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Feature #12558

Updated by rhenium (Kazuki Yamaguchi) over 3 years ago

In server keystore file, it specifies Owner like Owner: CN=default.server. When used SSL connection to connect to the server, it reported a error #<OpenSSL::SSL::SSLError: hostname "xxx.xx.xxx.xxx" does not match the server certificate>. I checked the ruby code and found that it seemed Ruby did not support this scenario when an Owner is specified in keystore file and its value is not the server real hostname or IP address.

First, lets have a look at the error message and call stacks

~~~

(Time: 2016-07-06 09:33:51 +0800)(PID: 30558)(LVL: ERROR) -: Failed to POST data due to error: #<OpenSSL::SSL::SSLError: hostname "xxx.xx.xxx.xxx" does not match the server certificate>
(Time: 2016-07-06 09:33:51 +0800)(PID: 30558)(LVL: ERROR) -: Trace: ["/usr/local/ruby/lib/ruby/site_ruby/2.1.0/openssl/ssl.rb:139:in `post_connection_check'", "/usr/local/ruby/lib/ruby/2.1.0/net/http.rb:922:in `connect'", "/usr/local/ruby/lib/ruby/2.1.0/net/http.rb:863
~~~



From code /usr/local/ruby/lib/ruby/2.1.0/net/http.rb:922
it calls s.post_connection_check(@address) function which raise the error I mentioned. This function takes @address as the parameters which is passed by initialize function as below. From the description of the initialize function, the address should be a DNS hostname or IP address.

# Creates a new Net::HTTP object for the specified server address,
# without opening the TCP connection or initializing the HTTP session.
# The +address+ should be a DNS hostname or IP address.
def initialize(address, port = nil)
@address = address

/usr/local/ruby/lib/ruby/2.1.0/net/http.rb:922


if use_ssl?
begin
if proxy?
buf = "CONNECT #{@address}:#{@port} HTTP/#{HTTPVersion}\r\n"
buf << "Host: #{@address}:#{@port}\r\n"
if proxy_user
credential = ["#{proxy_user}:#{proxy_pass}"].pack('m')
credential.delete!("\r\n")
buf << "Proxy-Authorization: Basic #{credential}\r\n"
end
buf << "\r\n"
@socket.write(buf)
HTTPResponse.read_new(@socket).value
end
s.session = @ssl_session if @ssl_session
# Server Name Indication (SNI) RFC 3546
s.hostname = @address if s.respond_to? :hostname=
Timeout.timeout(@open_timeout, Net::OpenTimeout) { s.connect }
if @ssl_context.verify_mode != OpenSSL::SSL::VERIFY_NONE
s.post_connection_check(@address)
end
@ssl_session = s.session
rescue => exception
D "Conn close because of connect error #{exception}"
@socket.close if @socket and not @socket.closed?
raise exception
end
end
on_connect
end

Then take a look at s.post_connection_check(@address) function in /usr/local/ruby/lib/ruby/site_ruby/2.1.0/openssl/ssl.rb,

def post_connection_check(hostname)
unless OpenSSL::SSL.verify_certificate_identity(peer_cert, hostname)
raise SSLError, "hostname \"#{hostname}\" does not match the server certificate"
end
return true
end

it calls verify_certificate_identity(peer_cert, hostname) as below:


def verify_certificate_identity(cert, hostname)
should_verify_common_name = true
cert.extensions.each{|ext|
next if ext.oid != "subjectAltName"
ostr = OpenSSL::ASN1.decode(ext.to_der).value.last
sequence = OpenSSL::ASN1.decode(ostr.value)
sequence.value.each{|san|
case san.tag
when 2 # dNSName in GeneralName (RFC5280)
should_verify_common_name = false
reg = Regexp.escape(san.value).gsub(/\\\*/, "[^.]+")
return true if /\A#{reg}\z/i =~ hostname
when 7 # iPAddress in GeneralName (RFC5280)
should_verify_common_name = false
# follows GENERAL_NAME_print() in x509v3/v3_alt.c
if san.value.size == 4
return true if san.value.unpack('C*').join('.') == hostname
elsif san.value.size == 16
return true if san.value.unpack('n*').map { |e| sprintf("%X", e) }.join(':') == hostname
end
end
}
}
if should_verify_common_name
cert.subject.to_a.each{|oid, value|
if oid == "CN"
reg = Regexp.escape(value).gsub(/\\\*/, "[^.]+")
return true if /\A#{reg}\z/i =~ hostname
end
}
end
return false
end

As you can see from above code, there is options that can set a alternative server hostname so that SSL verification can pass.

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