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, 56 insertions, 0 deletions

diff --git a/net/wireless/tests/util.c b/net/wireless/tests/util.c
new file mode 100644
index 000000000..118f7fb42
--- /dev/null
+++ b/net/wireless/tests/util.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * KUnit fixture to have a (configurable) wiphy
+ *
+ * Copyright (C) 2023 Intel Corporation
+ */
+#include <linux/ieee80211.h>
+#include <net/cfg80211.h>
+#include <kunit/test.h>
+#include <kunit/test-bug.h>
+#include "util.h"
+
+int t_wiphy_init(struct kunit_resource *resource, void *ctx)
+{
+	struct kunit *test = kunit_get_current_test();
+	struct cfg80211_ops *ops;
+	struct wiphy *wiphy;
+	struct t_wiphy_priv *priv;
+
+	ops = kzalloc_obj(*ops);
+	KUNIT_ASSERT_NOT_NULL(test, ops);
+
+	wiphy = wiphy_new_nm(ops, sizeof(*priv), "kunit");
+	KUNIT_ASSERT_NOT_NULL(test, wiphy);
+
+	priv = wiphy_priv(wiphy);
+	priv->ctx = ctx;
+	priv->ops = ops;
+
+	/* Initialize channels, feel free to add more here channels/bands */
+	memcpy(priv->channels_2ghz, channels_2ghz, sizeof(channels_2ghz));
+	wiphy->bands[NL80211_BAND_2GHZ] = &priv->band_2ghz;
+	priv->band_2ghz.channels = priv->channels_2ghz;
+	priv->band_2ghz.n_channels = ARRAY_SIZE(channels_2ghz);
+
+	resource->data = wiphy;
+	resource->name = "wiphy";
+
+	return 0;
+}
+
+void t_wiphy_exit(struct kunit_resource *resource)
+{
+	struct t_wiphy_priv *priv;
+	struct cfg80211_ops *ops;
+
+	priv = wiphy_priv(resource->data);
+	ops = priv->ops;
+
+	/* Should we ensure anything about the state here?
+	 * e.g. full destruction or no calls to any ops on destruction?
+	 */
+
+	wiphy_free(resource->data);
+	kfree(ops);
+}