From 478effbfd9c3cc5a627fc671d4bf94d13670d65f Mon Sep 17 00:00:00 2001
From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Fri, 27 Sep 2019 12:21:49 +0100
Subject: [PATCH] Fix buffer overflow in string_vformat.  Bug 2449

Fixes CVE-2019-16928:
https://lists.exim.org/lurker/message/20190928.003428.2b4c81a7.en.html

Downloaded from upstream commit
https://git.exim.org/exim.git/patch/478effbfd9c3cc5a627fc671d4bf94d13670d65f

[adjusted patch of string.c and removed patches for test/]
Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
---
 src/string.c             |  4 ++--
 scripts/0000-Basic/0214 | 11 +++++++++++
 stdout/0214             |  7 +++++++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/src/string.c b/src/src/string.c
index c6549bf..3445f8a 100644
--- a/src/string.c
+++ b/src/string.c
@@ -1132,7 +1132,7 @@ store_reset(g->s + (g->size = g->ptr + 1));
 Arguments:
   g		the growable-string
   p		current end of data
-  count		amount to grow by
+  count		amount to grow by, offset from p
 */
 
 static void
@@ -1590,7 +1590,7 @@ while (*fp)
 	}
       else if (g->ptr >= lim - width)
 	{
-	gstring_grow(g, g->ptr, width - (lim - g->ptr));
+	gstring_grow(g, g->ptr, width);
 	lim = g->size - 1;
 	gp = CS g->s + g->ptr;
 	}
-- 
1.9.1