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, 18 insertions, 0 deletions

diff --git a/drivers/net/arcnet/com9026.h b/drivers/net/arcnet/com9026.h
new file mode 100644
index 000000000..6adbc1871
--- /dev/null
+++ b/drivers/net/arcnet/com9026.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __COM9026_H
+#define __COM9026_H
+
+/* COM 9026 controller chip --> ARCnet register addresses */
+
+#define COM9026_REG_W_INTMASK	0	/* writable */
+#define COM9026_REG_R_STATUS	0	/* readable */
+#define COM9026_REG_W_COMMAND	1	/* writable, returns random vals on read (?) */
+#define COM9026_REG_RW_CONFIG	2	/* Configuration register */
+#define COM9026_REG_R_RESET	8	/* software reset (on read) */
+#define COM9026_REG_RW_MEMDATA	12	/* Data port for IO-mapped memory */
+#define COM9026_REG_W_ADDR_LO	14	/* Control registers for said */
+#define COM9026_REG_W_ADDR_HI	15
+
+#define COM9026_REG_R_STATION	1	/* Station ID */
+
+#endif