Mercurial > hg > nginx
view src/os/unix/ngx_socket.c @ 7048:80224192163c
Resolver: fixed possible use-after-free while resolving SRV.
Resolving an SRV record includes resolving its host names in subrequests.
Previously, if memory allocation failed while reporting a subrequest result
after receiving a response from a DNS server, the SRV resolve handler was
called immediately with the NGX_ERROR state. However, if the SRV record
included another copy of the resolved name, it was reported once again.
This could trigger the use-after-free memory access after SRV resolve
handler freed the resolve context by calling ngx_resolve_name_done().
Now the SRV resolve handler is called only when all its subrequests are
completed.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Tue, 04 Jul 2017 18:07:29 +0300 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> /* * ioctl(FIONBIO) sets a non-blocking mode with the single syscall * while fcntl(F_SETFL, O_NONBLOCK) needs to learn the current state * using fcntl(F_GETFL). * * ioctl() and fcntl() are syscalls at least in FreeBSD 2.x, Linux 2.2 * and Solaris 7. * * ioctl() in Linux 2.4 and 2.6 uses BKL, however, fcntl(F_SETFL) uses it too. */ #if (NGX_HAVE_FIONBIO) int ngx_nonblocking(ngx_socket_t s) { int nb; nb = 1; return ioctl(s, FIONBIO, &nb); } int ngx_blocking(ngx_socket_t s) { int nb; nb = 0; return ioctl(s, FIONBIO, &nb); } #endif #if (NGX_FREEBSD) int ngx_tcp_nopush(ngx_socket_t s) { int tcp_nopush; tcp_nopush = 1; return setsockopt(s, IPPROTO_TCP, TCP_NOPUSH, (const void *) &tcp_nopush, sizeof(int)); } int ngx_tcp_push(ngx_socket_t s) { int tcp_nopush; tcp_nopush = 0; return setsockopt(s, IPPROTO_TCP, TCP_NOPUSH, (const void *) &tcp_nopush, sizeof(int)); } #elif (NGX_LINUX) int ngx_tcp_nopush(ngx_socket_t s) { int cork; cork = 1; return setsockopt(s, IPPROTO_TCP, TCP_CORK, (const void *) &cork, sizeof(int)); } int ngx_tcp_push(ngx_socket_t s) { int cork; cork = 0; return setsockopt(s, IPPROTO_TCP, TCP_CORK, (const void *) &cork, sizeof(int)); } #else int ngx_tcp_nopush(ngx_socket_t s) { return 0; } int ngx_tcp_push(ngx_socket_t s) { return 0; } #endif