postgresql/src/backend/libpq
Tom Lane 481c8e9232 Assume that we have utime() and <utime.h>.
These are required by POSIX since SUSv2, and no live platforms fail
to provide them.  On Windows, utime() exists and we bring our own
<utime.h>, so we're good there too.  So remove the configure probes
and ad-hoc substitute code.  We don't need to check for utimes()
anymore either, since that was only used as a substitute.

In passing, make the Windows build include <sys/utime.h> only where
we need it, not everywhere.

This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code.  I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.

Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
2020-02-21 14:30:47 -05:00
..
Makefile Split all OBJS style lines in makefiles into one-line-per-entry style. 2019-11-05 14:41:07 -08:00
README.SSL Move EDH support to common files 2018-01-23 07:11:38 -05:00
auth-scram.c Remove excess parens in ereport() calls 2020-01-30 13:32:04 -03:00
auth.c Clean up some code, comments and docs referring to Windows 2000 and older 2020-02-19 13:20:33 +09:00
be-fsstubs.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
be-gssapi-common.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
be-secure-common.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
be-secure-gssapi.c Extensive code review for GSSAPI encryption mechanism. 2020-01-11 17:14:08 -05:00
be-secure-openssl.c Remove excess parens in ereport() calls 2020-01-30 13:32:04 -03:00
be-secure.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
crypt.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
hba.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
ifaddr.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
pg_hba.conf.sample Rename "scram" to "scram-sha-256" in pg_hba.conf and password_encryption. 2017-04-18 14:50:50 +03:00
pg_ident.conf.sample Reformat the comments in pg_hba.conf and pg_ident.conf 2010-01-26 06:58:39 +00:00
pqcomm.c Assume that we have utime() and <utime.h>. 2020-02-21 14:30:47 -05:00
pqformat.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
pqmq.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
pqsignal.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00

README.SSL

src/backend/libpq/README.SSL

SSL
===

>From the servers perspective:


  Receives StartupPacket
           |
           |
 (Is SSL_NEGOTIATE_CODE?) -----------  Normal startup
           |                  No
           |
           | Yes
           |
           |
 (Server compiled with USE_SSL?) ------- Send 'N'
           |                       No        |
           |                                 |
           | Yes                         Normal startup
           |
           |
        Send 'S'
           |
           |
      Establish SSL
           |
           |
      Normal startup





>From the clients perspective (v6.6 client _with_ SSL):


      Connect
         |
         |
  Send packet with SSL_NEGOTIATE_CODE
         |
         |
  Receive single char  ------- 'S' -------- Establish SSL
         |                                       |
         | '<else>'                              |
         |                                  Normal startup
         |
         |
   Is it 'E' for error  ------------------- Retry connection
         |                  Yes             without SSL
         | No
         |
   Is it 'N' for normal ------------------- Normal startup
         |                  Yes
         |
   Fail with unknown

---------------------------------------------------------------------------

Ephemeral DH
============

Since the server static private key ($DataDir/server.key) will
normally be stored unencrypted so that the database backend can
restart automatically, it is important that we select an algorithm
that continues to provide confidentiality even if the attacker has the
server's private key.  Ephemeral DH (EDH) keys provide this and more
(Perfect Forward Secrecy aka PFS).

N.B., the static private key should still be protected to the largest
extent possible, to minimize the risk of impersonations.

Another benefit of EDH is that it allows the backend and clients to
use DSA keys.  DSA keys can only provide digital signatures, not
encryption, and are often acceptable in jurisdictions where RSA keys
are unacceptable.

The downside to EDH is that it makes it impossible to use ssldump(1)
if there's a problem establishing an SSL session.  In this case you'll
need to temporarily disable EDH (see initialize_dh()).