linux/net/batman-adv/tvlv.c
Sven Eckelmann ae3cdc97dc batman-adv: Prevent duplicated tvlv handler
The function batadv_tvlv_handler_register is responsible for adding new
tvlv_handler to the handler_list. It first checks whether the entry
already is in the list or not. If it is, then the creation of a new entry
is aborted.

But the lock for the list is only held when the list is really modified.
This could lead to duplicated entries because another context could create
an entry with the same key between the check and the list manipulation.

The check and the manipulation of the list must therefore be in the same
locked code section.

Fixes: ef26157747 ("batman-adv: tvlv - basic infrastructure")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-09-06 14:37:13 +02:00

644 lines
19 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2007-2018 B.A.T.M.A.N. contributors:
*
* Marek Lindner, Simon Wunderlich
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "main.h"
#include <linux/byteorder/generic.h>
#include <linux/etherdevice.h>
#include <linux/gfp.h>
#include <linux/if_ether.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/pkt_sched.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/types.h>
#include <uapi/linux/batadv_packet.h>
#include "originator.h"
#include "send.h"
#include "tvlv.h"
/**
* batadv_tvlv_handler_release() - release tvlv handler from lists and queue for
* free after rcu grace period
* @ref: kref pointer of the tvlv
*/
static void batadv_tvlv_handler_release(struct kref *ref)
{
struct batadv_tvlv_handler *tvlv_handler;
tvlv_handler = container_of(ref, struct batadv_tvlv_handler, refcount);
kfree_rcu(tvlv_handler, rcu);
}
/**
* batadv_tvlv_handler_put() - decrement the tvlv container refcounter and
* possibly release it
* @tvlv_handler: the tvlv handler to free
*/
static void batadv_tvlv_handler_put(struct batadv_tvlv_handler *tvlv_handler)
{
kref_put(&tvlv_handler->refcount, batadv_tvlv_handler_release);
}
/**
* batadv_tvlv_handler_get() - retrieve tvlv handler from the tvlv handler list
* based on the provided type and version (both need to match)
* @bat_priv: the bat priv with all the soft interface information
* @type: tvlv handler type to look for
* @version: tvlv handler version to look for
*
* Return: tvlv handler if found or NULL otherwise.
*/
static struct batadv_tvlv_handler *
batadv_tvlv_handler_get(struct batadv_priv *bat_priv, u8 type, u8 version)
{
struct batadv_tvlv_handler *tvlv_handler_tmp, *tvlv_handler = NULL;
rcu_read_lock();
hlist_for_each_entry_rcu(tvlv_handler_tmp,
&bat_priv->tvlv.handler_list, list) {
if (tvlv_handler_tmp->type != type)
continue;
if (tvlv_handler_tmp->version != version)
continue;
if (!kref_get_unless_zero(&tvlv_handler_tmp->refcount))
continue;
tvlv_handler = tvlv_handler_tmp;
break;
}
rcu_read_unlock();
return tvlv_handler;
}
/**
* batadv_tvlv_container_release() - release tvlv from lists and free
* @ref: kref pointer of the tvlv
*/
static void batadv_tvlv_container_release(struct kref *ref)
{
struct batadv_tvlv_container *tvlv;
tvlv = container_of(ref, struct batadv_tvlv_container, refcount);
kfree(tvlv);
}
/**
* batadv_tvlv_container_put() - decrement the tvlv container refcounter and
* possibly release it
* @tvlv: the tvlv container to free
*/
static void batadv_tvlv_container_put(struct batadv_tvlv_container *tvlv)
{
kref_put(&tvlv->refcount, batadv_tvlv_container_release);
}
/**
* batadv_tvlv_container_get() - retrieve tvlv container from the tvlv container
* list based on the provided type and version (both need to match)
* @bat_priv: the bat priv with all the soft interface information
* @type: tvlv container type to look for
* @version: tvlv container version to look for
*
* Has to be called with the appropriate locks being acquired
* (tvlv.container_list_lock).
*
* Return: tvlv container if found or NULL otherwise.
