From 7ad1a2b2cc57b5f4bcb59186a9a8abcbed9f4f76 Mon Sep 17 00:00:00 2001
From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Fri, 11 Nov 2022 18:22:00 +0000
Subject: [PATCH 2/2] Fix regex substring capture variables for null matches
 (again).  Bug 2933

Broken-by: 59d66fdc13f0
---
 src/exim.c               | 11 +++++------
 src/malware.c            | 10 +++++-----
 src/regex.c              |  8 ++++----
 test/aux-var-src/0383.F      |  4 ++--
 test/log/0383                |  4 ++--
 test/mail/0383.CALLER        |  8 ++++----
 test/scripts/0000-Basic/0002 |  2 ++
 test/stdout/0002             |  2 ++
 8 files changed, 26 insertions(+), 23 deletions(-)

--- a/src/exim.c
+++ b/src/exim.c
@@ -160,20 +160,19 @@
 			PCRE_EOPT | options, md, pcre_mtc_ctx);
 BOOL yield;
 
 if ((yield = (res >= 0)))
   {
+  PCRE2_SIZE * ovec = pcre2_get_ovector_pointer(md);
   res = pcre2_get_ovector_count(md);
   expand_nmax = setup < 0 ? 0 : setup + 1;
   for (int matchnum = setup < 0 ? 0 : 1; matchnum < res; matchnum++)
     {
-    PCRE2_SIZE len;
-    pcre2_substring_get_bynumber(md, matchnum,
-      (PCRE2_UCHAR **)&expand_nstring[expand_nmax], &len);
-    if (!expand_nstring[expand_nmax])
-      { expand_nstring[expand_nmax] = US""; len = 0; }
-    expand_nlength[expand_nmax++] = (int)len;
+    int off = matchnum * 2;
+    int len = ovec[off + 1] - ovec[off];
+    expand_nstring[expand_nmax] = string_copyn(subject + ovec[off], len);
+    expand_nlength[expand_nmax++] = len;
     }
   expand_nmax--;
   }
 else if (res != PCRE2_ERROR_NOMATCH) DEBUG(D_any)
   {
--- a/src/malware.c
+++ b/src/malware.c
@@ -319,19 +319,19 @@
 uschar *
 m_pcre_exec(const pcre2_code * cre, uschar * text)
 {
 pcre2_match_data * md = pcre2_match_data_create(2, pcre_gen_ctx);
 int i = pcre2_match(cre, text, PCRE2_ZERO_TERMINATED, 0, 0, md, pcre_mtc_ctx);
-PCRE2_UCHAR * substr = NULL;
-PCRE2_SIZE slen;
+uschar * substr = NULL;
 
 if (i >= 2)				/* Got it */
   {
-  pcre2_substring_get_bynumber(md, 1, &substr, &slen);
-  if (!substr) substr = US"";
+  PCRE2_SIZE * ovec = pcre2_get_ovector_pointer(md);
+  int len = ovec[3] - ovec[2];
+  substr = string_copyn(text + ovec[2], len);
   }
-return US substr;
+return substr;
 }
 
 static const pcre2_code *
 m_pcre_nextinlist(const uschar ** list, int * sep,
  char * listerr, uschar ** errstr)
--- a/src/regex.c
+++ b/src/regex.c
@@ -81,14 +81,14 @@
 	      sizeof(regex_match_string_buffer)-1);
     regex_match_string = regex_match_string_buffer;
 
     for (int nn = 1; nn < n; nn++)
       {
-      PCRE2_UCHAR * cstr;
-      PCRE2_SIZE cslen;
-      pcre2_substring_get_bynumber(md, nn, &cstr, &cslen);
-      regex_vars[nn-1] = cstr ? CUS cstr : CUS"";
+      PCRE2_SIZE * ovec = pcre2_get_ovector_pointer(md);
+      int off = nn * 2;
+      int len = ovec[off + 1] - ovec[off];
+      regex_vars[nn-1] = string_copyn(linebuffer + ovec[off], len);
       }
 
     return OK;
     }
   }