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, 51 insertions, 0 deletions

diff --git a/lib/test_debug_virtual.c b/lib/test_debug_virtual.c
new file mode 100644
index 000000000..518ee8d21
--- /dev/null
+++ b/lib/test_debug_virtual.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/sizes.h>
+#include <linux/io.h>
+
+#include <asm/page.h>
+#ifdef CONFIG_MIPS
+#include <asm/bootinfo.h>
+#endif
+
+struct foo {
+	unsigned int bar;
+};
+
+static struct foo *foo;
+
+static int __init test_debug_virtual_init(void)
+{
+	phys_addr_t pa;
+	void *va;
+
+	va = (void *)VMALLOC_START;
+	pa = virt_to_phys(va);
+
+	pr_info("PA: %pa for VA: 0x%lx\n", &pa, (unsigned long)va);
+
+	foo = kzalloc_obj(*foo);
+	if (!foo)
+		return -ENOMEM;
+
+	pa = virt_to_phys(foo);
+	va = foo;
+	pr_info("PA: %pa for VA: 0x%lx\n", &pa, (unsigned long)va);
+
+	return 0;
+}
+module_init(test_debug_virtual_init);
+
+static void __exit test_debug_virtual_exit(void)
+{
+	kfree(foo);
+}
+module_exit(test_debug_virtual_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Test module for CONFIG_DEBUG_VIRTUAL");