Alan Stern wrote:
> On Sun, 8 Mar 2009, Roel Kluin wrote:
>
>> A test for a negative urb->transfer_buffer_length has become obsolete.
>
>> usb_internal_control_msg() returns both error values and a length. To ensure
>> that it does not return an unsigned length that is converted into a negative,
>> the returned length is limited to INT_MAX.
>
> Instead of doing it this way, it would be simpler and more robust to
> change the test for a negative urb->transfer_buffer_length in
> submit_urb() into a test for urb->transfer_buffer_length > INT_MAX.
While I think this test may be useful for conversions elsewhere, In this
functions actual_length is converted, not transfer_buffer_length, or am I
missing something?
I have adapted it however, since it should occur in usb_start_wait_urb().
in that function the first conversion occurs.
> (Strictly speaking, this shouldn't be INT_MAX -- it should be the
> largest possible 32-bit signed integer. But until 64-bit integers
> become the default we will be safe...)
The largest possible signed integer?
> Then we would know that the
> length returned by usb_internal_control_msg() could never be too large.
>
> Alan Stern
how's this?
------------------------------>8-------------8<---------------------------------
transfer_buffer_length and actual_length have become unsigned, therefore some
additional conversion of local variables, function arguments and print
specifications is desired.
A test for a negative urb->transfer_buffer_length became obsolete; instead
we ensure that it does not exceed INT_MAX.
rh_string() does no longer return -EPIPE in the case of an unsupported ID.
Instead its only caller, rh_call_control() does the check.
usb_start_wait_urb() returns both error values and a length. To ensure that it
does not return an unsigned length that is converted into a negative, the
returned length is limited to INT_MAX.
Signed-off-by: Roel Kluin <roel.kluin@xxxxxxxxx>
---
drivers/usb/core/devio.c | 6 +++---
drivers/usb/core/hcd.c | 31 ++++++++++++-------------------
drivers/usb/core/hub.c | 2 +-
drivers/usb/core/message.c | 8 ++++----
drivers/usb/core/urb.c | 2 +-
5 files changed, 21 insertions(+), 28 deletions(-)
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 7513bb0..64ed07c 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -302,7 +302,7 @@ static inline struct async *async_getpending(struct dev_state *ps,
static void snoop_urb(struct urb *urb, void __user *userurb)
{
- int j;
+ u32 j;
unsigned char *data = urb->transfer_buffer;
if (!usbfs_snoop)
@@ -311,9 +311,9 @@ static void snoop_urb(struct urb *urb, void __user *userurb)
dev_info(&urb->dev->dev, "direction=%s\n",
usb_urb_dir_in(urb) ? "IN" : "OUT");
dev_info(&urb->dev->dev, "userurb=%p\n", userurb);
- dev_info(&urb->dev->dev, "transfer_buffer_length=%d\n",
+ dev_info(&urb->dev->dev, "transfer_buffer_length=%u\n",
urb->transfer_buffer_length);
- dev_info(&urb->dev->dev, "actual_length=%d\n", urb->actual_length);
+ dev_info(&urb->dev->dev, "actual_length=%u\n", urb->actual_length);
dev_info(&urb->dev->dev, "data: ");
for (j = 0; j < urb->transfer_buffer_length; ++j)
printk("%02x ", data[j]);
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 3c711db..8cec7cc 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -279,9 +279,9 @@ static const u8 hs_rh_config_descriptor [] = {
* helper routine for returning string descriptors in UTF-16LE
* input can actually be ISO-8859-1; ASCII is its 7-bit subset
*/
-static int ascii2utf (char *s, u8 *utf, int utfmax)
+static u32 ascii2utf(char *s, u8 *utf, int utfmax)
{
- int retval;
+ u32 retval;
for (retval = 0; *s && utfmax > 1; utfmax -= 2, retval += 2) {
*utf++ = *s++;
@@ -304,19 +304,15 @@ static int ascii2utf (char *s, u8 *utf, int utfmax)
* Produces either a manufacturer, product or serial number string for the
* virtual root hub device.
