Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_addition_filter_module.c @ 7977:7731c710796f
Memcached: protect from too long responses.
If a memcached response was followed by a correct trailer, and then
the NUL character followed by some extra data - this was accepted by
the trailer checking code. This in turn resulted in ctx->rest underflow
and caused negative size buffer on the next reading from the upstream,
followed by the "negative size buf in writer" alert.
Fix is to always check for too long responses, so a correct trailer cannot
be followed by extra data.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 06 Jul 2020 18:36:17 +0300 |
parents | f583559aadc7 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { ngx_str_t before_body; ngx_str_t after_body; ngx_hash_t types; ngx_array_t *types_keys; } ngx_http_addition_conf_t; typedef struct { ngx_uint_t before_body_sent; } ngx_http_addition_ctx_t; static void *ngx_http_addition_create_conf(ngx_conf_t *cf); static char *ngx_http_addition_merge_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_addition_filter_init(ngx_conf_t *cf); static ngx_command_t ngx_http_addition_commands[] = { { ngx_string("add_before_body"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_str_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_addition_conf_t, before_body), NULL }, { ngx_string("add_after_body"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_str_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_addition_conf_t, after_body), NULL }, { ngx_string("addition_types"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE, ngx_http_types_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_addition_conf_t, types_keys), &ngx_http_html_default_types[0] }, ngx_null_command }; static ngx_http_module_t ngx_http_addition_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_addition_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_addition_create_conf, /* create location configuration */ ngx_http_addition_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_addition_filter_module = { NGX_MODULE_V1, &ngx_http_addition_filter_module_ctx, /* module context */ ngx_http_addition_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_http_output_header_filter_pt ngx_http_next_header_filter; static ngx_http_output_body_filter_pt ngx_http_next_body_filter; static ngx_int_t ngx_http_addition_header_filter(ngx_http_request_t *r) { ngx_http_addition_ctx_t *ctx; ngx_http_addition_conf_t *conf; if (r->headers_out.status != NGX_HTTP_OK || r != r->main) { return ngx_http_next_header_filter(r); } conf = ngx_http_get_module_loc_conf(r, ngx_http_addition_filter_module); if (conf->before_body.len == 0 && conf->after_body.len == 0) { return ngx_http_next_header_filter(r); } if (ngx_http_test_content_type(r, &conf->types) == NULL) { return ngx_http_next_header_filter(r); } ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_addition_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } ngx_http_set_ctx(r, ctx, ngx_http_addition_filter_module); ngx_http_clear_content_length(r); ngx_http_clear_accept_ranges(r); ngx_http_weak_etag(r); r->preserve_body = 1; return ngx_http_next_header_filter(r); } static ngx_int_t ngx_http_addition_body_filter(ngx_http_request_t *r, ngx_chain_t *in) { ngx_int_t rc; ngx_uint_t last; ngx_chain_t *cl; ngx_http_request_t *sr; ngx_http_addition_ctx_t *ctx; ngx_http_addition_conf_t *conf; if (in == NULL || r->header_only) { return ngx_http_next_body_filter(r, in); } ctx = ngx_http_get_module_ctx(r, ngx_http_addition_filter_module); if (ctx == NULL) { return ngx_http_next_body_filter(r, in); } conf = ngx_http_get_module_loc_conf(r, ngx_http_addition_filter_module); if (!ctx->before_body_sent) { ctx->before_body_sent = 1; if (conf->before_body.len) { if (ngx_http_subrequest(r, &conf->before_body, NULL, &sr, NULL, 0) != NGX_OK) { return NGX_ERROR; } } } if (conf->after_body.len == 0) { ngx_http_set_ctx(r, NULL, ngx_http_addition_filter_module); return ngx_http_next_body_filter(r, in); } last = 0; for (cl = in; cl; cl = cl->next) { if (cl->buf->last_buf) { cl->buf->last_buf = 0; cl->buf->last_in_chain = 1; cl->buf->sync = 1; last = 1; } } rc = ngx_http_next_body_filter(r, in); if (rc == NGX_ERROR || !last || conf->after_body.len == 0) { return rc; } if (ngx_http_subrequest(r, &conf->after_body, NULL, &sr, NULL, 0) != NGX_OK) { return NGX_ERROR; } ngx_http_set_ctx(r, NULL, ngx_http_addition_filter_module); return ngx_http_send_special(r, NGX_HTTP_LAST); } static ngx_int_t ngx_http_addition_filter_init(ngx_conf_t *cf) { ngx_http_next_header_filter = ngx_http_top_header_filter; ngx_http_top_header_filter = ngx_http_addition_header_filter; ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_addition_body_filter; return NGX_OK; } static void * ngx_http_addition_create_conf(ngx_conf_t *cf) { ngx_http_addition_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_addition_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->before_body = { 0, NULL }; * conf->after_body = { 0, NULL }; * conf->types = { NULL }; * conf->types_keys = NULL; */ return conf; } static char * ngx_http_addition_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_addition_conf_t *prev = parent; ngx_http_addition_conf_t *conf = child; ngx_conf_merge_str_value(conf->before_body, prev->before_body, ""); ngx_conf_merge_str_value(conf->after_body, prev->after_body, ""); if (ngx_http_merge_types(cf, &conf->types_keys, &conf->types, &prev->types_keys, &prev->types, ngx_http_html_default_types) != NGX_OK) { return NGX_CONF_ERROR; } return NGX_CONF_OK; }