Commit 07568d03 authored by Simon Wunderlich's avatar Simon Wunderlich Committed by Antonio Quartulli
Browse files

batman-adv: don't rely on positions in struct for hashing 



The hash functions in the bridge loop avoidance code expects the
VLAN vid to be right after the mac address, but this is not guaranteed.

Fix this by explicitly hashing over the right fields of the struct.

Reported-by: default avatarMarek Lindner <lindner_marek@yahoo.de>
Signed-off-by: default avatarSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: default avatarAntonio Quartulli <ordex@autistici.org>
parent bf0098f2

net/batman-adv/bridge_loop_avoidance.c

+6 −14
Original line number Original line Diff line number Diff line
@@ -40,15 +40,11 @@ static void batadv_bla_send_announce(struct batadv_priv *bat_priv, 
/* return the index of the claim */

/* return the index of the claim */

static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)

static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)

{

{

	const unsigned char *key = data;

	struct batadv_claim *claim = (struct batadv_claim *)data;

	uint32_t hash = 0;

	uint32_t hash = 0;

	size_t i;





	for (i = 0; i < ETH_ALEN + sizeof(short); i++) {

	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));

		hash += key[i];

	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));

		hash += (hash << 10);

		hash ^= (hash >> 6);

	}





	hash += (hash << 3);

	hash += (hash << 3);

	hash ^= (hash >> 11);

	hash ^= (hash >> 11);
@@ -61,15 +57,11 @@ static inline uint32_t batadv_choose_claim(const void *data, uint32_t size) 
static inline uint32_t batadv_choose_backbone_gw(const void *data,

static inline uint32_t batadv_choose_backbone_gw(const void *data,

						 uint32_t size)

						 uint32_t size)

{

{

	const unsigned char *key = data;

	struct batadv_claim *claim = (struct batadv_claim *)data;

	uint32_t hash = 0;

	uint32_t hash = 0;

	size_t i;





	for (i = 0; i < ETH_ALEN + sizeof(short); i++) {

	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));

		hash += key[i];

	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));

		hash += (hash << 10);

		hash ^= (hash >> 6);

	}





	hash += (hash << 3);

	hash += (hash << 3);

	hash ^= (hash >> 11);

	hash ^= (hash >> 11);

net/batman-adv/hash.h

+22 −0
Original line number Original line Diff line number Diff line
@@ -81,6 +81,28 @@ static inline void batadv_hash_delete(struct batadv_hashtable *hash, 
	batadv_hash_destroy(hash);

	batadv_hash_destroy(hash);

}

}





/**

 *	batadv_hash_bytes - hash some bytes and add them to the previous hash

 *	@hash: previous hash value

 *	@data: data to be hashed

 *	@size: number of bytes to be hashed

 *

 *	Returns the new hash value.

 */

static inline uint32_t batadv_hash_bytes(uint32_t hash, void *data,

					 uint32_t size)

{

	const unsigned char *key = data;

	int i;



	for (i = 0; i < size; i++) {

		hash += key[i];

		hash += (hash << 10);

		hash ^= (hash >> 6);

	}

	return hash;

}



/**

/**

 *	batadv_hash_add - adds data to the hashtable

 *	batadv_hash_add - adds data to the hashtable

 *	@hash: storage hash table

 *	@hash: storage hash table

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