Replace PostmasterRandom() with a stronger source, second attempt

Enterprise / PostgreSQL - Heikki Linnakangas [iki.fi] - 5 December 2016 05:42 UTC

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

fe0a0b5 Replace PostmasterRandom() with a stronger source, second attempt.
configure | 109 +++++
configure.in | 52 +++
contrib/pgcrypto/Makefile | 2 +-
contrib/pgcrypto/expected/pgp-compression_1.out | 42 ++
contrib/pgcrypto/expected/pgp-decrypt_1.out | 424 ++++++++++++++++++
contrib/pgcrypto/expected/pgp-encrypt_1.out | 161 +++++++
contrib/pgcrypto/expected/pgp-pubkey-encrypt_1.out | 62 +++
contrib/pgcrypto/fortuna.c | 463 --------------------
contrib/pgcrypto/fortuna.h | 38 --
contrib/pgcrypto/internal.c | 63 ---
contrib/pgcrypto/openssl.c | 46 --
contrib/pgcrypto/pgcrypto.c | 27 +-
contrib/pgcrypto/pgp-encrypt.c | 22 +-
contrib/pgcrypto/pgp-mpi-internal.c | 10 +-
contrib/pgcrypto/pgp-pgsql.c | 95 +---
contrib/pgcrypto/pgp-pubenc.c | 26 +-
contrib/pgcrypto/pgp-s2k.c | 15 +-
contrib/pgcrypto/px-crypt.c | 7 +-
contrib/pgcrypto/px.c | 34 +-
contrib/pgcrypto/px.h | 7 +-
contrib/pgcrypto/random.c | 247 -----------
doc/src/sgml/installation.sgml | 17 +
src/Makefile.global.in | 1 +
src/backend/libpq/auth.c | 62 ++-
src/backend/libpq/crypt.c | 10 +-
src/backend/postmaster/postmaster.c | 146 +++---
src/backend/storage/ipc/ipci.c | 3 +
src/backend/storage/lmgr/lwlocknames.txt | 1 +
src/backend/utils/init/globals.c | 2 +-
src/backend/utils/misc/Makefile | 5 +-
src/backend/utils/misc/backend_random.c | 158 +++++++
src/include/libpq/crypt.h | 2 +-
src/include/libpq/libpq-be.h | 1 -
src/include/miscadmin.h | 2 +-
src/include/pg_config.h.in | 12 +
src/include/pg_config.h.win32 | 12 +
src/include/port.h | 6 +
src/include/utils/backend_random.h | 19 +
src/port/Makefile | 4 +
src/port/erand48.c | 7 +
src/port/pg_strong_random.c | 149 +++++++
src/tools/msvc/Mkvcbuild.pm | 5 +-
42 files changed, 1472 insertions(+), 1104 deletions(-)

Upstream: git.postgresql.org

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