*/
static struct batadv_tvlv_container *
batadv_tvlv_container_get(struct batadv_priv *bat_priv, u8 type, u8 version)
{
struct batadv_tvlv_container *tvlv_tmp, *tvlv = NULL;
lockdep_assert_held(&bat_priv->tvlv.container_list_lock);
hlist_for_each_entry(tvlv_tmp, &bat_priv->tvlv.container_list, list) {
if (tvlv_tmp->tvlv_hdr.type != type)
continue;
if (tvlv_tmp->tvlv_hdr.version != version)
continue;
kref_get(&tvlv_tmp->refcount);
tvlv = tvlv_tmp;
break;
}
return tvlv;
}
/**
* batadv_tvlv_container_list_size() - calculate the size of the tvlv container
* list entries
* @bat_priv: the bat priv with all the soft interface information
*
* Has to be called with the appropriate locks being acquired
* (tvlv.container_list_lock).
*
* Return: size of all currently registered tvlv containers in bytes.
*/
static u16 batadv_tvlv_container_list_size(struct batadv_priv *bat_priv)
{
struct batadv_tvlv_container *tvlv;
u16 tvlv_len = 0;
lockdep_assert_held(&bat_priv->tvlv.container_list_lock);
hlist_for_each_entry(tvlv, &bat_priv->tvlv.container_list, list) {
tvlv_len += sizeof(struct batadv_tvlv_hdr);
tvlv_len += ntohs(tvlv->tvlv_hdr.len);
}
return tvlv_len;
}
/**
* batadv_tvlv_container_remove() - remove tvlv container from the tvlv
* container list
* @bat_priv: the bat priv with all the soft interface information
* @tvlv: the to be removed tvlv container
*
* Has to be called with the appropriate locks being acquired
* (tvlv.container_list_lock).
*/
static void batadv_tvlv_container_remove(struct batadv_priv *bat_priv,
struct batadv_tvlv_container *tvlv)
{
lockdep_assert_held(&bat_priv->tvlv.container_list_lock);
if (!tvlv)
return;
hlist_del(&tvlv->list);
/* first call to decrement the counter, second call to free */
batadv_tvlv_container_put(tvlv);
batadv_tvlv_container_put(tvlv);
}
/**
* batadv_tvlv_container_unregister() - unregister tvlv container based on the
* provided type and version (both need to match)
* @bat_priv: the bat priv with all the soft interface information
* @type: tvlv container type to unregister
* @version: tvlv container type to unregister
*/
void batadv_tvlv_container_unregister(struct batadv_priv *bat_priv,
u8 type, u8 version)
{
struct batadv_tvlv_container *tvlv;
spin_lock_bh(&bat_priv->tvlv.container_list_lock);
tvlv = batadv_tvlv_container_get(bat_priv, type, version);
batadv_tvlv_container_remove(bat_priv, tvlv);
spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
}
/**
* batadv_tvlv_container_register() - register tvlv type, version and content
* to be propagated with each (primary interface) OGM
* @bat_priv: the bat priv with all the soft interface information
* @type: tvlv container type
* @version: tvlv container version
* @tvlv_value: tvlv container content
* @tvlv_value_len: tvlv container content length
*
* If a container of the same type and version was already registered the new
* content is going to replace the old one.
*/
void batadv_tvlv_container_register(struct batadv_priv *bat_priv,
u8 type, u8 version,
void *tvlv_value, u16 tvlv_value_len)
{
struct batadv_tvlv_container *tvlv_old, *tvlv_new;
if (!tvlv_value)
tvlv_value_len = 0;
tvlv_new = kzalloc(sizeof(*tvlv_new) + tvlv_value_len, GFP_ATOMIC);
if (!tvlv_new)
return;
tvlv_new->tvlv_hdr.version = version;
tvlv_new->tvlv_hdr.type = type;
tvlv_new->tvlv_hdr.len = htons(tvlv_value_len);
memcpy(tvlv_new + 1, tvlv_value, ntohs(tvlv_new->tvlv_hdr.len));
INIT_HLIST_NODE(&tvlv_new->list);
kref_init(&tvlv_new->refcount);
spin_lock_bh(&bat_priv->tvlv.container_list_lock);
tvlv_old = batadv_tvlv_container_get(bat_priv, type, version);
batadv_tvlv_container_remove(bat_priv, tvlv_old);
kref_get(&tvlv_new->refcount);
hlist_add_head(&tvlv_new->list, &bat_priv->tvlv.container_list);
spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
/* don't return reference to new tvlv_container */
batadv_tvlv_container_put(tvlv_new);
}
/**
* batadv_tvlv_realloc_packet_buff() - reallocate packet buffer to accommodate
* requested packet size
* @packet_buff: packet buffer
* @packet_buff_len: packet buffer size
* @min_packet_len: requested packet minimum size
* @additional_packet_len: requested additional packet size on top of minimum
* size
*
* Return: true of the packet buffer could be changed to the requested size,
* false otherwise.
