From: Heiko Schlittermann (HS12-RIPE) <hs@schlittermann.de>
Date: Mon, 29 Mar 2021 20:44:47 +0000 (+0200)
Subject: CVE-2020-28013: Heap buffer overflow in parse_fix_phrase()
X-Git-Tag: exim-4.95-RC0~51^2~19
X-Git-Url: https://git.exim.org/exim.git/commitdiff_plain/5e4fd0533c99c75cb27137ab469e2ce1e3efaf72?hp=a06ffc5a1b1a49e0e8cd6522ce5a005948333458

CVE-2020-28013: Heap buffer overflow in parse_fix_phrase()

Based on Phil Pennock's 8a50c88a, done by Qualys

(cherry picked from commit 8161c16ec7320ac6164954bade23179a0ed095eb)
(cherry picked from commit 71585e8fcb8704a9f431f5a8d019280cccaad069)
---

diff --git a/src/src/parse.c b/src/src/parse.c
index cfc1f996f..e0470c86f 100644
--- a/src/src/parse.c
+++ b/src/src/parse.c
@@ -1134,12 +1134,7 @@ while (s < end)
             {
             if (ss >= end) ss--;
             *t++ = '(';
-            if (ss < s)
-              {
-              /* Someone has ended the string with "<punct>(". */
-              ss = s;
-              }
-            else
+            if (ss > s)
               {
               Ustrncpy(t, s, ss-s);
               t += ss-s;