From 2e613ff8d8221da89904473a8136ee29efeca6f0 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 3 Nov 2014 13:57:46 +0100 Subject: mac80211: fix use-after-free in defragmentation commit b8fff407a180286aa683d543d878d98d9fc57b13 upstream. Upon receiving the last fragment, all but the first fragment are freed, but the multicast check for statistics at the end of the function refers to the current skb (the last fragment) causing a use-after-free bug. Since multicast frames cannot be fragmented and we check for this early in the function, just modify that check to also do the accounting to fix the issue. Reported-by: Yosef Khyal Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/mac80211/rx.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'net') diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index fae73b0ef14b..85bc6d498b46 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1585,11 +1585,14 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) sc = le16_to_cpu(hdr->seq_ctrl); frag = sc & IEEE80211_SCTL_FRAG; - if (likely((!ieee80211_has_morefrags(fc) && frag == 0) || - is_multicast_ether_addr(hdr->addr1))) { - /* not fragmented */ + if (likely(!ieee80211_has_morefrags(fc) && frag == 0)) + goto out; + + if (is_multicast_ether_addr(hdr->addr1)) { + rx->local->dot11MulticastReceivedFrameCount++; goto out; } + I802_DEBUG_INC(rx->local->rx_handlers_fragments); if (skb_linearize(rx->skb)) @@ -1682,10 +1685,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) out: if (rx->sta) rx->sta->rx_packets++; - if (is_multicast_ether_addr(hdr->addr1)) - rx->local->dot11MulticastReceivedFrameCount++; - else - ieee80211_led_rx(rx->local); + ieee80211_led_rx(rx->local); return RX_CONTINUE; } -- cgit v1.2.3