Mercurial > hg > nginx
view src/http/modules/ngx_http_addition_filter_module.c @ 9282:acb8548c00e9
HTTP/3: fixed dynamic table overflow.
While inserting a new entry into the dynamic table, first the entry is added,
and then older entries are evicted until table size is within capacity. After
the first step, the number of entries may temporarily exceed the maximum
calculated from capacity by one entry, which previously caused table overflow.
The easiest way to trigger the issue is to keep adding entries with empty names
and values until first eviction.
The issue was introduced by 987bee4363d1.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Tue, 28 May 2024 17:18:50 +0400 |
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; }