IB/hfi1: Add limit test for RC/UC send via loopback

commit 09ce351d upstream.

Fix potential memory corruption and panic in loopback for IB_WR_SEND
variants.

The code blindly assumes the posted length will fit in the fetched rwqe,
which is not a valid assumption.

Fix by adding a limit test, and triggering the appropriate send completion
and putting the QP in an error state.  This mimics the handling for
non-loopback QPs.

Fixes: 15703461 ("IB/{hfi1, qib, rdmavt}: Move ruc_loopback to rdmavt")
Cc: <stable@vger.kernel.org> #v4.20+
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>

drivers/infiniband/hw/hfi1/ruc.c

@@ -440,6 +440,8 @@ static void ruc_loopback(struct rvt_qp *sqp)
 			goto op_err;
 		if (!ret)
 			goto rnr_nak;
+		if (wqe->length > qp->r_len)
+			goto inv_err;
 		break;
 
 	case IB_WR_RDMA_WRITE_WITH_IMM:
@@ -607,7 +609,10 @@ static void ruc_loopback(struct rvt_qp *sqp)
 	goto err;
 
 inv_err:
-	send_status = IB_WC_REM_INV_REQ_ERR;
+	send_status =
+		sqp->ibqp.qp_type == IB_QPT_RC ?
+			IB_WC_REM_INV_REQ_ERR :
+			IB_WC_SUCCESS;
 	wc.status = IB_WC_LOC_QP_OP_ERR;
 	goto err;
 

drivers/infiniband/hw/qib/qib_ruc.c

@@ -425,6 +425,8 @@ static void qib_ruc_loopback(struct rvt_qp *sqp)
 			goto op_err;
 		if (!ret)
 			goto rnr_nak;
+		if (wqe->length > qp->r_len)
+			goto inv_err;
 		break;
 
 	case IB_WR_RDMA_WRITE_WITH_IMM:
@@ -585,7 +587,10 @@ static void qib_ruc_loopback(struct rvt_qp *sqp)
 	goto err;
 
 inv_err:
-	send_status = IB_WC_REM_INV_REQ_ERR;
+	send_status =
+		sqp->ibqp.qp_type == IB_QPT_RC ?
+			IB_WC_REM_INV_REQ_ERR :
+			IB_WC_SUCCESS;
 	wc.status = IB_WC_LOC_QP_OP_ERR;
 	goto err;