[Bionic][PATCH 11/12] powerpc/powernv/npu: Check mmio_atsd array bounds when populating

[Jose Ricardo Ziviani]

From: Alexey Kardashevskiy <aik at ozlabs.ru>

BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1819989

A broken device tree might contain more than 8 values and introduce hard
to debug memory corruption bug. This adds the boundary check.

Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
(cherry picked from commit 135ef954051b102870a8d47a8eb822af1f1b1ec1)
Signed-off-by: Jose Ricardo Ziviani <joserz at linux.ibm.com>
---
 arch/powerpc/platforms/powernv/npu-dma.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
index 53713ff439a9..0440d0c01142 100644
--- a/arch/powerpc/platforms/powernv/npu-dma.c
+++ b/arch/powerpc/platforms/powernv/npu-dma.c
@@ -964,8 +964,9 @@ int pnv_npu2_init(struct pci_controller *hose)
 
 	npu->nmmu_flush = of_property_read_bool(hose->dn, "ibm,nmmu-flush");
 
-	for (i = 0; !of_property_read_u64_index(hose->dn, "ibm,mmio-atsd",
-							i, &mmio_atsd); i++)
+	for (i = 0; i < ARRAY_SIZE(npu->mmio_atsd_regs) &&
+			!of_property_read_u64_index(hose->dn, "ibm,mmio-atsd",
+				i, &mmio_atsd); i++)
 		npu->mmio_atsd_regs[i] = ioremap(mmio_atsd, 32);
 
 	pr_info("NPU%d: Found %d MMIO ATSD registers", hose->global_number, i);
-- 
2.20.1