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, 66 insertions, 0 deletions

diff --git a/net/wireless/tests/util.h b/net/wireless/tests/util.h
new file mode 100644
index 000000000..6de712e0d
--- /dev/null
+++ b/net/wireless/tests/util.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Utilities for cfg80211 unit testing
+ *
+ * Copyright (C) 2023 Intel Corporation
+ */
+#ifndef __CFG80211_UTILS_H
+#define __CFG80211_UTILS_H
+
+#define CHAN2G(_freq)  { \
+	.band = NL80211_BAND_2GHZ, \
+	.center_freq = (_freq), \
+	.hw_value = (_freq), \
+}
+
+static const struct ieee80211_channel channels_2ghz[] = {
+	CHAN2G(2412), /* Channel 1 */
+	CHAN2G(2417), /* Channel 2 */
+	CHAN2G(2422), /* Channel 3 */
+	CHAN2G(2427), /* Channel 4 */
+	CHAN2G(2432), /* Channel 5 */
+	CHAN2G(2437), /* Channel 6 */
+	CHAN2G(2442), /* Channel 7 */
+	CHAN2G(2447), /* Channel 8 */
+	CHAN2G(2452), /* Channel 9 */
+	CHAN2G(2457), /* Channel 10 */
+	CHAN2G(2462), /* Channel 11 */
+	CHAN2G(2467), /* Channel 12 */
+	CHAN2G(2472), /* Channel 13 */
+	CHAN2G(2484), /* Channel 14 */
+};
+
+struct t_wiphy_priv {
+	struct kunit *test;
+	struct cfg80211_ops *ops;
+
+	void *ctx;
+
+	struct ieee80211_supported_band band_2ghz;
+	struct ieee80211_channel channels_2ghz[ARRAY_SIZE(channels_2ghz)];
+};
+
+#define T_WIPHY(test, ctx) ({						\
+		struct wiphy *__wiphy =					\
+			kunit_alloc_resource(test, t_wiphy_init,	\
+					     t_wiphy_exit,		\
+					     GFP_KERNEL, &(ctx));	\
+									\
+		KUNIT_ASSERT_NOT_NULL(test, __wiphy);			\
+		__wiphy;						\
+	})
+#define t_wiphy_ctx(wiphy) (((struct t_wiphy_priv *)wiphy_priv(wiphy))->ctx)
+
+int t_wiphy_init(struct kunit_resource *resource, void *data);
+void t_wiphy_exit(struct kunit_resource *resource);
+
+#define t_skb_remove_member(skb, type, member)	do {				\
+		memmove((skb)->data + (skb)->len - sizeof(type) +		\
+			offsetof(type, member),					\
+			(skb)->data + (skb)->len - sizeof(type) +		\
+			offsetofend(type, member),				\
+			offsetofend(type, member));				\
+		skb_trim(skb, (skb)->len - sizeof_field(type, member));		\
+	} while (0)
+
+#endif /* __CFG80211_UTILS_H */