Re: [PATCH 19/20] usbip: usbip_host: Manual replacement of the deprecated strlcpy() with return values

Shuah Khan
2021-02-22T17:23:58Z

On 2/22/21 8:12 AM, Romain Perier wrote:
> The strlcpy() reads the entire source buffer first, it is dangerous if
> the source buffer lenght is unbounded or possibility non NULL-terminated.
> It can lead to linear read overflows, crashes, etc...
>
> As recommended in the deprecated interfaces [1], it should be replaced
> by strscpy.
>
> This commit replaces all calls to strlcpy that handle the return values
> by the corresponding strscpy calls with new handling of the return
> values (as it is quite different between the two functions).
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
>
> Signed-off-by: Romain Perier <romain.perier@gmail.com>
> ---
> drivers/usb/usbip/stub_main.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c
> index 77a5b3f8736a..5bc2c09c0d10 100644
> --- a/drivers/usb/usbip/stub_main.c
> +++ b/drivers/usb/usbip/stub_main.c
> @@ -167,15 +167,15 @@ static ssize_t match_busid_show(struct device_driver *drv, char *buf)
> static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
> size_t count)
> {
> - int len;
> + ssize_t len;
> char busid[BUSID_SIZE];
>
> if (count < 5)
> return -EINVAL;
>
> /* busid needs to include \0 termination */
> - len = strlcpy(busid, buf + 4, BUSID_SIZE);
> - if (sizeof(busid) <= len)
> + len = strscpy(busid, buf + 4, BUSID_SIZE);
> + if (len == -E2BIG)
> return -EINVAL;
>
> if (!strncmp(buf, "add ", 4)) {
>

Looks good to me. Thank you.

Acked-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah