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, 61 insertions, 0 deletions

diff --git a/arch/mips/mm/sc-debugfs.c b/arch/mips/mm/sc-debugfs.c
new file mode 100644
index 000000000..80ff39471
--- /dev/null
+++ b/arch/mips/mm/sc-debugfs.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Paul Burton <paul.burton@mips.com>
+ */
+
+#include <asm/bcache.h>
+#include <asm/debug.h>
+#include <linux/uaccess.h>
+#include <linux/debugfs.h>
+#include <linux/init.h>
+
+static ssize_t sc_prefetch_read(struct file *file, char __user *user_buf,
+				size_t count, loff_t *ppos)
+{
+	bool enabled = bc_prefetch_is_enabled();
+	char buf[3];
+
+	buf[0] = enabled ? 'Y' : 'N';
+	buf[1] = '\n';
+	buf[2] = 0;
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
+}
+
+static ssize_t sc_prefetch_write(struct file *file,
+				 const char __user *user_buf,
+				 size_t count, loff_t *ppos)
+{
+	bool enabled;
+	int err;
+
+	err = kstrtobool_from_user(user_buf, count, &enabled);
+	if (err)
+		return err;
+
+	if (enabled)
+		bc_prefetch_enable();
+	else
+		bc_prefetch_disable();
+
+	return count;
+}
+
+static const struct file_operations sc_prefetch_fops = {
+	.open = simple_open,
+	.llseek = default_llseek,
+	.read = sc_prefetch_read,
+	.write = sc_prefetch_write,
+};
+
+static int __init sc_debugfs_init(void)
+{
+	struct dentry *dir;
+
+	dir = debugfs_create_dir("l2cache", mips_debugfs_dir);
+	debugfs_create_file("prefetch", S_IRUGO | S_IWUSR, dir, NULL,
+			    &sc_prefetch_fops);
+	return 0;
+}
+late_initcall(sc_debugfs_init);