From: Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>
Date: Tue, 12 Dec 2017 09:39:10 +0000 (+0800)
Subject: dm log writes: fix max length used for kstrndup
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=4b259fc4a8a12dcd0ffd670877a7a1ca2ab0f3e3;p=linux.git

dm log writes: fix max length used for kstrndup

If source string is longer than max, kstrndup will allocate max+1
space.  So make sure the result will not exceed max.

Signed-off-by: Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---

diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index 189badbeddaf7..3362d866793b3 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -594,7 +594,7 @@ static int log_mark(struct log_writes_c *lc, char *data)
 		return -ENOMEM;
 	}
 
-	block->data = kstrndup(data, maxsize, GFP_KERNEL);
+	block->data = kstrndup(data, maxsize - 1, GFP_KERNEL);
 	if (!block->data) {
 		DMERR("Error copying mark data");
 		kfree(block);