2022-12-23 03:36:14

by Yang Yang

Subject: [PATCH linux-next] rpmsg: use strscpy() to instead of strncpy()

From: Xu Panda <[email protected]>

The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL-terminated strings.

Signed-off-by: Xu Panda <[email protected]>
Signed-off-by: Yang Yang <[email protected]>
---
drivers/rpmsg/rpmsg_ns.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c
index c70ad03ff2e9..c7b5b60aef4d 100644
--- a/drivers/rpmsg/rpmsg_ns.c
+++ b/drivers/rpmsg/rpmsg_ns.c
@@ -48,9 +48,7 @@ static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
}

/* don't trust the remote processor for null terminating the name */
- msg->name[RPMSG_NAME_SIZE - 1] = '\0';
-
- strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
+ strscpy(chinfo.name, msg->name, sizeof(chinfo.name));
chinfo.src = RPMSG_ADDR_ANY;
chinfo.dst = rpmsg32_to_cpu(rpdev, msg->addr);

--
2.15.2

2023-01-05 22:07:18

by Mathieu Poirier

Subject: Re: [PATCH linux-next] rpmsg: use strscpy() to instead of strncpy()

On Fri, Dec 23, 2022 at 10:44:10AM +0800, [email protected] wrote:
> From: Xu Panda <[email protected]>
>
> The implementation of strscpy() is more robust and safer.
> That's now the recommended way to copy NUL-terminated strings.
>
> Signed-off-by: Xu Panda <[email protected]>
> Signed-off-by: Yang Yang <[email protected]>
> ---
> drivers/rpmsg/rpmsg_ns.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c
> index c70ad03ff2e9..c7b5b60aef4d 100644
> --- a/drivers/rpmsg/rpmsg_ns.c
> +++ b/drivers/rpmsg/rpmsg_ns.c
> @@ -48,9 +48,7 @@ static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
> }
>
> /* don't trust the remote processor for null terminating the name */
> - msg->name[RPMSG_NAME_SIZE - 1] = '\0';
> -

This is broken.

> - strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
> + strscpy(chinfo.name, msg->name, sizeof(chinfo.name));

In this case there isn't a need to use strscpy() since we _know_ from the above
that msg->name is NULL terminated.

> chinfo.src = RPMSG_ADDR_ANY;
> chinfo.dst = rpmsg32_to_cpu(rpdev, msg->addr);
>
> --
> 2.15.2