[nginx] Stream ssl_preread: added SSLv2 Client Hello support.

[Sergey Kandaurov]

details:   http://hg.nginx.org/nginx/rev/6649d4433266
branches:  
changeset: 7322:6649d4433266
user:      Sergey Kandaurov <pluknet at nginx.com>
date:      Wed Jul 18 18:51:25 2018 +0300
description:
Stream ssl_preread: added SSLv2 Client Hello support.

In particular, it was not possible to obtain SSLv2 protocol version.

diffstat:

 src/stream/ngx_stream_ssl_preread_module.c |  16 ++++++++++++++--
 1 files changed, 14 insertions(+), 2 deletions(-)

diffs (33 lines):

diff -r 45e513c3540d -r 6649d4433266 src/stream/ngx_stream_ssl_preread_module.c
--- a/src/stream/ngx_stream_ssl_preread_module.c	Tue Jul 17 15:30:43 2018 +0300
+++ b/src/stream/ngx_stream_ssl_preread_module.c	Wed Jul 18 18:51:25 2018 +0300
@@ -149,6 +149,14 @@ ngx_stream_ssl_preread_handler(ngx_strea
 
     while (last - p >= 5) {
 
+        if ((p[0] & 0x80) && p[2] == 1 && (p[3] == 0 || p[3] == 3)) {
+            ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+                           "ssl preread: version 2 ClientHello");
+            ctx->version[0] = p[3];
+            ctx->version[1] = p[4];
+            return NGX_OK;
+        }
+
         if (p[0] != 0x16) {
             ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
                            "ssl preread: not a handshake");
@@ -507,8 +515,12 @@ ngx_stream_ssl_preread_protocol_variable
     ngx_str_null(&version);
 
     switch (ctx->version[0]) {
-    case 2:
-        ngx_str_set(&version, "SSLv2");
+    case 0:
+        switch (ctx->version[1]) {
+        case 2:
+            ngx_str_set(&version, "SSLv2");
+            break;
+        }
         break;
     case 3:
         switch (ctx->version[1]) {