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Stream: avoid potential infinite loop at preread phase.

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Previously the preread phase code ignored NGX_AGAIN value returned from
c->recv() and relied only on c->read->ready.  But this flag is not reliable and
should only be checked for optimization purposes.  For example, when using
SSL, c->read->ready may be set when no input is available.  This can lead to
calling preread handler infinitely in a loop.
This commit is contained in:
Roman Arutyunyan 2018-08-29 15:56:42 +03:00
parent dd982bcc73
commit 4235a19595
1 changed files with 21 additions and 15 deletions
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36
src/stream/ngx_stream_core_module.c
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@ -249,34 +249,40 @@ ngx_stream_core_preread_phase(ngx_stream_session_t *s,
}
if (!c->read->ready) {
if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
rc = NGX_ERROR;
break;
}
if (!c->read->timer_set) {
ngx_add_timer(c->read, cscf->preread_timeout);
}
c->read->handler = ngx_stream_session_handler;
return NGX_OK;
break;
}
n = c->recv(c, c->buffer->last, size);
if (n == NGX_ERROR) {
if (n == NGX_ERROR || n == 0) {
rc = NGX_STREAM_OK;
break;
}
if (n > 0) {
c->buffer->last += n;
if (n == NGX_AGAIN) {
break;
}
c->buffer->last += n;
rc = ph->handler(s);
}
if (rc == NGX_AGAIN) {
if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR);
return NGX_OK;
}
if (!c->read->timer_set) {
ngx_add_timer(c->read, cscf->preread_timeout);
}
c->read->handler = ngx_stream_session_handler;
return NGX_OK;
}
if (c->read->timer_set) {
ngx_del_timer(c->read);
}