*/
static bool batadv_tvlv_realloc_packet_buff(unsigned char **packet_buff,
int *packet_buff_len,
int min_packet_len,
int additional_packet_len)
{
unsigned char *new_buff;
new_buff = kmalloc(min_packet_len + additional_packet_len, GFP_ATOMIC);
/* keep old buffer if kmalloc should fail */
if (!new_buff)
return false;
memcpy(new_buff, *packet_buff, min_packet_len);
kfree(*packet_buff);
*packet_buff = new_buff;
*packet_buff_len = min_packet_len + additional_packet_len;
return true;
}
/**
* batadv_tvlv_container_ogm_append() - append tvlv container content to given
* OGM packet buffer
* @bat_priv: the bat priv with all the soft interface information
* @packet_buff: ogm packet buffer
* @packet_buff_len: ogm packet buffer size including ogm header and tvlv
* content
* @packet_min_len: ogm header size to be preserved for the OGM itself
*
* The ogm packet might be enlarged or shrunk depending on the current size
* and the size of the to-be-appended tvlv containers.
*
* Return: size of all appended tvlv containers in bytes.
*/
u16 batadv_tvlv_container_ogm_append(struct batadv_priv *bat_priv,
unsigned char **packet_buff,
int *packet_buff_len, int packet_min_len)
{
struct batadv_tvlv_container *tvlv;
struct batadv_tvlv_hdr *tvlv_hdr;
u16 tvlv_value_len;
void *tvlv_value;
bool ret;
spin_lock_bh(&bat_priv->tvlv.container_list_lock);
tvlv_value_len = batadv_tvlv_container_list_size(bat_priv);
ret = batadv_tvlv_realloc_packet_buff(packet_buff, packet_buff_len,
packet_min_len, tvlv_value_len);
if (!ret)
goto end;
if (!tvlv_value_len)
goto end;
tvlv_value = (*packet_buff) + packet_min_len;
hlist_for_each_entry(tvlv, &bat_priv->tvlv.container_list, list) {
tvlv_hdr = tvlv_value;
tvlv_hdr->type = tvlv->tvlv_hdr.type;
tvlv_hdr->version = tvlv->tvlv_hdr.version;
tvlv_hdr->len = tvlv->tvlv_hdr.len;
tvlv_value = tvlv_hdr + 1;
memcpy(tvlv_value, tvlv + 1, ntohs(tvlv->tvlv_hdr.len));
tvlv_value = (u8 *)tvlv_value + ntohs(tvlv->tvlv_hdr.len);
}
end:
spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
return tvlv_value_len;
}
/**
* batadv_tvlv_call_handler() - parse the given tvlv buffer to call the
* appropriate handlers
* @bat_priv: the bat priv with all the soft interface information
* @tvlv_handler: tvlv callback function handling the tvlv content
* @ogm_source: flag indicating whether the tvlv is an ogm or a unicast packet
* @orig_node: orig node emitting the ogm packet
* @src: source mac address of the unicast packet
* @dst: destination mac address of the unicast packet
* @tvlv_value: tvlv content
* @tvlv_value_len: tvlv content length
*
* Return: success if handler was not found or the return value of the handler
* callback.
*/
static int batadv_tvlv_call_handler(struct batadv_priv *bat_priv,
struct batadv_tvlv_handler *tvlv_handler,
bool ogm_source,
struct batadv_orig_node *orig_node,
u8 *src, u8 *dst,
void *tvlv_value, u16 tvlv_value_len)
{
if (!tvlv_handler)
return NET_RX_SUCCESS;
if (ogm_source) {
if (!tvlv_handler->ogm_handler)
return NET_RX_SUCCESS;
if (!orig_node)
return NET_RX_SUCCESS;
tvlv_handler->ogm_handler(bat_priv, orig_node,
BATADV_NO_FLAGS,
tvlv_value, tvlv_value_len);
tvlv_handler->flags |= BATADV_TVLV_HANDLER_OGM_CALLED;
} else {
if (!src)
return NET_RX_SUCCESS;
if (!dst)
return NET_RX_SUCCESS;
if (!tvlv_handler->unicast_handler)
return NET_RX_SUCCESS;
return tvlv_handler->unicast_handler(bat_priv, src,
dst, tvlv_value,
tvlv_value_len);
}
return NET_RX_SUCCESS;
}
/**
* batadv_tvlv_containers_process() - parse the given tvlv buffer to call the
* appropriate handlers
* @bat_priv: the bat priv with all the soft interface information
* @ogm_source: flag indicating whether the tvlv is an ogm or a unicast packet
* @orig_node: orig node emitting the ogm packet
* @src: source mac address of the unicast packet
* @dst: destination mac address of the unicast packet
* @tvlv_value: tvlv content
* @tvlv_value_len: tvlv content length
*
* Return: success when processing an OGM or the return value of all called
* handler callbacks.
