *sl);
+int mac802154_llsec_seclevel_del(struct mac802154_llsec *sec,
+				 const struct ieee802154_llsec_seclevel *sl);
+
+#endif /* MAC802154_LLSEC_H */
diff --git a/net/mac802154/mac802154.h b/net/mac802154/mac802154.h
index 28ef59c..e05f66e 100644
--- a/net/mac802154/mac802154.h
+++ b/net/mac802154/mac802154.h
@@ -23,6 +23,7 @@
 #ifndef MAC802154_H
 #define MAC802154_H
 
+#include <net/mac802154.h>
 #include <net/ieee802154_netdev.h>
 
 /* mac802154 device private data */