2023-05-15 09:33:42

by Yang Li

Subject: [PATCH -next] fastrpc: Use memdup_user instead of kmalloc/copy_from_user

Use memdup_user rather than duplicating its implementation, which
makes code simple and easy to understand, and silence the following
warning:

./drivers/misc/fastrpc.c:1259:8-15: WARNING opportunity for memdup_user

Reported-by: Abaci Robot <[email protected]>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4949
Signed-off-by: Yang Li <[email protected]>
---
drivers/misc/fastrpc.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index f60bbf99485c..a897dab13c61 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1256,16 +1256,9 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
goto err;
}

- name = kzalloc(init.namelen, GFP_KERNEL);
- if (!name) {
- err = -ENOMEM;
- goto err;
- }
-
- if (copy_from_user(name, (void __user *)(uintptr_t)init.name, init.namelen)) {
- err = -EFAULT;
- goto err_name;
- }
+ name = memdup_user((void __user *)(uintptr_t)init.name, init.namelen);
+ if (IS_ERR(name))
+ return PTR_ERR(name);

if (!fl->cctx->remote_heap) {
err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,
--
2.20.1.7.g153144c

2023-05-15 09:47:59

by Luca Weiss

Subject: Re: [PATCH -next] fastrpc: Use memdup_user instead of kmalloc/copy_from_user

Hi Yang Li,

On Mon May 15, 2023 at 11:26 AM CEST, Yang Li wrote:
> Use memdup_user rather than duplicating its implementation, which
> makes code simple and easy to understand, and silence the following
> warning:
>
> ./drivers/misc/fastrpc.c:1259:8-15: WARNING opportunity for memdup_user
>
> Reported-by: Abaci Robot <[email protected]>
> Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4949
> Signed-off-by: Yang Li <[email protected]>
> ---
> drivers/misc/fastrpc.c | 13 +++----------
> 1 file changed, 3 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index f60bbf99485c..a897dab13c61 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -1256,16 +1256,9 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
> goto err;
> }
>
> - name = kzalloc(init.namelen, GFP_KERNEL);
> - if (!name) {
> - err = -ENOMEM;
> - goto err;
> - }
> -
> - if (copy_from_user(name, (void __user *)(uintptr_t)init.name, init.namelen)) {
> - err = -EFAULT;
> - goto err_name;
> - }
> + name = memdup_user((void __user *)(uintptr_t)init.name, init.namelen);
> + if (IS_ERR(name))
> + return PTR_ERR(name);

Don't we still need a "goto err;" here to free args?

Something like this:

if (IS_ERR(name)) {
err = PTR_ERR(name);
goto err;
}

Regards
Luca


>
> if (!fl->cctx->remote_heap) {
> err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,