Re: [B.A.T.M.A.N.] [PATCH] batman-adv: Fix integer overflow in batadv_iv_ogm_calc_tq

On Tuesday, February 16, 2016 10:47:07 Sven Eckelmann wrote:

From: Sven Eckelmann sven.eckelmann@open-mesh.com

The undefined behavior sanatizer detected an signed integer overflow in a setup with near perfect link quality

UBSAN: Undefined behaviour in net/batman-adv/bat_iv_ogm.c:1246:25
signed integer overflow:
8713350 * 255 cannot be represented in type 'int'

The problems happens because the calculation of mixed unsigned and signed integers resulted in an integer multiplication.

  batadv_ogm_packet::tq (u8 255)
* tq_own (u8 255)
* tq_asym_penalty (int 134; max 255)
* tq_iface_penalty (int 255; max 255)

The tq_iface_penalty, tq_asym_penalty and inv_asym_penalty can just be changed to unsigned int because they are not expected to become negative.

Fixes: 46e44fdb96ef ("batman-adv: add WiFi penalty") Signed-off-by: Sven Eckelmann sven.eckelmann@open-mesh.com

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net/batman-adv/bat_iv_ogm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

Applied in revision 789b846.

Thanks, Marek