From 57971dba06346b2d7179294f4528b8d4427a7c5d Mon Sep 17 00:00:00 2001
From: Richard Russon <rich@flatcap.org>
Date: Mon, 9 Jul 2018 15:26:26 +0100
Subject: [PATCH] Selectively cache headers

Co-authored-by: JerikoOne <jeriko.one@gmx.us>
---
 imap/util.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/imap/util.c b/imap/util.c
index 614d87a5612..58224fc3872 100644
--- a/imap/util.c
+++ b/imap/util.c
@@ -245,6 +245,12 @@ header_cache_t *imap_hcache_open(struct ImapData *idata, const char *path)
     FREE(&mx.mbox);
   }
 
+  if (strstr(mbox, "/../") || (strcmp(mbox, "..") == 0) || (strncmp(mbox, "../", 3) == 0))
+    return NULL;
+  size_t len = strlen(mbox);
+  if ((len > 3) && (strcmp(mbox + len - 3, "/..") == 0))
+    return NULL;
+
   mutt_account_tourl(&idata->conn->account, &url);
   url.path = mbox;
   url_tostring(&url, cachepath, sizeof(cachepath), U_PATH);