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, 123 insertions, 0 deletions

diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
new file mode 100644
index 000000000..d5df5466e
--- /dev/null
+++ b/drivers/mfd/atmel-flexcom.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Atmel Flexcom
+ *
+ * Copyright (C) 2015 Atmel Corporation
+ *
+ * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <dt-bindings/mfd/atmel-flexcom.h>
+
+/* I/O register offsets */
+#define FLEX_MR		0x0	/* Mode Register */
+#define FLEX_VERSION	0xfc	/* Version Register */
+
+/* Mode Register bit fields */
+#define FLEX_MR_OPMODE_OFFSET	(0)  /* Operating Mode */
+#define FLEX_MR_OPMODE_MASK	(0x3 << FLEX_MR_OPMODE_OFFSET)
+#define FLEX_MR_OPMODE(opmode)	(((opmode) << FLEX_MR_OPMODE_OFFSET) &	\
+				 FLEX_MR_OPMODE_MASK)
+
+struct atmel_flexcom {
+	void __iomem *base;
+	u32 opmode;
+	struct clk *clk;
+};
+
+static int atmel_flexcom_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct atmel_flexcom *ddata;
+	int err;
+
+	ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, ddata);
+
+	err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode);
+	if (err)
+		return err;
+
+	if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART ||
+	    ddata->opmode > ATMEL_FLEXCOM_MODE_TWI)
+		return -EINVAL;
+
+	ddata->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
+	if (IS_ERR(ddata->base))
+		return PTR_ERR(ddata->base);
+
+	ddata->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(ddata->clk))
+		return PTR_ERR(ddata->clk);
+
+	err = clk_prepare_enable(ddata->clk);
+	if (err)
+		return err;
+
+	/*
+	 * Set the Operating Mode in the Mode Register: only the selected device
+	 * is clocked. Hence, registers of the other serial devices remain
+	 * inaccessible and are read as zero. Also the external I/O lines of the
+	 * Flexcom are muxed to reach the selected device.
+	 */
+	writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);
+
+	clk_disable_unprepare(ddata->clk);
+
+	return devm_of_platform_populate(&pdev->dev);
+}
+
+static const struct of_device_id atmel_flexcom_of_match[] = {
+	{ .compatible = "atmel,sama5d2-flexcom" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
+
+static int __maybe_unused atmel_flexcom_resume_noirq(struct device *dev)
+{
+	struct atmel_flexcom *ddata = dev_get_drvdata(dev);
+	int err;
+	u32 val;
+
+	err = clk_prepare_enable(ddata->clk);
+	if (err)
+		return err;
+
+	val = FLEX_MR_OPMODE(ddata->opmode);
+	writel(val, ddata->base + FLEX_MR);
+
+	clk_disable_unprepare(ddata->clk);
+
+	return 0;
+}
+
+static const struct dev_pm_ops __maybe_unused atmel_flexcom_pm_ops = {
+	.resume_noirq = atmel_flexcom_resume_noirq,
+};
+
+static struct platform_driver atmel_flexcom_driver = {
+	.probe	= atmel_flexcom_probe,
+	.driver	= {
+		.name		= "atmel_flexcom",
+		.pm		= pm_ptr(&atmel_flexcom_pm_ops),
+		.of_match_table	= atmel_flexcom_of_match,
+	},
+};
+
+module_platform_driver(atmel_flexcom_driver);
+
+MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");
+MODULE_DESCRIPTION("Atmel Flexcom MFD driver");
+MODULE_LICENSE("GPL v2");