fpga: prevent integer overflow in dfl_feature_ioctl_set_irq()

The "hdr.count * sizeof(s32)" multiplication can overflow on 32 bit
systems leading to memory corruption.  Use array_size() to fix that.

Fixes: 322b598be4d9 ("fpga: dfl: introduce interrupt trigger setting API")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/YxBAtYCM38dM7yzI@kili
Signed-off-by: Xu Yilun <yilun.xu@intel.com>

diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index 5498bc3..b9aae85 100644 (file)
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -1866,7 +1866,7 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
                return -EINVAL;
 
        fds = memdup_user((void __user *)(arg + sizeof(hdr)),
-                         hdr.count * sizeof(s32));
+                         array_size(hdr.count, sizeof(s32)));
        if (IS_ERR(fds))
                return PTR_ERR(fds);