Mercurial > hg > nginx
view src/http/ngx_http_copy_filter_module.c @ 7674:7731c710796f
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 | ce37362a7a70 |
children | 555533169506 |
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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_bufs_t bufs; } ngx_http_copy_filter_conf_t; #if (NGX_HAVE_FILE_AIO) static void ngx_http_copy_aio_handler(ngx_output_chain_ctx_t *ctx, ngx_file_t *file); static void ngx_http_copy_aio_event_handler(ngx_event_t *ev); #if (NGX_HAVE_AIO_SENDFILE) static ssize_t ngx_http_copy_aio_sendfile_preload(ngx_buf_t *file); static void ngx_http_copy_aio_sendfile_event_handler(ngx_event_t *ev); #endif #endif #if (NGX_THREADS) static ngx_int_t ngx_http_copy_thread_handler(ngx_thread_task_t *task, ngx_file_t *file); static void ngx_http_copy_thread_event_handler(ngx_event_t *ev); #endif static void *ngx_http_copy_filter_create_conf(ngx_conf_t *cf); static char *ngx_http_copy_filter_merge_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_copy_filter_init(ngx_conf_t *cf); static ngx_command_t ngx_http_copy_filter_commands[] = { { ngx_string("output_buffers"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2, ngx_conf_set_bufs_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_copy_filter_conf_t, bufs), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_copy_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_copy_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_copy_filter_create_conf, /* create location configuration */ ngx_http_copy_filter_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_copy_filter_module = { NGX_MODULE_V1, &ngx_http_copy_filter_module_ctx, /* module context */ ngx_http_copy_filter_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_body_filter_pt ngx_http_next_body_filter; static ngx_int_t ngx_http_copy_filter(ngx_http_request_t *r, ngx_chain_t *in) { ngx_int_t rc; ngx_connection_t *c; ngx_output_chain_ctx_t *ctx; ngx_http_core_loc_conf_t *clcf; ngx_http_copy_filter_conf_t *conf; c = r->connection; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "http copy filter: \"%V?%V\"", &r->uri, &r->args); ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module); if (ctx == NULL) { ctx = ngx_pcalloc(r->pool, sizeof(ngx_output_chain_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } ngx_http_set_ctx(r, ctx, ngx_http_copy_filter_module); conf = ngx_http_get_module_loc_conf(r, ngx_http_copy_filter_module); clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); ctx->sendfile = c->sendfile; ctx->need_in_memory = r->main_filter_need_in_memory || r->filter_need_in_memory; ctx->need_in_temp = r->filter_need_temporary; ctx->alignment = clcf->directio_alignment; ctx->pool = r->pool; ctx->bufs = conf->bufs; ctx->tag = (ngx_buf_tag_t) &ngx_http_copy_filter_module; ctx->output_filter = (ngx_output_chain_filter_pt) ngx_http_next_body_filter; ctx->filter_ctx = r; #if (NGX_HAVE_FILE_AIO) if (ngx_file_aio && clcf->aio == NGX_HTTP_AIO_ON) { ctx->aio_handler = ngx_http_copy_aio_handler; #if (NGX_HAVE_AIO_SENDFILE) ctx->aio_preload = ngx_http_copy_aio_sendfile_preload; #endif } #endif #if (NGX_THREADS) if (clcf->aio == NGX_HTTP_AIO_THREADS) { ctx->thread_handler = ngx_http_copy_thread_handler; } #endif if (in && in->buf && ngx_buf_size(in->buf)) { r->request_output = 1; } } #if (NGX_HAVE_FILE_AIO || NGX_THREADS) ctx->aio = r->aio; #endif rc = ngx_output_chain(ctx, in); if (ctx->in == NULL) { r->buffered &= ~NGX_HTTP_COPY_BUFFERED; } else { r->buffered |= NGX_HTTP_COPY_BUFFERED; } ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0, "http copy filter: %i \"%V?