[PATCH 5.19 01/38] of: fdt: fix off-by-one error in unflatten_dt_nodes()

Greg Kroah-Hartman
2022-09-21T15:46:32Z

From: Sergey Shtylyov <s.shtylyov@omp.ru>

[ Upstream commit 2f945a792f67815abca26fa8a5e863ccf3fa1181 ]

Commit 78c44d910d3e ("drivers/of: Fix depth when unflattening devicetree")
forgot to fix up the depth check in the loop body in unflatten_dt_nodes()
which makes it possible to overflow the nps[] buffer...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Fixes: 78c44d910d3e ("drivers/of: Fix depth when unflattening devicetree")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/7c354554-006f-6b31-c195-cdfe4caee392@omp.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/of/fdt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 520ed965bb7a..583ca847a39c 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -314,7 +314,7 @@ static int unflatten_dt_nodes(const void *blob,
for (offset = 0;
offset >= 0 && depth >= initial_depth;
offset = fdt_next_node(blob, offset, &depth)) {
- if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH))
+ if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH - 1))
continue;

if (!IS_ENABLED(CONFIG_OF_KOBJ) &&
--
2.35.1