17 files changed, 21 insertions, 336 deletions

diff --git a/src/Makefile.global.in b/src/Makefile.global.in
index b47971edef5..4b6bab37dc9 100644
--- a/src/Makefile.global.in
+++ b/src/Makefile.global.in
@@ -203,7 +203,6 @@ enable_dtrace	= @enable_dtrace@
 enable_coverage	= @enable_coverage@
 enable_tap_tests	= @enable_tap_tests@
 enable_thread_safety	= @enable_thread_safety@
-enable_strong_random	= @enable_strong_random@
 
 python_includespec	= @python_includespec@
 python_libdir		= @python_libdir@
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 998818cbacc..26b4977acbe 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -65,7 +65,6 @@
 #include "storage/reinit.h"
 #include "storage/smgr.h"
 #include "storage/spin.h"
-#include "utils/backend_random.h"
 #include "utils/builtins.h"
 #include "utils/guc.h"
 #include "utils/memutils.h"
@@ -5132,7 +5131,7 @@ BootStrapXLOG(void)
 	 * a genuine-looking password challenge for the non-existent user, in lieu
 	 * of an actual stored password.
 	 */
-	if (!pg_backend_random(mock_auth_nonce, MOCK_AUTH_NONCE_LEN))
+	if (!pg_strong_random(mock_auth_nonce, MOCK_AUTH_NONCE_LEN))
 		ereport(PANIC,
 				(errcode(ERRCODE_INTERNAL_ERROR),
 				 errmsg("could not generate secret authorization token")));
diff --git a/src/backend/libpq/auth-scram.c b/src/backend/libpq/auth-scram.c
index e997c946001..9a969a7029e 100644
--- a/src/backend/libpq/auth-scram.c
+++ b/src/backend/libpq/auth-scram.c
@@ -102,7 +102,6 @@
 #include "libpq/crypt.h"
 #include "libpq/scram.h"
 #include "miscadmin.h"
-#include "utils/backend_random.h"
 #include "utils/builtins.h"
 #include "utils/timestamp.h"
 
@@ -468,7 +467,7 @@ pg_be_scram_build_verifier(const char *password)
 		password = (const char *) prep_password;
 
 	/* Generate random salt */
-	if (!pg_backend_random(saltbuf, SCRAM_DEFAULT_SALT_LEN))
+	if (!pg_strong_random(saltbuf, SCRAM_DEFAULT_SALT_LEN))
 		ereport(ERROR,
 				(errcode(ERRCODE_INTERNAL_ERROR),
 				 errmsg("could not generate random salt")));
@@ -1123,7 +1122,7 @@ build_server_first_message(scram_state *state)
 	char		raw_nonce[SCRAM_RAW_NONCE_LEN];
 	int			encoded_len;
 
-	if (!pg_backend_random(raw_nonce, SCRAM_RAW_NONCE_LEN))
+	if (!pg_strong_random(raw_nonce, SCRAM_RAW_NONCE_LEN))
 		ereport(ERROR,
 				(errcode(ERRCODE_INTERNAL_ERROR),
 				 errmsg("could not generate random nonce")));
diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index ff0832dba8b..0c2ca39d1bd 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -36,7 +36,6 @@
 #include "port/pg_bswap.h"
 #include "replication/walsender.h"
 #include "storage/ipc.h"
-#include "utils/backend_random.h"
 #include "utils/timestamp.h"
 
 
@@ -835,7 +834,7 @@ CheckMD5Auth(Port *port, char *shadow_pass, char **logdetail)
 				 errmsg("MD5 authentication is not supported when \"db_user_namespace\" is enabled")));
 
