Re: [PATCH v1] GSSAPI encryption support - Mailing list pgsql-hackers

From Michael Paquier
Subject Re: [PATCH v1] GSSAPI encryption support
Date
Msg-id CAB7nPqRGQ60PWLb-CLLrvMoQwPAbnu-961W+xGPvG62RMSkcZQ@mail.gmail.com
Whole thread Raw
In response to [PATCH v1] GSSAPI encryption support  (Robbie Harwood <rharwood@redhat.com>)
Responses Re: [PATCH v1] GSSAPI encryption support  (Robbie Harwood <rharwood@redhat.com>)
Re: [PATCH v2] GSSAPI encryption support  (Robbie Harwood <rharwood@redhat.com>)
List pgsql-hackers


On Fri, Jul 3, 2015 at 3:22 AM, Robbie Harwood <rharwood@redhat.com> wrote:
Hello -hackers,

As previously discussed on this list, I have coded up GSSAPI encryption
support.  If it is easier for anyone, this code is also available for
viewing on my github:
https://github.com/postgres/postgres/compare/master...frozencemetery:feature/gssencrypt

Fallback support is present in both directions for talking to old client
and old servers; GSSAPI encryption is by default auto-upgraded to where
available (for compatibility), but both client and server contain
settings for requiring it.

There are 8 commits in this series; I have tried to err on the side of
creating too much separation rather than too little.  A patch for each
is attached.  This is v1 of the series.

I just had a quick look at this patch, and here are some comments:
+   <para>
+    If the client has probed <acronym>GSSAPI</acronym> encryption support and
+    the connection is <acronym>GSSAPI</acronym>-authenticated, then after the
+    server sends AuthenticationOk, all traffic between the client and server
+    will be <acronym>GSSAPI</acronym>-encrypted. Because
+    <acronym>GSSAPI</acronym> does not provide framing,
+    <acronym>GSSAPI</acronym>-encrypted messages are modeled after protocol-3
+    messages: the first byte is the caracter g, then four bytes of length, and
+    then an encrypted message.
+   </para>
Message formats should be described in protocol.sgml in the section for message formats.

+      network. In the <filename>pg_hba.conf</> file, the GSS authenticaion
+      method has a parameter to require encryption; otherwise, connections
+      will be encrypted if available and requiested by the client. On the
s/authenticaion/authentication
s/requiested/requested

+        Whether to require GSSAPI encryption.  Default is off, which causes
+        GSSAPI encryption to be enabled if available and requested for
+        compatability with old clients.  It is recommended to set this unless
+        old clients are present.
s/compatability/compatibility

Going through the docs, the overall approach taken by the patch looks neat, and the default values as designed for both the client and the server are good things to do. Now actually looking at the code I am suspecting that some code portions could be largely simplified in the authentication protocol code, though I don't have the time yet to look at that in details.

Also, when trying to connect with GSSAPI, I found the following problem:
psql: lost synchronization with server: got message type "S", length 22
This happens whatever the value of require_encrypt on server-side is, either 0 or 1.
Regards,
--
Michael

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