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, 233 insertions, 0 deletions

diff --git a/drivers/video/backlight/rt4831-backlight.c b/drivers/video/backlight/rt4831-backlight.c
new file mode 100644
index 000000000..7ead75929
--- /dev/null
+++ b/drivers/video/backlight/rt4831-backlight.c
@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <dt-bindings/leds/rt4831-backlight.h>
+#include <linux/backlight.h>
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define RT4831_REG_BLCFG	0x02
+#define RT4831_REG_BLDIML	0x04
+#define RT4831_REG_ENABLE	0x08
+#define RT4831_REG_BLOPT2	0x11
+
+#define RT4831_BLMAX_BRIGHTNESS	2048
+
+#define RT4831_BLOVP_MASK	GENMASK(7, 5)
+#define RT4831_BLOVP_SHIFT	5
+#define RT4831_BLPWMEN_MASK	BIT(0)
+#define RT4831_BLEN_MASK	BIT(4)
+#define RT4831_BLCH_MASK	GENMASK(3, 0)
+#define RT4831_BLDIML_MASK	GENMASK(2, 0)
+#define RT4831_BLDIMH_MASK	GENMASK(10, 3)
+#define RT4831_BLDIMH_SHIFT	3
+#define RT4831_BLOCP_MASK	GENMASK(1, 0)
+
+#define RT4831_BLOCP_MINUA	900000
+#define RT4831_BLOCP_MAXUA	1800000
+#define RT4831_BLOCP_STEPUA	300000
+
+struct rt4831_priv {
+	struct device *dev;
+	struct regmap *regmap;
+	struct backlight_device *bl;
+};
+
+static int rt4831_bl_update_status(struct backlight_device *bl_dev)
+{
+	struct rt4831_priv *priv = bl_get_data(bl_dev);
+	int brightness = backlight_get_brightness(bl_dev);
+	unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
+	u8 v[2];
+	int ret;
+
+	if (brightness) {
+		v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
+		v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
+
+		ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+		if (ret)
+			return ret;
+	}
+
+	return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
+
+}
+
+static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
+{
+	struct rt4831_priv *priv = bl_get_data(bl_dev);
+	unsigned int val;
+	u8 v[2];
+	int ret;
+
+	ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
+	if (ret)
+		return ret;
+
+	if (!(val & RT4831_BLEN_MASK))
+		return 0;
+
+	ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+	if (ret)
+		return ret;
+
+	ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
+
+	return ret;
+}
+
+static const struct backlight_ops rt4831_bl_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = rt4831_bl_update_status,
+	.get_brightness = rt4831_bl_get_brightness,
+};
+
+static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
+					     struct backlight_properties *bl_props)
+{
+	struct device *dev = priv->dev;
+	u8 propval;
+	u32 brightness, ocp_uA;
+	unsigned int val = 0;
+	int ret;
+
+	/* common properties */
+	ret = device_property_read_u32(dev, "max-brightness", &brightness);
+	if (ret)
+		brightness = RT4831_BLMAX_BRIGHTNESS;
+
+	bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
+
+	ret = device_property_read_u32(dev, "default-brightness", &brightness);
+	if (ret)
+		brightness = bl_props->max_brightness;
+
+	bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
+
+	/* vendor properties */
+	if (device_property_read_bool(dev, "richtek,pwm-enable"))
+		val = RT4831_BLPWMEN_MASK;
+
+	ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
+	if (ret)
+		return ret;
+
+	ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
+	if (ret)
+		propval = RT4831_BLOVPLVL_21V;
+
+	propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
+	ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
+				 propval << RT4831_BLOVP_SHIFT);
+	if (ret)
+		return ret;
+
+	/*
+	 * This OCP level is used to protect and limit the inductor current.
+	 * If inductor peak current reach the level, low-side MOSFET will be
+	 * turned off. Meanwhile, the output channel current may be limited.
+	 * To match the configured channel current, the inductor chosen must
+	 * be higher than the OCP level.
+	 *
+	 * Not like the OVP level, the default 21V can be used in the most
+	 * application. But if the chosen OCP level is smaller than needed,
+	 * it will also affect the backlight channel output current to be
+	 * smaller than the register setting.
+	 */
+	ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp",
+				       &ocp_uA);
+	if (!ret) {
+		ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA,
+				   RT4831_BLOCP_MAXUA);
+		val = DIV_ROUND_UP(ocp_uA - RT4831_BLOCP_MINUA,
+				   RT4831_BLOCP_STEPUA);
+		ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2,
+					 RT4831_BLOCP_MASK, val);
+		if (ret)
+			return ret;
+	}
+
+	ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
+	if (ret) {
+		dev_err(dev, "richtek,channel-use DT property missing\n");
+		return ret;
+	}
+
+	if (!(propval & RT4831_BLCH_MASK)) {
+		dev_err(dev, "No channel specified\n");
+		return -EINVAL;
+	}
+
+	return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
+}
+
+static int rt4831_bl_probe(struct platform_device *pdev)
+{
+	struct rt4831_priv *priv;
+	struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
+						 .scale = BACKLIGHT_SCALE_LINEAR };
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &pdev->dev;
+
+	priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!priv->regmap) {
+		dev_err(&pdev->dev, "Failed to init regmap\n");
+		return -ENODEV;
+	}
+
+	ret = rt4831_parse_backlight_properties(priv, &bl_props);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to parse backlight properties\n");
+		return ret;
+	}
+
+	priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
+						  &rt4831_bl_ops, &bl_props);
+	if (IS_ERR(priv->bl)) {
+		dev_err(&pdev->dev, "Failed to register backlight\n");
+		return PTR_ERR(priv->bl);
+	}
+
+	backlight_update_status(priv->bl);
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+}
+
+static void rt4831_bl_remove(struct platform_device *pdev)
+{
+	struct rt4831_priv *priv = platform_get_drvdata(pdev);
+	struct backlight_device *bl_dev = priv->bl;
+
+	bl_dev->props.brightness = 0;
+	backlight_update_status(priv->bl);
+}
+
+static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
+	{ .compatible = "richtek,rt4831-backlight", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
+
+static struct platform_driver rt4831_bl_driver = {
+	.driver = {
+		.name = "rt4831-backlight",
+		.of_match_table = rt4831_bl_of_match,
+	},
+	.probe = rt4831_bl_probe,
+	.remove = rt4831_bl_remove,
+};
+module_platform_driver(rt4831_bl_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
+MODULE_DESCRIPTION("Richtek RT4831 Backlight Driver");
+MODULE_LICENSE("GPL v2");