[PATCH V5 3/4] Btrfs-progs: Fix set_label_unmounted() with label length validation

From: Jeff Liu <jeff.liu@oracle.com>
To: linux-btrfs@vger.kernel.org
Cc: anand.jain@oracle.com
Subject: [PATCH V5 3/4] Btrfs-progs: Fix set_label_unmounted() with label length validation
Date: Mon, 17 Dec 2012 19:35:27 +0800	[thread overview]
Message-ID: <50CF037F.2010509@oracle.com> (raw)
In-Reply-To: <50CF0053.4050906@oracle.com>

Currently, we keeping silent if the label length is exceeding BTRFS_LABEL_SIZE - 1, and just
truncating the characters beyond that.

This patch make it return error and exit in this situation.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>

---
 btrfslabel.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/btrfslabel.c b/btrfslabel.c
index 938e8b4..2826050 100644
--- a/btrfslabel.c
+++ b/btrfslabel.c
@@ -63,6 +63,12 @@ static int set_label_unmounted(const char *dev, const char *label)
 		return -1;
 	}
 
+	if (strlen(label) > BTRFS_LABEL_SIZE - 1) {
+		fprintf(stderr, "ERROR: Label %s is too long (max %d)\n",
+			label, BTRFS_LABEL_SIZE - 1);
+		return -1;
+	}
+
 	/* Open the super_block at the default location
 	 * and as read-write.
 	 */
@@ -71,8 +77,8 @@ static int set_label_unmounted(const char *dev, const char *label)
 		return -1;
 
 	trans = btrfs_start_transaction(root, 1);
-	strncpy(root->fs_info->super_copy.label, label, BTRFS_LABEL_SIZE);
-	root->fs_info->super_copy.label[BTRFS_LABEL_SIZE-1] = 0;
+	snprintf(root->fs_info->super_copy.label, BTRFS_LABEL_SIZE, "%s",
+		 label);
 	btrfs_commit_transaction(trans, root);
 
 	/* Now we close it since we are done. */
-- 
1.7.9.5
