PCI: Check dynids driver_data value for validity

Only accept dynids whose driver_data value matches one of the driver's
pci_driver_id entries. This prevents the user from accidentally passing
values the drivers do not expect.

Cc: Milton Miller <miltonm@bga.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

4 files changed, 20 insertions, 10 deletions

diff --git a/Documentation/PCI/pci.txt b/Documentation/PCI/pci.txt
index 8d4dc6250c58..fd4907a2968c 100644
--- a/Documentation/PCI/pci.txt
+++ b/Documentation/PCI/pci.txt
@@ -163,6 +163,10 @@ need pass only as many optional fields as necessary:
         o class and classmask fields default to 0
         o driver_data defaults to 0UL.
 
+Note that driver_data must match the value used by any of the pci_device_id
+entries defined in the driver. This makes the driver_data field mandatory
+if all the pci_device_id entries have a non-zero driver_data value.
+
 Once added, the driver probe routine will be invoked for any unclaimed
 PCI devices listed in its (newly updated) pci_ids list.
 
diff --git a/drivers/i2c/busses/i2c-amd756.c b/drivers/i2c/busses/i2c-amd756.c
index a3542b053c8e..424dad6f18d8 100644
--- a/drivers/i2c/busses/i2c-amd756.c
+++ b/drivers/i2c/busses/i2c-amd756.c
@@ -332,10 +332,6 @@ static int __devinit amd756_probe(struct pci_dev *pdev,
         int error;
         u8 temp;
         
-        /* driver_data might come from user-space, so check it */
-        if (id->driver_data >= ARRAY_SIZE(chipname))
-                return -EINVAL;
-
         if (amd756_ioport) {
                 dev_err(&pdev->dev, "Only one device supported "
                        "(you have a strange motherboard, btw)\n");
diff --git a/drivers/i2c/busses/i2c-viapro.c b/drivers/i2c/busses/i2c-viapro.c
index 2324780484c0..9f194d9efd91 100644
--- a/drivers/i2c/busses/i2c-viapro.c
+++ b/drivers/i2c/busses/i2c-viapro.c
@@ -332,10 +332,6 @@ static int __devinit vt596_probe(struct pci_dev *pdev,
         unsigned char temp;
         int error = -ENODEV;
 
-        /* driver_data might come from user-space, so check it */
-        if (id->driver_data & 1 || id->driver_data > 0xff)
-                return -EINVAL;
-
         /* Determine the address of the SMBus areas */
         if (force_addr) {
                 vt596_smba = force_addr & 0xfff0;
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 4940a53c56a3..b4cdd690ae71 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -43,18 +43,32 @@ store_new_id(struct device_driver *driver, const char *buf, size_t count)
 {
         struct pci_dynid *dynid;
         struct pci_driver *pdrv = to_pci_driver(driver);
+        const struct pci_device_id *ids = pdrv->id_table;
         __u32 vendor, device, subvendor=PCI_ANY_ID,
                 subdevice=PCI_ANY_ID, class=0, class_mask=0;
         unsigned long driver_data=0;
         int fields=0;
-        int retval = 0;
+        int retval;
 
-        fields = sscanf(buf, "%x %x %x %x %x %x %lux",
+        fields = sscanf(buf, "%x %x %x %x %x %x %lx",
                         &vendor, &device, &subvendor, &subdevice,
                         &class, &class_mask, &driver_data);
         if (fields < 2)
                 return -EINVAL;
 
+        /* Only accept driver_data values that match an existing id_table
+           entry */
+        retval = -EINVAL;
+        while (ids->vendor || ids->subvendor || ids->class_mask) {
+                if (driver_data == ids->driver_data) {
+                        retval = 0;
+                        break;
+                }
+                ids++;
+        }
+        if (retval)     /* No match */
+                return retval;
+
         dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
         if (!dynid)
                 return -ENOMEM;