linux-kernel - [PATCH 18/20] usb: get rid of pointless access

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Date:   Sun, 10 May 2020 00:45:55 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     linux-kernel@...r.kernel.org
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-fsdevel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH 18/20] usb: get rid of pointless access_ok() calls

From: Al Viro <viro@...iv.linux.org.uk>

in all affected cases addresses are passed only to
copy_from()_user or copy_to_user().

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 drivers/usb/core/devices.c          | 2 --
 drivers/usb/core/devio.c            | 9 ---------
 drivers/usb/gadget/function/f_hid.c | 6 ------
 3 files changed, 17 deletions(-)

diff --git a/drivers/usb/core/devices.c b/drivers/usb/core/devices.c
index 44f28a114c2b..94b6fa6e585e 100644
--- a/drivers/usb/core/devices.c
+++ b/drivers/usb/core/devices.c
@@ -598,8 +598,6 @@ static ssize_t usb_device_read(struct file *file, char __user *buf,
 		return -EINVAL;
 	if (nbytes <= 0)
 		return 0;
-	if (!access_ok(buf, nbytes))
-		return -EFAULT;
 
 	mutex_lock(&usb_bus_idr_lock);
 	/* print devices for all busses */
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 6833c918abce..544769807ab8 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1127,11 +1127,6 @@ static int proc_control(struct usb_dev_state *ps, void __user *arg)
 		ctrl.bRequestType, ctrl.bRequest, ctrl.wValue,
 		ctrl.wIndex, ctrl.wLength);
 	if (ctrl.bRequestType & 0x80) {
-		if (ctrl.wLength && !access_ok(ctrl.data,
-					       ctrl.wLength)) {
-			ret = -EINVAL;
-			goto done;
-		}
 		pipe = usb_rcvctrlpipe(dev, 0);
 		snoop_urb(dev, NULL, pipe, ctrl.wLength, tmo, SUBMIT, NULL, 0);
 
@@ -1216,10 +1211,6 @@ static int proc_bulk(struct usb_dev_state *ps, void __user *arg)
 	}
 	tmo = bulk.timeout;
 	if (bulk.ep & 0x80) {
-		if (len1 && !access_ok(bulk.data, len1)) {
-			ret = -EINVAL;
-			goto done;
-		}
 		snoop_urb(dev, NULL, pipe, len1, tmo, SUBMIT, NULL, 0);
 
 		usb_unlock_device(dev);
diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index f3816a5c861e..df671acdd464 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -252,9 +252,6 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer,
 	if (!count)
 		return 0;
 
-	if (!access_ok(buffer, count))
-		return -EFAULT;
-
 	spin_lock_irqsave(&hidg->read_spinlock, flags);
 
 #define READ_COND (!list_empty(&hidg->completed_out_req))
@@ -339,9 +336,6 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
 	unsigned long flags;
 	ssize_t status = -ENOMEM;
 
-	if (!access_ok(buffer, count))
-		return -EFAULT;
-
 	spin_lock_irqsave(&hidg->write_spinlock, flags);
 
 #define WRITE_COND (!hidg->write_pending)
-- 
2.11.0