From 9caf03640279e64d0ba36539b42daa1b43a49486 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 29 Nov 2012 01:25:20 +0100 Subject: cfg80211: fix BSS struct IE access races When a BSS struct is updated, the IEs are currently overwritten or freed. This can lead to races if some other CPU is accessing the BSS struct and using the IEs concurrently. Fix this by always allocating the IEs in a new struct that holds the data and length and protecting access to this new struct with RCU. Signed-off-by: Johannes Berg --- net/wireless/util.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'net/wireless/util.c') diff --git a/net/wireless/util.c b/net/wireless/util.c index 3cce6e486219..16d76a807c2f 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -688,10 +688,13 @@ EXPORT_SYMBOL(cfg80211_classify8021d); const u8 *ieee80211_bss_get_ie(struct cfg80211_bss *bss, u8 ie) { - if (bss->information_elements == NULL) + const struct cfg80211_bss_ies *ies; + + ies = rcu_dereference(bss->ies); + if (!ies) return NULL; - return cfg80211_find_ie(ie, bss->information_elements, - bss->len_information_elements); + + return cfg80211_find_ie(ie, ies->data, ies->len); } EXPORT_SYMBOL(ieee80211_bss_get_ie); -- cgit v1.2.1