From 8895d3bcb8ba960b1b83f95d772b641352ea8e51 Mon Sep 17 00:00:00 2001 From: Bandan Das Date: Tue, 1 Apr 2014 21:32:59 -0400 Subject: [PATCH] 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 Signed-off-by: Bjorn Helgaas Reviewed-by: Alex Williamson --- drivers/pci/pci-driver.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index d911e0c1f359..650ce8935fd7 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -107,7 +107,7 @@ store_new_id(struct device_driver *driver, const char *buf, size_t count) 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 @@ store_new_id(struct device_driver *driver, const char *buf, size_t count) 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) { -- 2.30.2