USB: serial: io_edgeport: fix descriptor error handling

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@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 15 insertions, 9 deletions

diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index 653ea2e35c31..464db17b5328 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -2105,8 +2105,7 @@ static int rom_write(struct usb_serial *serial, __u16 extAddr, __u16 addr,
  * 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)
@@ -2131,12 +2130,17 @@ static int rom_read(struct usb_serial *serial, __u16 extAddr,
                                         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);
@@ -2590,9 +2594,10 @@ static void get_manufacturing_desc(struct edgeport_serial *edge_serial)
                                 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",
@@ -2649,9 +2654,10 @@ static void get_boot_desc(struct edgeport_serial *edge_serial)
                                 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));