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, 43 insertions, 0 deletions

diff --git a/include/trace/events/mdio.h b/include/trace/events/mdio.h
new file mode 100644
index 000000000..285b3e4f8
--- /dev/null
+++ b/include/trace/events/mdio.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM mdio
+
+#if !defined(_TRACE_MDIO_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_MDIO_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT_CONDITION(mdio_access,
+
+	TP_PROTO(struct mii_bus *bus, char read,
+		 u8 addr, unsigned regnum, u16 val, int err),
+
+	TP_ARGS(bus, read, addr, regnum, val, err),
+
+	TP_CONDITION(err >= 0),
+
+	TP_STRUCT__entry(
+		__array(char, busid, MII_BUS_ID_SIZE)
+		__field(char, read)
+		__field(u8, addr)
+		__field(u16, val)
+		__field(unsigned, regnum)
+	),
+
+	TP_fast_assign(
+		strscpy(__entry->busid, bus->id, MII_BUS_ID_SIZE);
+		__entry->read = read;
+		__entry->addr = addr;
+		__entry->regnum = regnum;
+		__entry->val = val;
+	),
+
+	TP_printk("%s %-5s phy:0x%02hhx reg:0x%02x val:0x%04hx",
+		  __entry->busid, __entry->read ? "read" : "write",
+		  __entry->addr, __entry->regnum, __entry->val)
+);
+
+#endif /* if !defined(_TRACE_MDIO_H) || defined(TRACE_HEADER_MULTI_READ) */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>