[patch v2] vfio/pci: make an array larger

Dan Carpenter
2015-11-09T12:25:13Z

Smatch complains about a possible out of bounds error:

drivers/vfio/pci/vfio_pci_config.c:1241 vfio_cap_init()
error: buffer overflow 'pci_cap_length' 20 <= 20

The problem is that pci_cap_length[] was defined as large enough to
hold "PCI_CAP_ID_AF + 1" elements. The code in vfio_cap_init() assumes
it has PCI_CAP_ID_MAX + 1 elements. Originally, PCI_CAP_ID_AF and
PCI_CAP_ID_MAX were the same but then we introduced PCI_CAP_ID_EA in
f80b0ba95964 ('PCI: Add Enhanced Allocation register entries') so now
the array is too small.

Let's fix this by making the array size PCI_CAP_ID_MAX + 1. And let's
make a similar change to pci_ext_cap_length[] for consistency. Also
both these arrays can be made const.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: more cleanups

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index a8657ef..fe2b470 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -46,7 +46,7 @@
* 0: Removed from the user visible capability list
* FF: Variable length
*/
-static u8 pci_cap_length[] = {
+static const u8 pci_cap_length[PCI_CAP_ID_MAX + 1] = {
[PCI_CAP_ID_BASIC] = PCI_STD_HEADER_SIZEOF, /* pci config header */
[PCI_CAP_ID_PM] = PCI_PM_SIZEOF,
[PCI_CAP_ID_AGP] = PCI_AGP_SIZEOF,
@@ -74,7 +74,7 @@ static u8 pci_cap_length[] = {
* 0: Removed or masked from the user visible capabilty list
* FF: Variable length
*/
-static u16 pci_ext_cap_length[] = {
+static const u16 pci_ext_cap_length[PCI_EXT_CAP_ID_MAX + 1] = {
[PCI_EXT_CAP_ID_ERR] = PCI_ERR_ROOT_COMMAND,
[PCI_EXT_CAP_ID_VC] = 0xFF,
[PCI_EXT_CAP_ID_DSN] = PCI_EXT_CAP_DSN_SIZEOF,