[PATCH 1/3] mdadm: Replace snprintf with strncpy at some places to avoid truncation

[Xiao Ni <xni@redhat.com>]

In gcc7 there are some building errors like:
directive output may be truncated writing up to 31 bytes into a region of size 24
snprintf(str, MPB_SIG_LEN, %s, mpb->sig);

It just need to copy one string to target. So use strncpy to replace it.

Signed-off-by: Xiao Ni <xni@redhat.com>
---
 super-intel.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/super-intel.c b/super-intel.c
index d5e9517..e1618f1 100644
--- a/super-intel.c
+++ b/super-intel.c
@@ -1811,7 +1811,8 @@ static void examine_super_imsm(struct supertype *st, char *homehost)
 	__u32 reserved = imsm_reserved_sectors(super, super->disks);
 	struct dl *dl;
 
-	snprintf(str, MPB_SIG_LEN, "%s", mpb->sig);
+	strncpy(str, (char *)mpb->sig, MPB_SIG_LEN);
+	str[MPB_SIG_LEN-1] = '\0';
 	printf("          Magic : %s\n", str);
 	snprintf(str, strlen(MPB_VERSION_RAID0), "%s", get_imsm_version(mpb));
 	printf("        Version : %s\n", get_imsm_version(mpb));
@@ -5227,7 +5228,7 @@ static int init_super_imsm_volume(struct supertype *st, mdu_array_info_t *info,
 			disk->status = CONFIGURED_DISK | FAILED_DISK;
 			disk->scsi_id = __cpu_to_le32(~(__u32)0);
 			snprintf((char *) disk->serial, MAX_RAID_SERIAL_LEN,
-				 "missing:%d", i);
+				 "missing:%d", (__u8)i);
 		}
 		find_missing(super);
 	} else {
@@ -7142,14 +7143,16 @@ static int update_subarray_imsm(struct supertype *st, char *subarray,
 
 			u->type = update_rename_array;
 			u->dev_idx = vol;
-			snprintf((char *) u->name, MAX_RAID_SERIAL_LEN, "%s", name);
+			strncpy((char *) u->name, name, MAX_RAID_SERIAL_LEN);
+			u->name[MAX_RAID_SERIAL_LEN-1] = '\0';
 			append_metadata_update(st, u, sizeof(*u));
 		} else {
 			struct imsm_dev *dev;
 			int i;
 
 			dev = get_imsm_dev(super, vol);
-			snprintf((char *) dev->volume, MAX_RAID_SERIAL_LEN, "%s", name);
+			strncpy((char *) dev->volume, name, MAX_RAID_SERIAL_LEN);
+			dev->volume[MAX_RAID_SERIAL_LEN-1] = '\0';
 			for (i = 0; i < mpb->num_raid_devs; i++) {
 				dev = get_imsm_dev(super, i);
 				handle_missing(super, dev);
-- 
2.7.4