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

Dan Carpenter
2019-08-21T07:11:40Z

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.carpenter@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