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, 62 insertions, 0 deletions

diff --git a/drivers/accessibility/speakup/thread.c b/drivers/accessibility/speakup/thread.c
new file mode 100644
index 000000000..2fc75e60f
--- /dev/null
+++ b/drivers/accessibility/speakup/thread.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kthread.h>
+#include <linux/wait.h>
+
+#include "spk_types.h"
+#include "speakup.h"
+#include "spk_priv.h"
+
+DECLARE_WAIT_QUEUE_HEAD(speakup_event);
+EXPORT_SYMBOL_GPL(speakup_event);
+
+int speakup_thread(void *data)
+{
+	unsigned long flags;
+	int should_break;
+	struct bleep our_sound;
+
+	our_sound.active = 0;
+	our_sound.freq = 0;
+	our_sound.jiffies = 0;
+
+	mutex_lock(&spk_mutex);
+	while (1) {
+		DEFINE_WAIT(wait);
+
+		while (1) {
+			spin_lock_irqsave(&speakup_info.spinlock, flags);
+			our_sound = spk_unprocessed_sound;
+			spk_unprocessed_sound.active = 0;
+			prepare_to_wait(&speakup_event, &wait,
+					TASK_INTERRUPTIBLE);
+			should_break = kthread_should_stop() ||
+				our_sound.active ||
+				(synth && synth->catch_up && synth->alive &&
+					(speakup_info.flushing ||
+					!synth_buffer_empty()));
+			spin_unlock_irqrestore(&speakup_info.spinlock, flags);
+			if (should_break)
+				break;
+			mutex_unlock(&spk_mutex);
+			schedule();
+			mutex_lock(&spk_mutex);
+		}
+		finish_wait(&speakup_event, &wait);
+		if (kthread_should_stop())
+			break;
+
+		if (our_sound.active)
+			kd_mksound(our_sound.freq, our_sound.jiffies);
+		if (synth && synth->catch_up && synth->alive) {
+			/*
+			 * It is up to the callee to take the lock, so that it
+			 * can sleep whenever it likes
+			 */
+			synth->catch_up(synth);
+		}
+
+		speakup_start_ttys();
+	}
+	mutex_unlock(&spk_mutex);
+	return 0;
+}