From: Alan Stern <stern@rowland.harvard.edu>
Date: Fri, 24 Mar 2017 17:38:28 +0000 (-0400)
Subject: USB: fix linked-list corruption in rh_call_control()
X-Git-Tag: android-x86-6.0-r3~1^2~5^2~14
X-Git-Url: http://git.osdn.net/view?p=android-x86%2Fkernel.git;a=commitdiff_plain;h=eac3ab3e69151c21a0a71ec8711600022cc12fa3

USB: fix linked-list corruption in rh_call_control()

commit 1633682053a7ee8058e10c76722b9b28e97fb73f upstream.

Using KASAN, Dmitry found a bug in the rh_call_control() routine: If
buffer allocation fails, the routine returns immediately without
unlinking its URB from the control endpoint, eventually leading to
linked-list corruption.

This patch fixes the problem by jumping to the end of the routine
(where the URB is unlinked) when an allocation failure occurs.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 5724d7c41e29..ca2cbdb3aa67 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -499,8 +499,10 @@ static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
 	 */
 	tbuf_size =  max_t(u16, sizeof(struct usb_hub_descriptor), wLength);
 	tbuf = kzalloc(tbuf_size, GFP_KERNEL);
-	if (!tbuf)
-		return -ENOMEM;
+	if (!tbuf) {
+		status = -ENOMEM;
+		goto err_alloc;
+	}
 
 	bufp = tbuf;
 
@@ -705,6 +707,7 @@ error:
 	}
 
 	kfree(tbuf);
+ err_alloc:
 
 	/* any errors get returned through the urb completion */
 	spin_lock_irq(&hcd_root_hub_lock);