[PATCH 4/4] misc: xilinx_sdfec: Prevent integer overflow in xsdfec_table_write()

[Dan Carpenter]

The checking here needs to handle integer overflows because "offset" and
"len" come from the user.

Fixes: 20ec628e8007 ("misc: xilinx_sdfec: Add ability to configure LDPC")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
---
 drivers/misc/xilinx_sdfec.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/xilinx_sdfec.c b/drivers/misc/xilinx_sdfec.c
index 3fc53d20abf3..0bf3bcc8e1ef 100644
--- a/drivers/misc/xilinx_sdfec.c
+++ b/drivers/misc/xilinx_sdfec.c
@@ -611,7 +611,9 @@ static int xsdfec_table_write(struct xsdfec_dev *xsdfec, 
u32 offset,
         * Writes that go beyond the length of
         * Shared Scale(SC) table should fail
         */
-       if ((XSDFEC_REG_WIDTH_JUMP * (offset + len)) > depth) {
+       if (offset > depth / XSDFEC_REG_WIDTH_JUMP ||
+           len > depth / XSDFEC_REG_WIDTH_JUMP ||
+           offset + len > depth / XSDFEC_REG_WIDTH_JUMP) {
                dev_dbg(xsdfec->dev, "Write exceeds SC table length");
                return -EINVAL;
        }
-- 
2.20.1