New directive HttpProtocol which allows to disable HTTP/0.9 support

with min=0.9|1.0 syntax.
    
A tighter restriction off the version in the request line is still
possible with <If "%{SERVER_PROTOCOL_NUM} ..."> .
Submitted by: sf
Backports: r1406719, r1407643, r1425366



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x-merge-http-strict@1767941 13f79535-47bb-0310-9956-ffa450edef68

5 files changed, 50 insertions, 4 deletions

diff --git a/CHANGES b/CHANGES
index 0d6561b662..dd23d8c485 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2,6 +2,9 @@
 
 Changes with Apache 2.4.24
 
+  *) core: New directive HttpProtocol which allows to disable HTTP/0.9
+     support. [Stefan Fritsch]
+
   *) mod_http2: unannounced and multiple interim responses (status code < 200)
      are parsed and forwarded to client until a final response arrives.
      [Stefan Eissing]
diff --git a/include/ap_mmn.h b/include/ap_mmn.h
index a4feabc144..1cd06ff4f1 100644
--- a/include/ap_mmn.h
+++ b/include/ap_mmn.h
@@ -487,6 +487,7 @@
  * 20120211.65 (2.4.24-dev) Add ap_check_pipeline().
  * 20120211.66 (2.4.24-dev) Rename ap_proxy_check_backend() to
  *                          ap_proxy_check_connection().
+ * 20120211.67 (2.5.0-dev)  Add http09_enable to core_server_config
  */
 
 #define MODULE_MAGIC_COOKIE 0x41503234UL /* "AP24" */
@@ -494,7 +495,7 @@
 #ifndef MODULE_MAGIC_NUMBER_MAJOR
 #define MODULE_MAGIC_NUMBER_MAJOR 20120211
 #endif
-#define MODULE_MAGIC_NUMBER_MINOR 66                   /* 0...n */
+#define MODULE_MAGIC_NUMBER_MINOR 67                   /* 0...n */
 
 /**
  * Determine if the server's current MODULE_MAGIC_NUMBER is at least a
diff --git a/include/http_core.h b/include/http_core.h
index 2590b22d36..cbd924060a 100644
--- a/include/http_core.h
+++ b/include/http_core.h
@@ -723,10 +723,14 @@ typedef struct {
 #define AP_MERGE_TRAILERS_DISABLE  2
     int merge_trailers;
 
-
-
     apr_array_header_t *protocols;
     int protocols_honor_order;
+
+#define AP_HTTP09_UNSET   0
+#define AP_HTTP09_ENABLE  1
+#define AP_HTTP09_DISABLE 2
+    char http09_enable;
+
 } core_server_config;
 
 /* for AddOutputFiltersByType in core.c */
diff --git a/server/core.c b/server/core.c
index 2c64fdc4d2..4cb03ff854 100644
--- a/server/core.c
+++ b/server/core.c
@@ -519,6 +519,9 @@ static void *merge_core_server_configs(apr_pool_t *p, void *basev, void *virtv)
     if (virt->trace_enable != AP_TRACE_UNSET)
         conf->trace_enable = virt->trace_enable;
 
+    if (virt->http09_enable != AP_HTTP09_UNSET)
+        conf->http09_enable = virt->http09_enable;
+
     /* no action for virt->accf_map, not allowed per-vhost */
 
     if (virt->protocol)
@@ -3895,6 +3898,25 @@ static const char *set_protocols_honor_order(cmd_parms *cmd, void *dummy,
     return NULL;
 }
 
+static const char *set_http_protocol(cmd_parms *cmd, void *dummy,
+                                     const char *arg)
+{
+    core_server_config *conf =
+        ap_get_core_module_config(cmd->server->module_config);
+
+    if (strncmp(arg, "min=", 4) == 0) {
+        arg += 4;
+        if (strcmp(arg, "0.9") == 0)
+            conf->http09_enable = AP_HTTP09_ENABLE;
+        else if (strcmp(arg, "1.0") == 0)
+            conf->http09_enable = AP_HTTP09_DISABLE;
+        else
+            return "HttpProtocol min must be one of '0.9' and '1.0'";
+	return NULL;
+    }
+    return "HttpProtocol must be min=0.9|1.0";
+}
+
 static apr_hash_t *errorlog_hash;
 
 static int log_constant_item(const ap_errorlog_info *info, const char *arg,
@@ -4419,6 +4441,8 @@ AP_INIT_ITERATE("Protocols", set_protocols, NULL, RSRC_CONF,
 AP_INIT_TAKE1("ProtocolsHonorOrder", set_protocols_honor_order, NULL, RSRC_CONF,
               "'off' (default) or 'on' to respect given order of protocols, "
               "by default the client specified order determines selection"),
+AP_INIT_TAKE1("HttpProtocol", set_http_protocol, NULL, RSRC_CONF,
+              "'min=0.9' (default) or 'min=1.0' to allow/deny HTTP/0.9"),
 { NULL }
 };
 
diff --git a/server/protocol.c b/server/protocol.c
index 88d0f99251..558d70f32b 100644
--- a/server/protocol.c
+++ b/server/protocol.c
@@ -648,9 +648,22 @@ static int read_request_line(request_rec *r, apr_bucket_brigade *bb)
         pro = ll;
         len = strlen(ll);
     } else {
+        core_server_config *conf;
+        conf = ap_get_core_module_config(r->server->module_config);
         r->assbackwards = 1;
         pro = "HTTP/0.9";
         len = 8;
+        if (conf->http09_enable == AP_HTTP09_DISABLE) {
+                r->status = HTTP_VERSION_NOT_SUPPORTED;
+                r->protocol = apr_pstrmemdup(r->pool, pro, len);
+                /* If we deny 0.9, send error message with 1.x */
+                r->assbackwards = 0;
+                r->proto_num = HTTP_VERSION(0, 9);
+                r->connection->keepalive = AP_CONN_CLOSE;
+                ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(02401)
+                              "HTTP/0.9 denied by server configuration");
+                return 0;
+        }
     }
     r->protocol = apr_pstrmemdup(r->pool, pro, len);
 
@@ -972,7 +985,8 @@ request_rec *ap_read_request(conn_rec *conn)
     /* Get the request... */
     if (!read_request_line(r, tmp_bb)) {
         if (r->status == HTTP_REQUEST_URI_TOO_LARGE
-            || r->status == HTTP_BAD_REQUEST) {
+            || r->status == HTTP_BAD_REQUEST
+            || r->status == HTTP_VERSION_NOT_SUPPORTED) {
             if (r->status == HTTP_REQUEST_URI_TOO_LARGE) {
                 ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, APLOGNO(00565)
                               "request failed: client's request-line exceeds LimitRequestLine (longer than %d)",