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authorJohannes Berg <johannes.berg@intel.com>2011-11-08 12:28:33 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-11-26 09:08:34 -0800
commit4a4d69f0ec7cf7afdcc4346cf6bc8d3835358df8 (patch)
tree2bd83f50c99ce7a66a996c8f6e81291c31011d9a /net
parent7aa8983f0b2c57c25de227909072fe4f8edaa9ad (diff)
downloadlwn-4a4d69f0ec7cf7afdcc4346cf6bc8d3835358df8.tar.gz
lwn-4a4d69f0ec7cf7afdcc4346cf6bc8d3835358df8.zip
mac80211: fix NULL dereference in radiotap code
commit f8d1ccf15568268c76f913b45ecdd33134387f1a upstream. When receiving failed PLCP frames is enabled, there won't be a rate pointer when we add the radiotap header and thus the kernel will crash. Fix this by not assuming the rate pointer is always valid. It's still always valid for frames that have good PLCP though, and that is checked & enforced. This was broken by my commit fc88518916793af8ad6a02e05ff254d95c36d875 Author: Johannes Berg <johannes.berg@intel.com> Date: Fri Jul 30 13:23:12 2010 +0200 mac80211: don't check rates on PLCP error frames where I removed the check in this case but didn't take into account that the rate info would be used. Reported-by: Xiaokang Qin <xiaokang.qin@intel.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'net')
-rw-r--r--net/mac80211/rx.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index fe2c2a717793..a961003ffa28 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -140,8 +140,9 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
pos++;
/* IEEE80211_RADIOTAP_RATE */
- if (status->flag & RX_FLAG_HT) {
+ if (!rate || status->flag & RX_FLAG_HT) {
/*
+ * Without rate information don't add it. If we have,
* MCS information is a separate field in radiotap,
* added below. The byte here is needed as padding
* for the channel though, so initialise it to 0.
@@ -162,12 +163,14 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
else if (status->flag & RX_FLAG_HT)
put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
pos);
- else if (rate->flags & IEEE80211_RATE_ERP_G)
+ else if (rate && rate->flags & IEEE80211_RATE_ERP_G)
put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
pos);
- else
+ else if (rate)
put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
pos);
+ else
+ put_unaligned_le16(IEEE80211_CHAN_2GHZ, pos);
pos += 2;
/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */