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authorDan Carpenter <dan.carpenter@oracle.com>2017-09-22 16:43:25 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-09-25 04:57:13 -0400
commit57999d1107c1e60c2ca7088f2ac0f819e2f554b3 (patch)
tree6081b8b694eeae7c08ea2cc082c9966517cdb838
parent1fbbb78f25d1291274f320462bf6908906f538db (diff)
USB: devio: Prevent integer overflow in proc_do_submiturb()
There used to be an integer overflow check in proc_do_submiturb() but we removed it. It turns out that it's still required. The uurb->buffer_length variable is a signed integer and it's controlled by the user. It can lead to an integer overflow when we do: num_sgs = DIV_ROUND_UP(uurb->buffer_length, USB_SG_SIZE); If we strip away the macro then that line looks like this: num_sgs = (uurb->buffer_length + USB_SG_SIZE - 1) / USB_SG_SIZE; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ It's the first addition which can overflow. Fixes: 1129d270cbfb ("USB: Increase usbfs transfer limit") Cc: stable <stable@vger.kernel.org> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/core/devio.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 318bb3b96687..e9326f31db8d 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -140,6 +140,9 @@ module_param(usbfs_memory_mb, uint, 0644);
140MODULE_PARM_DESC(usbfs_memory_mb, 140MODULE_PARM_DESC(usbfs_memory_mb,
141 "maximum MB allowed for usbfs buffers (0 = no limit)"); 141 "maximum MB allowed for usbfs buffers (0 = no limit)");
142 142
143/* Hard limit, necessary to avoid arithmetic overflow */
144#define USBFS_XFER_MAX (UINT_MAX / 2 - 1000000)
145
143static atomic64_t usbfs_memory_usage; /* Total memory currently allocated */ 146static atomic64_t usbfs_memory_usage; /* Total memory currently allocated */
144 147
145/* Check whether it's okay to allocate more memory for a transfer */ 148/* 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
1460 USBDEVFS_URB_ZERO_PACKET | 1463 USBDEVFS_URB_ZERO_PACKET |
1461 USBDEVFS_URB_NO_INTERRUPT)) 1464 USBDEVFS_URB_NO_INTERRUPT))
1462 return -EINVAL; 1465 return -EINVAL;
1466 if ((unsigned int)uurb->buffer_length >= USBFS_XFER_MAX)
1467 return -EINVAL;
1463 if (uurb->buffer_length > 0 && !uurb->buffer) 1468 if (uurb->buffer_length > 0 && !uurb->buffer)
1464 return -EINVAL; 1469 return -EINVAL;
1465 if (!(uurb->type == USBDEVFS_URB_TYPE_CONTROL && 1470 if (!(uurb->type == USBDEVFS_URB_TYPE_CONTROL &&