[PATCH 3.16 062/366] parisc: Fix out of array access in match_pci_device()

Ben Hutchings
2018-10-14T23:20:52Z

From: Helge Deller <deller@gmx.de>

commit 615b2665fd20c327b631ff1e79426775de748094 upstream.

As found by the ubsan checker, the value of the 'index' variable can be
out of range for the bc[] array:

UBSAN: Undefined behaviour in arch/parisc/kernel/drivers.c:655:21
index 6 is out of range for type 'char [6]'
Backtrace:
[<104fa850>] __ubsan_handle_out_of_bounds+0x68/0x80
[<1019d83c>] check_parent+0xc0/0x170
[<1019d91c>] descend_children+0x30/0x6c
[<1059e164>] device_for_each_child+0x60/0x98
[<1019cd54>] parse_tree_node+0x40/0x54
[<1019d86c>] check_parent+0xf0/0x170
[<1019d91c>] descend_children+0x30/0x6c
[<1059e164>] device_for_each_child+0x60/0x98
[<1019d938>] descend_children+0x4c/0x6c
[<1059e164>] device_for_each_child+0x60/0x98
[<1019cd54>] parse_tree_node+0x40/0x54
[<1019cffc>] hwpath_to_device+0xa4/0xc4

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/parisc/kernel/drivers.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/arch/parisc/kernel/drivers.c
+++ b/arch/parisc/kernel/drivers.c
@@ -648,6 +648,10 @@ static int match_pci_device(struct devic
(modpath->mod == PCI_FUNC(devfn)));
}

+ /* index might be out of bounds for bc[] */
+ if (index >= 6)
+ return 0;
+
id = PCI_SLOT(pdev->devfn) | (PCI_FUNC(pdev->devfn) << 5);
return (modpath->bc[index] == id);
}