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authorJohannes Berg <johannes.berg@intel.com>2014-07-30 14:55:26 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-10-05 13:41:10 -0700
commitaaf5b838f37899e41a7f3efcde0bda9ac3363c3c (patch)
tree0830dd63c7eefa3ecc91ac258ef020331a4981bd /net
parentde65ff5b13c766494c6a85c679e82377cf1bea9d (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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-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 6668daf69326..d702af40ddea 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6978,6 +6978,9 @@ void __cfg80211_send_event_skb(struct sk_buff *skb, gfp_t gfp)
struct nlattr *data = ((void **)skb->cb)[2];
enum nl80211_multicast_groups mcgrp = NL80211_MCGRP_TESTMODE;
+ /* 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);
@@ -9300,6 +9303,9 @@ int cfg80211_vendor_cmd_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->cur_cmd_info)) {
kfree_skb(skb);
return -EINVAL;