On Fri, Aug 27, 2021 at 9:24 PM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> These checks are still not strict enough. The main problem is that if
> "cb->type == QRTR_TYPE_NEW_SERVER" is true then "len - hdrlen" is
> guaranteed to be 4 but we need to be at least 16 bytes. In fact, we
> can reject everything smaller than sizeof(*pkt) which is 20 bytes.
>
> Also I don't like the ALIGN(size, 4). It's better to just insist that
> data is needs to be aligned at the start.
>
> Fixes: 0baa99ee353c ("net: qrtr: Allow non-immediate node routing")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> This was from review. Not tested.
>
> net/qrtr/qrtr.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
> index b8508e35d20e..dbb647f5481b 100644
> --- a/net/qrtr/qrtr.c
> +++ b/net/qrtr/qrtr.c
> @@ -493,7 +493,7 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
> goto err;
> }
>
> - if (!size || len != ALIGN(size, 4) + hdrlen)
> + if (!size || size % 3 || len != size + hdrlen)
Hi, (size % 3) is wrong, is it (size & 3), right ?
> goto err;
>
> if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA &&
> @@ -506,8 +506,12 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
>
> if (cb->type == QRTR_TYPE_NEW_SERVER) {
> /* Remote node endpoint can bridge other distant nodes */
> - const struct qrtr_ctrl_pkt *pkt = data + hdrlen;
> + const struct qrtr_ctrl_pkt *pkt;
>
> + if (size < sizeof(*pkt))
Yes, the size should not be smaller than sizeof(*pkt).
> + goto err;
> +
> + pkt = data + hdrlen;
> qrtr_node_assign(node, le32_to_cpu(pkt->server.node));
> }
>
> --
> 2.20.1
>
Regards,
butt3rflyh4ck
--
Active Defense Lab of Venustech
