[PATCH 5.15 748/846] RDMA/cma: Remove open coding of overflow checking for private_data_len

[Greg Kroah-Hartman]

From: Håkon Bugge <haakon.bugge@xxxxxxxxxx>

commit 8d0d2b0f41b1b2add8a30dbd816051a964efa497 upstream.

The existing tests are a little hard to comprehend. Use
check_add_overflow() instead.

Fixes: 04ded1672402 ("RDMA/cma: Verify private data length")
Link: https://lore.kernel.org/r/1637661978-18770-1-git-send-email-haakon.bugge@xxxxxxxxxx
Signed-off-by: Håkon Bugge <haakon.bugge@xxxxxxxxxx>
Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/infiniband/core/cma.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -4037,8 +4037,7 @@ static int cma_resolve_ib_udp(struct rdm
 
 	memset(&req, 0, sizeof req);
 	offset = cma_user_data_offset(id_priv);
-	req.private_data_len = offset + conn_param->private_data_len;
-	if (req.private_data_len < conn_param->private_data_len)
+	if (check_add_overflow(offset, conn_param->private_data_len, &req.private_data_len))
 		return -EINVAL;
 
 	if (req.private_data_len) {
@@ -4097,8 +4096,7 @@ static int cma_connect_ib(struct rdma_id
 
 	memset(&req, 0, sizeof req);
 	offset = cma_user_data_offset(id_priv);
-	req.private_data_len = offset + conn_param->private_data_len;
-	if (req.private_data_len < conn_param->private_data_len)
+	if (check_add_overflow(offset, conn_param->private_data_len, &req.private_data_len))
 		return -EINVAL;
 
 	if (req.private_data_len) {