[PATCH v2] common: avb_verify: prevent opening incorrect session

[Jens Wiklander]

On Mon, Jan 23, 2023 at 04:51:29PM +0200, Ivan Khoronzhuk wrote:
> The arg->session is not valid if arg->ret != NULL, so can't be
> assigned. Leave retry for just "ret" error to save same behaviour.
> 
> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk at gmail.com>
> ---
>  common/avb_verify.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/common/avb_verify.c b/common/avb_verify.c
> index 0520a71455..97451592f5 100644
> --- a/common/avb_verify.c
> +++ b/common/avb_verify.c
> @@ -619,10 +619,14 @@ static int get_open_session(struct AvbOpsData *ops_data)
>  		memset(&arg, 0, sizeof(arg));
>  		tee_optee_ta_uuid_to_octets(arg.uuid, &uuid);
>  		rc = tee_open_session(tee, &arg, 0, NULL);
> -		if (!rc) {
> -			ops_data->tee = tee;
> -			ops_data->session = arg.session;
> -		}
> +		if (rc)
> +			continue;
> +
> +		if (arg.ret)
> +			return -EIO;
> +
> +		ops_data->tee = tee;
> +		ops_data->session = arg.session;
>  	}
>  
>  	return 0;

It looks like this function is still slightly broken. The function
should, if I understand it correctly, return usable tee and session
pointers on success, else return an error code. The unconditional return
0 at the end doesn't seem right.

Thanks,
Jens