commit 1a15692cded92d66dea1a51389a3c4b9e3b3631a
author Weiyin He <weiyin@appetize.io> Fri May 10 10:15:13 2019 -0400
committer Weiyin He <weiyin@appetize.io> Fri May 10 10:15:13 2019 -0400
tree 7f76cb4152206f4b089d3318ab37106d55801b72
parent 2da1707469c501168757c820cf5459c64a2ca128

proxy: Fix proxy chunked transfer encoding error.

There was a bug that prevented proper loading of response bodies under
these conditions:
- an http proxy server is configured
- AND the emulator makes an http request (port 80) via the proxy server
- AND the proxy server returns a body with chunked transfer encoding

Loading such a request in the Browser or Chrome would result in an
ERR_INCOMPLETE_CHUNKED_ENCODING error.

This change fixes two issues:
1) Incorrectly detecting a chunk data end error when reading the last
    '\r\n' of the chunk, due to an incorrect assumption that all prior
    data was flushed.
2) The terminating '0\r\n\r\n' chunk was not being sent.

Change-Id: I68cee8616d19993ed780213e8a38f0c3b3605a29
Signed-off-by: Weiyin He <weiyin@appetize.io>

android/android-emu/android/proxy/proxy_http_rewriter.c

diff --git a/android/android-emu/android/proxy/proxy_http_rewriter.c b/android/android-emu/android/proxy/proxy_http_rewriter.c
index 34e0411..a1ed73f 100644
--- a/android/android-emu/android/proxy/proxy_http_rewriter.c
+++ b/android/android-emu/android/proxy/proxy_http_rewriter.c
@@ -750,13 +750,14 @@
     case BODY_CHUNKED:
         if (conn->chunk_state == CHUNK_DATA_END) {
             /* We're waiting for the CR LF after the chunk data */
+            int old_n = str->n;
             ret = proxy_connection_receive_line(root, fd);
             if (ret != DATA_COMPLETED) {
                 PROXY_LOG("%s: receive line too early ret=%d", root->name, ret);
                 return ret;
             }
 
-            if (str->s[0] != 0) { /* this should be an empty line */
+            if (str->n != old_n) { /* should have received empty line, so nothing added */
                 PROXY_LOG("%s: invalid chunk data end: '%s'",
                             root->name, str->s);
                 return DATA_ERROR;
@@ -813,9 +814,10 @@
             conn->chunk_total  = 0;
             conn->chunk_state  = CHUNK_DATA;
             if (length == 0) {
-                /* the last chunk, no we need to add the trailer */
+                /* the last chunk, now we need to add the trailer */
                 conn->chunk_state         = CHUNK_TRAILER;
                 conn->parse_chunk_trailer = 0;
+                conn->body_has_data = 1;
             }
         }
 
@@ -829,7 +831,14 @@
                 conn->parse_chunk_trailer = 1;
             }
             ret = rewrite_connection_read_headers(conn, fd);
+            /* proxy_connection_receive_line() did remove the
+            * trailing \r\n, but we must preserve it when we
+            * send the trailer to the proxy
+            */
+            stralloc_add_str(root->str, "\r\n");
+
             if (ret == DATA_COMPLETED) {
+                conn->body_has_data = 1;
                 conn->body_is_closed = 1;
             }
             return ret;