mac80211: fix a crash bug in minstrel_ht

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
SVN-Revision: 43298

diff --git a/package/kernel/mac80211/patches/319-mac80211-minstrel_ht-fix-a-crash-in-rate-sorting.patch b/package/kernel/mac80211/patches/319-mac80211-minstrel_ht-fix-a-crash-in-rate-sorting.patch
new file mode 100644 (file)
index 0000000..784a973
--- /dev/null
+++ b/package/kernel/mac80211/patches/319-mac80211-minstrel_ht-fix-a-crash-in-rate-sorting.patch
@@ -0,0 +1,47 @@
+From: Felix Fietkau <nbd@openwrt.org>
+Date: Tue, 18 Nov 2014 21:43:25 +0100
+Subject: [PATCH] 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>
+---
+
+--- a/net/mac80211/rc80211_minstrel_ht.c
++++ b/net/mac80211/rc80211_minstrel_ht.c
+@@ -394,19 +394,16 @@ minstrel_ht_sort_best_tp_rates(struct mi
+       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) *