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Re: some bluetooth fixes

To: Andi Kleen <ak@xxxxxxx>
Subject: Re: some bluetooth fixes
From: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Date: Fri, 06 Feb 2004 15:58:32 +0100
Cc: bluez-devel@xxxxxxxxxxxxxxxxxxxxx, netdev@xxxxxxxxxxx, viro@xxxxxxxxxxxxxxxxxx
In-reply-to: <20040206050042.20a2b3b0.ak@suse.de>
References: <20040206050042.20a2b3b0.ak@suse.de>
Sender: netdev-bounce@xxxxxxxxxxx
Hi Andi,

> While reading bluetooth code I noticed some bugs and potential overflows.
> 
> Also I commented one ref-counting bug.
> 
> Patch against 2.6.2.

thanks for looking at it. Same applies to 2.4, right?

> diff -u linux-2.6.2-work32/net/bluetooth/cmtp/sock.c-o 
> linux-2.6.2-work32/net/bluetooth/cmtp/sock.c
> --- linux-2.6.2-work32/net/bluetooth/cmtp/sock.c-o    2004-02-05 
> 08:09:54.000000000 +0100
> +++ linux-2.6.2-work32/net/bluetooth/cmtp/sock.c      2004-02-05 
> 14:57:57.000000000 +0100
> @@ -87,8 +87,10 @@
>               if (!nsock)
>                       return err;
>  
> -             if (nsock->sk->sk_state != BT_CONNECTED)
> +             if (nsock->sk->sk_state != BT_CONNECTED) { 
> +                     fput(nsock->file);
>                       return -EBADFD;
> +             }
>  
>               err = cmtp_add_connection(&ca, nsock);
>               if (!err) {

The same should apply to net/bluetooth/bnep/sock.c

> diff -u linux-2.6.2-work32/net/bluetooth/hci_sock.c-o 
> linux-2.6.2-work32/net/bluetooth/hci_sock.c
> --- linux-2.6.2-work32/net/bluetooth/hci_sock.c-o     2004-02-05 
> 08:09:54.000000000 +0100
> +++ linux-2.6.2-work32/net/bluetooth/hci_sock.c       2004-02-05 
> 14:57:59.000000000 +0100
> @@ -392,6 +392,8 @@
>  
>       skb->pkt_type = *((unsigned char *) skb->data);
>       skb_pull(skb, 1);
> +     /* AK: looks broken. Who guarantees that hdev doesn't go away while
> +        the skb is queued ? */
>       skb->dev = (void *) hdev;
>  
>       if (skb->pkt_type == HCI_COMMAND_PKT) {

Why should hdev go away?

> diff -u linux-2.6.2-work32/net/bluetooth/hci_conn.c-o 
> linux-2.6.2-work32/net/bluetooth/hci_conn.c
> --- linux-2.6.2-work32/net/bluetooth/hci_conn.c-o     2004-02-05 
> 08:09:54.000000000 +0100
> +++ linux-2.6.2-work32/net/bluetooth/hci_conn.c       2004-02-05 
> 15:06:10.000000000 +0100
> @@ -353,21 +353,24 @@
>       struct hci_conn_info *ci;
>       struct hci_dev *hdev;
>       struct list_head *p;
> -     int n = 0, size;
> +     int n = 0, size, err;
>  
>       if (copy_from_user(&req, (void *) arg, sizeof(req)))
>               return -EFAULT;
>  
> -     if (!(hdev = hci_dev_get(req.dev_id)))
> -             return -ENODEV;
> +     if (req.conn_num >= (2*PAGE_SIZE)/sizeof(struct hci_conn_info))
> +             return -EINVAL; 
>  
>       size = req.conn_num * sizeof(struct hci_conn_info) + sizeof(req);
>  
> -     if (verify_area(VERIFY_WRITE, (void *)arg, size))
> -             return -EFAULT;
> -
>       if (!(cl = (void *) kmalloc(size, GFP_KERNEL)))
>               return -ENOMEM;
> +
> +     if (!(hdev = hci_dev_get(req.dev_id))) { 
> +             kfree(cl);
> +             return -ENODEV;
> +     }
> +
>       ci = cl->conn_info;
>  
>       hci_dev_lock_bh(hdev);

Why 2*PAGE_SIZE in this case? What is different?

Regards

Marcel



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