Mdmonitor: Fix segfault

Mdadm with "--monitor" parameter requires md device
as an argument to be monitored. If given argument is
not a md device, error shall be returned. Previously
it was not checked and invalid argument caused
segmentation fault. This commit adds checking
that devices passed to mdmonitor are md devices.

Signed-off-by: Kinga Tanska <kinga.tanska@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/mdopen.c b/mdopen.c
index 245be537..d18c9319 100644
--- a/mdopen.c
+++ b/mdopen.c
@@ -475,6 +475,23 @@ int open_mddev(char *dev, int report_errors)
 	return mdfd;
 }
 
+/**
+ * is_mddev() - check that file name passed is an md device.
+ * @dev: file name that has to be checked.
+ * Return: 1 if file passed is an md device, 0 if not.
+ */
+int is_mddev(char *dev)
+{
+	int fd = open_mddev(dev, 1);
+
+	if (fd >= 0) {
+		close(fd);
+		return 1;
+	}
+
+	return 0;
+}
+
 char *find_free_devnm(int use_partitions)
 {
 	static char devnm[32];