From a66b98db570a638afd909459e1e6bfa272344bd3 Mon Sep 17 00:00:00 2001 From: Arik Nemtsov Date: Thu, 23 Jun 2011 00:00:24 +0300 Subject: [PATCH] mac80211: fix rx->key NULL dereference during mic failure Sometimes when reporting a MIC failure rx->key may be unset. This code path is hit when receiving a packet meant for a multicast address, and decryption is performed in HW. Fortunately, the failing key_idx is not used for anything up to (and including) usermode, so we allow ourselves to drop it on the way up when a key cannot be retrieved. Signed-off-by: Arik Nemtsov Cc: stable@kernel.org Signed-off-by: John W. Linville --- include/net/cfg80211.h | 2 +- net/mac80211/wpa.c | 8 +++++++- net/wireless/nl80211.c | 3 ++- 3 files changed, 10 insertions(+), 3 deletions(-) diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index 0589f554788a..396e8fc8910e 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -2688,7 +2688,7 @@ void cfg80211_send_unprot_disassoc(struct net_device *dev, const u8 *buf, * @dev: network device * @addr: The source MAC address of the frame * @key_type: The key type that the received frame used - * @key_id: Key identifier (0..3) + * @key_id: Key identifier (0..3). Can be -1 if missing. * @tsc: The TSC value of the frame that generated the MIC failure (6 octets) * @gfp: allocation flags * diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index 9dc3b5f26e80..d91c1a26630d 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -154,7 +154,13 @@ update_iv: return RX_CONTINUE; mic_fail: - mac80211_ev_michael_mic_failure(rx->sdata, rx->key->conf.keyidx, + /* + * In some cases the key can be unset - e.g. a multicast packet, in + * a driver that supports HW encryption. Send up the key idx only if + * the key is set. + */ + mac80211_ev_michael_mic_failure(rx->sdata, + rx->key ? rx->key->conf.keyidx : -1, (void *) skb->data, NULL, GFP_ATOMIC); return RX_DROP_UNUSABLE; } diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 98fa8eb6cc4b..f07602d7bf68 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -6463,7 +6463,8 @@ void nl80211_michael_mic_failure(struct cfg80211_registered_device *rdev, if (addr) NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, addr); NLA_PUT_U32(msg, NL80211_ATTR_KEY_TYPE, key_type); - NLA_PUT_U8(msg, NL80211_ATTR_KEY_IDX, key_id); + if (key_id != -1) + NLA_PUT_U8(msg, NL80211_ATTR_KEY_IDX, key_id); if (tsc) NLA_PUT(msg, NL80211_ATTR_KEY_SEQ, 6, tsc); -- 2.20.1