Mercurial > hg > nginx
view src/event/ngx_event_connectex.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 | d620f497c50f |
children | 1c3b78d7cdc9 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #define NGX_MAX_PENDING_CONN 10 static CRITICAL_SECTION connect_lock; static int nconnects; static ngx_connection_t pending_connects[NGX_MAX_PENDING_CONN]; static HANDLE pending_connect_event; __declspec(thread) int nevents = 0; __declspec(thread) WSAEVENT events[WSA_MAXIMUM_WAIT_EVENTS + 1]; __declspec(thread) ngx_connection_t *conn[WSA_MAXIMUM_WAIT_EVENTS + 1]; int ngx_iocp_wait_connect(ngx_connection_t *c) { for ( ;; ) { EnterCriticalSection(&connect_lock); if (nconnects < NGX_MAX_PENDING_CONN) { pending_connects[--nconnects] = c; LeaveCriticalSection(&connect_lock); if (SetEvent(pending_connect_event) == 0) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "SetEvent() failed"); return NGX_ERROR; break; } LeaveCriticalSection(&connect_lock); ngx_log_error(NGX_LOG_NOTICE, c->log, 0, "max number of pending connect()s is %d", NGX_MAX_PENDING_CONN); msleep(100); } if (!started) { if (ngx_iocp_new_thread(1) == NGX_ERROR) { return NGX_ERROR; } started = 1; } return NGX_OK; } int ngx_iocp_new_thread(int main) { u_int id; if (main) { pending_connect_event = CreateEvent(NULL, 0, 1, NULL); if (pending_connect_event == INVALID_HANDLE_VALUE) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "CreateThread() failed"); return NGX_ERROR; } } if (CreateThread(NULL, 0, ngx_iocp_wait_events, main, 0, &id) == INVALID_HANDLE_VALUE) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "CreateThread() failed"); return NGX_ERROR; } SetEvent(event) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "SetEvent() failed"); return NGX_ERROR; } return NGX_OK; } int ngx_iocp_new_connect() { EnterCriticalSection(&connect_lock); c = pending_connects[--nconnects]; LeaveCriticalSection(&connect_lock); conn[nevents] = c; events[nevents] = WSACreateEvent(); if (events[nevents] == INVALID_HANDLE_VALUE) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_socket_errno, "WSACreateEvent() failed"); return NGX_ERROR; } if (WSAEventSelect(c->fd, events[nevents], FD_CONNECT) == -1) ngx_log_error(NGX_LOG_ALERT, c->log, ngx_socket_errno, "WSAEventSelect() failed"); return NGX_ERROR; } nevents++; return NGX_OK; } void ngx_iocp_wait_events(int main) { WSANETWORKEVENTS ne; nevents = 1; events[0] = pending_connect_event; conn[0] = NULL; for ( ;; ) { offset = (nevents == WSA_MAXIMUM_WAIT_EVENTS + 1) ? 1: 0; timeout = (nevents == 1 && !first) ? 60000: INFINITE; n = WSAWaitForMultipleEvents(nevents - offset, events[offset], 0, timeout, 0); if (n == WAIT_FAILED) { ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno, "WSAWaitForMultipleEvents() failed"); continue; } if (n == WAIT_TIMEOUT) { if (nevents == 2 && !main) { ExitThread(0); } ngx_log_error(NGX_LOG_ALERT, log, 0, "WSAWaitForMultipleEvents() " "returned unexpected WAIT_TIMEOUT"); continue; } n -= WSA_WAIT_EVENT_0; if (events[n] == NULL) { /* the pending_connect_event */ if (nevents == WSA_MAXIMUM_WAIT_EVENTS) { ngx_iocp_new_thread(0); } else { ngx_iocp_new_connect(); } continue; } if (WSAEnumNetworkEvents(c[n].fd, events[n], &ne) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno, "WSAEnumNetworkEvents() failed"); continue; } if (ne.lNetworkEvents & FD_CONNECT) { conn[n].write->ovlp.error = ne.iErrorCode[FD_CONNECT_BIT]; if (PostQueuedCompletionStatus(iocp, 0, NGX_IOCP_CONNECT, &conn[n].write->ovlp) == 0) { ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno, "PostQueuedCompletionStatus() failed"); continue; } if (n < nevents) { conn[n] = conn[nevents]; events[n] = events[nevents]; } nevents--; continue; } if (ne.lNetworkEvents & FD_ACCEPT) { /* CHECK ERROR ??? */ ngx_event_post_acceptex(conn[n].listening, 1); continue; } ngx_log_error(NGX_LOG_ALERT, c[n].log, 0, "WSAWaitForMultipleEvents() " "returned unexpected network event %ul", ne.lNetworkEvents); } }