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, 94 insertions, 0 deletions

diff --git a/drivers/fpga/xilinx-selectmap.c b/drivers/fpga/xilinx-selectmap.c
new file mode 100644
index 000000000..d0cbb5fdf
--- /dev/null
+++ b/drivers/fpga/xilinx-selectmap.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Xilinx Spartan6 and 7 Series SelectMAP interface driver
+ *
+ * (C) 2024 Charles Perry <charles.perry@savoirfairelinux.com>
+ *
+ * Manage Xilinx FPGA firmware loaded over the SelectMAP configuration
+ * interface.
+ */
+
+#include "xilinx-core.h"
+
+#include <linux/gpio/consumer.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+struct xilinx_selectmap_conf {
+	struct xilinx_fpga_core core;
+	void __iomem *base;
+};
+
+#define to_xilinx_selectmap_conf(obj) \
+	container_of(obj, struct xilinx_selectmap_conf, core)
+
+static int xilinx_selectmap_write(struct xilinx_fpga_core *core,
+				  const char *buf, size_t count)
+{
+	struct xilinx_selectmap_conf *conf = to_xilinx_selectmap_conf(core);
+	size_t i;
+
+	for (i = 0; i < count; ++i)
+		writeb(buf[i], conf->base);
+
+	return 0;
+}
+
+static int xilinx_selectmap_probe(struct platform_device *pdev)
+{
+	struct xilinx_selectmap_conf *conf;
+	struct gpio_desc *gpio;
+	void __iomem *base;
+
+	conf = devm_kzalloc(&pdev->dev, sizeof(*conf), GFP_KERNEL);
+	if (!conf)
+		return -ENOMEM;
+
+	conf->core.dev = &pdev->dev;
+	conf->core.write = xilinx_selectmap_write;
+
+	base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
+	if (IS_ERR(base))
+		return dev_err_probe(&pdev->dev, PTR_ERR(base),
+				     "ioremap error\n");
+	conf->base = base;
+
+	/* CSI_B is active low */
+	gpio = devm_gpiod_get_optional(&pdev->dev, "csi", GPIOD_OUT_HIGH);
+	if (IS_ERR(gpio))
+		return dev_err_probe(&pdev->dev, PTR_ERR(gpio),
+				     "Failed to get CSI_B gpio\n");
+
+	/* RDWR_B is active low */
+	gpio = devm_gpiod_get_optional(&pdev->dev, "rdwr", GPIOD_OUT_HIGH);
+	if (IS_ERR(gpio))
+		return dev_err_probe(&pdev->dev, PTR_ERR(gpio),
+				     "Failed to get RDWR_B gpio\n");
+
+	return xilinx_core_probe(&conf->core);
+}
+
+static const struct of_device_id xlnx_selectmap_of_match[] = {
+	{ .compatible = "xlnx,fpga-xc7s-selectmap", }, // Spartan-7
+	{ .compatible = "xlnx,fpga-xc7a-selectmap", }, // Artix-7
+	{ .compatible = "xlnx,fpga-xc7k-selectmap", }, // Kintex-7
+	{ .compatible = "xlnx,fpga-xc7v-selectmap", }, // Virtex-7
+	{},
+};
+MODULE_DEVICE_TABLE(of, xlnx_selectmap_of_match);
+
+static struct platform_driver xilinx_selectmap_driver = {
+	.driver = {
+		.name = "xilinx-selectmap",
+		.of_match_table = xlnx_selectmap_of_match,
+	},
+	.probe  = xilinx_selectmap_probe,
+};
+
+module_platform_driver(xilinx_selectmap_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Charles Perry <charles.perry@savoirfairelinux.com>");
+MODULE_DESCRIPTION("Load Xilinx FPGA firmware over SelectMap");