[PATCH 3.16 046/212] USB: serial: io_edgeport: fix descriptor error handling

From: Ben Hutchings
Date: Thu Jun 01 2017 - 12:37:13 EST


3.16.44-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@xxxxxxxxxx>

commit 3c0e25d883d06a1fbd1ad35257e8abaa57befb37 upstream.

Make sure to detect short control-message transfers and log an error
when reading incomplete manufacturer and boot descriptors.

Note that the default all-zero descriptors will now be used after a
short transfer is detected instead of partially initialised ones.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/usb/serial/io_edgeport.c | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)

--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -2109,8 +2109,7 @@ static int rom_write(struct usb_serial *
* rom_read
* reads a number of bytes from the Edgeport device starting at the given
* address.
- * If successful returns the number of bytes read, otherwise it returns
- * a negative error number of the problem.
+ * Returns zero on success or a negative error number.
****************************************************************************/
static int rom_read(struct usb_serial *serial, __u16 extAddr,
__u16 addr, __u16 length, __u8 *data)
@@ -2135,12 +2134,17 @@ static int rom_read(struct usb_serial *s
USB_REQUEST_ION_READ_ROM,
0xC0, addr, extAddr, transfer_buffer,
current_length, 300);
- if (result < 0)
+ if (result < current_length) {
+ if (result >= 0)
+ result = -EIO;
break;
+ }
memcpy(data, transfer_buffer, current_length);
length -= current_length;
addr += current_length;
data += current_length;
+
+ result = 0;
}

kfree(transfer_buffer);
@@ -2597,9 +2601,10 @@ static void get_manufacturing_desc(struc
EDGE_MANUF_DESC_LEN,
(__u8 *)(&edge_serial->manuf_descriptor));

- if (response < 1)
- dev_err(dev, "error in getting manufacturer descriptor\n");
- else {
+ if (response < 0) {
+ dev_err(dev, "error in getting manufacturer descriptor: %d\n",
+ response);
+ } else {
char string[30];
dev_dbg(dev, "**Manufacturer Descriptor\n");
dev_dbg(dev, " RomSize: %dK\n",
@@ -2656,9 +2661,10 @@ static void get_boot_desc(struct edgepor
EDGE_BOOT_DESC_LEN,
(__u8 *)(&edge_serial->boot_descriptor));

- if (response < 1)
- dev_err(dev, "error in getting boot descriptor\n");
- else {
+ if (response < 0) {
+ dev_err(dev, "error in getting boot descriptor: %d\n",
+ response);
+ } else {
dev_dbg(dev, "**Boot Descriptor:\n");
dev_dbg(dev, " BootCodeLength: %d\n",
le16_to_cpu(edge_serial->boot_descriptor.BootCodeLength));