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, 87 insertions, 0 deletions

diff --git a/drivers/pps/clients/pps-ktimer.c b/drivers/pps/clients/pps-ktimer.c
new file mode 100644
index 000000000..121bd29d8
--- /dev/null
+++ b/drivers/pps/clients/pps-ktimer.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * pps-ktimer.c -- kernel timer test client
+ *
+ * Copyright (C) 2005-2006   Rodolfo Giometti <giometti@linux.it>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/timer.h>
+#include <linux/pps_kernel.h>
+
+/*
+ * Global variables
+ */
+
+static struct pps_device *pps;
+static struct timer_list ktimer;
+
+/*
+ * The kernel timer
+ */
+
+static void pps_ktimer_event(struct timer_list *unused)
+{
+	struct pps_event_time ts;
+
+	/* First of all we get the time stamp... */
+	pps_get_ts(&ts);
+
+	pps_event(pps, &ts, PPS_CAPTUREASSERT, NULL);
+
+	mod_timer(&ktimer, jiffies + HZ);
+}
+
+/*
+ * The PPS info struct
+ */
+
+static struct pps_source_info pps_ktimer_info = {
+	.name		= "ktimer",
+	.path		= "",
+	.mode		= PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
+			  PPS_ECHOASSERT |
+			  PPS_CANWAIT | PPS_TSFMT_TSPEC,
+	.owner		= THIS_MODULE,
+};
+
+/*
+ * Module staff
+ */
+
+static void __exit pps_ktimer_exit(void)
+{
+	dev_dbg(&pps->dev, "ktimer PPS source unregistered\n");
+
+	timer_delete_sync(&ktimer);
+	pps_unregister_source(pps);
+}
+
+static int __init pps_ktimer_init(void)
+{
+	pps = pps_register_source(&pps_ktimer_info,
+				PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
+	if (IS_ERR(pps)) {
+		pr_err("cannot register PPS source\n");
+		return PTR_ERR(pps);
+	}
+
+	timer_setup(&ktimer, pps_ktimer_event, 0);
+	mod_timer(&ktimer, jiffies + HZ);
+
+	dev_dbg(&pps->dev, "ktimer PPS source registered\n");
+
+	return 0;
+}
+
+module_init(pps_ktimer_init);
+module_exit(pps_ktimer_exit);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("dummy PPS source by using a kernel timer (just for debug)");
+MODULE_LICENSE("GPL");