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, 79 insertions, 0 deletions

diff --git a/tools/testing/radix-tree/regression4.c b/tools/testing/radix-tree/regression4.c
new file mode 100644
index 000000000..cf4e5aba6
--- /dev/null
+++ b/tools/testing/radix-tree/regression4.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/radix-tree.h>
+#include <linux/rcupdate.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <assert.h>
+
+#include "regression.h"
+
+static pthread_barrier_t worker_barrier;
+static int obj0, obj1;
+static RADIX_TREE(mt_tree, GFP_KERNEL);
+
+static void *reader_fn(void *arg)
+{
+	int i;
+	void *entry;
+
+	rcu_register_thread();
+	pthread_barrier_wait(&worker_barrier);
+
+	for (i = 0; i < 1000000; i++) {
+		rcu_read_lock();
+		entry = radix_tree_lookup(&mt_tree, 0);
+		rcu_read_unlock();
+		if (entry != &obj0) {
+			printf("iteration %d bad entry = %p\n", i, entry);
+			abort();
+		}
+	}
+
+	rcu_unregister_thread();
+
+	return NULL;
+}
+
+static void *writer_fn(void *arg)
+{
+	int i;
+
+	rcu_register_thread();
+	pthread_barrier_wait(&worker_barrier);
+
+	for (i = 0; i < 1000000; i++) {
+		radix_tree_insert(&mt_tree, 1, &obj1);
+		radix_tree_delete(&mt_tree, 1);
+	}
+
+	rcu_unregister_thread();
+
+	return NULL;
+}
+
+void regression4_test(void)
+{
+	pthread_t reader, writer;
+
+	printv(1, "regression test 4 starting\n");
+
+	radix_tree_insert(&mt_tree, 0, &obj0);
+	pthread_barrier_init(&worker_barrier, NULL, 2);
+
+	if (pthread_create(&reader, NULL, reader_fn, NULL) ||
+	    pthread_create(&writer, NULL, writer_fn, NULL)) {
+		perror("pthread_create");
+		exit(1);
+	}
+
+	if (pthread_join(reader, NULL) || pthread_join(writer, NULL)) {
+		perror("pthread_join");
+		exit(1);
+	}
+
+	printv(1, "regression test 4 passed\n");
+}