From: Jason Wang <jasowang@redhat.com>
To: Joe Perches <joe@perches.com>
Cc: gleb@kernel.org, pbonzini@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, cornelia.huck@de.ibm.com,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH V2 1/3] kvm: use kmalloc() instead of kzalloc() during iodev register/unregister
Date: Wed, 26 Aug 2015 13:48:57 +0800 [thread overview]
Message-ID: <55DD5349.6030107@redhat.com> (raw)
In-Reply-To: <1440567947.2670.179.camel@perches.com>
On 08/26/2015 01:45 PM, Joe Perches wrote:
> On Wed, 2015-08-26 at 13:39 +0800, Jason Wang wrote:
>> >
>> > On 08/25/2015 11:29 PM, Joe Perches wrote:
>>> > > On Tue, 2015-08-25 at 15:47 +0800, Jason Wang wrote:
>>>>> > >> > All fields of kvm_io_range were initialized or copied explicitly
>>>>> > >> > afterwards. So switch to use kmalloc().
>>> > > Is there any compiler added alignment padding
>>> > > in either structure? If so, those padding
>>> > > areas would now be uninitialized and may leak
>>> > > kernel data if copied to user-space.
>>> > >
>> > I get your concern, but I don't a way to copy them to userspace, did you?
> I didn't look.
>
> I just wanted you to be aware there's a difference
> and a reason why kzalloc might be used even though
> all structure members are initialized.
>
I see, thanks for the reminding. Looks like we are safe and I will add
something like "kvm_io_range was never accessed by userspace" in the
commit log if there's a new version.
prev parent reply other threads:[~2015-08-26 5:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-25 7:47 [PATCH V2 1/3] kvm: use kmalloc() instead of kzalloc() during iodev register/unregister Jason Wang
2015-08-25 7:47 ` [PATCH V2 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses Jason Wang
2015-08-25 8:20 ` Cornelia Huck
2015-08-25 9:06 ` Jason Wang
2015-08-25 11:33 ` Michael S. Tsirkin
2015-08-26 5:07 ` Jason Wang
2015-08-25 7:47 ` [PATCH V2 3/3] kvm: add tracepoint for fast mmio Jason Wang
2015-08-25 11:34 ` Michael S. Tsirkin
2015-08-26 5:08 ` Jason Wang
2015-08-25 15:29 ` [PATCH V2 1/3] kvm: use kmalloc() instead of kzalloc() during iodev register/unregister Joe Perches
2015-08-26 5:39 ` Jason Wang
2015-08-26 5:45 ` Joe Perches
2015-08-26 5:48 ` Jason Wang [this message]
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