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, 176 insertions, 0 deletions

diff --git a/net/x25/x25_timer.c b/net/x25/x25_timer.c
new file mode 100644
index 000000000..7896cd43f
--- /dev/null
+++ b/net/x25/x25_timer.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	X.25 Packet Layer release 002
+ *
+ *	This is ALPHA test software. This code may break your machine,
+ *	randomly fail to work with new releases, misbehave and/or generally
+ *	screw up. It might even work.
+ *
+ *	This code REQUIRES 2.1.15 or higher
+ *
+ *	History
+ *	X.25 001	Jonathan Naylor	Started coding.
+ *	X.25 002	Jonathan Naylor	New timer architecture.
+ *					Centralised disconnection processing.
+ */
+
+#include <linux/errno.h>
+#include <linux/jiffies.h>
+#include <linux/timer.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <net/x25.h>
+
+static void x25_heartbeat_expiry(struct timer_list *t);
+static void x25_timer_expiry(struct timer_list *t);
+
+void x25_init_timers(struct sock *sk)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	timer_setup(&x25->timer, x25_timer_expiry, 0);
+
+	/* initialized by sock_init_data */
+	sk->sk_timer.function = x25_heartbeat_expiry;
+}
+
+void x25_start_heartbeat(struct sock *sk)
+{
+	sk_reset_timer(sk, &sk->sk_timer, jiffies + 5 * HZ);
+}
+
+void x25_stop_heartbeat(struct sock *sk)
+{
+	sk_stop_timer(sk, &sk->sk_timer);
+}
+
+void x25_start_t2timer(struct sock *sk)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	sk_reset_timer(sk, &x25->timer, jiffies + x25->t2);
+}
+
+void x25_start_t21timer(struct sock *sk)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	sk_reset_timer(sk, &x25->timer, jiffies + x25->t21);
+}
+
+void x25_start_t22timer(struct sock *sk)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	sk_reset_timer(sk, &x25->timer, jiffies + x25->t22);
+}
+
+void x25_start_t23timer(struct sock *sk)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	sk_reset_timer(sk, &x25->timer, jiffies + x25->t23);
+}
+
+void x25_stop_timer(struct sock *sk)
+{
+	sk_stop_timer(sk, &x25_sk(sk)->timer);
+}
+
+unsigned long x25_display_timer(struct sock *sk)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	if (!timer_pending(&x25->timer))
+		return 0;
+
+	return x25->timer.expires - jiffies;
+}
+
+static void x25_heartbeat_expiry(struct timer_list *t)
+{
+	struct sock *sk = timer_container_of(sk, t, sk_timer);
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
+		goto restart_heartbeat;
+
+	switch (x25_sk(sk)->state) {
+
+		case X25_STATE_0:
+			/*
+			 * Magic here: If we listen() and a new link dies
+			 * before it is accepted() it isn't 'dead' so doesn't
+			 * get removed.
+			 */
+			if (sock_flag(sk, SOCK_DESTROY) ||
+			    (sk->sk_state == TCP_LISTEN &&
+			     sock_flag(sk, SOCK_DEAD))) {
+				bh_unlock_sock(sk);
+				x25_destroy_socket_from_timer(sk);
+				goto out;
+			}
+			break;
+
+		case X25_STATE_3:
+			/*
+			 * Check for the state of the receive buffer.
+			 */
+			x25_check_rbuf(sk);
+			break;
+	}
+restart_heartbeat:
+	/* Do not rearm once __x25_destroy_socket() has unlinked the socket:
+	 * it is past its cancel point and owns the teardown from there on.
+	 */
+	if (sk_hashed(sk))
+		x25_start_heartbeat(sk);
+	bh_unlock_sock(sk);
+out:
+	sock_put(sk);
+}
+
+/*
+ *	Timer has expired, it may have been T2, T21, T22, or T23. We can tell
+ *	by the state machine state.
+ */
+static inline void x25_do_timer_expiry(struct sock * sk)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	switch (x25->state) {
+
+		case X25_STATE_3:	/* T2 */
+			if (x25->condition & X25_COND_ACK_PENDING) {
+				x25->condition &= ~X25_COND_ACK_PENDING;
+				x25_enquiry_response(sk);
+			}
+			break;
+
+		case X25_STATE_1:	/* T21 */
+		case X25_STATE_4:	/* T22 */
+			x25_write_internal(sk, X25_CLEAR_REQUEST);
+			x25->state = X25_STATE_2;
+			x25_start_t23timer(sk);
+			break;
+
+		case X25_STATE_2:	/* T23 */
+			x25_disconnect(sk, ETIMEDOUT, 0, 0);
+			break;
+	}
+}
+
+static void x25_timer_expiry(struct timer_list *t)
+{
+	struct x25_sock *x25 = timer_container_of(x25, t, timer);
+	struct sock *sk = &x25->sk;
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
+		if (x25_sk(sk)->state == X25_STATE_3)
+			x25_start_t2timer(sk);
+	} else
+		x25_do_timer_expiry(sk);
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}