Clean up some lack-of-STRICT issues in the core code, too.

A scan for missed proisstrict markings in the core code turned up
these functions:

brin_summarize_new_values
pg_stat_reset_single_table_counters
pg_stat_reset_single_function_counters
pg_create_logical_replication_slot
pg_create_physical_replication_slot
pg_drop_replication_slot

The first three of these take OID, so a null argument will normally look
like a zero to them, resulting in "ERROR: could not open relation with OID
0" for brin_summarize_new_values, and no action for the pg_stat_reset_XXX
functions.  The other three will dump core on a null argument, though this
is mitigated by the fact that they won't do so until after checking that
the caller is superuser or has rolreplication privilege.

In addition, the pg_logical_slot_get/peek[_binary]_changes family was
intentionally marked nonstrict, but failed to make nullness checks on all
the arguments; so again a null-pointer-dereference crash is possible but
only for superusers and rolreplication users.

Add the missing ARGISNULL checks to the latter functions, and mark the
former functions as strict in pg_proc.  Make that change in the back
branches too, even though we can't force initdb there, just so that
installations initdb'd in future won't have the issue.  Since none of these
bugs rise to the level of security issues (and indeed the pg_stat_reset_XXX
functions hardly misbehave at all), it seems sufficient to do this.

In addition, fix some order-of-operations oddities in the slot_get_changes
family, mostly cosmetic, but not the part that moves the function's last
few operations into the PG_TRY block.  As it stood, there was significant
risk for an error to exit without clearing historical information from
the system caches.

The slot_get_changes bugs go back to 9.4 where that code was introduced.
Back-patch appropriate subsets of the pg_proc changes into all active
branches, as well.

1 files changed, 40 insertions, 42 deletions

diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c
index 887440b19dd..56e47e4b9c4 100644
--- a/src/backend/replication/logical/logicalfuncs.c
+++ b/src/backend/replication/logical/logicalfuncs.c
@@ -276,25 +276,31 @@ logical_read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr,
 static Datum
 pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool binary)
 {
-	Name		name = PG_GETARG_NAME(0);
+	Name		name;
 	XLogRecPtr	upto_lsn;
 	int32		upto_nchanges;
-
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
 	MemoryContext per_query_ctx;
 	MemoryContext oldcontext;
-
 	XLogRecPtr	end_of_wal;
 	XLogRecPtr	startptr;
-
 	LogicalDecodingContext *ctx;
-
 	ResourceOwner old_resowner = CurrentResourceOwner;
 	ArrayType  *arr;
 	Size		ndim;
 	List	   *options = NIL;
 	DecodingOutputState *p;
 
+	check_permissions();
+
+	CheckLogicalDecodingRequirements();
+
+	if (PG_ARGISNULL(0))
+		ereport(ERROR,
+				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
+				 errmsg("slot name must not be null")));
+	name = PG_GETARG_NAME(0);
+
 	if (PG_ARGISNULL(1))
 		upto_lsn = InvalidXLogRecPtr;
 	else
@@ -305,6 +311,12 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
 	else
 		upto_nchanges = PG_GETARG_INT32(2);
 
+	if (PG_ARGISNULL(3))
+		ereport(ERROR,
+				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
+				 errmsg("options array must not be null")));
+	arr = PG_GETARG_ARRAYTYPE_P(3);
+
 	/* check to see if caller supports us returning a tuplestore */
 	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
 		ereport(ERROR,
@@ -324,16 +336,11 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
 	if (get_call_result_type(fcinfo, NULL, &p->tupdesc) != TYPEFUNC_COMPOSITE)
 		elog(ERROR, "return type must be a row type");
 
-	check_permissions();
-
-	CheckLogicalDecodingRequirements();
-
-	arr = PG_GETARG_ARRAYTYPE_P(3);
-	ndim = ARR_NDIM(arr);
-
 	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
 	oldcontext = MemoryContextSwitchTo(per_query_ctx);
 
+	/* Deconstruct options array */
+	ndim = ARR_NDIM(arr);
 	if (ndim > 1)
 	{
 		ereport(ERROR,
@@ -382,7 +389,6 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
 	else
 		end_of_wal = GetXLogReplayRecPtr(NULL);
 
-	CheckLogicalDecodingRequirements();
 	ReplicationSlotAcquire(NameStr(*name));
 
 	PG_TRY();
@@ -444,6 +450,23 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
 				break;
 			CHECK_FOR_INTERRUPTS();
 		}
+
+		tuplestore_donestoring(tupstore);
+
+		CurrentResourceOwner = old_resowner;
+
+		/*
+		 * Next time, start where we left off. (Hunting things, the family
+		 * business..)
+		 */
+		if (ctx->reader->EndRecPtr != InvalidXLogRecPtr && confirm)
+			LogicalConfirmReceivedLocation(ctx->reader->EndRecPtr);
+
+		/* free context, call shutdown callback */
+		FreeDecodingContext(ctx);
+
+		ReplicationSlotRelease();
+		InvalidateSystemCaches();
 	}
 	PG_CATCH();
 	{
@@ -454,23 +477,6 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
 	}
 	PG_END_TRY();
 
-	tuplestore_donestoring(tupstore);
-
-	CurrentResourceOwner = old_resowner;
-
-	/*
-	 * Next time, start where we left off. (Hunting things, the family
-	 * business..)
-	 */
-	if (ctx->reader->EndRecPtr != InvalidXLogRecPtr && confirm)
-		LogicalConfirmReceivedLocation(ctx->reader->EndRecPtr);
-
-	/* free context, call shutdown callback */
-	FreeDecodingContext(ctx);
-
-	ReplicationSlotRelease();
-	InvalidateSystemCaches();
-
 	return (Datum) 0;
 }
 
@@ -480,9 +486,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
 Datum
 pg_logical_slot_get_changes(PG_FUNCTION_ARGS)
 {
-	Datum		ret = pg_logical_slot_get_changes_guts(fcinfo, true, false);
-
-	return ret;
+	return pg_logical_slot_get_changes_guts(fcinfo, true, false);
 }
 
 /*
@@ -491,9 +495,7 @@ pg_logical_slot_get_changes(PG_FUNCTION_ARGS)
 Datum
 pg_logical_slot_peek_changes(PG_FUNCTION_ARGS)
 {
-	Datum		ret = pg_logical_slot_get_changes_guts(fcinfo, false, false);
-
-	return ret;
+	return pg_logical_slot_get_changes_guts(fcinfo, false, false);
 }
 
 /*
@@ -502,9 +504,7 @@ pg_logical_slot_peek_changes(PG_FUNCTION_ARGS)
 Datum
 pg_logical_slot_get_binary_changes(PG_FUNCTION_ARGS)
 {
-	Datum		ret = pg_logical_slot_get_changes_guts(fcinfo, true, true);
-
-	return ret;
+	return pg_logical_slot_get_changes_guts(fcinfo, true, true);
 }
 
 /*
@@ -513,7 +513,5 @@ pg_logical_slot_get_binary_changes(PG_FUNCTION_ARGS)
 Datum
 pg_logical_slot_peek_binary_changes(PG_FUNCTION_ARGS)
 {
-	Datum		ret = pg_logical_slot_get_changes_guts(fcinfo, false, true);
-
-	return ret;
+	return pg_logical_slot_get_changes_guts(fcinfo, false, true);
 }