Mercurial > hg > nginx-quic
view src/os/win32/ngx_wsarecv.c @ 7054:e02555553d0b
Range filter: protect from total size overflows.
The overflow can be used to circumvent the restriction on total size of
ranges introduced in c2a91088b0c0 (1.1.2). Additionally, overflow
allows producing ranges with negative start (such ranges can be created
by using a suffix, "bytes=-100"; normally this results in 200 due to
the total size check). These can result in the following errors in logs:
[crit] ... pread() ... failed (22: Invalid argument)
[alert] ... sendfile() failed (22: Invalid argument)
When using cache, it can be also used to reveal cache file header.
It is believed that there are no other negative effects, at least with
standard nginx modules.
In theory, this can also result in memory disclosure and/or segmentation
faults if multiple ranges are allowed, and the response is returned in a
single in-memory buffer. This never happens with standard nginx modules
though, as well as known 3rd party modules.
Fix is to properly protect from possible overflow when incrementing size.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 11 Jul 2017 16:06:23 +0300 |
parents | 3d2d3e1cf427 |
children | efd71d49bde0 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> ssize_t ngx_wsarecv(ngx_connection_t *c, u_char *buf, size_t size) { int rc; u_long bytes, flags; WSABUF wsabuf[1]; ngx_err_t err; ngx_int_t n; ngx_event_t *rev; wsabuf[0].buf = (char *) buf; wsabuf[0].len = size; flags = 0; bytes = 0; rc = WSARecv(c->fd, wsabuf, 1, &bytes, &flags, NULL, NULL); ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSARecv: fd:%d rc:%d %ul of %z", c->fd, rc, bytes, size); rev = c->read; if (rc == -1) { rev->ready = 0; err = ngx_socket_errno; if (err == WSAEWOULDBLOCK) { ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "WSARecv() not ready"); return NGX_AGAIN; } n = ngx_connection_error(c, err, "WSARecv() failed"); if (n == NGX_ERROR) { rev->error = 1; } return n; } if (bytes < size) { rev->ready = 0; } if (bytes == 0) { rev->eof = 1; } return bytes; } ssize_t ngx_overlapped_wsarecv(ngx_connection_t *c, u_char *buf, size_t size) { int rc; u_long bytes, flags; WSABUF wsabuf[1]; ngx_err_t err; ngx_int_t n; ngx_event_t *rev; LPWSAOVERLAPPED ovlp; rev = c->read; if (!rev->ready) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "second wsa post"); return NGX_AGAIN; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "rev->complete: %d", rev->complete); if (rev->complete) { rev->complete = 0; if (ngx_event_flags & NGX_USE_IOCP_EVENT) { if (rev->ovlp.error) { ngx_connection_error(c, rev->ovlp.error, "WSARecv() failed"); return NGX_ERROR; } ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSARecv ovlp: fd:%d %ul of %z", c->fd, rev->available, size); return rev->available; } if (WSAGetOverlappedResult(c->fd, (LPWSAOVERLAPPED) &rev->ovlp, &bytes, 0, NULL) == 0) { ngx_connection_error(c, ngx_socket_errno, "WSARecv() or WSAGetOverlappedResult() failed"); return NGX_ERROR; } ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSARecv: fd:%d %ul of %z", c->fd, bytes, size); return bytes; } ovlp = (LPWSAOVERLAPPED) &rev->ovlp; ngx_memzero(ovlp, sizeof(WSAOVERLAPPED)); wsabuf[0].buf = (char *) buf; wsabuf[0].len = size; flags = 0; bytes = 0; rc = WSARecv(c->fd, wsabuf, 1, &bytes, &flags, ovlp, NULL); rev->complete = 0; ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSARecv ovlp: fd:%d rc:%d %ul of %z", c->fd, rc, bytes, size); if (rc == -1) { err = ngx_socket_errno; if (err == WSA_IO_PENDING) { rev->active = 1; ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "WSARecv() posted"); return NGX_AGAIN; } n = ngx_connection_error(c, err, "WSARecv() failed"); if (n == NGX_ERROR) { rev->error = 1; } return n; } if (ngx_event_flags & NGX_USE_IOCP_EVENT) { /* * if a socket was bound with I/O completion port * then GetQueuedCompletionStatus() would anyway return its status * despite that WSARecv() was already complete */ rev->active = 1; return NGX_AGAIN; } if (bytes == 0) { rev->eof = 1; rev->ready = 0; } else { rev->ready = 1; } rev->active = 0; return bytes; }