Mercurial > hg > nginx-quic
view src/event/ngx_event_connectex.c @ 7629:f47f7d3d1bfa
Mp4: fixed possible chunk offset overflow.
In "co64" atom chunk start offset is a 64-bit unsigned integer. When trimming
the "mdat" atom, chunk offsets are casted to off_t values which are typically
64-bit signed integers. A specially crafted mp4 file with huge chunk offsets
may lead to off_t overflow and result in negative trim boundaries.
The consequences of the overflow are:
- Incorrect Content-Length header value in the response.
- Negative left boundary of the response file buffer holding the trimmed "mdat".
This leads to pread()/sendfile() errors followed by closing the client
connection.
On rare systems where off_t is a 32-bit integer, this scenario is also feasible
with the "stco" atom.
The fix is to add checks which make sure data chunks referenced by each track
are within the mp4 file boundaries. Additionally a few more checks are added to
ensure mp4 file consistency and log errors.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 26 Feb 2020 15:10:46 +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); } }