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authorJohannes Berg <johannes.berg@intel.com>2011-11-08 12:28:33 +0100
committerJohn W. Linville <linville@tuxdriver.com>2011-11-09 14:35:55 -0500
commitf8d1ccf15568268c76f913b45ecdd33134387f1a (patch)
tree01f25eb79f2022441bde6235958f36562b4bf9b2 /net
parentcc438fccd5783c9f7b4c4858358ac897dcf8a58d (diff)
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mac80211: fix NULL dereference in radiotap code
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> Cc: stable@vger.kernel.org Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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 b867bd55de7..097b42d286e 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 */