From e2fe154e918276e900067a9d1d3a6a963faee041 Mon Sep 17 00:00:00 2001 From: Christian Lamparter Date: Tue, 20 Jan 2009 00:27:57 +0100 Subject: [PATCH] p54usb: fix nasty use after free In theory, the firmware acks the received a data frame, before signaling the driver to free it again. However Artur Skawina has shown that it can happen in reverse order as well. This is very bad and could lead to memory corruptions, oopses and panics. Thanks to Artur Skawina for reporting and debugging this issue. Signed-off-by: Christian Lamparter Tested-by: Artur Skawina Signed-off-by: John W. Linville --- drivers/net/wireless/p54/p54usb.c | 34 +++++++++++++--------------------- 1 file changed, 13 insertions(+), 21 deletions(-) diff --git a/drivers/net/wireless/p54/p54usb.c b/drivers/net/wireless/p54/p54usb.c index 6a6a72f..4487cc5 100644 --- a/drivers/net/wireless/p54/p54usb.c +++ b/drivers/net/wireless/p54/p54usb.c @@ -144,11 +144,8 @@ static void p54u_tx_cb(struct urb *urb) struct sk_buff *skb = urb->context; struct ieee80211_hw *dev = (struct ieee80211_hw *) usb_get_intfdata(usb_ifnum_to_if(urb->dev, 0)); - struct p54u_priv *priv = dev->priv; - skb_pull(skb, priv->common.tx_hdr_len); - if (FREE_AFTER_TX(skb)) - p54_free_skb(dev, skb); + p54_free_skb(dev, skb); } static void p54u_tx_dummy_cb(struct urb *urb) { } @@ -230,7 +227,8 @@ static void p54u_tx_3887(struct ieee80211_hw *dev, struct sk_buff *skb) p54u_tx_dummy_cb, dev); usb_fill_bulk_urb(data_urb, priv->udev, usb_sndbulkpipe(priv->udev, P54U_PIPE_DATA), - skb->data, skb->len, p54u_tx_cb, skb); + skb->data, skb->len, FREE_AFTER_TX(skb) ? + p54u_tx_cb : p54u_tx_dummy_cb, skb); usb_anchor_urb(addr_urb, &priv->submitted); err = usb_submit_urb(addr_urb, GFP_ATOMIC); @@ -269,28 +267,24 @@ static void p54u_tx_lm87(struct ieee80211_hw *dev, struct sk_buff *skb) { struct p54u_priv *priv = dev->priv; struct urb *data_urb; - struct lm87_tx_hdr *hdr; - __le32 checksum; - __le32 addr = ((struct p54_hdr *)skb->data)->req_id; + struct lm87_tx_hdr *hdr = (void *)skb->data - sizeof(*hdr); data_urb = usb_alloc_urb(0, GFP_ATOMIC); if (!data_urb) return; - checksum = p54u_lm87_chksum((__le32 *)skb->data, skb->len); - hdr = (struct lm87_tx_hdr *)skb_push(skb, sizeof(*hdr)); - hdr->chksum = checksum; - hdr->device_addr = addr; + hdr->chksum = p54u_lm87_chksum((__le32 *)skb->data, skb->len); + hdr->device_addr = ((struct p54_hdr *)skb->data)->req_id; usb_fill_bulk_urb(data_urb, priv->udev, usb_sndbulkpipe(priv->udev, P54U_PIPE_DATA), - skb->data, skb->len, p54u_tx_cb, skb); + hdr, skb->len + sizeof(*hdr), FREE_AFTER_TX(skb) ? + p54u_tx_cb : p54u_tx_dummy_cb, skb); data_urb->transfer_flags |= URB_ZERO_PACKET; usb_anchor_urb(data_urb, &priv->submitted); if (usb_submit_urb(data_urb, GFP_ATOMIC)) { usb_unanchor_urb(data_urb); - skb_pull(skb, sizeof(*hdr)); p54_free_skb(dev, skb); } usb_free_urb(data_urb); @@ -300,11 +294,9 @@ static void p54u_tx_net2280(struct ieee80211_hw *dev, struct sk_buff *skb) { struct p54u_priv *priv = dev->priv; struct urb *int_urb, *data_urb; - struct net2280_tx_hdr *hdr; + struct net2280_tx_hdr *hdr = (void *)skb->data - sizeof(*hdr); struct net2280_reg_write *reg; int err = 0; - __le32 addr = ((struct p54_hdr *) skb->data)->req_id; - __le16 len = cpu_to_le16(skb->len); reg = kmalloc(sizeof(*reg), GFP_ATOMIC); if (!reg) @@ -327,10 +319,9 @@ static void p54u_tx_net2280(struct ieee80211_hw *dev, struct sk_buff *skb) reg->addr = cpu_to_le32(P54U_DEV_BASE); reg->val = cpu_to_le32(ISL38XX_DEV_INT_DATA); - hdr = (void *)skb_push(skb, sizeof(*hdr)); memset(hdr, 0, sizeof(*hdr)); - hdr->len = len; - hdr->device_addr = addr; + hdr->len = cpu_to_le16(skb->len); + hdr->device_addr = ((struct p54_hdr *) skb->data)->req_id; usb_fill_bulk_urb(int_urb, priv->udev, usb_sndbulkpipe(priv->udev, P54U_PIPE_DEV), reg, sizeof(*reg), @@ -345,7 +336,8 @@ static void p54u_tx_net2280(struct ieee80211_hw *dev, struct sk_buff *skb) usb_fill_bulk_urb(data_urb, priv->udev, usb_sndbulkpipe(priv->udev, P54U_PIPE_DATA), - skb->data, skb->len, p54u_tx_cb, skb); + hdr, skb->len + sizeof(*hdr), FREE_AFTER_TX(skb) ? + p54u_tx_cb : p54u_tx_dummy_cb, skb); usb_anchor_urb(int_urb, &priv->submitted); err = usb_submit_urb(int_urb, GFP_ATOMIC); -- 2.7.4