%V\"", rc, &r->uri, &r->args); return rc; } #if (NGX_HAVE_FILE_AIO) static void ngx_http_copy_aio_handler(ngx_output_chain_ctx_t *ctx, ngx_file_t *file) { ngx_http_request_t *r; r = ctx->filter_ctx; file->aio->data = r; file->aio->handler = ngx_http_copy_aio_event_handler; r->main->blocked++; r->aio = 1; ctx->aio = 1; } static void ngx_http_copy_aio_event_handler(ngx_event_t *ev) { ngx_event_aio_t *aio; ngx_connection_t *c; ngx_http_request_t *r; aio = ev->data; r = aio->data; c = r->connection; ngx_http_set_log_request(c->log, r); ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "http aio: \"%V?%V\"", &r->uri, &r->args); r->main->blocked--; r->aio = 0; r->write_event_handler(r); ngx_http_run_posted_requests(c); } #if (NGX_HAVE_AIO_SENDFILE) static ssize_t ngx_http_copy_aio_sendfile_preload(ngx_buf_t *file) { ssize_t n; static u_char buf[1]; ngx_event_aio_t *aio; ngx_http_request_t *r; ngx_output_chain_ctx_t *ctx; n = ngx_file_aio_read(file->file, buf, 1, file->file_pos, NULL); if (n == NGX_AGAIN) { aio = file->file->aio; aio->handler = ngx_http_copy_aio_sendfile_event_handler; r = aio->data; r->main->blocked++; r->aio = 1; ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module); ctx->aio = 1; } return n; } static void ngx_http_copy_aio_sendfile_event_handler(ngx_event_t *ev) { ngx_event_aio_t *aio; ngx_http_request_t *r; aio = ev->data; r = aio->data; r->main->blocked--; r->aio = 0; ev->complete = 0; r->connection->write->handler(r->connection->write); } #endif #endif #if (NGX_THREADS) static ngx_int_t ngx_http_copy_thread_handler(ngx_thread_task_t *task, ngx_file_t *file) { ngx_str_t name; ngx_thread_pool_t *tp; ngx_http_request_t *r; ngx_output_chain_ctx_t *ctx; ngx_http_core_loc_conf_t *clcf; r = file->thread_ctx; clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); tp = clcf->thread_pool; if (tp == NULL) { if (ngx_http_complex_value(r, clcf->thread_pool_value, &name) != NGX_OK) { return NGX_ERROR; } tp = ngx_thread_pool_get((ngx_cycle_t *) ngx_cycle, &name); if (tp == NULL) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "thread pool \"%V\" not found", &name); return NGX_ERROR; } } task->event.data = r; task->event.handler = ngx_http_copy_thread_event_handler; if (ngx_thread_task_post(tp, task) != NGX_OK) { return NGX_ERROR; } r->main->blocked++; r->aio = 1; ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module); ctx->aio = 1; return NGX_OK; } static void ngx_http_copy_thread_event_handler(ngx_event_t *ev) { ngx_connection_t *c; ngx_http_request_t *r; r = ev->data; c = r->connection; ngx_http_set_log_request(c->log, r); ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "http thread: \"%V?%V\"", &r->uri, &r->args); r->main->blocked--; r->aio = 0; if (r->done) { /* * trigger connection event handler if the subrequest was * already finalized; this can happen if the handler is used * for sendfile() in threads */ c->write->handler(c->write); } else { r->write_event_handler(r); ngx_http_run_posted_requests(c); } } #endif static void * ngx_http_copy_filter_create_conf(ngx_conf_t *cf) { ngx_http_copy_filter_conf_t *conf; conf = ngx_palloc(cf->pool, sizeof(ngx_http_copy_filter_conf_t)); if (conf == NULL) { return NULL; } conf->bufs.num = 0; return conf; } static char * ngx_http_copy_filter_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_copy_filter_conf_t *prev = parent; ngx_http_copy_filter_conf_t *conf = child; ngx_conf_merge_bufs_value(conf->bufs, prev->bufs, 2, 32768); return NULL; } static ngx_int_t ngx_http_copy_filter_init(ngx_conf_t *cf) { ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_copy_filter; return NGX_OK; }