mod_proxy_http: Correctly forward unexpected interim (HTTP 1xx) responses.

PR 16518

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@582631 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/CHANGES b/CHANGES
index 5aa1d332a6b9feb36a7f20ad801f49fdb0253c93..e2c92e678809da400c649db7730cb1699d29a2cc 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -2,6 +2,11 @@
 Changes with Apache 2.3.0
 [ When backported to 2.2.x, remove entry from this file ]
 
+  *) mod_proxy_http: Correctly forward unexpected interim (HTTP 1xx)
+     responses from the backend according to RFC2616.  But make it
+     configurable in case something breaks on it.
+     PR 16518 [Nick Kew]
+
   *) mod_ext_filter: Prevent a hang on Windows when the filter
      input data is pipelined. 
      PR 29901 [Eric Covener]

diff --git a/docs/manual/mod/mod_proxy_http.xml b/docs/manual/mod/mod_proxy_http.xml
index 4cd42f2abf7f77f1ceca98fcb1fdf1958ecf0188..13046a324c5c0fea4940f9fa4945b357f2d85466 100644 (file)
--- a/docs/manual/mod/mod_proxy_http.xml
+++ b/docs/manual/mod/mod_proxy_http.xml
@@ -90,6 +90,17 @@
         request bodies to be sent to the backend using chunked transfer
         encoding.  This allows the request to be efficiently streamed,
         but requires that the backend server supports HTTP/1.1.</dd>
+        <dt>proxy-interim-response</dt>
+        <dd>This variable takes values <code>RFC</code> or
+        <code>Suppress</code>.  Earlier httpd versions would suppress
+        HTTP interim (1xx) responses sent from the backend.  This is
+        technically a violation of the HTTP protocol.  In practice,
+        if a backend sends an interim response, it may itself be
+        extending the protocol in a manner we know nothing about,
+        or just broken.  So this is now configurable: set
+        <code>proxy-interim-response RFC</code> to be fully protocol
+        compliant, or <code>proxy-interim-response Suppress</code>
+        to suppress interim responses.</dd>
     </dl>
 </section>
 

diff --git a/modules/proxy/mod_proxy_http.c b/modules/proxy/mod_proxy_http.c
index a4959a2ff36c49abbbf84b6afe6364a1b0d29ba8..f2a6827f5c2e20b1f6bedab4c221394d63473dec 100644 (file)
--- a/modules/proxy/mod_proxy_http.c
+++ b/modules/proxy/mod_proxy_http.c
@@ -1494,9 +1494,33 @@ apr_status_t ap_proxy_http_process_response(apr_pool_t * p, request_rec *r,
 
         interim_response = ap_is_HTTP_INFO(r->status);
         if (interim_response) {
+           /* RFC2616 tells us to forward this.
+            *
+            * OTOH, an interim response here may mean the backend
+            * is playing sillybuggers.  The Client didn't ask for
+            * it within the defined HTTP/1.1 mechanisms, and if
+            * it's an extension, it may also be unsupported by us.
+            *
+            * There's also the possibility that changing existing
+            * behaviour here might break something.
+            *
+            * So let's make it configurable.
+            */
+            const char *policy = apr_table_get(r->subprocess_env,
+                                              "proxy-interim-response");
             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL,
                          "proxy: HTTP: received interim %d response",
                          r->status);
+           if (!policy || !strcasecmp(policy, "RFC")) {
+                ap_send_interim_response(r);
+           }
+           /* FIXME: refine this to be able to specify per-response-status
+            * policies and maybe also add option to bail out with 502
+            */
+           else if (strcasecmp(policy, "Suppress")) {
+                ap_log_error(APLOG_MARK, APLOG_WARNING, 0, NULL,
+                             "undefined proxy interim response policy");
+           }
         }
         /* Moved the fixups of Date headers and those affected by
          * ProxyPassReverse/etc from here to ap_proxy_read_headers