On Mittwoch, 6. Juni 2018 17:35:29 CEST Sven Eckelmann wrote:
Most of the implementations behind cfg80211_get_station will not initialize sinfo to zero before manipulating it. For example, the member "filled", which indicates the filled in parts of this struct, is often only modified by enabling certain bits in the bitfield while keeping the remaining bits in their original state. A caller without a preinitialized sinfo.filled can then no longer decide which parts of sinfo were filled in by cfg80211_get_station (or actually the underlying implementations).
cfg80211_get_station must therefore take care that sinfo is initialized to zero. Otherwise, the caller may tries to read information which was not filled in and which must therefore also be considered uninitialized. In batadv_v_elp_get_throughput's case, an invalid "random" expected throughput may be stored for this neighbor and thus the B.A.T.M.A.N V algorithm may switch to non-optimal neighbors for certain destinations.
batman-adv's compat layer must take care of intializing sinfo until it is fixed in the upstream kernel.
Fixes: 7406353d43c8 ("cfg80211: implement cfg80211_get_station cfg80211 API") Reported-by: Thomas Lauer firstname.lastname@example.org Reported-by: Marcel Schmidt email@example.com Signed-off-by: Sven Eckelmann firstname.lastname@example.org
compat-include/net/cfg80211.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
Added as d7280ffad5e9 
Kind regards, Sven