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. Thanks, Anant
