[PATCH] of: overlay: fix null pointer dereferencing in find_dup_cset_node_entry() and find_dup_cset_prop()

[ruanjinjie <ruanjinjie@xxxxxxxxxx>]

when kmalloc() fail to allocate memory in kasprintf(), fn_1 or fn_2 will
be NULL, strcmp() will cause null pointer dereference.

Fixes: 2fe0e8769df9 ("of: overlay: check prevents multiple fragments touching same property")
Signed-off-by: ruanjinjie <ruanjinjie@xxxxxxxxxx>
---
 drivers/of/overlay.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index bd8ff4df723d..49c066b51148 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -545,6 +545,11 @@ static int find_dup_cset_node_entry(struct overlay_changeset *ovcs,
 
 		fn_1 = kasprintf(GFP_KERNEL, "%pOF", ce_1->np);
 		fn_2 = kasprintf(GFP_KERNEL, "%pOF", ce_2->np);
+		if (!fn_1 || !fn_2) {
+			kfree(fn_1);
+			kfree(fn_2);
+			return -ENOMEM;
+		}
 		node_path_match = !strcmp(fn_1, fn_2);
 		kfree(fn_1);
 		kfree(fn_2);
@@ -580,6 +585,11 @@ static int find_dup_cset_prop(struct overlay_changeset *ovcs,
 
 		fn_1 = kasprintf(GFP_KERNEL, "%pOF", ce_1->np);
 		fn_2 = kasprintf(GFP_KERNEL, "%pOF", ce_2->np);
+		if (!fn_1 || !fn_2) {
+			kfree(fn_1);
+			kfree(fn_2);
+			return -ENOMEM;
+		}
 		node_path_match = !strcmp(fn_1, fn_2);
 		kfree(fn_1);
 		kfree(fn_2);
-- 
2.25.1