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, 25 insertions, 0 deletions

diff --git a/rust/macros/export.rs b/rust/macros/export.rs
new file mode 100644
index 000000000..6d53521f6
--- /dev/null
+++ b/rust/macros/export.rs
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro2::TokenStream;
+use quote::quote;
+
+/// Please see [`crate::export`] for documentation.
+pub(crate) fn export(f: syn::ItemFn) -> TokenStream {
+    let name = &f.sig.ident;
+
+    quote! {
+        // This verifies that the function has the same signature as the declaration generated by
+        // bindgen. It makes use of the fact that all branches of an if/else must have the same
+        // type.
+        const _: () = {
+            if true {
+                ::kernel::bindings::#name
+            } else {
+                #name
+            };
+        };
+
+        #[no_mangle]
+        #f
+    }
+}