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, 102 insertions, 0 deletions

diff --git a/drivers/mtd/chips/chipreg.c b/drivers/mtd/chips/chipreg.c
new file mode 100644
index 000000000..a05e10368
--- /dev/null
+++ b/drivers/mtd/chips/chipreg.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Registration for chip drivers
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kmod.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/mtd.h>
+
+static DEFINE_SPINLOCK(chip_drvs_lock);
+static LIST_HEAD(chip_drvs_list);
+
+void register_mtd_chip_driver(struct mtd_chip_driver *drv)
+{
+	spin_lock(&chip_drvs_lock);
+	list_add(&drv->list, &chip_drvs_list);
+	spin_unlock(&chip_drvs_lock);
+}
+
+void unregister_mtd_chip_driver(struct mtd_chip_driver *drv)
+{
+	spin_lock(&chip_drvs_lock);
+	list_del(&drv->list);
+	spin_unlock(&chip_drvs_lock);
+}
+
+static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
+{
+	struct mtd_chip_driver *ret = NULL, *this;
+
+	spin_lock(&chip_drvs_lock);
+
+	list_for_each_entry(this, &chip_drvs_list, list) {
+		if (!strcmp(this->name, name)) {
+			ret = this;
+			break;
+		}
+	}
+	if (ret && !try_module_get(ret->module))
+		ret = NULL;
+
+	spin_unlock(&chip_drvs_lock);
+
+	return ret;
+}
+
+	/* Hide all the horrid details, like some silly person taking
+	   get_module_symbol() away from us, from the caller. */
+
+struct mtd_info *do_map_probe(const char *name, struct map_info *map)
+{
+	struct mtd_chip_driver *drv;
+	struct mtd_info *ret;
+
+	drv = get_mtd_chip_driver(name);
+
+	if (!drv && !request_module("%s", name))
+		drv = get_mtd_chip_driver(name);
+
+	if (!drv)
+		return NULL;
+
+	ret = drv->probe(map);
+
+	/* We decrease the use count here. It may have been a
+	   probe-only module, which is no longer required from this
+	   point, having given us a handle on (and increased the use
+	   count of) the actual driver code.
+	*/
+	module_put(drv->module);
+
+	return ret;
+}
+/*
+ * Destroy an MTD device which was created for a map device.
+ * Make sure the MTD device is already unregistered before calling this
+ */
+void map_destroy(struct mtd_info *mtd)
+{
+	struct map_info *map = mtd->priv;
+
+	if (map->fldrv->destroy)
+		map->fldrv->destroy(mtd);
+
+	module_put(map->fldrv->module);
+
+	kfree(mtd);
+}
+
+EXPORT_SYMBOL(register_mtd_chip_driver);
+EXPORT_SYMBOL(unregister_mtd_chip_driver);
+EXPORT_SYMBOL(do_map_probe);
+EXPORT_SYMBOL(map_destroy);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
+MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");