[PATCH 4.2.y-ckt 062/305] PCI: Prevent out of bounds access in numa_node override

[Kamal Mostafa]

4.2.8-ckt2 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Mathias Krause <minipli@xxxxxxxxxxxxxx>

commit 3dcc8d39cf15fa3ceabedcffcbd3958fe953555a upstream.

Commit 1266963170f5 ("PCI: Prevent out of bounds access in numa_node
override") missed that the user-provided node could also be negative.
Handle this case as well to avoid out-of-bounds accesses to the
node_states[] array.  However, allow the special value -1, i.e.
NUMA_NO_NODE, to be able to set the 'no specific node' configuration.

Fixes: 1266963170f5 ("PCI: Prevent out of bounds access in numa_node override")
Fixes: 63692df103e9 ("PCI: Allow numa_node override via sysfs")
Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
CC: Sasha Levin <sasha.levin@xxxxxxxxxx>
CC: Prarit Bhargava <prarit@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 drivers/pci/pci-sysfs.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 9261868..eead54c 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -216,7 +216,10 @@ static ssize_t numa_node_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	if (node >= MAX_NUMNODES || !node_online(node))
+	if ((node < 0 && node != NUMA_NO_NODE) || node >= MAX_NUMNODES)
+		return -EINVAL;
+
+	if (node != NUMA_NO_NODE && !node_online(node))
 		return -EINVAL;
 
 	add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
-- 
1.9.1