of: fdt: fix off-by-one error in unflatten_dt_nodes()

[ 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>

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 9fecac72c358c88584b232d9058add6e4ef2f658..7c284ca0212c507d5690ee0f82e29610daa8035c 100644 (file)
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -392,7 +392,7 @@ 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) &&