Mercurial > hg > nginx
view src/http/modules/ngx_http_not_modified_filter_module.c @ 7507:ea05113adbdb
Range filter: fixed loss of incoming chain links.
Filters are not allowed to change incoming chain links, and should allocate
their own links if any modifications are needed. Nevertheless
ngx_http_range_singlepart_body() modified incoming chain links in some
cases, notably at the end of the requested range.
No problems caused by this are currently known, mostly because of
limited number of possible modifications and the position of the range
body filter in the filter chain. Though this behaviour is clearly incorrect
and tests demonstrate that it can at least cause some proxy buffers being
lost when using proxy_force_ranges, leading to less effective handling
of responses.
Fix is to always allocate new chain links in ngx_http_range_singlepart_body().
Links are explicitly freed to ensure constant memory usage with long-lived
requests.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 13 May 2019 22:44:02 +0300 |
parents | 8b6fa4842133 |
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> static ngx_uint_t ngx_http_test_if_unmodified(ngx_http_request_t *r); static ngx_uint_t ngx_http_test_if_modified(ngx_http_request_t *r); static ngx_uint_t ngx_http_test_if_match(ngx_http_request_t *r, ngx_table_elt_t *header, ngx_uint_t weak); static ngx_int_t ngx_http_not_modified_filter_init(ngx_conf_t *cf); static ngx_http_module_t ngx_http_not_modified_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_not_modified_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_not_modified_filter_module = { NGX_MODULE_V1, &ngx_http_not_modified_filter_module_ctx, /* module context */ NULL, /* 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_int_t ngx_http_not_modified_header_filter(ngx_http_request_t *r) { if (r->headers_out.status != NGX_HTTP_OK || r != r->main || r->disable_not_modified) { return ngx_http_next_header_filter(r); } if (r->headers_in.if_unmodified_since && !ngx_http_test_if_unmodified(r)) { return ngx_http_filter_finalize_request(r, NULL, NGX_HTTP_PRECONDITION_FAILED); } if (r->headers_in.if_match && !ngx_http_test_if_match(r, r->headers_in.if_match, 0)) { return ngx_http_filter_finalize_request(r, NULL, NGX_HTTP_PRECONDITION_FAILED); } if (r->headers_in.if_modified_since || r->headers_in.if_none_match) { if (r->headers_in.if_modified_since && ngx_http_test_if_modified(r)) { return ngx_http_next_header_filter(r); } if (r->headers_in.if_none_match && !ngx_http_test_if_match(r, r->headers_in.if_none_match, 1)) { return ngx_http_next_header_filter(r); } /* not modified */ r->headers_out.status = NGX_HTTP_NOT_MODIFIED; r->headers_out.status_line.len = 0; r->headers_out.content_type.len = 0; ngx_http_clear_content_length(r); ngx_http_clear_accept_ranges(r); if (r->headers_out.content_encoding) { r->headers_out.content_encoding->hash = 0; r->headers_out.content_encoding = NULL; } return ngx_http_next_header_filter(r); } return ngx_http_next_header_filter(r); } static ngx_uint_t ngx_http_test_if_unmodified(ngx_http_request_t *r) { time_t iums; if (r->headers_out.last_modified_time == (time_t) -1) { return 0; } iums = ngx_parse_http_time(r->headers_in.if_unmodified_since->value.data, r->headers_in.if_unmodified_since->value.len); ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http iums:%T lm:%T", iums, r->headers_out.last_modified_time); if (iums >= r->headers_out.last_modified_time) { return 1; } return 0; } static ngx_uint_t ngx_http_test_if_modified(ngx_http_request_t *r) { time_t ims; ngx_http_core_loc_conf_t *clcf; if (r->headers_out.last_modified_time == (time_t) -1) { return 1; } clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); if (clcf->if_modified_since == NGX_HTTP_IMS_OFF) { return 1; } ims = ngx_parse_http_time(r->headers_in.if_modified_since->value.data, r->headers_in.if_modified_since->value.len); ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http ims:%T lm:%T", ims, r->headers_out.last_modified_time); if (ims == r->headers_out.last_modified_time) { return 0; } if (clcf->if_modified_since == NGX_HTTP_IMS_EXACT || ims < r->headers_out.last_modified_time) { return 1; } return 0; } static ngx_uint_t ngx_http_test_if_match(ngx_http_request_t *r, ngx_table_elt_t *header, ngx_uint_t weak) { u_char *start, *end, ch; ngx_str_t etag, *list; list = &header->value; if (list->len == 1 && list->data[0] == '*') { return 1; } if (r->headers_out.etag == NULL) { return 0; } etag = r->headers_out.etag->value; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http im:\"%V\" etag:%V", list, &etag); if (weak && etag.len > 2 && etag.data[0] == 'W' && etag.data[1] == '/') { etag.len -= 2; etag.data += 2; } start = list->data; end = list->data + list->len; while (start < end) { if (weak && end - start > 2 && start[0] == 'W' && start[1] == '/') { start += 2; } if (etag.len > (size_t) (end - start)) { return 0; } if (ngx_strncmp(start, etag.data, etag.len) != 0) { goto skip; } start += etag.len; while (start < end) { ch = *start; if (ch == ' ' || ch == '\t') { start++; continue; } break; } if (start == end || *start == ',') { return 1; } skip: while (start < end && *start != ',') { start++; } while (start < end) { ch = *start; if (ch == ' ' || ch == '\t' || ch == ',') { start++; continue; } break; } } return 0; } static ngx_int_t ngx_http_not_modified_filter_init(ngx_conf_t *cf) { ngx_http_next_header_filter = ngx_http_top_header_filter; ngx_http_top_header_filter = ngx_http_not_modified_header_filter; return NGX_OK; }