From 0486590c2944b39b480ab1713026ea402420863e Mon Sep 17 00:00:00 2001
From: Jakub Hrozek <jhrozek@redhat.com>
Date: Mon, 16 Mar 2020 21:09:37 +0100
Subject: [PATCH 4/6] Backport of improve validation of the post-logout URL;
closes #449
---
src/mod_auth_openidc.c | 90 +++++++++++++++++++++++++-----------------
1 file changed, 53 insertions(+), 37 deletions(-)
diff --git a/src/mod_auth_openidc.c b/src/mod_auth_openidc.c
index b504ecbf62f839a82ad205fa5f825f9a8428dfdb..431e89e086fbb72f56ea2a212e63c6ac693f62a2 100644
--- a/src/mod_auth_openidc.c
+++ b/src/mod_auth_openidc.c
@@ -2083,6 +2083,52 @@ static int oidc_handle_logout_request(request_rec *r, oidc_cfg *c,
return HTTP_MOVED_TEMPORARILY;
}
+static apr_byte_t oidc_validate_post_logout_url(request_rec *r, const char *url, char **err_str, char **err_desc) {
+ apr_uri_t uri;
+ const char *c_host = NULL;
+
+ if (apr_uri_parse(r->pool, url, &uri) != APR_SUCCESS) {
+ *err_str = apr_pstrdup(r->pool, "Malformed URL");
+ *err_desc = apr_psprintf(r->pool, "Logout URL malformed: %s", url);
+ oidc_error(r, "%s: %s", *err_str, *err_desc);
+ return FALSE;
+ }
+
+ c_host = oidc_get_current_url_host(r);
+ if ((uri.hostname != NULL)
+ && ((strstr(c_host, uri.hostname) == NULL)
+ || (strstr(uri.hostname, c_host) == NULL))) {
+ *err_str = apr_pstrdup(r->pool, "Invalid Request");
+ *err_desc =
+ apr_psprintf(r->pool,
+ "logout value \"%s\" does not match the hostname of the current request \"%s\"",
+ apr_uri_unparse(r->pool, &uri, 0), c_host);
+ oidc_error(r, "%s: %s", *err_str, *err_desc);
+ return FALSE;
+ } else if (strstr(url, "/") != url) {
+ *err_str = apr_pstrdup(r->pool, "Malformed URL");
+ *err_desc =
+ apr_psprintf(r->pool,
+ "No hostname was parsed and it does not seem to be relative, i.e starting with '/': %s",
+ url);
+ oidc_error(r, "%s: %s", *err_str, *err_desc);
+ return FALSE;
+ }
+
+ /* validate the URL to prevent HTTP header splitting */
+ if (((strstr(url, "\n") != NULL) || strstr(url, "\r") != NULL)) {
+ *err_str = apr_pstrdup(r->pool, "Invalid Request");
+ *err_desc =
+ apr_psprintf(r->pool,
+ "logout value \"%s\" contains illegal \"\n\" or \"\r\" character(s)",
+ url);
+ oidc_error(r, "%s: %s", *err_str, *err_desc);
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
/*
* perform (single) logout
*/
@@ -2090,6 +2136,8 @@ static int oidc_handle_logout(request_rec *r, oidc_cfg *c, session_rec *session)
/* pickup the command or URL where the user wants to go after logout */
char *url = NULL;
+ char *error_str = NULL;
+ char *error_description = NULL;
oidc_util_get_request_parameter(r, "logout", &url);
oidc_debug(r, "enter (url=%s)", url);
@@ -2103,44 +2151,12 @@ static int oidc_handle_logout(request_rec *r, oidc_cfg *c, session_rec *session)
url = c->default_slo_url;
} else {
-
/* do input validation on the logout parameter value */
-
- const char *error_description = NULL;
- apr_uri_t uri;
-
- if (apr_uri_parse(r->pool, url, &uri) != APR_SUCCESS) {
- const char *error_description = apr_psprintf(r->pool,
- "Logout URL malformed: %s", url);
- oidc_error(r, "%s", error_description);
- return oidc_util_html_send_error(r, c->error_template,
- "Malformed URL", error_description,
- HTTP_INTERNAL_SERVER_ERROR);
-
- }
-
- if ((strstr(r->hostname, uri.hostname) == NULL)
- || (strstr(uri.hostname, r->hostname) == NULL)) {
- error_description =
- apr_psprintf(r->pool,
- "logout value \"%s\" does not match the hostname of the current request \"%s\"",
- apr_uri_unparse(r->pool, &uri, 0), r->hostname);
- oidc_error(r, "%s", error_description);
- return oidc_util_html_send_error(r, c->error_template,
- "Invalid Request", error_description,
- HTTP_INTERNAL_SERVER_ERROR);
- }
-
- /* validate the URL to prevent HTTP header splitting */
- if (((strstr(url, "\n") != NULL) || strstr(url, "\r") != NULL)) {
- error_description =
- apr_psprintf(r->pool,
- "logout value \"%s\" contains illegal \"\n\" or \"\r\" character(s)",
- url);
- oidc_error(r, "%s", error_description);
- return oidc_util_html_send_error(r, c->error_template,
- "Invalid Request", error_description,
- HTTP_INTERNAL_SERVER_ERROR);
+ if (oidc_validate_post_logout_url(r, url, &error_str,
+ &error_description) == FALSE) {
+ return oidc_util_html_send_error(r, c->error_template, error_str,
+ error_description,
+ HTTP_BAD_REQUEST);
}
}
--
2.21.1