* Fixed an issue where a proxy_http2 handler entered an infinit loop…

… when encountering

   certain errors on the backend connection.
   See <https://bz.apache.org/bugzilla/show_bug.cgi?id=63170>.

ChangeLog

@@ -1,3 +1,9 @@
+v1.12.4
+--------------------------------------------------------------------------------
+ * Fixed an issue where a proxy_http2 handler entered an infinit loop when encountering
+   certain errors on the backend connection. 
+   See <https://bz.apache.org/bugzilla/show_bug.cgi?id=63170>.
+
 v1.12.3
 --------------------------------------------------------------------------------
  * fixed bug in nghttp output parsing that filters now Frames sent/received inbetween

configure.ac

@@ -14,7 +14,7 @@
 #
 
 AC_PREREQ([2.69])
-AC_INIT([mod_http2], [1.12.3], [[email protected]])
+AC_INIT([mod_http2], [1.12.4], [[email protected]])
 
 LT_PREREQ([2.2.6])
 LT_INIT()

mod_http2/h2_version.h

@@ -27,15 +27,15 @@
  * @macro
  * Version number of the http2 module as c string
  */
-#define MOD_HTTP2_VERSION "1.12.3-git"
+#define MOD_HTTP2_VERSION "1.12.4-git"
 
 /**
  * @macro
  * Numerical representation of the version number of the http2 module
  * release. This is a 24 bit number with 8 bits for major number, 8 bits
  * for minor and 8 bits for patch. Version 1.2.3 becomes 0x010203.
  */
-#define MOD_HTTP2_VERSION_NUM 0x010c03
+#define MOD_HTTP2_VERSION_NUM 0x010c04
 
 
 #endif /* mod_h2_h2_version_h */

mod_http2/mod_proxy_http2.c

@@ -362,58 +362,65 @@ static apr_status_t proxy_engine_run(h2_proxy_ctx *ctx) {
                   "eng(%s): run session %s", ctx->engine_id, ctx->session->id);
     ctx->session->user_data = ctx;
 
-    while (!ctx->owner->aborted) {
+    while (1) {
+        if (ctx->owner->aborted) {
+            status = APR_ECONNABORTED;
+            goto out;
+        }
+
         if (APR_SUCCESS == h2_proxy_fifo_try_pull(ctx->requests, (void**)&r)) {
             add_request(ctx->session, r);
         }
-
         status = h2_proxy_session_process(ctx->session);
 
         if (status == APR_SUCCESS) {
-            apr_status_t s2;
-            /* ongoing processing, call again */
+            /* ongoing processing, check if we have room to handle more streams,
+             * maybe the remote side changed their limit */
             if (ctx->session->remote_max_concurrent > 0
                 && ctx->session->remote_max_concurrent != ctx->capacity) {
                 ctx->capacity = H2MIN((int)ctx->session->remote_max_concurrent, 
                                       h2_proxy_fifo_capacity(ctx->requests));
             }
-            s2 = next_request(ctx, 0);
-            if (s2 == APR_ECONNABORTED) {
-                /* master connection gone */
-                ap_log_cerror(APLOG_MARK, APLOG_DEBUG, s2, ctx->owner, 
-                              APLOGNO(03374) "eng(%s): pull request", 
-                              ctx->engine_id);
-                /* give notice that we're leaving and cancel all ongoing
-                 * streams. */
-                next_request(ctx, 1); 
-                h2_proxy_session_cancel_all(ctx->session);
-                h2_proxy_session_process(ctx->session);
-                status = ctx->r_status = APR_SUCCESS;
-                break;
+            /* try to pull more request, if our capacity allows it */
+            if (APR_ECONNABORTED == next_request(ctx, 0)) {
+                status = APR_ECONNABORTED;
+                goto out;
             }
+            /* If we have no ongoing streams and nothing in our queue, we
+             * terminate processing and return to our caller. */
             if ((h2_proxy_fifo_count(ctx->requests) == 0) 
                 && h2_proxy_ihash_empty(ctx->session->streams)) {
-                break;
+                goto out;
             }
         }
         else {
-            /* end of processing, maybe error */
+            /* Encountered an error during session processing */
             ap_log_cerror(APLOG_MARK, APLOG_DEBUG, status, ctx->owner, 
                           APLOGNO(03375) "eng(%s): end of session %s", 
                           ctx->engine_id, ctx->session->id);
-            /*
-             * Any open stream of that session needs to
+            /* Any open stream of that session needs to
              * a) be reopened on the new session iff safe to do so
              * b) reported as done (failed) otherwise
              */
             h2_proxy_session_cleanup(ctx->session, session_req_done);
-            break;
+            goto out;
         }
     }
 
+out:
+    if (APR_ECONNABORTED == status) {
+        /* master connection gone */
+        ap_log_cerror(APLOG_MARK, APLOG_DEBUG, status, ctx->owner, 
+                      APLOGNO(03374) "eng(%s): master connection gone", ctx->engine_id);
+        /* give notice that we're leaving and cancel all ongoing streams. */
+        next_request(ctx, 1); 
+        h2_proxy_session_cancel_all(ctx->session);
+        h2_proxy_session_process(ctx->session);
+        status = ctx->r_status = APR_SUCCESS;
+    }
+
     ctx->session->user_data = NULL;
     ctx->session = NULL;
-
     return status;
 }
 
@@ -641,7 +648,7 @@ static int proxy_http2_handler(request_rec *r,
         ctx->p_conn = NULL;
     }
 
-    /* Any requests will still have need to fail */
+    /* Any requests we still have need to fail */
     while (APR_SUCCESS == h2_proxy_fifo_try_pull(ctx->requests, (void**)&r)) {
         request_done(ctx, r, HTTP_SERVICE_UNAVAILABLE, 1);
     }