PCI: Fail new_id for vendor/device values already built into driver
While using the sysfs new_id interface, the user can unintentionally feed
incorrect values if the driver static table has a matching entry. This is
possible since only the device and vendor fields are mandatory and the rest
are optional. As a result, store_new_id() will fill in default values that
are then passed on to the driver and can have unintended consequences.
As an example, consider the ixgbe driver and the 82599EB network card:
echo "8086 10fb" > /sys/bus/pci/drivers/ixgbe/new_id
This will pass a pci_device_id with driver_data = 0 to ixgbe_probe(), which
uses that zero to index a table of card operations. The zeroth entry of
the table does *not* correspond to the 82599 operations.
This change returns an error if the user attempts to add a dynid for a
vendor/device combination for which a static entry already exists.
However, if the user intentionally wants a different set of values, she
must provide all the 7 fields and that will be accepted.
[bhelgaas: drop KVM text since the problem isn't KVM-specific]
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index d911e0c..650ce89 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -107,7 +107,7 @@
subdevice=PCI_ANY_ID, class=0, class_mask=0;
unsigned long driver_data=0;
int fields=0;
- int retval;
+ int retval = 0;
fields = sscanf(buf, "%x %x %x %x %x %x %lx",
&vendor, &device, &subvendor, &subdevice,
@@ -115,6 +115,26 @@
if (fields < 2)
return -EINVAL;
+ if (fields != 7) {
+ struct pci_dev *pdev = kzalloc(sizeof(*pdev), GFP_KERNEL);
+ if (!pdev)
+ return -ENOMEM;
+
+ pdev->vendor = vendor;
+ pdev->device = device;
+ pdev->subsystem_vendor = subvendor;
+ pdev->subsystem_device = subdevice;
+ pdev->class = class;
+
+ if (pci_match_id(pdrv->id_table, pdev))
+ retval = -EEXIST;
+
+ kfree(pdev);
+
+ if (retval)
+ return retval;
+ }
+
/* Only accept driver_data values that match an existing id_table
entry */
if (ids) {