bcache-tools: check whether allocating memory fails in tree()

In tree(), we do not check whether malloc() returns NULL,
it may cause potential Null pointer dereference problem.
In addition, when we fail to list devices, we should free(out)
before return.

Signed-off-by: Zhiqiang Liu <lzhq28@mail.ustc.edu.cn>
Signed-off-by: Coly Li <colyli@suse.de>

1 files changed, 8 insertions, 1 deletions

diff --git a/bcache.c b/bcache.c
index 55589140..18dfa42e 100644
--- a/bcache.c
+++ b/bcache.c
@@ -173,7 +173,7 @@ void replace_line(char **dest, const char *from, const char *to)
 
 int tree(void)
 {
-	char *out = (char *)malloc(4096);
+	char *out;
 	const char *begin = ".\n";
 	const char *middle = "├─";
 	const char *tail = "└─";
@@ -183,8 +183,15 @@ int tree(void)
 	INIT_LIST_HEAD(&head);
 	int ret;
 
+	out = (char *)malloc(4096);
+	if (out == NULL) {
+		fprintf(stderr, "Error: fail to allocate memory buffer\n");
+		return 1;
+	}
+
 	ret = list_bdevs(&head);
 	if (ret != 0) {
+		free(out);
 		fprintf(stderr, "Failed to list devices\n");
 		return ret;
 	}