On Tue, 2020-12-01 at 17:26 +0530, Anant Thazhemadam wrote: > On 01/12/20 3:30 pm, Johannes Berg wrote: > > On Tue, 2020-12-01 at 15:26 +0530, Anant Thazhemadam wrote: > > > Currently, it is assumed that key_idx values that are passed to > > > ieee80211_del_key() are all valid indexes as is, and no sanity checks > > > are performed for it. > > > However, syzbot was able to trigger an array-index-out-of-bounds bug > > > by passing a key_idx value of 5, when the maximum permissible index > > > value is (NUM_DEFAULT_KEYS - 1). > > > Enforcing sanity checks helps in preventing this bug, or a similar > > > instance in the context of ieee80211_del_key() from occurring. > > I think we should do this more generally in cfg80211, like in > > nl80211_new_key() we do it via cfg80211_validate_key_settings(). > > > > I suppose we cannot use the same function, but still, would be good to > > address this generally in nl80211 for all drivers. > > Hello, > > This gave me the idea of trying to use cfg80211_validate_key_settings() > directly in ieee80211_del_key(). I did try that out, tested it, and this bug > doesn't seem to be getting triggered anymore. > If this is okay, then I can send in a v2 soon. :) > > If there is any reason that I'm missing as to why cfg80211_validate_key_settings() > cannot be used in this context, please let me know. If it works then I guess that's OK. I thought we didn't have all the right information, e.g. whether a key is pairwise or not? johannes
