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Prevented scheduling events on a shared connection.

Browse Source 
A shared connection does not own its file descriptor, which means that
ngx_handle_read_event/ngx_handle_write_event calls should do nothing for it.
Currently the c->shared flag is checked in several places in the stream proxy
module prior to calling these functions.  However it was not done everywhere.
Missing checks could lead to calling
ngx_handle_read_event/ngx_handle_write_event on shared connections.

The problem manifested itself when using proxy_upload_rate and resulted in
either duplicate file descriptor error (e.g. with epoll) or incorrect further
udp packet processing (e.g. with kqueue).

The fix is to set and reset the event active flag in a way that prevents
ngx_handle_read_event/ngx_handle_write_event from scheduling socket events.
This commit is contained in:
Roman Arutyunyan 2019-01-14 20:36:23 +03:00
parent b6b39b2fb9
commit 36a0713244
2 changed files with 8 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/event/ngx_event_udp.c
View File

@ -256,7 +256,9 @@ ngx_event_recvmsg(ngx_event_t *ev)
rev = c->read;
c->udp->buffer = &buf;
rev->ready = 1;
rev->active = 0;
rev->handler(rev);
@ -265,6 +267,7 @@ ngx_event_recvmsg(ngx_event_t *ev)
}
rev->ready = 0;
rev->active = 1;
goto next;
}
@ -343,6 +346,7 @@ ngx_event_recvmsg(ngx_event_t *ev)
rev = c->read;
wev = c->write;
rev->active = 1;
wev->ready = 1;
rev->log = log;
@ -453,7 +457,9 @@ ngx_udp_shared_recv(ngx_connection_t *c, u_char *buf, size_t size)
ngx_memcpy(buf, b->pos, n);
c->udp->buffer = NULL;
c->read->ready = 0;
c->read->active = 1;
return n;
}

4
src/stream/ngx_stream_proxy_module.c
View File

@ -1667,13 +1667,13 @@ ngx_stream_proxy_process(ngx_stream_session_t *s, ngx_uint_t from_upstream,
flags = src->read->eof ? NGX_CLOSE_EVENT : 0;
if (!src->shared && ngx_handle_read_event(src->read, flags) != NGX_OK) {
if (ngx_handle_read_event(src->read, flags) != NGX_OK) {
ngx_stream_proxy_finalize(s, NGX_STREAM_INTERNAL_SERVER_ERROR);
return;
}
if (dst) {
if (!dst->shared && ngx_handle_write_event(dst->write, 0) != NGX_OK) {
if (ngx_handle_write_event(dst->write, 0) != NGX_OK) {
ngx_stream_proxy_finalize(s, NGX_STREAM_INTERNAL_SERVER_ERROR);
return;
}