[exim-cvs] SECURITY: fix Qualys CVE-2020-PFPSN

Commit:     cb08e2f59f2166660abc998a0554e64c61d4a0f5
Parent:     5dc522966ae58ac845dc280495af651c9858f152
Author:     Phil Pennock <phil+git@???>
AuthorDate: Thu Oct 29 19:00:51 2020 -0400
Committer:  Heiko Schlittermann (HS12-RIPE) <hs@???>
CommitDate: Thu May 27 21:30:25 2021 +0200

    SECURITY: fix Qualys CVE-2020-PFPSN

    (cherry picked from commit 93b6044e1636404f3463f3e1113098742e295542)
    (cherry picked from commit 4e59a5d5c448e1fcdcbead268ffe6561adf0224d)
---
 doc/doc-txt/ChangeLog |  4 ++++
 src/src/parse.c       | 14 +++++++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index ba9cc1c..07fba9c 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -269,6 +269,10 @@ PP/03 Impose security length checks on various command-line options.
 PP/04 Fix Linux security issue CVE-2020-SLCWD and guard against PATH_MAX
       better.  Reported by Qualys.

+PP/05 Fix security issue CVE-2020-PFPSN and guard against cmdline invoker
+      providing a particularly obnoxious sender full name.
+      Reported by Qualys.
+

 Exim version 4.94
 -----------------
diff --git a/src/src/parse.c b/src/src/parse.c
index 18a6df1..7dfb9a7 100644
--- a/src/src/parse.c
+++ b/src/src/parse.c
@@ -1129,9 +1129,17 @@ while (s < end)
             {
             if (ss >= end) ss--;
             *t++ = '(';
-            Ustrncpy(t, s, ss-s);
-            t += ss-s;
-            s = ss;
+            if (ss < s)
+              {
+              /* Someone has ended the string with "<punct>(". */
+              ss = s;
+              }
+            else
+              {
+              Ustrncpy(t, s, ss-s);
+              t += ss-s;
+              s = ss;
+              }
             }
           }