1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 318bb3b96687..4664e543cf2f 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -140,6 +140,9 @@ module_param(usbfs_memory_mb, uint, 0644);
 MODULE_PARM_DESC(usbfs_memory_mb,
                 "maximum MB allowed for usbfs buffers (0 = no limit)");
 
+/* Hard limit, necessary to avoid arithmetic overflow */
+#define USBFS_XFER_MAX         (UINT_MAX / 2 - 1000000)
+
 static atomic64_t usbfs_memory_usage;   /* Total memory currently allocated */
 
 /* Check whether it's okay to allocate more memory for a transfer */
@@ -1460,6 +1463,8 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
                                 USBDEVFS_URB_ZERO_PACKET |
                                 USBDEVFS_URB_NO_INTERRUPT))
                 return -EINVAL;
+        if ((unsigned int)uurb->buffer_length >= USBFS_XFER_MAX)
+                return -EINVAL;
         if (uurb->buffer_length > 0 && !uurb->buffer)
                 return -EINVAL;
         if (!(uurb->type == USBDEVFS_URB_TYPE_CONTROL &&
@@ -1571,7 +1576,11 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
                         totlen += isopkt[u].length;
                 }
                 u *= sizeof(struct usb_iso_packet_descriptor);
-                uurb->buffer_length = totlen;
+                if (totlen <= uurb->buffer_length)
+                        uurb->buffer_length = totlen;
+                else
+                        WARN_ONCE(1, "uurb->buffer_length is too short %d vs %d",
+                                  totlen, uurb->buffer_length);
                 break;
 
         default: