Patch "mac80211: fix invalid read in minstrel_sort_best_tp_rates()" has been added to the 4.1-stable tree

Patch "mac80211: fix invalid read in minstrel_sort_best_tp_rates()" has been added to the 4.1-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    mac80211: fix invalid read in minstrel_sort_best_tp_rates()

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mac80211-fix-invalid-read-in-minstrel_sort_best_tp_rates.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From f5eeb5fa191fd7b634cbc4883ac58f3b2184dbc5 Mon Sep 17 00:00:00 2001
From: Adrien Schildknecht <adrien+dev@schischi.me>
Date: Tue, 28 Jul 2015 10:30:16 +0200
Subject: mac80211: fix invalid read in minstrel_sort_best_tp_rates()

From: Adrien Schildknecht <adrien+dev@schischi.me>

commit f5eeb5fa191fd7b634cbc4883ac58f3b2184dbc5 upstream.

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.

Signed-off-by: Adrien Schildknecht <adrien+dev@schischi.me>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/mac80211/rc80211_minstrel.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -92,14 +92,15 @@ int minstrel_get_tp_avg(struct minstrel_
 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)


Patches currently in stable-queue which might be from adrien+dev@schischi.me are

queue-4.1/mac80211-fix-invalid-read-in-minstrel_sort_best_tp_rates.patch