From c21228a0f170c025d79625207dc94759f480418f Mon Sep 17 00:00:00 2001
From: Jakub Hrozek <jhrozek@redhat.com>
Date: Sun, 10 May 2020 20:02:23 +0200
Subject: [PATCH 4/4] Backport of Fix open redirect starting with a slash and a
 backslash

---
 src/mod_auth_openidc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/mod_auth_openidc.c b/src/mod_auth_openidc.c
index 3c6efb4..e16d500 100644
--- a/src/mod_auth_openidc.c
+++ b/src/mod_auth_openidc.c
@@ -2612,6 +2612,14 @@ static apr_byte_t oidc_validate_post_logout_url(request_rec *r, const char *url,
                                                 url);
                 oidc_error(r, "%s: %s", *err_str, *err_desc);
                 return FALSE;
+        } else if ((uri.hostname == NULL) && (strstr(url, "/\\") == url)) {
+                *err_str = apr_pstrdup(r->pool, "Malformed URL");
+                *err_desc =
+                                apr_psprintf(r->pool,
+                                                "No hostname was parsed and starting with '/\\': %s",
+                                                url);
+                oidc_error(r, "%s: %s", *err_str, *err_desc);
+                return FALSE;
        }
 
        return TRUE;
-- 
2.21.3