[PATCH] usb:host: fix divide-by-zero in function fhci_queue_urb

zhuyan
2019-04-09T14:39:50Z

In function fhci_queue_urb, the divisor of expression
(urb->transfer_buffer_length % usb_maxpacket(urb->dev, urb->pipe,
usb_pipeout(urb->pipe))) may be zero. When it is zero, unexpected results
may occur, so it is necessary to ensure that the divisor is not zero.

Signed-off-by: zhuyan <zhuyan34@huawei.com>
---
drivers/usb/host/fhci-sched.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/fhci-sched.c b/drivers/usb/host/fhci-sched.c
index 3d12cdd..27ed63c 100644
--- a/drivers/usb/host/fhci-sched.c
+++ b/drivers/usb/host/fhci-sched.c
@@ -704,6 +704,7 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb)
struct td *td;
u8 *data;
u16 cnt = 0;
+ u16 max_pkt_size = 0;

if (ed == NULL) {
ed = fhci_get_empty_ed(fhci);
@@ -765,11 +766,13 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb)

switch (ed->mode) {
case FHCI_TF_BULK:
+ max_pkt_size = usb_maxpacket(urb->dev, urb->pipe,
+ usb_pipeout(urb->pipe));
if (urb->transfer_flags & URB_ZERO_PACKET &&
urb->transfer_buffer_length > 0 &&
+ (max_pkt_size != 0) &&
((urb->transfer_buffer_length %
- usb_maxpacket(urb->dev, urb->pipe,
- usb_pipeout(urb->pipe))) == 0))
+ max_pkt_size) == 0))
urb_state = US_BULK0;
while (data_len > 4096) {
td = fhci_td_fill(fhci, urb, urb_priv, ed, cnt,
--
1.8.5.6