From: Sven Eckelmann sven@narfation.org

[ Upstream commit 4cc4a1708903f404d2ca0dfde30e71e052c6cbc9 ]

The distributed arp table is using a DHT to store and retrieve MAC address information for an IP address. This is done using unicast messages to selected peers. The potential peers are looked up using the IP address and the VID.

While the IP address is always stored in big endian byte order, this is not the case of the VID. It can (depending on the host system) either be big endian or little endian. The host must therefore always convert it to big endian to ensure that all devices calculate the same peers for the same lookup data.

Fixes: be1db4f6615b ("batman-adv: make the Distributed ARP Table vlan aware") Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de Signed-off-by: Sasha Levin sashal@kernel.org --- net/batman-adv/distributed-arp-table.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c index 8d1d0fdb157e7..1519cbf70150b 100644 --- a/net/batman-adv/distributed-arp-table.c +++ b/net/batman-adv/distributed-arp-table.c @@ -243,6 +243,7 @@ static u32 batadv_hash_dat(const void *data, u32 size) u32 hash = 0; const struct batadv_dat_entry *dat = data; const unsigned char *key; + __be16 vid; u32 i;

key = (const unsigned char *)&dat->ip; @@ -252,7 +253,8 @@ static u32 batadv_hash_dat(const void *data, u32 size) hash ^= (hash >> 6); }

- key = (const unsigned char *)&dat->vid; + vid = htons(dat->vid); + key = (__force const unsigned char *)&vid; for (i = 0; i < sizeof(dat->vid); i++) { hash += key[i]; hash += (hash << 10);