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, 163 insertions, 0 deletions

diff --git a/drivers/input/input-compat.c b/drivers/input/input-compat.c
new file mode 100644
index 000000000..a5043193e
--- /dev/null
+++ b/drivers/input/input-compat.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 32bit compatibility wrappers for the input subsystem.
+ *
+ * Very heavily based on evdev.c - Copyright (c) 1999-2002 Vojtech Pavlik
+ */
+
+#include <linux/export.h>
+#include <linux/sprintf.h>
+#include <linux/uaccess.h>
+#include "input-compat.h"
+
+#ifdef CONFIG_COMPAT
+
+int input_event_from_user(const char __user *buffer,
+			  struct input_event *event)
+{
+	if (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) {
+		struct input_event_compat compat_event;
+
+		if (copy_from_user(&compat_event, buffer,
+				   sizeof(struct input_event_compat)))
+			return -EFAULT;
+
+		event->input_event_sec = compat_event.sec;
+		event->input_event_usec = compat_event.usec;
+		event->type = compat_event.type;
+		event->code = compat_event.code;
+		event->value = compat_event.value;
+
+	} else {
+		if (copy_from_user(event, buffer, sizeof(struct input_event)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+int input_event_to_user(char __user *buffer,
+			const struct input_event *event)
+{
+	if (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) {
+		struct input_event_compat compat_event;
+
+		compat_event.sec = event->input_event_sec;
+		compat_event.usec = event->input_event_usec;
+		compat_event.type = event->type;
+		compat_event.code = event->code;
+		compat_event.value = event->value;
+
+		if (copy_to_user(buffer, &compat_event,
+				 sizeof(struct input_event_compat)))
+			return -EFAULT;
+
+	} else {
+		if (copy_to_user(buffer, event, sizeof(struct input_event)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+int input_ff_effect_from_user(const char __user *buffer, size_t size,
+			      struct ff_effect *effect)
+{
+	if (in_compat_syscall()) {
+		struct ff_effect_compat *compat_effect;
+
+		if (size != sizeof(struct ff_effect_compat))
+			return -EINVAL;
+
+		/*
+		 * It so happens that the pointer which needs to be changed
+		 * is the last field in the structure, so we can retrieve the
+		 * whole thing and replace just the pointer.
+		 */
+		compat_effect = (struct ff_effect_compat *)effect;
+
+		if (copy_from_user(compat_effect, buffer,
+				   sizeof(struct ff_effect_compat)))
+			return -EFAULT;
+
+		if (compat_effect->type == FF_PERIODIC &&
+		    compat_effect->u.periodic.waveform == FF_CUSTOM)
+			effect->u.periodic.custom_data =
+				compat_ptr(compat_effect->u.periodic.custom_data);
+	} else {
+		if (size != sizeof(struct ff_effect))
+			return -EINVAL;
+
+		if (copy_from_user(effect, buffer, sizeof(struct ff_effect)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+int input_bits_to_string(char *buf, int buf_size, unsigned long bits,
+			 bool skip_empty)
+{
+	int len = 0;
+
+	if (in_compat_syscall()) {
+		u32 dword = bits >> 32;
+		if (dword || !skip_empty)
+			len += snprintf(buf, buf_size, "%x ", dword);
+
+		dword = bits & 0xffffffffUL;
+		if (dword || !skip_empty || len)
+			len += snprintf(buf + len, max(buf_size - len, 0),
+					"%x", dword);
+	} else {
+		if (bits || !skip_empty)
+			len += snprintf(buf, buf_size, "%lx", bits);
+	}
+
+	return len;
+}
+
+#else
+
+int input_event_from_user(const char __user *buffer,
+			 struct input_event *event)
+{
+	if (copy_from_user(event, buffer, sizeof(struct input_event)))
+		return -EFAULT;
+
+	return 0;
+}
+
+int input_event_to_user(char __user *buffer,
+			const struct input_event *event)
+{
+	if (copy_to_user(buffer, event, sizeof(struct input_event)))
+		return -EFAULT;
+
+	return 0;
+}
+
+int input_ff_effect_from_user(const char __user *buffer, size_t size,
+			      struct ff_effect *effect)
+{
+	if (size != sizeof(struct ff_effect))
+		return -EINVAL;
+
+	if (copy_from_user(effect, buffer, sizeof(struct ff_effect)))
+		return -EFAULT;
+
+	return 0;
+}
+
+int input_bits_to_string(char *buf, int buf_size, unsigned long bits,
+			 bool skip_empty)
+{
+	return bits || !skip_empty ?
+		snprintf(buf, buf_size, "%lx", bits) : 0;
+}
+
+#endif /* CONFIG_COMPAT */
+
+EXPORT_SYMBOL_GPL(input_event_from_user);
+EXPORT_SYMBOL_GPL(input_event_to_user);
+EXPORT_SYMBOL_GPL(input_ff_effect_from_user);