From: Dan Carpenter Date: Fri, 3 May 2019 13:09:13 +0000 (+0300) Subject: mt76: mt7615: Use after free in mt7615_mcu_set_bcn() X-Git-Tag: v5.4-rc1~616^2~52^2~2^2~62 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9db1aec0c2d72a3b7b115ba56e8dbb5b46855333;p=platform%2Fkernel%2Flinux-rpi.git mt76: mt7615: Use after free in mt7615_mcu_set_bcn() We dereference "skb" when we assign: req.pkt_len = cpu_to_le16(MT_TXD_SIZE + skb->len); ^^^^^^^^ So this patch just moves the dev_kfree_skb() down a bit to avoid the use after free. Fixes: 04b8e65922f6 ("mt76: add mac80211 driver for MT7615 PCIe-based chipsets") Signed-off-by: Dan Carpenter Acked-by: Lorenzo Bianconi Signed-off-by: Felix Fietkau --- diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c index ea67c60..dc1301e 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c +++ b/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c @@ -1270,7 +1270,6 @@ int mt7615_mcu_set_bcn(struct mt7615_dev *dev, struct ieee80211_vif *vif, mt7615_mac_write_txwi(dev, (__le32 *)(req.pkt), skb, wcid, NULL, 0, NULL); memcpy(req.pkt + MT_TXD_SIZE, skb->data, skb->len); - dev_kfree_skb(skb); req.omac_idx = mvif->omac_idx; req.enable = en; @@ -1281,6 +1280,7 @@ int mt7615_mcu_set_bcn(struct mt7615_dev *dev, struct ieee80211_vif *vif, req.pkt_len = cpu_to_le16(MT_TXD_SIZE + skb->len); req.tim_ie_pos = cpu_to_le16(MT_TXD_SIZE + tim_off); + dev_kfree_skb(skb); skb = mt7615_mcu_msg_alloc(&req, sizeof(req)); return mt7615_mcu_msg_send(dev, skb, MCU_EXT_CMD_BCN_OFFLOAD,