[PATCH 4.2 080/110] PCI: Prevent out of bounds access in numa_node override

[Greg Kroah-Hartman]

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sasha Levin <sasha.levin@xxxxxxxxxx>

commit 1266963170f576d4d08e6310b6963e26d3ff9d1e upstream.

63692df103e9 ("PCI: Allow numa_node override via sysfs") didn't check that
the numa node provided by userspace is valid.  Passing a node number too
high would attempt to access invalid memory and trigger a kernel panic.

Fixes: 63692df103e9 ("PCI: Allow numa_node override via sysfs")
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/pci/pci-sysfs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -216,7 +216,7 @@ static ssize_t numa_node_store(struct de
 	if (ret)
 		return ret;
 
-	if (!node_online(node))
+	if (node >= MAX_NUMNODES || !node_online(node))
 		return -EINVAL;
 
 	add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);


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