--- /dev/null
+From 000c2fa2c144c499c881a101819cf1936a1f7cf2 Mon Sep 17 00:00:00 2001
+From: Ruihan Li <lrh2000@pku.edu.cn>
+Date: Sun, 16 Apr 2023 16:02:51 +0800
+Subject: bluetooth: Add cmd validity checks at the start of hci_sock_ioctl()
+
+From: Ruihan Li <lrh2000@pku.edu.cn>
+
+commit 000c2fa2c144c499c881a101819cf1936a1f7cf2 upstream.
+
+Previously, channel open messages were always sent to monitors on the first
+ioctl() call for unbound HCI sockets, even if the command and arguments
+were completely invalid. This can leave an exploitable hole with the abuse
+of invalid ioctl calls.
+
+This commit hardens the ioctl processing logic by first checking if the
+command is valid, and immediately returning with an ENOIOCTLCMD error code
+if it is not. This ensures that ioctl calls with invalid commands are free
+of side effects, and increases the difficulty of further exploitation by
+forcing exploitation to find a way to pass a valid command first.
+
+Signed-off-by: Ruihan Li <lrh2000@pku.edu.cn>
+Co-developed-by: Marcel Holtmann <marcel@holtmann.org>
+Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
+Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
+Signed-off-by: Dragos-Marian Panait <dragos.panait@windriver.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ net/bluetooth/hci_sock.c | 28 ++++++++++++++++++++++++++++
+ 1 file changed, 28 insertions(+)
+
+--- a/net/bluetooth/hci_sock.c
++++ b/net/bluetooth/hci_sock.c
+@@ -987,6 +987,34 @@ static int hci_sock_ioctl(struct socket
+
+ BT_DBG("cmd %x arg %lx", cmd, arg);
+
++ /* Make sure the cmd is valid before doing anything */
++ switch (cmd) {
++ case HCIGETDEVLIST:
++ case HCIGETDEVINFO:
++ case HCIGETCONNLIST:
++ case HCIDEVUP:
++ case HCIDEVDOWN:
++ case HCIDEVRESET:
++ case HCIDEVRESTAT:
++ case HCISETSCAN:
++ case HCISETAUTH:
++ case HCISETENCRYPT:
++ case HCISETPTYPE:
++ case HCISETLINKPOL:
++ case HCISETLINKMODE:
++ case HCISETACLMTU:
++ case HCISETSCOMTU:
++ case HCIINQUIRY:
++ case HCISETRAW:
++ case HCIGETCONNINFO:
++ case HCIGETAUTHINFO:
++ case HCIBLOCKADDR:
++ case HCIUNBLOCKADDR:
++ break;
++ default:
++ return -ENOIOCTLCMD;
++ }
++
+ lock_sock(sk);
+
+ if (hci_pi(sk)->channel != HCI_CHANNEL_RAW) {