Revert "Replace PostmasterRandom() with a stronger way of generating randomness."

This reverts commit 9e083fd4683294f41544e6d0d72f6e258ff3a77c. That was a
few bricks shy of a load:

* Query cancel stopped working
* Buildfarm member pademelon stopped working, because the box doesn't have
  /dev/urandom nor /dev/random.

This clearly needs some more discussion, and a quite different patch, so
revert for now.

1 files changed, 0 insertions, 148 deletions

diff --git a/src/port/pg_strong_random.c b/src/port/pg_strong_random.c
deleted file mode 100644
index a404111d745..00000000000
--- a/src/port/pg_strong_random.c
+++ /dev/null
@@ -1,148 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * pg_strong_random.c
- *	  pg_strong_random() function to return a strong random number
- *
- * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
- *
- *
- * IDENTIFICATION
- *	  src/port/pg_strong_random.c
- *
- *-------------------------------------------------------------------------
- */
-
-#ifndef FRONTEND
-#include "postgres.h"
-#else
-#include "postgres_fe.h"
-#endif
-
-#include <fcntl.h>
-#include <unistd.h>
-
-#ifdef USE_SSL
-#include <openssl/rand.h>
-#endif
-#ifdef WIN32
-#include <Wincrypt.h>
-#endif
-
-static bool random_from_file(char *filename, void *buf, size_t len);
-
-#ifdef WIN32
-/*
- * Cache a global crypto provider that only gets freed when the process
- * exits, in case we need random numbers more than once.
- */
-static HCRYPTPROV hProvider = 0;
-#endif
-
-/*
- * Read (random) bytes from a file.
- */
-static bool
-random_from_file(char *filename, void *buf, size_t len)
-{
-	int			f;
-	char	   *p = buf;
-	ssize_t		res;
-
-	f = open(filename, O_RDONLY, 0);
-	if (f == -1)
-		return false;
-
-	while (len)
-	{
-		res = read(f, p, len);
-		if (res <= 0)
-		{
-			if (errno == EINTR)
-				continue;		/* interrupted by signal, just retry */
-
-			close(f);
-			return false;
-		}
-
-		p += res;
-		len -= res;
-	}
-
-	close(f);
-	return true;
-}
-
-/*
- * pg_strong_random
- *
- * Generate requested number of random bytes. The bytes are
- * cryptographically strong random, suitable for use e.g. in key
- * generation.
- *
- * The bytes can be acquired from a number of sources, depending
- * on what's available. We try the following, in this order:
- *
- * 1. OpenSSL's RAND_bytes()
- * 2. Windows' CryptGenRandom() function
- * 3. /dev/urandom
- * 4. /dev/random
- *
- * Returns true on success, and false if none of the sources
- * were available. NB: It is important to check the return value!
- * Proceeding with key generation when no random data was available
- * would lead to predictable keys and security issues.
- */
-bool
-pg_strong_random(void *buf, size_t len)
-{
-#ifdef USE_SSL
-
-	/*
-	 * When built with OpenSSL, first try the random generation function from
-	 * there.
-	 */
-	if (RAND_bytes(buf, len) == 1)
-		return true;
-#endif
-
-#ifdef WIN32
-
-	/*
-	 * Windows has CryptoAPI for strong cryptographic numbers.
-	 */
-	if (hProvider == 0)
-	{
-		if (!CryptAcquireContext(&hProvider,
-								 NULL,
-								 MS_DEF_PROV,
-								 PROV_RSA_FULL,
-								 CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
-		{
-			/*
-			 * On failure, set back to 0 in case the value was for some reason
-			 * modified.
-			 */
-			hProvider = 0;
-		}
-	}
-
-	/* Re-check in case we just retrieved the provider */
-	if (hProvider != 0)
-	{
-		if (CryptGenRandom(hProvider, len, buf))
-			return true;
-	}
-#endif
-
-	/*
-	 * If there is no OpenSSL and no CryptoAPI (or they didn't work), then
-	 * fall back on reading /dev/urandom or even /dev/random.
-	 */
-	if (random_from_file("/dev/urandom", buf, len))
-		return true;
-	if (random_from_file("/dev/random", buf, len))
-		return true;
-
-	/* None of the sources were available. */
-	return false;
-}