[PATCH 4/5] accel/qaic: move and expand integer overflow checks for map_user_pages()

[Dan Carpenter]

The integer overflow checking for find_and_map_user_pages() was done in
encode_dma().  Presumably this was to do it before the allocation.  But
it's not super important that the failure path is a fast path and it
hurts readability to put the check so far from the where the variable is
used.

Move the check to find_and_map_user_pages() instead and add some more
additional potential integer overflow checks.

Fixes: 129776ac2e38 ("accel/qaic: Add control path")
Signed-off-by: Dan Carpenter <dan.carpenter at linaro.org>
---
I kind of went to town adding integer overflow checks here.  Please,
review this extra carefully.

 drivers/accel/qaic/qaic_control.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/accel/qaic/qaic_control.c b/drivers/accel/qaic/qaic_control.c
index 96a26539df18..03932197f1ac 100644
--- a/drivers/accel/qaic/qaic_control.c
+++ b/drivers/accel/qaic/qaic_control.c
@@ -401,6 +401,12 @@ static int find_and_map_user_pages(struct qaic_device *qdev,
 
 	xfer_start_addr = in_trans->addr + resources->xferred_dma_size;
 
+	if (in_trans->size == 0 ||
+	    in_trans->addr + in_trans->size < in_trans->addr ||
+	    in_trans->addr + resources->xferred_dma_size < in_trans->addr ||
+	    in_trans->size + offset_in_page(xfer_start_addr) < resources->xferred_dma_size)
+		return -EINVAL;
+
 	need_pages = DIV_ROUND_UP(in_trans->size + offset_in_page(xfer_start_addr) -
 				  resources->xferred_dma_size, PAGE_SIZE);
 
@@ -563,9 +569,6 @@ static int encode_dma(struct qaic_device *qdev, void *trans, struct wrapper_list
 		     QAIC_MANAGE_EXT_MSG_LENGTH)
 		return -ENOMEM;
 
-	if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size)
-		return -EINVAL;
-
 	xfer = kmalloc(sizeof(*xfer), GFP_KERNEL);
 	if (!xfer)
 		return -ENOMEM;
-- 
2.39.2