# HG changeset patch
# User Maxim Dounin <mdounin@mdounin.ru>
# Date 1594049782 -10800
# Node ID bffcc5af1d7281c8e5fc93a28bb6f9d77a99f7fe
# Parent  a786e491d08dda4f677eb9afa3075dbab26c3dc5
Upstream: drop extra data sent by upstream.

Previous behaviour was to pass everything to the client, but this
seems to be suboptimal and causes issues (ticket #1695).  Fix is to
drop extra data instead, as it naturally happens in most clients.

This change covers generic buffered and unbuffered filters as used
in the scgi and uwsgi modules.  Appropriate input filter init
handlers are provided by the scgi and uwsgi modules to set corresponding
lengths.

Note that for responses to HEAD requests there is an exception:
we do allow any response length.  This is because responses to HEAD
requests might be actual full responses, and it is up to nginx
to remove the response body.  If caching is enabled, only full
responses matching the Content-Length header will be cached
(see b779728b180c).

diff --git a/src/event/ngx_event_pipe.c b/src/event/ngx_event_pipe.c
--- a/src/event/ngx_event_pipe.c
+++ b/src/event/ngx_event_pipe.c
@@ -960,6 +960,22 @@ ngx_event_pipe_copy_input_filter(ngx_eve
         return NGX_OK;
     }
 
+    if (p->upstream_done) {
+        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, p->log, 0,
+                       "input data after close");
+        return NGX_OK;
+    }
+
+    if (p->length == 0) {
+        p->upstream_done = 1;
+
+        ngx_log_error(NGX_LOG_WARN, p->log, 0,
+                      "upstream sent more data than specified in "
+                      "\"Content-Length\" header");
+
+        return NGX_OK;
+    }
+
     cl = ngx_chain_get_free_buf(p->pool, &p->free);
     if (cl == NULL) {
         return NGX_ERROR;
@@ -987,6 +1003,18 @@ ngx_event_pipe_copy_input_filter(ngx_eve
         return NGX_OK;
     }
 
+    if (b->last - b->pos > p->length) {
+
+        ngx_log_error(NGX_LOG_WARN, p->log, 0,
+                      "upstream sent more data than specified in "
+                      "\"Content-Length\" header");
+
+        b->last = b->pos + p->length;
+        p->upstream_done = 1;
+
+        return NGX_OK;
+    }
+
     p->length -= b->last - b->pos;
 
     return NGX_OK;
diff --git a/src/http/modules/ngx_http_scgi_module.c b/src/http/modules/ngx_http_scgi_module.c
--- a/src/http/modules/ngx_http_scgi_module.c
+++ b/src/http/modules/ngx_http_scgi_module.c
@@ -49,6 +49,7 @@ static ngx_int_t ngx_http_scgi_create_re
 static ngx_int_t ngx_http_scgi_reinit_request(ngx_http_request_t *r);
 static ngx_int_t ngx_http_scgi_process_status_line(ngx_http_request_t *r);
 static ngx_int_t ngx_http_scgi_process_header(ngx_http_request_t *r);
+static ngx_int_t ngx_http_scgi_input_filter_init(void *data);
 static void ngx_http_scgi_abort_request(ngx_http_request_t *r);
 static void ngx_http_scgi_finalize_request(ngx_http_request_t *r, ngx_int_t rc);
 
@@ -534,6 +535,10 @@ ngx_http_scgi_handler(ngx_http_request_t
     u->pipe->input_filter = ngx_event_pipe_copy_input_filter;
     u->pipe->input_ctx = r;
 
+    u->input_filter_init = ngx_http_scgi_input_filter_init;
+    u->input_filter = ngx_http_upstream_non_buffered_filter;
+    u->input_filter_ctx = r;
+
     if (!scf->upstream.request_buffering
         && scf->upstream.pass_request_body
         && !r->headers_in.chunked)
@@ -1145,6 +1150,37 @@ ngx_http_scgi_process_header(ngx_http_re
 }
 
