staging: rtl8723bs: fix OOB read in rtw_action_frame_parse()grafted

rtw_action_frame_parse() takes a frame_len parameter but never
actually checks it before indexing into the frame body:

	const u8 *frame_body = frame + sizeof(struct ieee80211_hdr_3addr);
	...
	c = frame_body[0];
	...
	a = frame_body[1];

frame_body already points 24 bytes (sizeof(struct
ieee80211_hdr_3addr)) into frame, so reading frame_body[0] and
frame_body[1] requires frame_len >= 26. A management action frame
shorter than that (e.g. exactly 24 bytes, the minimum a malicious
peer can send) causes a 1-2 byte out-of-bounds read.

This is reachable from rtw_cfg80211_monitor_if_xmit_entry() and
cfg80211_rtw_mgmt_tx() in ioctl_cfg80211.c, both of which pass
attacker/user-influenced frame buffers and lengths straight through.

Add the missing length check before frame_body is dereferenced.

Fixes: 554c0a3abf216 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
Link: https://patch.msgid.link/20260728125456.32359-3-meatuni001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 27 insertions, 0 deletions

diff --git a/include/net/firewire.h b/include/net/firewire.h
new file mode 100644
index 000000000..8fbff8d77
--- /dev/null
+++ b/include/net/firewire.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_FIREWIRE_H
+#define _NET_FIREWIRE_H
+
+#include <linux/types.h>
+
+/* Pseudo L2 address */
+#define FWNET_ALEN	16
+union fwnet_hwaddr {
+	u8 u[FWNET_ALEN];
+	/* "Hardware address" defined in RFC2734/RF3146 */
+	struct {
+		__be64 uniq_id;		/* EUI-64			*/
+		u8 max_rec;		/* max packet size		*/
+		u8 sspd;		/* max speed			*/
+		u8 fifo[6];		/* FIFO addr			*/
+	} __packed uc;
+};
+
+/* Pseudo L2 Header */
+#define FWNET_HLEN	18
+struct fwnet_header {
+	u8 h_dest[FWNET_ALEN];	/* destination address */
+	__be16 h_proto;		/* packet type ID field */
+} __packed;
+
+#endif