[PATCH 40/36] xfs_io: fix label parsing and validation

["Darrick J. Wong" <darrick.wong@xxxxxxxxxx>]

From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>

When we're trying to set a new label, check the length to make sure we
won't overflow the label size, and size label[] so that we can use
strncpy without static checker complaints.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 io/label.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/io/label.c b/io/label.c
index 602ece89..72e07964 100644
--- a/io/label.c
+++ b/io/label.c
@@ -40,7 +40,7 @@ label_f(
 {
 	int		c;
 	int		error;
-	char		label[FSLABEL_MAX];
+	char		label[FSLABEL_MAX + 1];
 
 	if (argc == 1) {
 		memset(label, 0, sizeof(label));
@@ -54,7 +54,13 @@ label_f(
 			label[0] = '\0';
 			break;
 		case 's':
-			strncpy(label, optarg, sizeof(label));
+			if (strlen(optarg) > FSLABEL_MAX) {
+				errno = EINVAL;
+				error = 1;
+				goto out;
+			}
+			strncpy(label, optarg, sizeof(label) - 1);
+			label[sizeof(label) - 1] = 0;
 			break;
 		default:
 			return command_usage(&label_cmd);