Mercurial > hg > nginx
view src/event/ngx_event_pipe.h @ 4489:9806bf07d119
Event pipe: fixed buffer loss in p->length case.
With previous code raw buffer might be lost if p->input_filter() was called
on a buffer without any data and used ngx_event_pipe_add_free_buf() to
return it to the free list. This eventually might cause "all buffers busy"
problem, resulting in segmentation fault due to null pointer dereference in
ngx_event_pipe_write_chain_to_temp_file().
In ngx_event_pipe_add_free_buf() the buffer was added to the list start
due to pos == last, and then "p->free_raw_bufs = cl->next" in
ngx_event_pipe_read_upstream() dropped both chain links to the buffer
from the p->free_raw_bufs list.
Fix is to move "p->free_raw_bufs = cl->next" before calling the
p->input_filter().
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 22 Feb 2012 11:28:53 +0000 |
parents | d620f497c50f |
children | 973ee2276300 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_EVENT_PIPE_H_INCLUDED_ #define _NGX_EVENT_PIPE_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> typedef struct ngx_event_pipe_s ngx_event_pipe_t; typedef ngx_int_t (*ngx_event_pipe_input_filter_pt)(ngx_event_pipe_t *p, ngx_buf_t *buf); typedef ngx_int_t (*ngx_event_pipe_output_filter_pt)(void *data, ngx_chain_t *chain); struct ngx_event_pipe_s { ngx_connection_t *upstream; ngx_connection_t *downstream; ngx_chain_t *free_raw_bufs; ngx_chain_t *in; ngx_chain_t **last_in; ngx_chain_t *out; ngx_chain_t *free; ngx_chain_t *busy; /* * the input filter i.e. that moves HTTP/1.1 chunks * from the raw bufs to an incoming chain */ ngx_event_pipe_input_filter_pt input_filter; void *input_ctx; ngx_event_pipe_output_filter_pt output_filter; void *output_ctx; unsigned read:1; unsigned cacheable:1; unsigned single_buf:1; unsigned free_bufs:1; unsigned upstream_done:1; unsigned upstream_error:1; unsigned upstream_eof:1; unsigned upstream_blocked:1; unsigned downstream_done:1; unsigned downstream_error:1; unsigned cyclic_temp_file:1; ngx_int_t allocated; ngx_bufs_t bufs; ngx_buf_tag_t tag; ssize_t busy_size; off_t read_length; off_t length; off_t max_temp_file_size; ssize_t temp_file_write_size; ngx_msec_t read_timeout; ngx_msec_t send_timeout; ssize_t send_lowat; ngx_pool_t *pool; ngx_log_t *log; ngx_chain_t *preread_bufs; size_t preread_size; ngx_buf_t *buf_to_file; ngx_temp_file_t *temp_file; /* STUB */ int num; }; ngx_int_t ngx_event_pipe(ngx_event_pipe_t *p, ngx_int_t do_write); ngx_int_t ngx_event_pipe_copy_input_filter(ngx_event_pipe_t *p, ngx_buf_t *buf); ngx_int_t ngx_event_pipe_add_free_buf(ngx_event_pipe_t *p, ngx_buf_t *b); #endif /* _NGX_EVENT_PIPE_H_INCLUDED_ */