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, 48 insertions, 0 deletions

diff --git a/include/net/dsa_stubs.h b/include/net/dsa_stubs.h
new file mode 100644
index 000000000..6f384897f
--- /dev/null
+++ b/include/net/dsa_stubs.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * include/net/dsa_stubs.h - Stubs for the Distributed Switch Architecture framework
+ */
+
+#include <linux/mutex.h>
+#include <linux/netdevice.h>
+#include <linux/net_tstamp.h>
+#include <net/dsa.h>
+
+#if IS_ENABLED(CONFIG_NET_DSA)
+
+extern const struct dsa_stubs *dsa_stubs;
+
+struct dsa_stubs {
+	int (*conduit_hwtstamp_validate)(struct net_device *dev,
+					 const struct kernel_hwtstamp_config *config,
+					 struct netlink_ext_ack *extack);
+};
+
+static inline int dsa_conduit_hwtstamp_validate(struct net_device *dev,
+						const struct kernel_hwtstamp_config *config,
+						struct netlink_ext_ack *extack)
+{
+	if (!netdev_uses_dsa(dev))
+		return 0;
+
+	/* rtnl_lock() is a sufficient guarantee, because as long as
+	 * netdev_uses_dsa() returns true, the dsa_core module is still
+	 * registered, and so, dsa_unregister_stubs() couldn't have run.
+	 * For netdev_uses_dsa() to start returning false, it would imply that
+	 * dsa_conduit_teardown() has executed, which requires rtnl_lock().
+	 */
+	ASSERT_RTNL();
+
+	return dsa_stubs->conduit_hwtstamp_validate(dev, config, extack);
+}
+
+#else
+
+static inline int dsa_conduit_hwtstamp_validate(struct net_device *dev,
+						const struct kernel_hwtstamp_config *config,
+						struct netlink_ext_ack *extack)
+{
+	return 0;
+}
+
+#endif