Re: [PATCH] mac80211: ethtool: avoid 32 bit multiplication overflow

From: Johannes Berg
Date: Tue May 08 2018 - 09:01:31 EST


On Tue, 2018-05-08 at 13:57 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> The multiplication of 100000 * cfg80211_calculate_bitrate() is a 32 bit
> operation and can overflow if cfg80211_calculate_bitrate is greater
> than 42949. Although I don't believe this is occurring at present, it
> would be safer to avoid the potential overflow by making the constant
> 100000 an ULL to ensure a 64 multiplication occurs.

Yeah it can't happen since mac80211 doesn't support 60 GHz devices, and
all others are limited to less than than.

Still, applied.

johannes