 	/* include the salt to use for computing the response */
-	if (!pg_backend_random(md5Salt, 4))
+	if (!pg_strong_random(md5Salt, 4))
 	{
 		ereport(LOG,
 				(errmsg("could not generate random MD5 salt")));
@@ -3036,7 +3035,7 @@ PerformRadiusTransaction(const char *server, const char *secret, const char *por
 	/* Construct RADIUS packet */
 	packet->code = RADIUS_ACCESS_REQUEST;
 	packet->length = RADIUS_HEADER_LENGTH;
-	if (!pg_backend_random((char *) packet->vector, RADIUS_VECTOR_LENGTH))
+	if (!pg_strong_random(packet->vector, RADIUS_VECTOR_LENGTH))
 	{
 		ereport(LOG,
 				(errmsg("could not generate random encryption vector")));
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 2d5a0ac7d3b..406cc2cf2d4 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -367,16 +367,6 @@ static volatile sig_atomic_t WalReceiverRequested = false;
 static volatile bool StartWorkerNeeded = true;
 static volatile bool HaveCrashedWorker = false;
 
-#ifndef HAVE_STRONG_RANDOM
-/*
- * State for assigning cancel keys.
- * Also, the global MyCancelKey passes the cancel key assigned to a given
- * backend from the postmaster to that backend (via fork).
- */
-static unsigned int random_seed = 0;
-static struct timeval random_start_time;
-#endif
-
 #ifdef USE_SSL
 /* Set when and if SSL has been initialized properly */
 static bool LoadedSSL = false;
@@ -1361,10 +1351,6 @@ PostmasterMain(int argc, char *argv[])
 	 * Remember postmaster startup time
 	 */
 	PgStartTime = GetCurrentTimestamp();
-#ifndef HAVE_STRONG_RANDOM
-	/* RandomCancelKey wants its own copy */
-	gettimeofday(&random_start_time, NULL);
-#endif
 
 	/*
 	 * Report postmaster status in the postmaster.pid file, to allow pg_ctl to
@@ -2532,26 +2518,11 @@ InitProcessGlobals(void)
 	MyStartTime = timestamptz_to_time_t(MyStartTimestamp);
 
 	/*
-	 * Don't want backend to be able to see the postmaster random number
-	 * generator state.  We have to clobber the static random_seed.
-	 */
-#ifndef HAVE_STRONG_RANDOM
-	random_seed = 0;
-	random_start_time.tv_usec = 0;
-#endif
-
-	/*
 	 * Set a different seed for random() in every process.  We want something
 	 * unpredictable, so if possible, use high-quality random bits for the
 	 * seed.  Otherwise, fall back to a seed based on timestamp and PID.
-	 *
-	 * Note we can't use pg_backend_random here, since this is used in the
-	 * postmaster, and even in a backend we might not be attached to shared
-	 * memory yet.
 	 */
-#ifdef HAVE_STRONG_RANDOM
 	if (!pg_strong_random(&rseed, sizeof(rseed)))
-#endif
 	{
 		/*
 		 * Since PIDs and timestamps tend to change more frequently in their
@@ -5256,38 +5227,7 @@ StartupPacketTimeoutHandler(void)
 static bool
 RandomCancelKey(int32 *cancel_key)
 {
-#ifdef HAVE_STRONG_RANDOM
-	return pg_strong_random((char *) cancel_key, sizeof(int32));
-#else
-
-	/*
-	 * If built with --disable-strong-random, use plain old erand48.
-	 *
-	 * We cannot use pg_backend_random() in postmaster, because it stores its
-	 * state in shared memory.
-	 */
-	static unsigned short seed[3];
-
-	/*
-	 * Select a random seed at the time of first receiving a request.
-	 */
-	if (random_seed == 0)
-	{
-		struct timeval random_stop_time;
-
-		gettimeofday(&random_stop_time, NULL);
-
-		seed[0] = (unsigned short) random_start_time.tv_usec;
-		seed[1] = (unsigned short) (random_stop_time.tv_usec) ^ (random_start_time.tv_usec >> 16);
-		seed[2] = (unsigned short) (random_stop_time.tv_usec >> 16);
-
-		random_seed = 1;
-	}
-
-	*cancel_key = pg_jrand48(seed);
-
-	return true;
-#endif
+	return pg_strong_random(cancel_key, sizeof(int32));
 }
 
