Re: [PATCH v2] net: vmw_vsock: vmci: Check memcpy_from_msg()

[Artem Chernyshev <artem.chernyshev@red-soft.ru>]

Hi,
On Mon, Dec 05, 2022 at 10:47:36AM +0100, Stefano Garzarella wrote:
> On Sat, Dec 03, 2022 at 11:33:12AM +0300, Artem Chernyshev wrote:
> > vmci_transport_dgram_enqueue() does not check the return value
> > of memcpy_from_msg(). Return with an error if the memcpy fails.
> > 
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> > 
> > Fixes: 0f7db23a07af ("vmci_transport: switch ->enqeue_dgram, ->enqueue_stream and ->dequeue_stream to msghdr")
> > Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
> > ---
> > V1->V2 Fix memory leaking and updates for description
> > 
> > net/vmw_vsock/vmci_transport.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
> > index 842c94286d31..c94c3deaa09d 100644
> > --- a/net/vmw_vsock/vmci_transport.c
> > +++ b/net/vmw_vsock/vmci_transport.c
> > @@ -1711,7 +1711,10 @@ static int vmci_transport_dgram_enqueue(
> > 	if (!dg)
> > 		return -ENOMEM;
> > 
> > -	memcpy_from_msg(VMCI_DG_PAYLOAD(dg), msg, len);
> > +	if (memcpy_from_msg(VMCI_DG_PAYLOAD(dg), msg, len)) {
> > +		kfree(dg);
> > +		return -EFAULT;
> 
> Since memcpy_from_msg() is a wrapper of copy_from_iter_full() that simply
> returns -EFAULT in case of an error, perhaps it would be better here to
> return the value of memcpy_from_msg() instead of wiring the error.
> 
> However in the end the behavior is the same, so even if you don't want to
> change it I'll leave my R-b:
> 
> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
> 
> Thanks,
> Stefano

Thank you for review. Sure, I will change that in V3

Artem