2020-06-12 05:37:14

by Macpaul Lin

[permalink] [raw]
Subject: [PATCH] usb: replace hardcoded maximum usb string length by definition

Replace hardcoded maximum usb string length (126 bytes) by definition
"MAX_USB_STRING_LEN".

Signed-off-by: Macpaul Lin <[email protected]>
---
drivers/usb/gadget/composite.c | 4 ++--
drivers/usb/gadget/configfs.c | 3 ++-
drivers/usb/gadget/usbstring.c | 5 +++--
include/linux/usb.h | 2 ++
4 files changed, 9 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..c9d61ac 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -4,6 +4,7 @@
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/nls.h>
+#include <linux/usb.h>
#include <linux/usb/composite.h>
#include <linux/usb/gadget_configfs.h>
#include "configfs.h"
@@ -115,7 +116,7 @@ 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..c125d59 100644
--- a/drivers/usb/gadget/usbstring.c
+++ b/drivers/usb/gadget/usbstring.c
@@ -11,6 +11,7 @@
#include <linux/device.h>
#include <linux/nls.h>

+#include <linux/usb.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

@@ -55,9 +56,9 @@
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/linux/usb.h b/include/linux/usb.h
index 9f3c721..df4a9cb 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1815,6 +1815,8 @@ static inline int usb_get_ptm_status(struct usb_device *dev, void *data)
0, data);
}

+/* USB String descriptors can contain at most 126 characters. */
+#define MAX_USB_STRING_LEN 126
extern int usb_string(struct usb_device *dev, int index,
char *buf, size_t size);

--
1.7.9.5


2020-06-12 14:04:36

by Alan Stern

[permalink] [raw]
Subject: Re: [PATCH] usb: replace hardcoded maximum usb string length by definition

On Fri, Jun 12, 2020 at 01:32:47PM +0800, Macpaul Lin wrote:
> Replace hardcoded maximum usb string length (126 bytes) by definition
> "MAX_USB_STRING_LEN".
>
> Signed-off-by: Macpaul Lin <[email protected]>

...

> diff --git a/include/linux/usb.h b/include/linux/usb.h
> index 9f3c721..df4a9cb 100644
> --- a/include/linux/usb.h
> +++ b/include/linux/usb.h
> @@ -1815,6 +1815,8 @@ static inline int usb_get_ptm_status(struct usb_device *dev, void *data)
> 0, data);
> }
>
> +/* USB String descriptors can contain at most 126 characters. */
> +#define MAX_USB_STRING_LEN 126

This definition belongs in include/uapi/linux/usb/ch9.h (near the
definition of struct usb_string_descriptor) because it is part of the USB
standard rather than specific to the Linux USB stack.

Alan Stern

2020-06-15 06:20:30

by Macpaul Lin

[permalink] [raw]
Subject: [PATCH v2] usb: replace hardcode maximum usb string length by definition

Replace hardcode maximum usb string length (126 bytes) by definition
"MAX_USB_STRING_LEN".

Signed-off-by: Macpaul Lin <[email protected]>
---
Changes for v2:
- Add definition "MAX_USB_STRING_LEN" in ch9.h instead of in usb.h.
Thanks for Alan's suggestion.

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
+
/* USB_DT_STRING: String descriptor */
struct usb_string_descriptor {
__u8 bLength;
--
1.7.9.5

2020-06-15 14:45:10

by Alan Stern

[permalink] [raw]
Subject: Re: [PATCH v2] usb: replace hardcode maximum usb string length by definition

On Mon, Jun 15, 2020 at 02:17:35PM +0800, Macpaul Lin wrote:
> Replace hardcode maximum usb string length (126 bytes) by definition
> "MAX_USB_STRING_LEN".
>
> Signed-off-by: Macpaul Lin <[email protected]>
> ---
> Changes for v2:
> - Add definition "MAX_USB_STRING_LEN" in ch9.h instead of in usb.h.
> Thanks for Alan's suggestion.

Acked-by: Alan Stern <[email protected]>

2020-06-18 09:56:21

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH v2] usb: replace hardcode maximum usb string length by definition

On Mon, Jun 15, 2020 at 02:17:35PM +0800, Macpaul Lin wrote:
> Replace hardcode maximum usb string length (126 bytes) by definition
> "MAX_USB_STRING_LEN".
>
> Signed-off-by: Macpaul Lin <[email protected]>
> ---
> Changes for v2:
> - Add definition "MAX_USB_STRING_LEN" in ch9.h instead of in usb.h.
> Thanks for Alan's suggestion.
>
> 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(-)

This patch fails to apply to my tree (or to 5.8-rc1). Please rebase it
and resend.

thanks,

greg k-h

2020-06-18 11:48:18

by Macpaul Lin

[permalink] [raw]
Subject: [PATCH v3] usb: replace hardcode maximum usb string length by definition

Replace hardcode maximum usb string length (126 bytes) by definition
"MAX_USB_STRING_LEN".

Signed-off-by: Macpaul Lin <[email protected]>
Acked-by: Alan Stern <[email protected]>
---
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
+
/* USB_DT_STRING: String descriptor */
struct usb_string_descriptor {
__u8 bLength;
--
1.7.9.5

2020-06-18 14:06:45

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH v3] usb: replace hardcode maximum usb string length by definition

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 <[email protected]>
> Acked-by: Alan Stern <[email protected]>
> ---
> 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