commit 4375beb477c73e8ccc82dba3f921caa9d87f3abb
author Roman Arutyunyan <arut@nginx.com> Tue Jul 04 18:07:29 2017 +0300
committer Roman Arutyunyan <arut@nginx.com> Tue Jul 04 18:07:29 2017 +0300
tree 3e29a0d3f4f492bd41f11b4f4fea79a5de17f08e
parent efbbf31023483691a9467124a38bf8103f41d3ae

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.