Backport #8240
closedSSLSocket breaks other connections or files on GC
Description
When an OpenSSL::SSL::SSLSocket is recycled by GC, SSL_shutdown() is called,
and SSL_shutdown() sends a close-notify alert message.
However at the GC time, the original socket might have already been closed,
and thus its file descriptor might be reused for another socket or file.
This problem can be reproduced as follows:
$ cat t.rb
require "socket"
require "openssl"
loop do
sock = TCPSocket.new("localhost", 443)
GC.start
ssl = OpenSSL::SSL::SSLSocket.new(sock)
ssl.connect
sock.close
end
$ ruby -v t.rb
ruby 2.1.0dev (2013-04-08 trunk 40183) [i686-linux]
t.rb:8:in connect': SSL_connect SYSCALL returned=5 errno=0 state=unknown state (OpenSSL::SSL::SSLError) from t.rb:8:in
block in '
from t.rb:4:in loop' from t.rb:4:in
'
An SSLError is raised because a close-notify alert message is sent to the server by GC
instead of a client hello message.
If the file descriptor is reused for a file, not a socket, the file would get broken.
This problem occurs rarely, but its impact is very serious.
IMHO, the free function of a DATA object should not do any task other than resource release.
Furthermore, SSLSocket#close calls SSL_shutdown(), but the original socket might have been closed,
in which case SSL_shutdown() (and @io.close) should not be called either.
The attached patch fixes these problems.
Files