[PATCH 3.16 335/366] usbip: stub_rx: fix static checker warning on unnecessary checks

Ben Hutchings
2018-11-11T20:29:05Z

From: Shuah Khan <shuahkh@osg.samsung.com>

commit 10c90120930628e8b959bf58d4a0aaef3ae5d945 upstream.

Fix the following static checker warnings:

The patch c6688ef9f297: "usbip: fix stub_rx: harden CMD_SUBMIT path
to handle malicious input" from Dec 7, 2017, leads to the following
static checker warning:

drivers/usb/usbip/stub_rx.c:346 get_pipe()
warn: impossible condition
'(pdu->u.cmd_submit.transfer_buffer_length > ((~0 >> 1))) =>
(s32min-s32max > s32max)'
drivers/usb/usbip/stub_rx.c:486 stub_recv_cmd_submit()
warn: always true condition
'(pdu->u.cmd_submit.transfer_buffer_length <= ((~0 >> 1))) =>
(s32min-s32max <= s32max)'

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/staging/usbip/stub_rx.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)

--- a/drivers/staging/usbip/stub_rx.c
+++ b/drivers/staging/usbip/stub_rx.c
@@ -353,14 +353,6 @@ static int get_pipe(struct stub_device *

epd = &ep->desc;

- /* validate transfer_buffer_length */
- if (pdu->u.cmd_submit.transfer_buffer_length > INT_MAX) {
- dev_err(&sdev->udev->dev,
- "CMD_SUBMIT: -EMSGSIZE transfer_buffer_length %d\n",
- pdu->u.cmd_submit.transfer_buffer_length);
- return -1;
- }
-
if (usb_endpoint_xfer_control(epd)) {
if (dir == USBIP_DIR_OUT)
return usb_sndctrlpipe(udev, epnum);
@@ -494,8 +486,7 @@ static void stub_recv_cmd_submit(struct
}

/* allocate urb transfer buffer, if needed */
- if (pdu->u.cmd_submit.transfer_buffer_length > 0 &&
- pdu->u.cmd_submit.transfer_buffer_length <= INT_MAX) {
+ if (pdu->u.cmd_submit.transfer_buffer_length > 0) {
priv->urb->transfer_buffer =
kzalloc(pdu->u.cmd_submit.transfer_buffer_length,
GFP_KERNEL);