 /*
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 0c86a581c03..473513a9272 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -44,7 +44,6 @@
 #include "storage/procsignal.h"
 #include "storage/sinvaladt.h"
 #include "storage/spin.h"
-#include "utils/backend_random.h"
 #include "utils/snapmgr.h"
 
 
@@ -149,7 +148,6 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
-		size = add_size(size, BackendRandomShmemSize());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -269,7 +267,6 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
 	BTreeShmemInit();
 	SyncScanShmemInit();
 	AsyncShmemInit();
-	BackendRandomShmemInit();
 
 #ifdef EXEC_BACKEND
 
diff --git a/src/backend/storage/lmgr/lwlocknames.txt b/src/backend/storage/lmgr/lwlocknames.txt
index e6025ecedb3..db478432291 100644
--- a/src/backend/storage/lmgr/lwlocknames.txt
+++ b/src/backend/storage/lmgr/lwlocknames.txt
@@ -47,6 +47,5 @@ CommitTsLock						39
 ReplicationOriginLock				40
 MultiXactTruncationLock				41
 OldSnapshotTimeMapLock				42
-BackendRandomLock					43
-LogicalRepWorkerLock				44
-CLogTruncationLock					45
+LogicalRepWorkerLock				43
+CLogTruncationLock					44
diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
index add099ec9dc..1407f9612ca 100644
--- a/src/backend/utils/adt/float.c
+++ b/src/backend/utils/adt/float.c
@@ -24,7 +24,6 @@
 #include "libpq/pqformat.h"
 #include "miscadmin.h"
 #include "utils/array.h"
-#include "utils/backend_random.h"
 #include "utils/float.h"
 #include "utils/fmgrprotos.h"
 #include "utils/sortsupport.h"
@@ -2393,7 +2392,7 @@ drandom(PG_FUNCTION_ARGS)
 		 * Should that fail for some reason, we fall back on a lower-quality
 		 * seed based on current time and PID.
 		 */
-		if (!pg_backend_random((char *) drandom_seed, sizeof(drandom_seed)))
+		if (!pg_strong_random(drandom_seed, sizeof(drandom_seed)))
 		{
 			TimestampTz now = GetCurrentTimestamp();
 			uint64		iseed;
diff --git a/src/backend/utils/misc/Makefile b/src/backend/utils/misc/Makefile
index a53fcdf1889..ec7ec131e5a 100644
--- a/src/backend/utils/misc/Makefile
+++ b/src/backend/utils/misc/Makefile
@@ -14,9 +14,9 @@ include $(top_builddir)/src/Makefile.global
 
 override CPPFLAGS := -I. -I$(srcdir) $(CPPFLAGS)
 
-OBJS = backend_random.o guc.o help_config.o pg_config.o pg_controldata.o \
-       pg_rusage.o ps_status.o queryenvironment.o rls.o sampling.o \
-       superuser.o timeout.o tzparser.o
+OBJS = guc.o help_config.o pg_config.o pg_controldata.o pg_rusage.o \
+       ps_status.o queryenvironment.o rls.o sampling.o superuser.o \
+       timeout.o tzparser.o
 
