Patch cleaned up for Gentoo
- applied to 4.94
- removed unnecessary whitespace changes

From 4e9ed49f8f12eb331b29bd5b6dc3693c520fddc2 Mon Sep 17 00:00:00 2001
From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Wed, 31 Aug 2022 15:37:40 +0100
Subject: [PATCH 1/1] Fix $regex<n> use-after-free.  Bug 2915

--- exim-4.94.2/src/exim.c	2021-04-30 14:08:21.000000000 +0200
+++ exim-4.94.2/src/exim.c	2022-10-19 09:15:58.611447982 +0200
@@ -1886,8 +1886,6 @@
   regex_must_compile(US"^[A-Za-z0-9_/.-]*$", FALSE, TRUE);
 #endif
 
-for (i = 0; i < REGEX_VARS; i++) regex_vars[i] = NULL;
-
 /* If the program is called as "mailq" treat it as equivalent to "exim -bp";
 this seems to be a generally accepted convention, since one finds symbolic
 links called "mailq" in standard OS configurations. */
@@ -5841,7 +5839,7 @@
   deliver_localpart_data = deliver_domain_data =
   recipient_data = sender_data = NULL;
   acl_var_m = NULL;
-  for(int i = 0; i < REGEX_VARS; i++) regex_vars[i] = NULL;
+  regex_vars_clear();
 
   store_reset(reset_point);
   }
--- exim-4.94.2/src/functions.h	2021-04-30 14:08:21.000000000 +0200
+++ exim-4.94.2/src/functions.h	2022-10-19 09:17:44.882122667 +0200
@@ -417,6 +417,7 @@
 #endif
 extern BOOL    regex_match_and_setup(const pcre *, const uschar *, int, int);
 extern const pcre *regex_must_compile(const uschar *, BOOL, BOOL);
+extern void    regex_vars_clear(void);
 extern void    retry_add_item(address_item *, uschar *, int);
 extern BOOL    retry_check_address(const uschar *, host_item *, uschar *, BOOL,
                  uschar **, uschar **);
--- exim-4.94.2/src/globals.c	2022-10-19 09:14:19.344751853 +0200
+++ exim-4.94.2/src/globals.c	2022-10-19 09:18:27.675991666 +0200
@@ -1289,7 +1289,7 @@
 #endif
 const pcre *regex_ismsgid      = NULL;
 const pcre *regex_smtp_code    = NULL;
-uschar *regex_vars[REGEX_VARS];
+uschar *regex_vars[REGEX_VARS] = { 0 };
 #ifdef WHITELIST_D_MACROS
 const pcre *regex_whitelisted_macro = NULL;
 #endif
--- exim-4.94.2/src/regex.c	2021-04-30 14:08:21.000000000 +0200
+++ exim-4.94.2/src/regex.c	2022-10-19 09:35:03.229084750 +0200
@@ -98,7 +106,7 @@
 int ret = FAIL;
 
 /* reset expansion variable */
-regex_match_string = NULL;
+regex_vars_clear();
 
 if (!mime_stream)				/* We are in the DATA ACL */
   {
@@ -166,8 +174,7 @@
 int mime_subject_len = 0;
 int ret;
 
-/* reset expansion variable */
-regex_match_string = NULL;
+regex_vars_clear();
 
 /* precompile our regexes */
 if (!(re_list_head = compile(*listptr)))
@@ -213,3 +205,14 @@
 }
 
 #endif /* WITH_CONTENT_SCAN */
+
+/* reset expansion variables */
+void
+regex_vars_clear(void)
+{
+#ifdef WITH_CONTENT_SCAN
+regex_match_string = NULL;
+#endif
+for (int i = 0; i < REGEX_VARS; i++) regex_vars[i] = NULL;
+}
+
--- exim-4.94.2/src/smtp_in.c	2021-04-30 14:08:21.000000000 +0200
+++ exim-4.94.2/src/smtp_in.c	2022-10-19 09:15:58.613447975 +0200
@@ -2161,8 +2161,10 @@
 #ifdef SUPPORT_I18N
 message_smtputf8 = FALSE;
 #endif
+regex_vars_clear();
 body_linecount = body_zerocount = 0;
 
+lookup_value = NULL;				/* Can be set by ACL */
 sender_rate = sender_rate_limit = sender_rate_period = NULL;
 ratelimiters_mail = NULL;           /* Updated by ratelimit ACL condition */
                    /* Note that ratelimiters_conn persists across resets. */