*/
int batadv_tvlv_containers_process(struct batadv_priv *bat_priv,
bool ogm_source,
struct batadv_orig_node *orig_node,
u8 *src, u8 *dst,
void *tvlv_value, u16 tvlv_value_len)
{
struct batadv_tvlv_handler *tvlv_handler;
struct batadv_tvlv_hdr *tvlv_hdr;
u16 tvlv_value_cont_len;
u8 cifnotfound = BATADV_TVLV_HANDLER_OGM_CIFNOTFND;
int ret = NET_RX_SUCCESS;
while (tvlv_value_len >= sizeof(*tvlv_hdr)) {
tvlv_hdr = tvlv_value;
tvlv_value_cont_len = ntohs(tvlv_hdr->len);
tvlv_value = tvlv_hdr + 1;
tvlv_value_len -= sizeof(*tvlv_hdr);
if (tvlv_value_cont_len > tvlv_value_len)
break;
tvlv_handler = batadv_tvlv_handler_get(bat_priv,
tvlv_hdr->type,
tvlv_hdr->version);
ret |= batadv_tvlv_call_handler(bat_priv, tvlv_handler,
ogm_source, orig_node,
src, dst, tvlv_value,
tvlv_value_cont_len);
if (tvlv_handler)
batadv_tvlv_handler_put(tvlv_handler);
tvlv_value = (u8 *)tvlv_value + tvlv_value_cont_len;
tvlv_value_len -= tvlv_value_cont_len;
}
if (!ogm_source)
return ret;
rcu_read_lock();
hlist_for_each_entry_rcu(tvlv_handler,
&bat_priv->tvlv.handler_list, list) {
if ((tvlv_handler->flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND) &&
!(tvlv_handler->flags & BATADV_TVLV_HANDLER_OGM_CALLED))
tvlv_handler->ogm_handler(bat_priv, orig_node,
cifnotfound, NULL, 0);
tvlv_handler->flags &= ~BATADV_TVLV_HANDLER_OGM_CALLED;
}
rcu_read_unlock();
return NET_RX_SUCCESS;
}
/**
* batadv_tvlv_ogm_receive() - process an incoming ogm and call the appropriate
* handlers
* @bat_priv: the bat priv with all the soft interface information
* @batadv_ogm_packet: ogm packet containing the tvlv containers
* @orig_node: orig node emitting the ogm packet
*/
void batadv_tvlv_ogm_receive(struct batadv_priv *bat_priv,
struct batadv_ogm_packet *batadv_ogm_packet,
struct batadv_orig_node *orig_node)
{
void *tvlv_value;
u16 tvlv_value_len;
if (!batadv_ogm_packet)
return;
tvlv_value_len = ntohs(batadv_ogm_packet->tvlv_len);
if (!tvlv_value_len)
return;
tvlv_value = batadv_ogm_packet + 1;
batadv_tvlv_containers_process(bat_priv, true, orig_node, NULL, NULL,
tvlv_value, tvlv_value_len);
}
/**
* batadv_tvlv_handler_register() - register tvlv handler based on the provided
* type and version (both need to match) for ogm tvlv payload and/or unicast
* payload
* @bat_priv: the bat priv with all the soft interface information
* @optr: ogm tvlv handler callback function. This function receives the orig
* node, flags and the tvlv content as argument to process.
* @uptr: unicast tvlv handler callback function. This function receives the
* source & destination of the unicast packet as well as the tvlv content
* to process.
