From: Greg KH <greg@kroah.com>
To: bugzilla-daemon@bugzilla.kernel.org
Cc: linux-usb@vger.kernel.org
Subject: Re: [Bug 212995] New: A possible divide by zero in qh_urb_transaction
Date: Sat, 8 May 2021 13:18:00 +0200 [thread overview]
Message-ID: <YJZzaGrRbGYLuWRj@kroah.com> (raw)
In-Reply-To: <bug-212995-208809@https.bugzilla.kernel.org/>
On Sat, May 08, 2021 at 11:14:25AM +0000, bugzilla-daemon@bugzilla.kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=212995
>
> Bug ID: 212995
> Summary: A possible divide by zero in qh_urb_transaction
> Product: Drivers
> Version: 2.5
> Kernel Version: 5.12.2
> Hardware: All
> OS: Linux
> Tree: Mainline
> Status: NEW
> Severity: normal
> Priority: P1
> Component: USB
> Assignee: drivers_usb@kernel-bugs.kernel.org
> Reporter: yguoaz@gmail.com
> Regression: No
>
> In the file drivers/usb/host/ehci-q.c, the function qh_urb_transaction has the
> following code (link to the code location:
> https://github.com/torvalds/linux/blob/dd860052c99b1e088352bdd4fb7aef46f8d2ef47/drivers/usb/host/ehci-q.c#L715):
>
> maxpacket = usb_maxpacket(urb->dev, urb->pipe, !is_input);
> ...
> if (usb_pipeout(urb->pipe) && (urb->transfer_flags & URB_ZERO_PACKET)
> && !(urb->transfer_buffer_length % maxpacket))
>
> However, the function usb_maxpacket may retun 0, leading to a possible divide
> zero problem in the remainder operation:
Please feel free to submit a patch to the developers, but first see how
it could be possible for usb_maxpacket to ever return 0 for this. Are
you sure it's not already sanitized by the time it gets here?
thanks,
greg k-h
next prev parent reply other threads:[~2021-05-08 11:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-08 11:14 [Bug 212995] New: A possible divide by zero in qh_urb_transaction bugzilla-daemon
2021-05-08 11:18 ` Greg KH [this message]
2021-05-08 11:18 ` [Bug 212995] " bugzilla-daemon
2021-05-08 11:37 ` bugzilla-daemon
2021-05-08 14:36 ` bugzilla-daemon
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