On Thu, Jun 18, 2020 at 05:13:38PM +0800, Macpaul Lin wrote:
> Replace hardcode maximum usb string length (126 bytes) by definition
> "MAX_USB_STRING_LEN".
>
> Signed-off-by: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx>
> Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> ---
> Changes for v2:
> - Add definition "MAX_USB_STRING_LEN" in ch9.h instead of in usb.h.
> Thanks for Alan's suggestion.
> Changes for v3:
> - Rebase to 5.8-rc1 and resolve conflict.
>
> drivers/usb/gadget/composite.c | 4 ++--
> drivers/usb/gadget/configfs.c | 2 +-
> drivers/usb/gadget/usbstring.c | 4 ++--
> include/uapi/linux/usb/ch9.h | 3 +++
> 4 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index cb4950c..d0de016 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -1041,7 +1041,7 @@ static void collect_langs(struct usb_gadget_strings **sp, __le16 *buf)
> while (*sp) {
> s = *sp;
> language = cpu_to_le16(s->language);
> - for (tmp = buf; *tmp && tmp < &buf[126]; tmp++) {
> + for (tmp = buf; *tmp && tmp < &buf[MAX_USB_STRING_LEN]; tmp++) {
> if (*tmp == language)
> goto repeat;
> }
> @@ -1116,7 +1116,7 @@ static int get_string(struct usb_composite_dev *cdev,
> collect_langs(sp, s->wData);
> }
>
> - for (len = 0; len <= 126 && s->wData[len]; len++)
> + for (len = 0; len <= MAX_USB_STRING_LEN && s->wData[len]; len++)
> continue;
> if (!len)
> return -EINVAL;
> diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
> index 32b637e..70dd4ba 100644
> --- a/drivers/usb/gadget/configfs.c
> +++ b/drivers/usb/gadget/configfs.c
> @@ -115,7 +115,7 @@ static int usb_string_copy(const char *s, char **s_copy)
> char *str;
> char *copy = *s_copy;
> ret = strlen(s);
> - if (ret > 126)
> + if (ret > MAX_USB_STRING_LEN)
> return -EOVERFLOW;
>
> str = kstrdup(s, GFP_KERNEL);
> diff --git a/drivers/usb/gadget/usbstring.c b/drivers/usb/gadget/usbstring.c
> index 7c24d1c..8a8d647 100644
> --- a/drivers/usb/gadget/usbstring.c
> +++ b/drivers/usb/gadget/usbstring.c
> @@ -55,9 +55,9 @@
> return -EINVAL;
>
> /* string descriptors have length, tag, then UTF16-LE text */
> - len = min ((size_t) 126, strlen (s->s));
> + len = min((size_t)MAX_USB_STRING_LEN, strlen(s->s));
> len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN,
> - (wchar_t *) &buf[2], 126);
> + (wchar_t *) &buf[2], MAX_USB_STRING_LEN);
> if (len < 0)
> return -EINVAL;
> buf [0] = (len + 1) * 2;
> diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h
> index 2b623f3..cc02d05 100644
> --- a/include/uapi/linux/usb/ch9.h
> +++ b/include/uapi/linux/usb/ch9.h
> @@ -364,6 +364,9 @@ struct usb_config_descriptor {
>
> /*-------------------------------------------------------------------------*/
>
> +/* USB String descriptors can contain at most 126 characters. */
> +#define MAX_USB_STRING_LEN 126
Nit, as this is part of the userspace api, we should make this
"USB_MAX_STRING_LEN" as we should be using "USB_" for all exports here.
That seems to be the case already except for one really odd set of
"TEST_" defines, which I'll go fix up after this...
I will just hand-edit this patch to make that change so you don't have
to respin it again...
thanks,
greg k-h
