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authorFelix Fietkau <nbd@openwrt.org>2014-11-18 22:35:31 +0100
committerJohannes Berg <johannes.berg@intel.com>2014-11-18 22:39:16 +0100
commit280ba51d60be6f4ca3347eaa60783314f38df72e (patch)
tree4b6f66ce8187b59e755f02f14ffd5d488b6084df /net
parent4f031fa9f188b2b0641ac20087d9e16bcfb4e49d (diff)
mac80211: minstrel_ht: fix a crash in rate sorting
The commit 5935839ad73583781b8bbe8d91412f6826e218a4 "mac80211: improve minstrel_ht rate sorting by throughput & probability" introduced a crash on rate sorting that occurs when the rate added to the sorting array is faster than all the previous rates. Due to an off-by-one error, it reads the rate index from tp_list[-1], which contains uninitialized stack garbage, and then uses the resulting index for accessing the group rate stats, leading to a crash if the garbage value is big enough. Cc: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Reported-by: Jouni Malinen <j@w1.fi> Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net')
-rw-r--r--net/mac80211/rc80211_minstrel_ht.c15
1 files changed, 6 insertions, 9 deletions
diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index df90ce2db00..408fd8ab4ee 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -252,19 +252,16 @@ minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u8 index,
cur_thr = mi->groups[cur_group].rates[cur_idx].cur_tp;
cur_prob = mi->groups[cur_group].rates[cur_idx].probability;
- tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
- tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
- tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
- tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
-
- while (j > 0 && (cur_thr > tmp_thr ||
- (cur_thr == tmp_thr && cur_prob > tmp_prob))) {
- j--;
+ do {
tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
- }
+ if (cur_thr < tmp_thr ||
+ (cur_thr == tmp_thr && cur_prob <= tmp_prob))
+ break;
+ j--;
+ } while (j > 0);
if (j < MAX_THR_RATES - 1) {
memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *