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, 81 insertions, 0 deletions

diff --git a/drivers/input/input-compat.h b/drivers/input/input-compat.h
new file mode 100644
index 000000000..99c87ceb9
--- /dev/null
+++ b/drivers/input/input-compat.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _INPUT_COMPAT_H
+#define _INPUT_COMPAT_H
+
+/*
+ * 32bit compatibility wrappers for the input subsystem.
+ *
+ * Very heavily based on evdev.c - Copyright (c) 1999-2002 Vojtech Pavlik
+ */
+
+#include <linux/compiler.h>
+#include <linux/compat.h>
+#include <linux/input.h>
+
+#ifdef CONFIG_COMPAT
+
+struct input_event_compat {
+	compat_ulong_t sec;
+	compat_ulong_t usec;
+	__u16 type;
+	__u16 code;
+	__s32 value;
+};
+
+struct ff_periodic_effect_compat {
+	__u16 waveform;
+	__u16 period;
+	__s16 magnitude;
+	__s16 offset;
+	__u16 phase;
+
+	struct ff_envelope envelope;
+
+	__u32 custom_len;
+	compat_uptr_t custom_data;
+};
+
+struct ff_effect_compat {
+	__u16 type;
+	__s16 id;
+	__u16 direction;
+	struct ff_trigger trigger;
+	struct ff_replay replay;
+
+	union {
+		struct ff_constant_effect constant;
+		struct ff_ramp_effect ramp;
+		struct ff_periodic_effect_compat periodic;
+		struct ff_condition_effect condition[2]; /* One for each axis */
+		struct ff_rumble_effect rumble;
+	} u;
+};
+
+static inline size_t input_event_size(void)
+{
+	return (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) ?
+		sizeof(struct input_event_compat) : sizeof(struct input_event);
+}
+
+#else
+
+static inline size_t input_event_size(void)
+{
+	return sizeof(struct input_event);
+}
+
+#endif /* CONFIG_COMPAT */
+
+int input_event_from_user(const char __user *buffer,
+			 struct input_event *event);
+
+int input_event_to_user(char __user *buffer,
+			const struct input_event *event);
+
+int input_ff_effect_from_user(const char __user *buffer, size_t size,
+			      struct ff_effect *effect);
+
+int input_bits_to_string(char *buf, int buf_size, unsigned long bits,
+                         bool skip_empty);
+
+#endif /* _INPUT_COMPAT_H */