[PATCH rdma-next v3 3/7] RDMA/irdma: Clear udata response buffers where necessary

[Jacob Moroni <jmoroni@google.com>]

Methods that may accept udata input but do not provide a
udata response should use the ib_respond_empty_udata()
helper to ensure that user response buffers are cleared.

Since the ib_respond_empty_udata() call itself can fail if
the user intentionally provides a bogus output buffer, it is
called at the beginning of the method to fail early before
mutating any state that would be difficult to unwind.

Additionally, add missing bounds validation for udata->outlen
in irdma_create_srq() to ensure it is large enough to hold the
response struct as per its original (and so far, only) definition.

Signed-off-by: Jacob Moroni <jmoroni@google.com>
---
 drivers/infiniband/hw/irdma/verbs.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/infiniband/hw/irdma/verbs.c b/drivers/infiniband/hw/irdma/verbs.c
index be964f777e64..d5795d4fe7b3 100644
--- a/drivers/infiniband/hw/irdma/verbs.c
+++ b/drivers/infiniband/hw/irdma/verbs.c
@@ -1316,6 +1316,11 @@ int irdma_modify_qp_roce(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 	u8 issue_modify_qp = 0;
 	int ret = 0;
 
+	/* Clear the response buffer (if any). It may be updated again later. */
+	ret = ib_respond_empty_udata(udata);
+	if (ret)
+		return ret;
+
 	ctx_info = &iwqp->ctx_info;
 	roce_info = &iwqp->roce_info;
 	udp_info = &iwqp->udp_info;
@@ -1676,6 +1681,10 @@ int irdma_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask,
 	int err;
 	unsigned long flags;
 
+	err = ib_respond_empty_udata(udata);
+	if (err)
+		return err;
+
 	if (udata) {
 		/* udata inlen/outlen can be 0 when supporting legacy libi40iw */
 		if ((udata->inlen && udata->inlen < IRDMA_MODIFY_QP_MIN_REQ_LEN) ||
@@ -2095,6 +2104,10 @@ static int irdma_resize_cq(struct ib_cq *ibcq, unsigned int entries,
 	if (entries > rf->max_cqe)
 		return -EINVAL;
 
+	ret = ib_respond_empty_udata(udata);
+	if (ret)
+		return ret;
+
 	if (!iwcq->user_mode) {
 		entries += 2;
 
@@ -2395,6 +2408,7 @@ static int irdma_create_srq(struct ib_srq *ibsrq,
 			    struct ib_srq_init_attr *initattrs,
 			    struct ib_udata *udata)
 {
+#define IRDMA_CREATE_SRQ_MIN_RESP_LEN offsetofend(struct irdma_create_srq_resp, srq_size)
 	struct irdma_device *iwdev = to_iwdev(ibsrq->device);
 	struct ib_srq_attr *attr = &initattrs->attr;
 	struct irdma_pd *iwpd = to_iwpd(ibsrq->pd);
@@ -2415,6 +2429,9 @@ static int irdma_create_srq(struct ib_srq *ibsrq,
 	if (initattrs->srq_type != IB_SRQT_BASIC)
 		return -EOPNOTSUPP;
 
+	if (udata && udata->outlen < IRDMA_CREATE_SRQ_MIN_RESP_LEN)
+		return -EINVAL;
+
 	if (!(uk_attrs->feature_flags & IRDMA_FEATURE_SRQ) ||
 	    attr->max_sge > uk_attrs->max_hw_wq_frags)
 		return -EINVAL;
@@ -3607,6 +3624,10 @@ static struct ib_mr *irdma_reg_user_mr(struct ib_pd *pd, u64 start, u64 len,
 	if (dmah)
 		return ERR_PTR(-EOPNOTSUPP);
 
+	err = ib_respond_empty_udata(udata);
+	if (err)
+		return ERR_PTR(err);
+
 	if (len > iwdev->rf->sc_dev.hw_attrs.max_mr_size)
 		return ERR_PTR(-EINVAL);
 
-- 
2.55.0.rc0.799.gd6f94ed593-goog