[Fix] Fix host header usage in lua_http

The issue is that `rspamd_http_message_get_http_host` actually returns
non zero-terminated string in the case where `Host` header is found in a
message. Hence, we *cannot* treat it as a zero terminated string.

The proper approach is to use `rspamd_ftok_t` everywhere for strings
but the change will be too intrusive, since it also involves many libraries,
e.g. `rdns` and others.

The current approach is much simplier: just copy a string into a temporary
buffer ensuring that it is zero terminated in all the cases.

Issue: #4051

1 files changed, 17 insertions, 5 deletions

diff --git a/src/lua/lua_http.c b/src/lua/lua_http.c
index ce2a48d63..0ff8695d3 100644
--- a/src/lua/lua_http.c
+++ b/src/lua/lua_http.c
@@ -75,7 +75,7 @@ struct lua_http_cbdata {
 	struct rspamd_cryptobox_pubkey *peer_pk;
 	rspamd_inet_addr_t *addr;
 	gchar *mime_type;
-	const gchar *host;
+	gchar *host;
 	gchar *auth;
 	const gchar *url;
 	gsize max_size;
@@ -134,6 +134,10 @@ lua_http_fin (gpointer arg)
 		g_free (cbd->auth);
 	}
 
+	if (cbd->host) {
+		g_free (cbd->host);
+	}
+
 	if (cbd->local_kp) {
 		rspamd_keypair_unref (cbd->local_kp);
 	}
@@ -1060,13 +1064,18 @@ lua_http_request (lua_State *L)
 	bool numeric_ip = false;
 
 	/* Check if we can skip resolving */
-	cbd->host = rspamd_http_message_get_http_host (msg);
+	gsize hostlen = 0;
+	const gchar *host = rspamd_http_message_get_http_host (msg, &hostlen);
+
+	if (host) {
+		cbd->host = malloc (hostlen + 1);
+		rspamd_strlcpy (cbd->host, host, hostlen + 1);
 
-	if (cbd->host) {
 		if (cbd->flags & RSPAMD_LUA_HTTP_FLAG_KEEP_ALIVE) {
 			const rspamd_inet_addr_t *ka_addr = rspamd_http_context_has_keepalive(NULL,
-					rspamd_http_message_get_http_host (msg),
-					msg->port, msg->flags & RSPAMD_HTTP_FLAG_WANT_SSL);
+					cbd->host,
+					msg->port,
+					msg->flags & RSPAMD_HTTP_FLAG_WANT_SSL);
 
 			if (ka_addr) {
 				cbd->addr = rspamd_inet_address_copy(ka_addr);
@@ -1083,6 +1092,9 @@ lua_http_request (lua_State *L)
 			}
 		}
 	}
+	else {
+		cbd->host = NULL;
+	}
 
 	if (numeric_ip) {
 		/* Host is numeric IP, no need to resolve */