[PATCH] drivers/fpga: copy userspace array safely

From: Philipp Stanner
Date: Thu Nov 02 2023 - 14:50:16 EST


dfl.c utilizes memdup_user() and array_size() to copy a userspace array.
Currently, this does not check for an overflow.

Use the new wrapper memdup_array_user() to copy the array more safely.

Suggested-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx>
---
Linus recently merged this new wrapper for Kernel v6.7
---
drivers/fpga/dfl.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index dd7a783d53b5..e69b9f1f2a50 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -2008,8 +2008,8 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
(hdr.start + hdr.count < hdr.start))
return -EINVAL;

- fds = memdup_user((void __user *)(arg + sizeof(hdr)),
- array_size(hdr.count, sizeof(s32)));
+ fds = memdup_array_user((void __user *)(arg + sizeof(hdr)),
+ hdr.count, sizeof(s32));
if (IS_ERR(fds))
return PTR_ERR(fds);

--
2.41.0