 
+static ngx_int_t
+ngx_http_scgi_input_filter_init(void *data)
+{
+    ngx_http_request_t   *r = data;
+    ngx_http_upstream_t  *u;
+
+    u = r->upstream;
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "http scgi filter init s:%ui l:%O",
+                   u->headers_in.status_n, u->headers_in.content_length_n);
+
+    if (u->headers_in.status_n == NGX_HTTP_NO_CONTENT
+        || u->headers_in.status_n == NGX_HTTP_NOT_MODIFIED)
+    {
+        u->pipe->length = 0;
+        u->length = 0;
+
+    } else if (r->method == NGX_HTTP_HEAD) {
+        u->pipe->length = -1;
+        u->length = -1;
+
+    } else {
+        u->pipe->length = u->headers_in.content_length_n;
+        u->length = u->headers_in.content_length_n;
+    }
+
+    return NGX_OK;
+}
+
+
 static void
 ngx_http_scgi_abort_request(ngx_http_request_t *r)
 {
diff --git a/src/http/modules/ngx_http_uwsgi_module.c b/src/http/modules/ngx_http_uwsgi_module.c
--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -67,6 +67,7 @@ static ngx_int_t ngx_http_uwsgi_create_r
 static ngx_int_t ngx_http_uwsgi_reinit_request(ngx_http_request_t *r);
 static ngx_int_t ngx_http_uwsgi_process_status_line(ngx_http_request_t *r);
 static ngx_int_t ngx_http_uwsgi_process_header(ngx_http_request_t *r);
+static ngx_int_t ngx_http_uwsgi_input_filter_init(void *data);
 static void ngx_http_uwsgi_abort_request(ngx_http_request_t *r);
 static void ngx_http_uwsgi_finalize_request(ngx_http_request_t *r,
     ngx_int_t rc);
@@ -703,6 +704,10 @@ ngx_http_uwsgi_handler(ngx_http_request_
     u->pipe->input_filter = ngx_event_pipe_copy_input_filter;
     u->pipe->input_ctx = r;
 
+    u->input_filter_init = ngx_http_uwsgi_input_filter_init;
+    u->input_filter = ngx_http_upstream_non_buffered_filter;
+    u->input_filter_ctx = r;
+
     if (!uwcf->upstream.request_buffering
         && uwcf->upstream.pass_request_body
         && !r->headers_in.chunked)
@@ -1356,6 +1361,37 @@ ngx_http_uwsgi_process_header(ngx_http_r
 }
 
 
+static ngx_int_t
+ngx_http_uwsgi_input_filter_init(void *data)
+{
+    ngx_http_request_t   *r = data;
+    ngx_http_upstream_t  *u;
+
+    u = r->upstream;
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "http uwsgi filter init s:%ui l:%O",
+                   u->headers_in.status_n, u->headers_in.content_length_n);
+
+    if (u->headers_in.status_n == NGX_HTTP_NO_CONTENT
+        || u->headers_in.status_n == NGX_HTTP_NOT_MODIFIED)
+    {
+        u->pipe->length = 0;
+        u->length = 0;
+
+    } else if (r->method == NGX_HTTP_HEAD) {
+        u->pipe->length = -1;
+        u->length = -1;
+
+    } else {
+        u->pipe->length = u->headers_in.content_length_n;
+        u->length = u->headers_in.content_length_n;
+    }
+
+    return NGX_OK;
+}
+
+
 static void
 ngx_http_uwsgi_abort_request(ngx_http_request_t *r)
 {
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -77,9 +77,6 @@ static void
 static void
     ngx_http_upstream_process_non_buffered_request(ngx_http_request_t *r,
     ngx_uint_t do_write);
-static ngx_int_t ngx_http_upstream_non_buffered_filter_init(void *data);
-static ngx_int_t ngx_http_upstream_non_buffered_filter(void *data,
-    ssize_t bytes);
 #if (NGX_THREADS)
 static ngx_int_t ngx_http_upstream_thread_handler(ngx_thread_task_t *task,
     ngx_file_t *file);
@@ -3705,14 +3702,14 @@ ngx_http_upstream_process_non_buffered_r
 }
 
 
-static ngx_int_t
+ngx_int_t
 ngx_http_upstream_non_buffered_filter_init(void *data)
 {
     return NGX_OK;
 }
 
 
-static ngx_int_t
+ngx_int_t
 ngx_http_upstream_non_buffered_filter(void *data, ssize_t bytes)
 {
     ngx_http_request_t  *r = data;
@@ -3748,6 +3745,18 @@ ngx_http_upstream_non_buffered_filter(vo
         return NGX_OK;
     }
 
+    if (bytes > u->length) {
+
+        ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
+                      "upstream sent more data than specified in "
+                      "\"Content-Length\" header");
+
+        cl->buf->last = cl->buf->pos + u->length;
+        u->length = 0;
+
+        return NGX_OK;
+    }
+
     u->length -= bytes;
 
     return NGX_OK;
diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -414,6 +414,8 @@ typedef struct {
 
 ngx_int_t ngx_http_upstream_create(ngx_http_request_t *r);
 void ngx_http_upstream_init(ngx_http_request_t *r);
+ngx_int_t ngx_http_upstream_non_buffered_filter_init(void *data);
+ngx_int_t ngx_http_upstream_non_buffered_filter(void *data, ssize_t bytes);
 ngx_http_upstream_srv_conf_t *ngx_http_upstream_add(ngx_conf_t *cf,
     ngx_url_t *u, ngx_uint_t flags);
 char *ngx_http_upstream_bind_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,