[PATCH v5 1/9] block: partitions: of: Skip child nodes without reg property

[Loic Poulain]

Child nodes of a fixed-partitions node are not necessarily partition
entries, for example an nvmem-layout node has no reg property. The
current code passes a NULL reg pointer and uninitialized len to the
length check, which can result in a kernel panic or silent failure to
register any partitions.

Fix validate_of_partition() to return a skip indicator when no reg
property is present. Guard add_of_partition() with a reg property
check for the same reason.

Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxxxxxxxx>
---
 block/partitions/of.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/block/partitions/of.c b/block/partitions/of.c
index c22b6066109819c71568f73e8db8833d196b1cf6..534e02a9d85f62611d880af9b302d9fd49aa4d46 100644
--- a/block/partitions/of.c
+++ b/block/partitions/of.c
@@ -15,6 +15,10 @@ static int validate_of_partition(struct device_node *np, int slot)
 	int a_cells = of_n_addr_cells(np);
 	int s_cells = of_n_size_cells(np);
 
+	/* Skip nodes without a reg property (e.g. nvmem-layout) */
+	if (!reg)
+		return 1;
+
 	/* Make sure reg len match the expected addr and size cells */
 	if (len / sizeof(*reg) != a_cells + s_cells)
 		return -EINVAL;
@@ -80,14 +84,15 @@ int of_partition(struct parsed_partitions *state)
 	slot = 1;
 	/* Validate parition offset and size */
 	for_each_child_of_node(partitions_np, np) {
-		if (validate_of_partition(np, slot)) {
+		int err = validate_of_partition(np, slot);
+
+		if (err < 0) {
 			of_node_put(np);
 			of_node_put(partitions_np);
-
 			return -1;
 		}
-
-		slot++;
+		if (!err)
+			slot++;
 	}
 
 	slot = 1;
@@ -97,9 +102,10 @@ int of_partition(struct parsed_partitions *state)
 			break;
 		}
 
-		add_of_partition(state, slot, np);
-
-		slot++;
+		if (of_property_present(np, "reg")) {
+			add_of_partition(state, slot, np);
+			slot++;
+		}
 	}
 
 	seq_buf_puts(&state->pp_buf, "\n");

-- 
2.34.1