batman-adv: reject oversized global TT response buffers

batadv_tt_prepare_tvlv_global_data() builds the allocation length for a
global TT response in 16-bit temporaries. When a remote originator
advertises a large enough global TT, the TT payload length plus the VLAN
header offset can exceed 65535 and wrap before kmalloc().

The full-table response path still uses the original TT payload length when
it fills tt_change, so the wrapped allocation is too small and
batadv_tt_prepare_tvlv_global_data() writes past the end of the heap object
before the later packet-size check runs.

Fix this by rejecting TT responses whose TVLV value length cannot fit in
the 16-bit TVLV payload length field.

Fixes: 7ea7b4a14275 ("batman-adv: make the TT CRC logic VLAN specific")
Cc: stable@vger.kernel.org
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Tested-by: Ren Wei <enjou1224z@gmail.com>
Signed-off-by: Ruide Cao <caoruide123@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

0 files changed, 0 insertions, 0 deletions