* @type: tvlv handler type to be registered
* @version: tvlv handler version to be registered
* @flags: flags to enable or disable TVLV API behavior
*/
void batadv_tvlv_handler_register(struct batadv_priv *bat_priv,
void (*optr)(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig,
u8 flags,
void *tvlv_value,
u16 tvlv_value_len),
int (*uptr)(struct batadv_priv *bat_priv,
u8 *src, u8 *dst,
void *tvlv_value,
u16 tvlv_value_len),
u8 type, u8 version, u8 flags)
{
struct batadv_tvlv_handler *tvlv_handler;
spin_lock_bh(&bat_priv->tvlv.handler_list_lock);
tvlv_handler = batadv_tvlv_handler_get(bat_priv, type, version);
if (tvlv_handler) {
spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
batadv_tvlv_handler_put(tvlv_handler);
return;
}
tvlv_handler = kzalloc(sizeof(*tvlv_handler), GFP_ATOMIC);
if (!tvlv_handler) {
spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
return;
}
tvlv_handler->ogm_handler = optr;
tvlv_handler->unicast_handler = uptr;
tvlv_handler->type = type;
tvlv_handler->version = version;
tvlv_handler->flags = flags;
kref_init(&tvlv_handler->refcount);
INIT_HLIST_NODE(&tvlv_handler->list);
kref_get(&tvlv_handler->refcount);
hlist_add_head_rcu(&tvlv_handler->list, &bat_priv->tvlv.handler_list);
spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
/* don't return reference to new tvlv_handler */
batadv_tvlv_handler_put(tvlv_handler);
}
/**
* batadv_tvlv_handler_unregister() - unregister tvlv handler based on the
* provided type and version (both need to match)
* @bat_priv: the bat priv with all the soft interface information
* @type: tvlv handler type to be unregistered
* @version: tvlv handler version to be unregistered
*/
void batadv_tvlv_handler_unregister(struct batadv_priv *bat_priv,
u8 type, u8 version)
{
struct batadv_tvlv_handler *tvlv_handler;
tvlv_handler = batadv_tvlv_handler_get(bat_priv, type, version);
if (!tvlv_handler)
return;
batadv_tvlv_handler_put(tvlv_handler);
spin_lock_bh(&bat_priv->tvlv.handler_list_lock);
hlist_del_rcu(&tvlv_handler->list);
spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
batadv_tvlv_handler_put(tvlv_handler);
}
/**
* batadv_tvlv_unicast_send() - send a unicast packet with tvlv payload to the
* specified host
* @bat_priv: the bat priv with all the soft interface information
* @src: source mac address of the unicast packet
* @dst: destination mac address of the unicast packet
* @type: tvlv type
* @version: tvlv version
* @tvlv_value: tvlv content
* @tvlv_value_len: tvlv content length
*/
void batadv_tvlv_unicast_send(struct batadv_priv *bat_priv, u8 *src,
u8 *dst, u8 type, u8 version,
void *tvlv_value, u16 tvlv_value_len)
{
struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
struct batadv_tvlv_hdr *tvlv_hdr;
struct batadv_orig_node *orig_node;
struct sk_buff *skb;
unsigned char *tvlv_buff;
unsigned int tvlv_len;
ssize_t hdr_len = sizeof(*unicast_tvlv_packet);
orig_node = batadv_orig_hash_find(bat_priv, dst);
if (!orig_node)
return;
tvlv_len = sizeof(*tvlv_hdr) + tvlv_value_len;
skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + hdr_len + tvlv_len);
if (!skb)
goto out;
skb->priority = TC_PRIO_CONTROL;
skb_reserve(skb, ETH_HLEN);
tvlv_buff = skb_put(skb, sizeof(*unicast_tvlv_packet) + tvlv_len);
unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)tvlv_buff;
unicast_tvlv_packet->packet_type = BATADV_UNICAST_TVLV;
unicast_tvlv_packet->version = BATADV_COMPAT_VERSION;
unicast_tvlv_packet->ttl = BATADV_TTL;
unicast_tvlv_packet->reserved = 0;
unicast_tvlv_packet->tvlv_len = htons(tvlv_len);
unicast_tvlv_packet->align = 0;
ether_addr_copy(unicast_tvlv_packet->src, src);
ether_addr_copy(unicast_tvlv_packet->dst, dst);
tvlv_buff = (unsigned char *)(unicast_tvlv_packet + 1);
tvlv_hdr = (struct batadv_tvlv_hdr *)tvlv_buff;
tvlv_hdr->version = version;
tvlv_hdr->type = type;
tvlv_hdr->len = htons(tvlv_value_len);
tvlv_buff += sizeof(*tvlv_hdr);
memcpy(tvlv_buff, tvlv_value, tvlv_value_len);
batadv_send_skb_to_orig(skb, orig_node, NULL);
out:
batadv_orig_node_put(orig_node);
}