From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Mon, 13 Jul 2020 12:46:14 +0000 (+0100)
Subject: Taint: fix ACL "spam" condition, to permit tainted name arguments
X-Git-Url: https://git.exim.org/users/heiko/exim.git/commitdiff_plain/532800c8bf0e4bc2c27739477e70e0d7eef7df21

Taint: fix ACL "spam" condition, to permit tainted name arguments

Follow-on from: 62b2ccce05
---

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 6d688d1b4..60627364d 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -69,9 +69,9 @@ JH/13 Fix dsearch "subdir" filter to ignore ".".  Previously only ".." was
 JH/14 Bug 2606: Fix a segfault in sqlite lookups.  When no, or a bad, filename
       was given for the sqlite_dbfile a trap resulted.
 
-JH/15 Fix "spam" ACL condition.  Previously, tainted values for the "name"
-      argument resulted in a trap.  There is no reason to disallow such; this
-      was a coding error.
+JH/15 Bug 2620: Fix "spam" ACL condition.  Previously, tainted values for the
+      "name" argument resulted in a trap.  There is no reason to disallow such;
+      this was a coding error.
 
 JH/16 Bug 2615: Fix pause during message reception, on systems that have been
       suspended/resumed.  The Linux CLOCK_MONOTONIC does not account for time
diff --git a/src/src/spam.c b/src/src/spam.c
index bd34dba82..3318bff49 100644
--- a/src/src/spam.c
+++ b/src/src/spam.c
@@ -18,7 +18,7 @@ uschar spam_score_int_buffer[16];
 uschar spam_bar_buffer[128];
 uschar spam_action_buffer[32];
 uschar spam_report_buffer[32600];
-uschar prev_user_name[128] = "";
+uschar * prev_user_name = NULL;
 int spam_ok = 0;
 int spam_rc = 0;
 uschar *prev_spamd_address_work = NULL;
@@ -388,13 +388,12 @@ if (sd->is_rspamd)
   }
 else
   {				/* spamassassin variant */
-  (void)string_format(spamd_buffer,
-	  sizeof(spamd_buffer),
-	  "REPORT SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n",
-	  user_name,
-	  mbox_size);
+  int n;
+  uschar * s = string_sprintf(
+	  "REPORT SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n%n",
+	  user_name, mbox_size, &n);
   /* send our request */
-  wrote = send(spamd_cctx.sock, spamd_buffer, Ustrlen(spamd_buffer), 0);
+  wrote = send(spamd_cctx.sock, s, n, 0);
   }
 
 if (wrote == -1)
@@ -625,7 +624,7 @@ if (spamd_address_work != spamd_address)
   prev_spamd_address_work = string_copy(spamd_address_work);
 
 /* remember user name and "been here" for it */
-Ustrcpy(prev_user_name, user_name);
+prev_user_name = user_name;
 spam_ok = 1;
 
 return override