Re: [PATCH 3/9] Bluetooth: Validate PSM values in calls to connect() and bind().

[Marcel Holtmann <marcel@xxxxxxxxxxxx>]

Hi Mat,

> Valid L2CAP PSMs are odd numbers, and the least significant bit of the
> most significant byte must be 0.
> 
> Signed-off-by: Mat Martineau <mathewm@xxxxxxxxxxxxxx>
> ---
>  net/bluetooth/l2cap.c |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
> index bc10be8..77ba106 100644
> --- a/net/bluetooth/l2cap.c
> +++ b/net/bluetooth/l2cap.c
> @@ -1008,6 +1008,12 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
>  		goto done;
>  	}
>  
> +	/* If specified, PSM must be odd and lsb of upper byte must be 0 */
> +	if (la.l2_psm && (__le16_to_cpu(la.l2_psm) & 0x0101) != 0x0001) {
> +		err = -EINVAL;
> +		goto done;
> +	}
> +
>  	if (la.l2_psm && __le16_to_cpu(la.l2_psm) < 0x1001 &&
>  				!capable(CAP_NET_BIND_SERVICE)) {
>  		err = -EACCES;

we might wanna do this a bit nicer here:

	if (la.l2_psm) {
		__u16 psm = __le16_to_cpu(la.l2_psm);

		if ((psm & 0x0101) != 0x0001) {
			err = -EINVAL;
			goto done;
		}

		if (psm < 0x1001 && ...) {
			...
		}
	}

Regards

Marcel


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