Messages in this thread | | | Date | Mon, 15 Nov 2021 14:48:21 -0600 | From | Bjorn Helgaas <> | Subject | Re: [PATCH 03/11] PCI: pci_stub: Suppress kernel DMA ownership auto-claiming |
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On Mon, Nov 15, 2021 at 10:05:44AM +0800, Lu Baolu wrote: > pci_stub allows the admin to block driver binding on a device and make > it permanently shared with userspace. Since pci_stub does not do DMA, > it is safe.
Can you elaborate on what "permanently shared with userspace" means here? I assume it's only permanent as long as pci-stub is bound to the device?
Also, a few words about what "it is safe" means here would be helpful.
> However the admin must understand that using pci_stub allows > userspace to attack whatever device it was bound to.
The admin isn't going to read this sentence. Should there be a doc update related to this? What sort of attack does this refer to?
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > --- > drivers/pci/pci-stub.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/pci/pci-stub.c b/drivers/pci/pci-stub.c > index e408099fea52..6324c68602b4 100644 > --- a/drivers/pci/pci-stub.c > +++ b/drivers/pci/pci-stub.c > @@ -36,6 +36,9 @@ static struct pci_driver stub_driver = { > .name = "pci-stub", > .id_table = NULL, /* only dynamic id's */ > .probe = pci_stub_probe, > + .driver = { > + .suppress_auto_claim_dma_owner = true, > + }, > }; > > static int __init pci_stub_init(void) > -- > 2.25.1 >
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