From 00c94beaf0d73457e15f55170ab088db337b7435 Mon Sep 17 00:00:00 2001
From: Dmitry Ilyin <dima@doty.ru>
Date: Mon, 22 Jul 2024 21:47:53 +0300
Subject: [PATCH] ws: allow Upgrade in Connection header anywhere

This will make it work for Firefox, which uses "Connection: keep-alive, Upgrade"
Reimplemented our own evutil_ascii_strcasestr function (same as
non-portable strcasestr)
---
 evutil.c          | 19 +++++++++++++++++++
 test/regress_ws.c | 15 +++++++++++----
 util-internal.h   |  6 ++++++
 ws.c              |  2 +-
 4 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/evutil.c b/evutil.c
index ea3df613..72b87ce9 100644
--- a/evutil.c
+++ b/evutil.c
@@ -2625,6 +2625,25 @@ int evutil_ascii_strncasecmp(const char *s1, const char *s2, size_t n)
 	return 0;
 }
 
+const char* evutil_ascii_strcasestr(const char* s, const char *find)
+{
+	char c, sc;
+	size_t len;
+
+	if ((c = *find++) != 0) {
+		c = EVUTIL_TOLOWER_(c);
+		len = strlen(find);
+		do {
+			do {
+				if ((sc = *s++) == 0)
+					return (NULL);
+			} while ((char)EVUTIL_TOLOWER_(sc) != c);
+		} while (evutil_ascii_strncasecmp(s, find, len) != 0);
+		s--;
+	}
+	return s;
+}
+
 void
 evutil_rtrim_lws_(char *str)
 {
diff --git a/test/regress_ws.c b/test/regress_ws.c
index e9b62953..5dc29009 100644
--- a/test/regress_ws.c
+++ b/test/regress_ws.c
@@ -337,8 +337,8 @@ http_ws_readcb_bad(struct bufferevent *bev, void *arg)
 		free(line);
 }
 
-void
-http_ws_test(void *arg)
+static void
+http_ws_test_with_connection(void *arg, const char* conn_value)
 {
 	struct basic_test_data *data = arg;
 	struct bufferevent *bev = NULL;
@@ -377,10 +377,10 @@ http_ws_test(void *arg)
 
 	evbuffer_add_printf(out, "GET /ws HTTP/1.1\r\n"
 							 "Host: somehost\r\n"
-							 "Connection: Upgrade\r\n"
+							 "Connection: %s\r\n"
 							 "Upgrade: websocket\r\n"
 							 "Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw==\r\n"
-							 "\r\n");
+							 "\r\n", conn_value);
 
 	test_ok = 0;
 	event_base_dispatch(data->base);
@@ -391,3 +391,10 @@ end:
 	if (bev)
 		bufferevent_free(bev);
 }
+
+void
+http_ws_test(void *arg)
+{
+	http_ws_test_with_connection(arg, "Upgrade");
+	http_ws_test_with_connection(arg, "keep-alive, Upgrade");
+}
diff --git a/util-internal.h b/util-internal.h
index f6f4856a..8cd08497 100644
--- a/util-internal.h
+++ b/util-internal.h
@@ -569,6 +569,12 @@ int evutil_v4addr_is_local_(const struct in_addr *in);
 EVENT2_EXPORT_SYMBOL
 int evutil_v6addr_is_local_(const struct in6_addr *in);
 
+/** As strcasestr, but always searching substring in locale-independent
+    ASCII.  That's useful if you're handling data in ASCII-based protocols.
+ */
+EVENT2_EXPORT_SYMBOL
+const char* evutil_ascii_strcasestr(const char* s, const char *find);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/ws.c b/ws.c
index e9cd9785..8764080e 100644
--- a/ws.c
+++ b/ws.c
@@ -386,7 +386,7 @@ evws_new_session(
 		goto error;
 
 	connection = evhttp_find_header(in_hdrs, "Connection");
-	if (connection == NULL || evutil_ascii_strcasecmp(connection, "Upgrade"))
+	if (connection == NULL || evutil_ascii_strcasestr(connection, "Upgrade") == NULL)
 		goto error;
 
 	ws_key = evhttp_find_header(in_hdrs, "Sec-WebSocket-Key");