postgresql/src
Heikki Linnakangas fe0a0b5993 Replace PostmasterRandom() with a stronger source, second attempt.
This adds a new routine, pg_strong_random() for generating random bytes,
for use in both frontend and backend. At the moment, it's only used in
the backend, but the upcoming SCRAM authentication patches need strong
random numbers in libpq as well.

pg_strong_random() is based on, and replaces, the existing implementation
in pgcrypto. It can acquire strong random numbers from a number of sources,
depending on what's available:

- OpenSSL RAND_bytes(), if built with OpenSSL
- On Windows, the native cryptographic functions are used
- /dev/urandom

Unlike the current pgcrypto function, the source is chosen by configure.
That makes it easier to test different implementations, and ensures that
we don't accidentally fall back to a less secure implementation, if the
primary source fails. All of those methods are quite reliable, it would be
pretty surprising for them to fail, so we'd rather find out by failing
hard.

If no strong random source is available, we fall back to using erand48(),
seeded from current timestamp, like PostmasterRandom() was. That isn't
cryptographically secure, but allows us to still work on platforms that
don't have any of the above stronger sources. Because it's not very secure,
the built-in implementation is only used if explicitly requested with
--disable-strong-random.

This replaces the more complicated Fortuna algorithm we used to have in
pgcrypto, which is unfortunate, but all modern platforms have /dev/urandom,
so it doesn't seem worth the maintenance effort to keep that. pgcrypto
functions that require strong random numbers will be disabled with
--disable-strong-random.

Original patch by Magnus Hagander, tons of further work by Michael Paquier
and me.

Discussion: https://www.postgresql.org/message-id/CAB7nPqRy3krN8quR9XujMVVHYtXJ0_60nqgVc6oUk8ygyVkZsA@mail.gmail.com
Discussion: https://www.postgresql.org/message-id/CAB7nPqRWkNYRRPJA7-cF+LfroYV10pvjdz6GNvxk-Eee9FypKA@mail.gmail.com
2016-12-05 13:42:59 +02:00
..
backend Replace PostmasterRandom() with a stronger source, second attempt. 2016-12-05 13:42:59 +02:00
bin Add max_parallel_workers GUC. 2016-12-02 07:42:58 -05:00
common Rename "pg_xlog" directory to "pg_wal". 2016-10-20 11:32:18 -04:00
fe_utils Teach appendShellString() to not quote strings containing "-". 2016-09-06 14:53:31 -04:00
include Replace PostmasterRandom() with a stronger source, second attempt. 2016-12-05 13:42:59 +02:00
interfaces libpq: Fix inadvertent change in PQhost() behavior. 2016-12-01 14:36:39 -05:00
makefiles Provide NO_INSTALLCHECK option for pgxs. 2016-11-14 14:53:07 -08:00
pl Check that result tupdesc has exactly 1 column in return_next scalar case. 2016-11-15 16:48:19 -05:00
port Replace PostmasterRandom() with a stronger source, second attempt. 2016-12-05 13:42:59 +02:00
template Remove "sco" and "unixware" ports. 2016-10-11 11:26:04 -04:00
test Document recipe for testing compatibility with old Perl. 2016-12-04 00:16:55 -05:00
timezone More zic cleanup. 2016-11-06 10:45:58 -05:00
tools Replace PostmasterRandom() with a stronger source, second attempt. 2016-12-05 13:42:59 +02:00
tutorial Update copyright for 2016 2016-01-02 13:33:40 -05:00
.gitignore Convert cvsignore to gitignore, and add .gitignore for build targets. 2010-09-22 12:57:04 +02:00
bcc32.mak Autoconfiscate selection of 64-bit int type for 64-bit large object API. 2012-10-07 21:52:43 -04:00
DEVELOPERS
Makefile Install TAP test infrastructure so it's available for extension testing. 2016-09-23 15:50:00 -04:00
Makefile.global.in Replace PostmasterRandom() with a stronger source, second attempt. 2016-12-05 13:42:59 +02:00
Makefile.shlib Remove "sco" and "unixware" ports. 2016-10-11 11:26:04 -04:00
nls-global.mk nls-global.mk: search build dir for source files, too 2016-06-07 18:55:18 -04:00
win32.mak Autoconfiscate selection of 64-bit int type for 64-bit large object API. 2012-10-07 21:52:43 -04:00