 # This location might depend on the installation directories. Therefore
 # we can't substitute it into pg_config.h.
diff --git a/src/backend/utils/misc/backend_random.c b/src/backend/utils/misc/backend_random.c
deleted file mode 100644
index a64f3ac3980..00000000000
--- a/src/backend/utils/misc/backend_random.c
+++ /dev/null
@@ -1,158 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * backend_random.c
- *	  Backend random number generation routine.
- *
- * pg_backend_random() function fills a buffer with random bytes. Normally,
- * it is just a thin wrapper around pg_strong_random(), but when compiled
- * with --disable-strong-random, we provide a built-in implementation.
- *
- * This function is used for generating nonces in authentication, and for
- * random salt generation in pgcrypto. The built-in implementation is not
- * cryptographically strong, but if the user asked for it, we'll go ahead
- * and use it anyway.
- *
- * The built-in implementation uses the standard erand48 algorithm, with
- * a seed shared between all backends.
- *
- * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
- * Portions Copyright (c) 1994, Regents of the University of California
- *
- *
- * IDENTIFICATION
- *	  src/backend/utils/misc/backend_random.c
- *
- *-------------------------------------------------------------------------
- */
-
-#include "postgres.h"
-
-#include <sys/time.h>
-
-#include "miscadmin.h"
-#include "storage/lwlock.h"
-#include "storage/shmem.h"
-#include "utils/backend_random.h"
-#include "utils/timestamp.h"
-
-#ifdef HAVE_STRONG_RANDOM
-
-Size
-BackendRandomShmemSize(void)
-{
-	return 0;
-}
-
-void
-BackendRandomShmemInit(void)
-{
-	/* do nothing */
-}
-
-bool
-pg_backend_random(char *dst, int len)
-{
-	/* should not be called in postmaster */
-	Assert(IsUnderPostmaster || !IsPostmasterEnvironment);
-
-	return pg_strong_random(dst, len);
-}
-
-#else
-
-/*
- * Seed for the PRNG, stored in shared memory.
- *
- * Protected by BackendRandomLock.
- */
-typedef struct
-{
-	bool		initialized;
-	unsigned short seed[3];
-}			BackendRandomShmemStruct;
-
-static BackendRandomShmemStruct * BackendRandomShmem;
-
-Size
-BackendRandomShmemSize(void)
-{
-	return sizeof(BackendRandomShmemStruct);
-}
-
-void
-BackendRandomShmemInit(void)
-{
-	bool		found;
-
-	BackendRandomShmem = (BackendRandomShmemStruct *)
-		ShmemInitStruct("Backend PRNG state",
-						BackendRandomShmemSize(),
-						&found);
-
-	if (!IsUnderPostmaster)
-	{
-		Assert(!found);
-
-		BackendRandomShmem->initialized = false;
-	}
-	else
-		Assert(found);
-}
-
-bool
-pg_backend_random(char *dst, int len)
-{
-	int			i;
-	char	   *end = dst + len;
-
-	/* should not be called in postmaster */
-	Assert(IsUnderPostmaster || !IsPostmasterEnvironment);
-
-	LWLockAcquire(BackendRandomLock, LW_EXCLUSIVE);
-
-	/*
-	 * Seed the PRNG on the first use.
-	 */
-	if (!BackendRandomShmem->initialized)
-	{
-		struct timeval now;
-
-		gettimeofday(&now, NULL);
-
-		BackendRandomShmem->seed[0] = now.tv_sec;
-		BackendRandomShmem->seed[1] = (unsigned short) (now.tv_usec);
-		BackendRandomShmem->seed[2] = (unsigned short) (now.tv_usec >> 16);
-
-		/*
-		 * Mix in the cancel key, generated by the postmaster. This adds what
-		 * little entropy the postmaster had to the seed.
-		 */
-		BackendRandomShmem->seed[0] ^= (MyCancelKey);
-		BackendRandomShmem->seed[1] ^= (MyCancelKey >> 16);
-
-		BackendRandomShmem->initialized = true;
-	}
-
-	for (i = 0; dst < end; i++)
-	{
-		uint32		r;
-		int			j;
-
-		/*
-		 * pg_jrand48 returns a 32-bit integer. Fill the next 4 bytes from it.
-		 */
-		r = (uint32) pg_jrand48(BackendRandomShmem->seed);
-
-		for (j = 0; j < 4 && dst < end; j++)
-		{
-			*(dst++) = (char) (r & 0xFF);
-			r >>= 8;
-		}
-	}
-	LWLockRelease(BackendRandomLock);
-
-	return true;
-}
-
-
-#endif							/* HAVE_STRONG_RANDOM */
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index c64e16187ad..f3f4ac3e3c2 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -4844,13 +4844,9 @@ set_random_seed(const char *seed)
 	else if (strcmp(seed, "rand") == 0)
 	{
 		/* use some "strong" random source */
-#ifdef HAVE_STRONG_RANDOM
 		if (!pg_strong_random(&iseed, sizeof(iseed)))
-#endif
 		{
-			fprintf(stderr,
-					"cannot seed random from a strong source, none available: "
-					"use \"time\" or an unsigned integer value.\n");
+			fprintf(stderr, "could not generate random seed.\n");
 			return false;
 		}
 	}
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 76bd81e9bf2..9d99816eae9 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -552,9 +552,6 @@
 /* Define to 1 if you have the `strnlen' function. */
 #undef HAVE_STRNLEN
 
