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.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_ALLOC_H_INCLUDED_
#define _NGX_ALLOC_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


void *ngx_alloc(size_t size, ngx_log_t *log);
void *ngx_calloc(size_t size, ngx_log_t *log);

#define ngx_free          free
#define ngx_memalign(alignment, size, log)  ngx_alloc(size, log)

extern ngx_uint_t  ngx_pagesize;
extern ngx_uint_t  ngx_pagesize_shift;
extern ngx_uint_t  ngx_cacheline_size;


#endif /* _NGX_ALLOC_H_INCLUDED_ */