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

[Marek Lindner <mareklindner@neomailbox.ch>]

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

Applied in revision 789b846.

Thanks,
Marek

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