From f3f141664cd17c6d9847069ae5a4f29531bd93bb Mon Sep 17 00:00:00 2001
From: Bron Gondwana <brong@fastmailteam.com>
Date: Thu, 29 Feb 2024 22:39:20 -0500
Subject: [PATCH] sync_support: duplicate the sieve script

---
 imap/sync_support.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/imap/sync_support.c b/imap/sync_support.c
index bc6551f0b9..72ce291fab 100644
--- a/imap/sync_support.c
+++ b/imap/sync_support.c
@@ -1024,14 +1024,20 @@ static int sync_sieve_validate(struct index_record *record,
         sieve_script_t *s = NULL;
         char *err = NULL;
 
-        r = sieve_script_parse_string(NULL,
-                                      msg_base + body->header_size, &err, &s);
+        // XXX: if mmap is a multiple of 4096 bytes, we can read past the
+	// end of the mmap - the string won't be correctly NULL terminated
+        char *script = xstrndup(msg_base + body->header_size, msg_len - body->header_size);
+        r = sieve_script_parse_string(NULL, script, &err, &s);
+        free(script);
         sieve_script_free(&s);
 
         if (r == SIEVE_OK) {
             // create the record now to avoid a re-parse in sync_append_copyfile
             message_create_record(record, body);
         }
+        else if (err) {
+            syslog(LOG_ERR, "sieve script parse error uid=%u: %s", record->uid, err);
+        }
     }
 
     if (body) {