From: Adrien Schildknecht Date: Tue, 28 Jul 2015 08:30:16 +0000 (+0200) Subject: mac80211: fix invalid read in minstrel_sort_best_tp_rates() X-Git-Tag: firefly_0821_release~176^2~1254^2~6^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f5eeb5fa191fd7b634cbc4883ac58f3b2184dbc5;p=firefly-linux-kernel-4.4.55.git mac80211: fix invalid read in minstrel_sort_best_tp_rates() At the last iteration of the loop, j may equal zero and thus tp_list[j - 1] causes an invalid read. Change the logic of the loop so that j - 1 is always >= 0. Cc: stable@vger.kernel.org Signed-off-by: Adrien Schildknecht Signed-off-by: Johannes Berg --- diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c index 247552a7f6c2..3ece7d1034c8 100644 --- a/net/mac80211/rc80211_minstrel.c +++ b/net/mac80211/rc80211_minstrel.c @@ -92,14 +92,15 @@ int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_ewma) static inline void minstrel_sort_best_tp_rates(struct minstrel_sta_info *mi, int i, u8 *tp_list) { - int j = MAX_THR_RATES; - struct minstrel_rate_stats *tmp_mrs = &mi->r[j - 1].stats; + int j; + struct minstrel_rate_stats *tmp_mrs; struct minstrel_rate_stats *cur_mrs = &mi->r[i].stats; - while (j > 0 && (minstrel_get_tp_avg(&mi->r[i], cur_mrs->prob_ewma) > - minstrel_get_tp_avg(&mi->r[tp_list[j - 1]], tmp_mrs->prob_ewma))) { - j--; + for (j = MAX_THR_RATES; j > 0; --j) { tmp_mrs = &mi->r[tp_list[j - 1]].stats; + if (minstrel_get_tp_avg(&mi->r[i], cur_mrs->prob_ewma) <= + minstrel_get_tp_avg(&mi->r[tp_list[j - 1]], tmp_mrs->prob_ewma)) + break; } if (j < MAX_THR_RATES - 1)