postgresql/src/backend/libpq
Tom Lane e4d5854555 Fix build breakage on Solaris-alikes with late-model GCC.
Solaris has never bothered to add "const" to the second argument
of PAM conversation procs, as all other Unixen did decades ago.
This resulted in an "incompatible pointer" compiler warning when
building --with-pam, but had no more serious effect than that,
so we never did anything about it.  However, as of GCC 14 the
case is an error not warning by default.

To complicate matters, recent OpenIndiana (and maybe illumos
in general?) *does* supply the "const" by default, so we can't
just assume that platforms using our solaris template need help.

What we can do, short of building a configure-time probe,
is to make solaris.h #define _PAM_LEGACY_NONCONST, which
causes OpenIndiana's pam_appl.h to revert to the traditional
definition, and hopefully will have no effect anywhere else.
Then we can use that same symbol to control whether we include
"const" in the declaration of pam_passwd_conv_proc().

Bug: #18995
Reported-by: Andrew Watkins <awatkins1966@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/18995-82058da9ab4337a7@postgresql.org
Backpatch-through: 13
2025-07-23 15:44:29 -04:00
..
auth-sasl.c Update copyright for 2023 2023-01-02 15:00:37 -05:00
auth-scram.c Make SCRAM iteration count configurable 2023-03-27 09:46:29 +02:00
auth.c Fix build breakage on Solaris-alikes with late-model GCC. 2025-07-23 15:44:29 -04:00
be-fsstubs.c Fix bugs in manipulation of large objects. 2023-12-15 13:55:05 -05:00
be-gssapi-common.c De-Revert "Add support for Kerberos credential delegation" 2023-04-13 08:55:07 -04:00
be-secure-common.c Common function for percent placeholder replacement 2023-01-11 10:42:35 +01:00
be-secure-gssapi.c Don't reduce output request size on non-Unix-socket connections. 2025-06-10 18:39:34 -04:00
be-secure-openssl.c Fix regression in TLS session ticket disabling 2024-08-19 12:55:11 +02:00
be-secure.c Update copyright for 2023 2023-01-02 15:00:37 -05:00
crypt.c Update copyright for 2023 2023-01-02 15:00:37 -05:00
hba.c Eliminate fixed token-length limit in hba.c. 2023-07-27 11:56:35 -04:00
ifaddr.c Update copyright for 2023 2023-01-02 15:00:37 -05:00
Makefile Refactor SASL code with a generic interface for its mechanisms 2021-07-07 10:55:15 +09:00
meson.build Update copyright for 2023 2023-01-02 15:00:37 -05:00
pg_hba.conf.sample Add description for new patterns supported in HBA and ident sample files 2023-02-16 07:38:52 +09:00
pg_ident.conf.sample Add description for new patterns supported in HBA and ident sample files 2023-02-16 07:38:52 +09:00
pqcomm.c Disconnect if socket cannot be put into non-blocking mode 2024-03-12 10:18:44 +02:00
pqformat.c Change argument type of pq_sendbytes from char * to void * 2023-02-14 13:32:19 +01:00
pqmq.c Perform apply of large transactions by parallel workers. 2023-01-09 07:52:45 +05:30
pqsignal.c Use WaitEventSet API for postmaster's event loop. 2023-01-12 16:32:20 +13:00
README.SSL Move EDH support to common files 2018-01-23 07:11:38 -05:00

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()).