Re: [syzbot] [bluetooth?] WARNING in hci_conn_del

[Pavel Skripkin]

On 6/14/24 11:42 AM, Pavel Skripkin wrote:
> On 6/14/24 2:29 AM, syzbot wrote:
> > Hello,
> >
> > syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> > SYZFAIL: NL802154_CMD_SET_SHORT_ADDR failed
> >
> > 2024/06/13 23:28:26 ignoring optional flag "sandboxArg"="0"
> > 2024/06/13 23:28:27 parsed 1 programs
> > 2024/06/13 23:28:27 [FATAL] failed to run ["./syz-executor" "setup" "fault" "binfmt_misc" "usb" "802154" "swap"]: exit status 67
> > mkdir(/syzcgroup) failed: 17
> > mount(binfmt_misc) failed: 16
> > SYZFAIL: NL802154_CMD_SET_SHORT_ADDR failed
> >   (errno 16: Device or resource busy)

#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


--
With regards,
Pavel SkripkinFrom cd75c43796451af0e3c5e6b42aa7276603c4bb1b Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@xxxxxxxxx>
Date: Fri, 14 Jun 2024 00:02:51 +0300
Subject: [PATCH] bluetooth/hci: disallow setting handle bigger than
 HCI_CONN_HANDLE_MAX

Syzbot hit warning in hci_conn_del() caused by freeing handle that was
not allocated using ida allocator.

This is caused by handle bigger than HCI_CONN_HANDLE_MAX passed by
hci_le_big_sync_established_evt(), which makes code think it's unset
connection.

Add same check for handle upper bound as in hci_conn_set_handle() to
prevent warning.

Fixes: https://syzkaller.appspot.com/bug?extid=b2545b087a01a7319474
Reported-by: syzbot+b2545b087a01a7319474@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 181a42edddf5 ("Bluetooth: Make handle of hci_conn be unique")
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
---
 net/bluetooth/hci_conn.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 0c76dcde5361..dd21fee1d7c6 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -899,8 +899,8 @@ static int hci_conn_hash_alloc_unset(struct hci_dev *hdev)
 			       U16_MAX, GFP_ATOMIC);
 }
 
-struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
-			      u8 role, u16 handle)
+static struct hci_conn *__hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
+				       u8 role, u16 handle)
 {
 	struct hci_conn *conn;
 
@@ -1044,6 +1044,15 @@ struct hci_conn *hci_conn_add_unset(struct hci_dev *hdev, int type,
 	return hci_conn_add(hdev, type, dst, role, handle);
 }
 
+struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
+			      u8 role, u16 handle)
+{
+	if (handle > HCI_CONN_HANDLE_MAX)
+		return ERR_PTR(-EINVAL);
+
+	return __hci_conn_add(hdev, type, dst, role, handle);
+}
+
 static void hci_conn_cleanup_child(struct hci_conn *conn, u8 reason)
 {
 	if (!reason)
-- 
2.45.2