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, 75 insertions, 0 deletions

diff --git a/net/atm/raw.c b/net/atm/raw.c
new file mode 100644
index 000000000..87d136c75
--- /dev/null
+++ b/net/atm/raw.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+/* net/atm/raw.c - Raw AAL0 and AAL5 transports */
+
+/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
+
+#include <linux/module.h>
+#include <linux/atmdev.h>
+#include <linux/capability.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+
+#include "common.h"
+#include "protocols.h"
+
+/*
+ * SKB == NULL indicates that the link is being closed
+ */
+
+static void atm_push_raw(struct atm_vcc *vcc, struct sk_buff *skb)
+{
+	if (skb) {
+		struct sock *sk = sk_atm(vcc);
+
+		skb_queue_tail(&sk->sk_receive_queue, skb);
+		sk->sk_data_ready(sk);
+	}
+}
+
+static void atm_pop_raw(struct atm_vcc *vcc, struct sk_buff *skb)
+{
+	struct sock *sk = sk_atm(vcc);
+
+	pr_debug("(%d) %d -= %d\n",
+		 vcc->vci, sk_wmem_alloc_get(sk), ATM_SKB(skb)->acct_truesize);
+	atm_return_tx(vcc, skb);
+	dev_kfree_skb_any(skb);
+	sk->sk_write_space(sk);
+}
+
+static int atm_send_aal0(struct atm_vcc *vcc, struct sk_buff *skb)
+{
+	/*
+	 * Note that if vpi/vci are _ANY or _UNSPEC the below will
+	 * still work
+	 */
+	if (!capable(CAP_NET_ADMIN) &&
+	    (((u32 *)skb->data)[0] & (ATM_HDR_VPI_MASK | ATM_HDR_VCI_MASK)) !=
+	    ((vcc->vpi << ATM_HDR_VPI_SHIFT) |
+	     (vcc->vci << ATM_HDR_VCI_SHIFT))) {
+		kfree_skb(skb);
+		return -EADDRNOTAVAIL;
+	}
+	return vcc->dev->ops->send(vcc, skb);
+}
+
+int atm_init_aal0(struct atm_vcc *vcc)
+{
+	vcc->push = atm_push_raw;
+	vcc->pop = atm_pop_raw;
+	vcc->send = atm_send_aal0;
+	return 0;
+}
+
+int atm_init_aal5(struct atm_vcc *vcc)
+{
+	vcc->push = atm_push_raw;
+	vcc->pop = atm_pop_raw;
+	vcc->send = vcc->dev->ops->send;
+	return 0;
+}
+EXPORT_SYMBOL(atm_init_aal5);