2021-12-10 03:38:45

by Jiapeng Chong

Subject: [PATCH] staging: r8188eu: Use memdup_user instead of kmalloc/copy_from_user

Fix following coccicheck warning:

./drivers/staging/r8188eu/os_dep/ioctl_linux.c:4253:8-15: WARNING
opportunity for memdup_user.

Reported-by: Abaci Robot <[email protected]>
Signed-off-by: Jiapeng Chong <[email protected]>
---
drivers/staging/r8188eu/os_dep/ioctl_linux.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/r8188eu/os_dep/ioctl_linux.c b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
index 56adfe4087a8..c6a2fbfe8f26 100644
--- a/drivers/staging/r8188eu/os_dep/ioctl_linux.c
+++ b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
@@ -4250,17 +4250,12 @@ static int rtw_test(
DBG_88E("+%s\n", __func__);
len = wrqu->data.length;

- pbuf = kzalloc(len, GFP_KERNEL);
- if (!pbuf) {
- DBG_88E("%s: no memory!\n", __func__);
- return -ENOMEM;
- }
-
- if (copy_from_user(pbuf, wrqu->data.pointer, len)) {
- kfree(pbuf);
+ pbuf = memdup_user(wrqu->data.pointer, len);
+ if (IS_ERR(pbuf)) {
DBG_88E("%s: copy from user fail!\n", __func__);
- return -EFAULT;
+ return PTR_ERR(pbuf);
}
+
DBG_88E("%s: string =\"%s\"\n", __func__, pbuf);

ptmp = (char *)pbuf;
--
2.34.0

2021-12-10 08:30:49

by Dan Carpenter

Subject: Re: [PATCH] staging: r8188eu: Use memdup_user instead of kmalloc/copy_from_user

On Fri, Dec 10, 2021 at 11:38:32AM +0800, Jiapeng Chong wrote:
> Fix following coccicheck warning:
>
> ./drivers/staging/r8188eu/os_dep/ioctl_linux.c:4253:8-15: WARNING
> opportunity for memdup_user.
>
> Reported-by: Abaci Robot <[email protected]>
> Signed-off-by: Jiapeng Chong <[email protected]>
> ---
> drivers/staging/r8188eu/os_dep/ioctl_linux.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/staging/r8188eu/os_dep/ioctl_linux.c b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
> index 56adfe4087a8..c6a2fbfe8f26 100644
> --- a/drivers/staging/r8188eu/os_dep/ioctl_linux.c
> +++ b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
> @@ -4250,17 +4250,12 @@ static int rtw_test(
> DBG_88E("+%s\n", __func__);
> len = wrqu->data.length;
>
> - pbuf = kzalloc(len, GFP_KERNEL);
> - if (!pbuf) {
> - DBG_88E("%s: no memory!\n", __func__);
> - return -ENOMEM;
> - }
> -
> - if (copy_from_user(pbuf, wrqu->data.pointer, len)) {
> - kfree(pbuf);
> + pbuf = memdup_user(wrqu->data.pointer, len);

This code assumes that the user is going to give us a NUL terminated
string which is not necessarily true. The original code was buggy too.
Anyway, please fix it. Use strndup_user() and mention that it is a bug
fix in the commit message:

pbuf = strndup_user(wrqu->data.pointer, len);

Add a Fixes tag.

regards,
dan carpenter