From 0854193a684acc2b3a13ab28091a4397000c8822 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Sat, 17 Dec 2016 18:04:30 +0000
Subject: sprintf.c: fix width underflow

* sprintf.c (rb_str_format): fix memory corruption by width
  underflow.  https://github.com/mruby/mruby/issues/3347

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57108 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 sprintf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'sprintf.c')

diff --git a/sprintf.c b/sprintf.c
index 5884926b3e..4342904bdc 100644
--- a/sprintf.c
+++ b/sprintf.c
@@ -705,10 +705,10 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt)
 		    CHECK(n);
 		    rb_enc_mbcput(c, &buf[blen], enc);
 		    blen += n;
-		    FILL(' ', width-1);
+		    if (width > 1) FILL(' ', width-1);
 		}
 		else {
-		    FILL(' ', width-1);
+		    if (width > 1) FILL(' ', width-1);
 		    CHECK(n);
 		    rb_enc_mbcput(c, &buf[blen], enc);
 		    blen += n;
-- 
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