*/
-static int rh_string (
- int id,
- struct usb_hcd *hcd,
- u8 *data,
- int len
-) {
+static u32 rh_string(int id, struct usb_hcd *hcd, u8 *data, u32 len)
+{
char buf [100];
// language ids
if (id == 0) {
buf[0] = 4; buf[1] = 3; /* 4 bytes string data */
buf[2] = 0x09; buf[3] = 0x04; /* MSFT-speak for "en-us" */
- len = min (len, 4);
+ len = min_t(u32, len, 4);
memcpy (data, buf, len);
return len;
@@ -332,10 +328,7 @@ static int rh_string (
} else if (id == 3) {
snprintf (buf, sizeof buf, "%s %s %s", init_utsname()->sysname,
init_utsname()->release, hcd->driver->description);
-
- // unsupported IDs --> "protocol stall"
- } else
- return -EPIPE;
+ }
switch (len) { /* All cases fall through */
default:
@@ -360,9 +353,8 @@ static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
u8 tbuf [sizeof (struct usb_hub_descriptor)]
__attribute__((aligned(4)));
const u8 *bufp = tbuf;
- int len = 0;
+ u32 len = 0;
int status;
- int n;
u8 patch_wakeup = 0;
u8 patch_protocol = 0;
@@ -456,10 +448,11 @@ static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
patch_wakeup = 1;
break;
case USB_DT_STRING << 8:
- n = rh_string (wValue & 0xff, hcd, ubuf, wLength);
- if (n < 0)
+ if ((wValue & 0xff) < 4)
+ urb->actual_length = rh_string(wValue & 0xff,
+ hcd, ubuf, wLength);
+ else /* unsupported IDs --> "protocol stall" */
goto error;
- urb->actual_length = n;
break;
default:
goto error;
@@ -629,7 +622,7 @@ static int rh_queue_status (struct usb_hcd *hcd, struct urb *urb)
{
int retval;
unsigned long flags;
- int len = 1 + (urb->dev->maxchild / 8);
+ u32 len = 1 + (urb->dev->maxchild / 8);
spin_lock_irqsave (&hcd_root_hub_lock, flags);
if (hcd->status_urb || urb->transfer_buffer_length < len) {
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index cd50d86..9e09539 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -392,7 +392,7 @@ static void hub_irq(struct urb *urb)
{
struct usb_hub *hub = urb->context;
int status = urb->status;
- int i;
+ u32 i;
unsigned long bits;
switch (status) {
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 49e7f56..cd77357 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -59,7 +59,7 @@ static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status);
dev_dbg(&urb->dev->dev,
- "%s timed out on ep%d%s len=%d/%d\n",
+ "%s timed out on ep%d%s len=%u/%u\n",
current->comm,
usb_endpoint_num(&urb->ep->desc),
usb_urb_dir_in(urb) ? "in" : "out",
@@ -69,7 +69,7 @@ static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
retval = ctx.status;
out:
if (actual_length)
- *actual_length = urb->actual_length;
+ *actual_length = min_t(u32, urb->actual_length, INT_MAX);
usb_free_urb(urb);
return retval;
@@ -402,7 +402,7 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
urb_flags |= URB_SHORT_NOT_OK;
for_each_sg(sg, sg, io->entries, i) {
- unsigned len;
+ size_t len;
io->urbs[i] = usb_alloc_urb(0, mem_flags);
if (!io->urbs[i]) {
@@ -449,7 +449,7 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
}
if (length) {
- len = min_t(unsigned, len, length);
+ len = min_t(size_t, len, length);
length -= len;
if (length == 0)
io->entries = i + 1;
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index 58bc5e3..673e2fb 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -370,7 +370,7 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
}
/* the I/O buffer must be mapped/unmapped, except when length=0 */
- if (urb->transfer_buffer_length < 0)
+ if (urb->transfer_buffer_length > INT_MAX)
return -EMSGSIZE;
#ifdef DEBUG
--
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