2021-02-19 10:00:21

by Dan Carpenter

Subject: [PATCH] cxl/mem: return -EFAULT if copy_to_user() fails

The copy_to_user() function returns the number of bytes remaining to be
copied, but we want to return -EFAULT if the copy doesn't complete.

Fixes: b754ffbbc0ee ("cxl/mem: Add basic IOCTL interface")
Signed-off-by: Dan Carpenter <[email protected]>
---
drivers/cxl/mem.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 8331a2fc7667..d73ab363ad71 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -745,7 +745,10 @@ static int cxl_send_cmd(struct cxl_memdev *cxlmd,
if (rc)
return rc;

- return copy_to_user(s, &send, sizeof(send));
+ if (copy_to_user(s, &send, sizeof(send)))
+ return -EFAULT;
+
+ return 0;
}

static long __cxl_memdev_ioctl(struct cxl_memdev *cxlmd, unsigned int cmd,
--
2.30.0

2021-02-19 15:41:56

by Dan Williams

Subject: Re: [PATCH] cxl/mem: return -EFAULT if copy_to_user() fails

On Fri, Feb 19, 2021 at 1:55 AM Dan Carpenter <[email protected]> wrote:
>
> The copy_to_user() function returns the number of bytes remaining to be
> copied, but we want to return -EFAULT if the copy doesn't complete.
>
> Fixes: b754ffbbc0ee ("cxl/mem: Add basic IOCTL interface")
> Signed-off-by: Dan Carpenter <[email protected]>
> ---

Looks good, Dan, thanks!