-/* Define to use have a strong random number source */
-#undef HAVE_STRONG_RANDOM
-
 /* Define to 1 if you have the `strsignal' function. */
 #undef HAVE_STRSIGNAL
 
diff --git a/src/include/pg_config.h.win32 b/src/include/pg_config.h.win32
index de0c4d9997b..1a89a8c24e2 100644
--- a/src/include/pg_config.h.win32
+++ b/src/include/pg_config.h.win32
@@ -412,9 +412,6 @@
 /* Define to 1 if you have the <string.h> header file. */
 #define HAVE_STRING_H 1
 
-/* Define to use have a strong random number source */
-#define HAVE_STRONG_RANDOM 1
-
 /* Define to 1 if you have the `strsignal' function. */
 /* #undef HAVE_STRSIGNAL */
 
diff --git a/src/include/port.h b/src/include/port.h
index 570a9052a28..ebf9d55979d 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -498,9 +498,12 @@ extern char *inet_net_ntop(int af, const void *src, int bits,
 			  char *dst, size_t size);
 
 /* port/pg_strong_random.c */
-#ifdef HAVE_STRONG_RANDOM
 extern bool pg_strong_random(void *buf, size_t len);
-#endif
+/*
+ * pg_backend_random used to be a wrapper for pg_strong_random before
+ * Postgres 12 for the backend code.
+ */
+#define pg_backend_random pg_strong_random
 
 /* port/pgcheckdir.c */
 extern int	pg_check_dir(const char *dir);
diff --git a/src/include/utils/backend_random.h b/src/include/utils/backend_random.h
deleted file mode 100644
index 99ea2cb9fb5..00000000000
--- a/src/include/utils/backend_random.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * backend_random.h
- *		Declarations for backend random number generation
- *
- * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
- *
- *	  src/include/utils/backend_random.h
- *
- *-------------------------------------------------------------------------
- */
-#ifndef BACKEND_RANDOM_H
-#define BACKEND_RANDOM_H
-
-extern Size BackendRandomShmemSize(void);
-extern void BackendRandomShmemInit(void);
-extern bool pg_backend_random(char *dst, int len);
-
-#endif							/* BACKEND_RANDOM_H */
diff --git a/src/interfaces/libpq/fe-auth-scram.c b/src/interfaces/libpq/fe-auth-scram.c
index 603ef4c0020..6f9e6789d56 100644
--- a/src/interfaces/libpq/fe-auth-scram.c
+++ b/src/interfaces/libpq/fe-auth-scram.c
@@ -19,11 +19,6 @@
 #include "common/scram-common.h"
 #include "fe-auth.h"
 
-/* These are needed for getpid(), in the fallback implementation */
-#ifndef HAVE_STRONG_RANDOM
-#include <sys/types.h>
-#include <unistd.h>
-#endif
 
