ocfs2: use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Link: http://lkml.kernel.org/r/20200311093516.25300-1-tiwai@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 78cb48d6a596..89d13e0705fe 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -1307,7 +1307,7 @@ static int o2hb_debug_open(struct inode *inode, struct file *file)
 
 	case O2HB_DB_TYPE_REGION_NUMBER:
 		reg = (struct o2hb_region *)db->db_data;
-		out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
+		out += scnprintf(buf + out, PAGE_SIZE - out, "%d\n",
 				reg->hr_region_num);
 		goto done;
 
@@ -1317,12 +1317,12 @@ static int o2hb_debug_open(struct inode *inode, struct file *file)
 		/* If 0, it has never been set before */
 		if (lts)
 			lts = jiffies_to_msecs(jiffies - lts);
-		out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
+		out += scnprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
 		goto done;
 
 	case O2HB_DB_TYPE_REGION_PINNED:
 		reg = (struct o2hb_region *)db->db_data;
-		out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
+		out += scnprintf(buf + out, PAGE_SIZE - out, "%u\n",
 				!!reg->hr_item_pinned);
 		goto done;
 
@@ -1331,8 +1331,8 @@ static int o2hb_debug_open(struct inode *inode, struct file *file)
 	}
 
 	while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
-		out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
-	out += snprintf(buf + out, PAGE_SIZE - out, "\n");
+		out += scnprintf(buf + out, PAGE_SIZE - out, "%d ", i);
+	out += scnprintf(buf + out, PAGE_SIZE - out, "\n");
 
 done:
 	i_size_write(inode, out);