[PATCH 6.1 573/609] staging: rtl8723bs: validate monitor transmit frame lengths

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mariano Baragiola <[email protected]>

commit 6829665d050983907b560173e49dcc6c11cb2730 upstream.

rtw_cfg80211_monitor_if_xmit_entry() removes the radiotap header and
then reads the 802.11 frame control field without checking that a base
802.11 header remains.

The data path also pulls the calculated 802.11, QoS and SNAP header
span before confirming that the skb contains it. A truncated frame can
therefore cause out-of-bounds reads or leave insufficient data for the
Ethernet address writes.

Reject frames that do not contain the base 802.11 header and data
frames that do not contain their complete calculated header span.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable <[email protected]>
Signed-off-by: Mariano Baragiola <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
+++ b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
@@ -2075,6 +2075,8 @@ static netdev_tx_t rtw_cfg80211_monitor_
 
 	/* Skip the ratio tap header */
 	skb_pull(skb, rtap_len);
+	if (skb->len < dot11_hdr_len)
+		goto fail;
 
 	dot11_hdr = (struct ieee80211_hdr *)skb->data;
 	frame_control = le16_to_cpu(dot11_hdr->frame_control);
@@ -2087,6 +2089,8 @@ static netdev_tx_t rtw_cfg80211_monitor_
 			qos_len = 2;
 		if ((frame_control & 0x0300) == 0x0300)
 			dot11_hdr_len += 6;
+		if (skb->len < dot11_hdr_len + qos_len + snap_len)
+			goto fail;
 
 		memcpy(dst_mac_addr, dot11_hdr->addr1, sizeof(dst_mac_addr));
 		memcpy(src_mac_addr, dot11_hdr->addr2, sizeof(src_mac_addr));