 /*
  * Status of exchange messages used for SCRAM authentication via the
@@ -72,7 +67,6 @@ static bool verify_server_signature(fe_scram_state *state);
 static void calculate_client_proof(fe_scram_state *state,
 					   const char *client_final_message_without_proof,
 					   uint8 *result);
-static bool pg_frontend_random(char *dst, int len);
 
 /*
  * Initialize SCRAM exchange status.
@@ -320,7 +314,7 @@ build_client_first_message(fe_scram_state *state)
 	 * Generate a "raw" nonce.  This is converted to ASCII-printable form by
 	 * base64-encoding it.
 	 */
-	if (!pg_frontend_random(raw_nonce, SCRAM_RAW_NONCE_LEN))
+	if (!pg_strong_random(raw_nonce, SCRAM_RAW_NONCE_LEN))
 	{
 		printfPQExpBuffer(&conn->errorMessage,
 						  libpq_gettext("could not generate nonce\n"));
@@ -764,7 +758,7 @@ pg_fe_scram_build_verifier(const char *password)
 		password = (const char *) prep_password;
 
 	/* Generate a random salt */
-	if (!pg_frontend_random(saltbuf, SCRAM_DEFAULT_SALT_LEN))
+	if (!pg_strong_random(saltbuf, SCRAM_DEFAULT_SALT_LEN))
 	{
 		if (prep_password)
 			free(prep_password);
@@ -779,55 +773,3 @@ pg_fe_scram_build_verifier(const char *password)
 
 	return result;
 }
-
-/*
- * Random number generator.
- */
-static bool
-pg_frontend_random(char *dst, int len)
-{
-#ifdef HAVE_STRONG_RANDOM
-	return pg_strong_random(dst, len);
-#else
-	int			i;
-	char	   *end = dst + len;
-
-	static unsigned short seed[3];
-	static int	mypid = 0;
-
-	pglock_thread();
-
-	if (mypid != getpid())
-	{
-		struct timeval now;
-
-		gettimeofday(&now, NULL);
-
-		seed[0] = now.tv_sec ^ getpid();
-		seed[1] = (unsigned short) (now.tv_usec);
-		seed[2] = (unsigned short) (now.tv_usec >> 16);
-	}
-
-	for (i = 0; dst < end; i++)
-	{
-		uint32		r;
-		int			j;
-
-		/*
-		 * pg_jrand48 returns a 32-bit integer.  Fill the next 4 bytes from
-		 * it.
-		 */
-		r = (uint32) pg_jrand48(seed);
-
-		for (j = 0; j < 4 && dst < end; j++)
-		{
-			*(dst++) = (char) (r & 0xFF);
-			r >>= 8;
-		}
-	}
-
-	pgunlock_thread();
-
-	return true;
-#endif
-}
diff --git a/src/port/Makefile b/src/port/Makefile
index ae3f973ae14..9cfc0f92796 100644
--- a/src/port/Makefile
+++ b/src/port/Makefile
@@ -37,14 +37,10 @@ LIBS += $(PTHREAD_LIBS)
 
 OBJS = $(LIBOBJS) $(PG_CRC32C_OBJS) chklocale.o erand48.o inet_net_ntop.o \
 	noblock.o path.o pgcheckdir.o pgmkdirp.o pgsleep.o \
-	pgstrcasecmp.o pgstrsignal.o pqsignal.o \
+	pg_strong_random.o pgstrcasecmp.o pgstrsignal.o pqsignal.o \
 	qsort.o qsort_arg.o quotes.o snprintf.o sprompt.o strerror.o \
 	tar.o thread.o
 
-ifeq ($(enable_strong_random), yes)
-OBJS += pg_strong_random.o
-endif
-
 # libpgport.a, libpgport_shlib.a, and libpgport_srv.a contain the same files
 # foo.o, foo_shlib.o, and foo_srv.o are all built from foo.c
 OBJS_SHLIB = $(OBJS:%.o=%_shlib.o)