Re: [PATCH] RDMA/rxe: Implement packet length validation on responder

lizhijian
2022-11-05T09:38:40Z

On 28/10/2022 17:04, Daisuke Matsuda wrote:
> The function check_length() is supposed to check the length of inbound
> packets on responder, but it actually has been a stub since the driver was
> born. Let it check the payload length and the DMA length.
>
> Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
> ---
> FOR REVIEWERS
> I referred to IB Specification Vol 1-Revision-1.5 to create this patch.
> Please see 9.7.4.1.6 (page.330).
>
> drivers/infiniband/sw/rxe/rxe_resp.c | 36 ++++++++++++++++++++++------
> 1 file changed, 29 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
> index ed5a09e86417..62e3a8195072 100644
> --- a/drivers/infiniband/sw/rxe/rxe_resp.c
> +++ b/drivers/infiniband/sw/rxe/rxe_resp.c
> @@ -390,16 +390,38 @@ static enum resp_states check_resource(struct rxe_qp *qp,
> static enum resp_states check_length(struct rxe_qp *qp,
> struct rxe_pkt_info *pkt)
> {
> - switch (qp_type(qp)) {
> - case IB_QPT_RC:
> - return RESPST_CHK_RKEY;
> + int mtu = qp->mtu;
> + u32 payload = payload_size(pkt);
> + u32 dmalen = reth_len(pkt);
>
> - case IB_QPT_UC:
> - return RESPST_CHK_RKEY;
> + /* RoCEv2 packets do not have LRH.
> + * Let's skip checking it.
> + */
>
> - default:
> - return RESPST_CHK_RKEY;
> + if ((pkt->opcode & RXE_START_MASK) &&
> + (pkt->opcode & RXE_END_MASK)) {
> + /* "only" packets */
> + if (payload > mtu)
> + return RESPST_ERR_LENGTH;
> +
> + } else if ((pkt->opcode & RXE_START_MASK) ||
> + (pkt->opcode & RXE_MIDDLE_MASK)) {
> + /* "first" or "middle" packets */
> + if (payload != mtu)
> + return RESPST_ERR_LENGTH;
> +
> + } else if (pkt->opcode & RXE_END_MASK) {
> + /* "last" packets */
> + if ((pkt->paylen == 0) || (pkt->paylen > mtu))

As per IBA spec, i didn't see any difference about the 'packet payload
length' from others,

so May I know why here you are using 'pkt->paylen' instead of payload ?

Thanks

Zhijian

> + return RESPST_ERR_LENGTH;
> + }
> +
> + if (pkt->opcode & (RXE_WRITE_MASK | RXE_READ_MASK)) {
> + if (dmalen > (1 << 31))
> + return RESPST_ERR_LENGTH;
> }
> +
> + return RESPST_CHK_RKEY;
> }
>
> static enum resp_states check_rkey(struct rxe_qp *qp,