view src/http/modules/ngx_http_ssi_filter_module.h @ 7060:1adc6b0d5eaa stable-1.12

Range filter: protect from total size overflows. The overflow can be used to circumvent the restriction on total size of ranges introduced in c2a91088b0c0 (1.1.2). Additionally, overflow allows producing ranges with negative start (such ranges can be created by using a suffix, "bytes=-100"; normally this results in 200 due to the total size check). These can result in the following errors in logs: [crit] ... pread() ... failed (22: Invalid argument) [alert] ... sendfile() failed (22: Invalid argument) When using cache, it can be also used to reveal cache file header. It is believed that there are no other negative effects, at least with standard nginx modules. In theory, this can also result in memory disclosure and/or segmentation faults if multiple ranges are allowed, and the response is returned in a single in-memory buffer. This never happens with standard nginx modules though, as well as known 3rd party modules. Fix is to properly protect from possible overflow when incrementing size.
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 11 Jul 2017 16:06:23 +0300
parents d620f497c50f
children 49e7db44b57c
line wrap: on
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_HTTP_SSI_FILTER_H_INCLUDED_
#define _NGX_HTTP_SSI_FILTER_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


#define NGX_HTTP_SSI_MAX_PARAMS       16

#define NGX_HTTP_SSI_COMMAND_LEN      32
#define NGX_HTTP_SSI_PARAM_LEN        32
#define NGX_HTTP_SSI_PARAMS_N         4


#define NGX_HTTP_SSI_COND_IF          1
#define NGX_HTTP_SSI_COND_ELSE        2


#define NGX_HTTP_SSI_NO_ENCODING      0
#define NGX_HTTP_SSI_URL_ENCODING     1
#define NGX_HTTP_SSI_ENTITY_ENCODING  2


typedef struct {
    ngx_hash_t                hash;
    ngx_hash_keys_arrays_t    commands;
} ngx_http_ssi_main_conf_t;


typedef struct {
    ngx_buf_t                *buf;

    u_char                   *pos;
    u_char                   *copy_start;
    u_char                   *copy_end;

    ngx_uint_t                key;
    ngx_str_t                 command;
    ngx_array_t               params;
    ngx_table_elt_t          *param;
    ngx_table_elt_t           params_array[NGX_HTTP_SSI_PARAMS_N];

    ngx_chain_t              *in;
    ngx_chain_t              *out;
    ngx_chain_t             **last_out;
    ngx_chain_t              *busy;
    ngx_chain_t              *free;

    ngx_uint_t                state;
    ngx_uint_t                saved_state;
    size_t                    saved;
    size_t                    looked;

    size_t                    value_len;

    ngx_list_t               *variables;
    ngx_array_t              *blocks;

#if (NGX_PCRE)
    ngx_uint_t                ncaptures;
    int                      *captures;
    u_char                   *captures_data;
#endif

    unsigned                  conditional:2;
    unsigned                  encoding:2;
    unsigned                  block:1;
    unsigned                  output:1;
    unsigned                  output_chosen:1;

    ngx_http_request_t       *wait;
    void                     *value_buf;
    ngx_str_t                 timefmt;
    ngx_str_t                 errmsg;
} ngx_http_ssi_ctx_t;


typedef ngx_int_t (*ngx_http_ssi_command_pt) (ngx_http_request_t *r,
    ngx_http_ssi_ctx_t *ctx, ngx_str_t **);


typedef struct {
    ngx_str_t                 name;
    ngx_uint_t                index;

    unsigned                  mandatory:1;
    unsigned                  multiple:1;
} ngx_http_ssi_param_t;


typedef struct {
    ngx_str_t                 name;
    ngx_http_ssi_command_pt   handler;
    ngx_http_ssi_param_t     *params;

    unsigned                  conditional:2;
    unsigned                  block:1;
    unsigned                  flush:1;
} ngx_http_ssi_command_t;


extern ngx_module_t  ngx_http_ssi_filter_module;


#endif /* _NGX_HTTP_SSI_FILTER_H_INCLUDED_ */