rule: json: fix returned string length

It was returning one byte more than the real string length.

Signed-off-by: Alvaro Neira Ayuso <alvaroneay@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/rule.c b/src/rule.c
index b4ce8f1..5fd8814 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -745,7 +745,9 @@ static int nft_rule_snprintf_json(char *buf, size_t size, struct nft_rule *r,
 		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
 
 	}
-	ret = snprintf(buf+offset-1, len, "]}}");
+	/* Remove comma from last element */
+	offset--;
+	ret = snprintf(buf+offset, len, "]}}");
 	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
 
 	return offset;