ngx_http_discard_request_body may read incomplete data?

Simon Liu simohayha.bobo at gmail.com
Tue Sep 27 06:33:34 UTC 2011


Thanks Maxim.

This is new patch, I think this may be better.

I think ngx_handle_read_event can't be avoid(in
ngx_http_discard_request_body), because it doesn't known whether or not need
to add read event in ngx_http_discard_request_body. So there  need
ngx_handle_read_event to judge.

Index: src/http/ngx_http_request_body.c
===================================================================
--- src/http/ngx_http_request_body.c    (revision 4146)
+++ src/http/ngx_http_request_body.c    (working copy)
@@ -476,11 +476,13 @@

     r->read_event_handler = ngx_http_discarded_request_body_handler;

-    if (ngx_handle_read_event(rev, 0) != NGX_OK) {
-        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    rc = ngx_http_read_discarded_request_body(r);
+
+    if (rc == NGX_ERROR) {
+        return NGX_HTTP_CLIENT_CLOSED_REQUEST;
     }

-    if (ngx_http_read_discarded_request_body(r) == NGX_OK) {
+    if (rc == NGX_OK) {
         r->lingering_close = 0;

     } else {
@@ -488,6 +490,10 @@
         r->discard_body = 1;
     }

+    if (ngx_handle_read_event(rev, 0) != NGX_OK) {
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+
     return NGX_OK;
 }

@@ -527,6 +533,11 @@

     rc = ngx_http_read_discarded_request_body(r);

+    if (rc == NGX_ERROR) {
+        ngx_http_finalize_request(r, NGX_HTTP_CLIENT_CLOSED_REQUEST);
+        return;
+    }
+
     if (rc == NGX_OK) {
         r->discard_body = 0;
         r->lingering_close = 0;
@@ -583,19 +594,15 @@

         n = r->connection->recv(r->connection, buffer, size);

-        if (n == NGX_ERROR) {
+        if (n == 0 || n == NGX_ERROR) {
             r->connection->error = 1;
-            return NGX_OK;
+            return NGX_ERROR;
         }

         if (n == NGX_AGAIN) {
             return NGX_AGAIN;
         }

-        if (n == 0) {
-            return NGX_OK;
-        }
-
         r->headers_in.content_length_n -= n;
     }
 }


On Mon, Sep 26, 2011 at 11:50 PM, Maxim Dounin <mdounin at mdounin.ru> wrote:

> Hello!
>
> On Mon, Sep 26, 2011 at 11:34:42PM +0800, Simon Liu wrote:
>
> > Thanks .
> >
> > This is patch:
> >
> > Index: src/http/ngx_http_request_body.c
> > ===================================================================
> > --- src/http/ngx_http_request_body.c    (revision 4146)
> > +++ src/http/ngx_http_request_body.c    (working copy)
> > @@ -476,10 +476,6 @@
> >
> >      r->read_event_handler = ngx_http_discarded_request_body_handler;
> >
> > -    if (ngx_handle_read_event(rev, 0) != NGX_OK) {
> > -        return NGX_HTTP_INTERNAL_SERVER_ERROR;
> > -    }
> > -
> >      if (ngx_http_read_discarded_request_body(r) == NGX_OK) {
> >          r->lingering_close = 0;
> >
> > @@ -488,6 +484,10 @@
> >          r->discard_body = 1;
> >      }
> >
> > +    if (ngx_handle_read_event(rev, 0) != NGX_OK) {
> > +        return NGX_HTTP_INTERNAL_SERVER_ERROR;
> > +    }
> > +
> >      return NGX_OK;
> >  }
>
> It's better to avoid ngx_handle_read_event() altogether in
> case ngx_http_read_discarded_request_body() returns NGX_OK (i.e.
> everything is read, no futher actions required).
>
> It would be a bit more readable and slightly more optimal.
>
> Maxim Dounin
>
> >
> >
> > On Mon, Sep 26, 2011 at 11:08 PM, Maxim Dounin <mdounin at mdounin.ru>
> wrote:
> >
> > > Hello!
> > >
> > > On Mon, Sep 26, 2011 at 10:42:20PM +0800, Simon Liu wrote:
> > >
> > > > Hi all.
> > > >
> > > > My nginx version is svn trunk.
> > > >
> > > > Nginx will call ngx_handle_read_event, and then
> > > > call ngx_http_read_discarded_request_body In
> > > ngx_http_discard_request_body .
> > > >  So this will cause client's body read  incomplete data , because
> > > > ngx_handle_read_event
> > > > may delete read event when use level event.
> > > >
> > > > ngx_handle_read_event:
> > > >
> > > > else if (ngx_event_flags & NGX_USE_LEVEL_EVENT) {
> > > >
> > > >         /* select, poll, /dev/poll */
> > > > .................................................................
> > > >
> > > >         if (rev->active && (rev->ready || (flags & NGX_CLOSE_EVENT)))
> {
> > > >             if (ngx_del_event(rev, NGX_READ_EVENT, NGX_LEVEL_EVENT |
> > > flags)
> > > >                 == NGX_ERROR)
> > > >             {
> > > >                 return NGX_ERROR;
> > > >             }
> > > >
> > > >             return NGX_OK;
> > > >         }
> > > >
> > > >
> > > > ngx_http_discard_request_body:
> > > >
> > > >     r->read_event_handler = ngx_http_discarded_request_body_handler;
> > > >
> > > >     if (ngx_handle_read_event(rev, 0) != NGX_OK) {
> > > >         return NGX_HTTP_INTERNAL_SERVER_ERROR;
> > > >     }
> > > >
> > > >     if (ngx_http_read_discarded_request_body(r) == NGX_OK) {
> > > >         r->lingering_close = 0;
> > > >
> > > >
> > > > thanks!
> > >
> > > Ack, ngx_handle_read_event() should be after
> > > ngx_http_read_discarded_request_body() call, like it's done in
> > > ngx_http_discarded_request_body_handler().
> > >
> > > Care to provide patch?
> > >
> > > Maxim Dounin
> > >
> > > _______________________________________________
> > > nginx-devel mailing list
> > > nginx-devel at nginx.org
> > > http://mailman.nginx.org/mailman/listinfo/nginx-devel
> > >
>
> > Index: src/http/ngx_http_request_body.c
> > ===================================================================
> > --- src/http/ngx_http_request_body.c  (revision 4146)
> > +++ src/http/ngx_http_request_body.c  (working copy)
> > @@ -476,10 +476,6 @@
> >
> >      r->read_event_handler = ngx_http_discarded_request_body_handler;
> >
> > -    if (ngx_handle_read_event(rev, 0) != NGX_OK) {
> > -        return NGX_HTTP_INTERNAL_SERVER_ERROR;
> > -    }
> > -
> >      if (ngx_http_read_discarded_request_body(r) == NGX_OK) {
> >          r->lingering_close = 0;
> >
> > @@ -488,6 +484,10 @@
> >          r->discard_body = 1;
> >      }
> >
> > +    if (ngx_handle_read_event(rev, 0) != NGX_OK) {
> > +        return NGX_HTTP_INTERNAL_SERVER_ERROR;
> > +    }
> > +
> >      return NGX_OK;
> >  }
> >
>
> > _______________________________________________
> > nginx-devel mailing list
> > nginx-devel at nginx.org
> > http://mailman.nginx.org/mailman/listinfo/nginx-devel
>
> _______________________________________________
> nginx-devel mailing list
> nginx-devel at nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx-devel
>



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