Patch "cfg80211: limit scan results cache size" has been added to the 4.4-stable tree

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

cfg80211: limit scan results cache size

to the 4.4-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:
cfg80211-limit-scan-results-cache-size.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Johannes Berg <[email protected]>
Date: Tue, 15 Nov 2016 12:05:11 +0100
Subject: cfg80211: limit scan results cache size

From: Johannes Berg <[email protected]>

commit 9853a55ef1bb66d7411136046060bbfb69c714fa upstream.

It's possible to make scanning consume almost arbitrary amounts of memory, e.g. by sending beacon frames with random BSSIDs at high rates while somebody is scanning.

Limit the number of BSS table entries we're willing to cache to 1000, limiting maximum memory usage to maybe 4-5MB, but lower in practice - that would be the case for having both full-sized beacon and probe response frames for each entry; this seems not possible in practice, so a limit of 1000 entries will likely be closer to 0.5 MB.

---
 net/wireless/core.h |    1 
 net/wireless/scan.c |   69 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

@@ -72,6 +72,7 @@ struct cfg80211_registered_device {
 	struct list_head bss_list;
 	struct rb_root bss_tree;
 	u32 bss_generation;
+	u32 bss_entries;
 	struct cfg80211_scan_request *scan_req; /* protected by RTNL */
 	struct sk_buff *scan_msg;
 	struct cfg80211_sched_scan_request __rcu *sched_scan_req;

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/cfg80211-limit-scan-results-cache-size.patch