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authorJohannes Berg <johannes.berg@intel.com>2014-07-30 14:55:26 +0200
committerBen Hutchings <ben@decadent.org.uk>2014-11-05 20:27:44 +0000
commita93db944b6250d4345ed30095001f8bee5ecaed7 (patch)
treed67f0617c259b84ddec65cb9ce7e225e99abfaaf
parentb2d0a271e3785900eaef4d02d0c7c86a01a9f25b (diff)
nl80211: clear skb cb before passing to netlink
commit bd8c78e78d5011d8111bc2533ee73b13a3bd6c42 upstream. In testmode and vendor command reply/event SKBs we use the skb cb data to store nl80211 parameters between allocation and sending. This causes the code for CONFIG_NETLINK_MMAP to get confused, because it takes ownership of the skb cb data when the SKB is handed off to netlink, and it doesn't explicitly clear it. Clear the skb cb explicitly when we're done and before it gets passed to netlink to avoid this issue. Reported-by: Assaf Azulay <assaf.azulay@intel.com> Reported-by: David Spinadel <david.spinadel@intel.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r--net/wireless/nl80211.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 6d4d26321028..cdf77a261509 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4804,6 +4804,9 @@ int cfg80211_testmode_reply(struct sk_buff *skb)
void *hdr = ((void **)skb->cb)[1];
struct nlattr *data = ((void **)skb->cb)[2];
+ /* clear CB data for netlink core to own from now on */
+ memset(skb->cb, 0, sizeof(skb->cb));
+
if (WARN_ON(!rdev->testmode_info)) {
kfree_skb(skb);
return -EINVAL;
@@ -4830,6 +4833,9 @@ void cfg80211_testmode_event(struct sk_buff *skb, gfp_t gfp)
void *hdr = ((void **)skb->cb)[1];
struct nlattr *data = ((void **)skb->cb)[2];
+ /* clear CB data for netlink core to own from now on */
+ memset(skb->cb, 0, sizeof(skb->cb));
+
nla_nest_end(skb, data);
genlmsg_end(skb, hdr);
genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), skb, 0,