0001-Fix-inappropriate-uses-of-PG_GETARG_UINT32.patch

From 4b14d698486d6c46c3d91c9bf5c380f8acddb095 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 1 Dec 2021 19:18:08 +0100
Subject: [PATCH] Fix inappropriate uses of PG_GETARG_UINT32()

The chr() function used PG_GETARG_UINT32() even though the argument is
declared as (signed) integer.  As a result, you can pass negative
arguments to this function and it internally interprets them as
positive.  Ultimately ends up being harmless, but it seems wrong, so
fix this and rearrange the internal error checking a bit to
accommodate this.

Another case was in the documentation, where example code used
PG_GETARG_UINT32() with an argument declared as signed integer.
---
 doc/src/sgml/xfunc.sgml               |  2 +-
 src/backend/utils/adt/oracle_compat.c | 33 ++++++++++++++++-----------
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index 584d389d45..0d55909734 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -3193,7 +3193,7 @@ <title>Returning Sets</title>
         oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
         /* total number of tuples to be returned */
-        funcctx->max_calls = PG_GETARG_UINT32(0);
+        funcctx->max_calls = PG_GETARG_INT32(0);
 
         /* Build a tuple descriptor for our result type */
         if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
diff --git a/src/backend/utils/adt/oracle_compat.c b/src/backend/utils/adt/oracle_compat.c
index f737aa6fbd..ec99f2b738 100644
--- a/src/backend/utils/adt/oracle_compat.c
+++ b/src/backend/utils/adt/oracle_compat.c
@@ -999,10 +999,26 @@ ascii(PG_FUNCTION_ARGS)
 Datum
 chr			(PG_FUNCTION_ARGS)
 {
-	uint32		cvalue = PG_GETARG_UINT32(0);
+	int32		arg = PG_GETARG_INT32(0);
+	uint32		cvalue;
 	text	   *result;
 	int			encoding = GetDatabaseEncoding();
 
+	/*
+	 * Error out on arguments that make no sense or that we can't validly
+	 * represent in the encoding.
+	 */
+	if (arg < 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("character number must be positive")));
+	else if (arg == 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("null character not permitted")));
+
+	cvalue = arg;
+
 	if (encoding == PG_UTF8 && cvalue > 127)
 	{
 		/* for Unicode we treat the argument as a code point */
@@ -1017,7 +1033,7 @@ chr			(PG_FUNCTION_ARGS)
 		if (cvalue > 0x0010ffff)
 			ereport(ERROR,
 					(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-					 errmsg("requested character too large for encoding: %d",
+					 errmsg("requested character too large for encoding: %u",
 							cvalue)));
 
 		if (cvalue > 0xffff)
@@ -1058,28 +1074,19 @@ chr			(PG_FUNCTION_ARGS)
 		if (!pg_utf8_islegal(wch, bytes))
 			ereport(ERROR,
 					(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-					 errmsg("requested character not valid for encoding: %d",
+					 errmsg("requested character not valid for encoding: %u",
 							cvalue)));
 	}
 	else
 	{
 		bool		is_mb;
 
-		/*
-		 * Error out on arguments that make no sense or that we can't validly
-		 * represent in the encoding.
-		 */
-		if (cvalue == 0)
-			ereport(ERROR,
-					(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-					 errmsg("null character not permitted")));
-
 		is_mb = pg_encoding_max_length(encoding) > 1;
 
 		if ((is_mb && (cvalue > 127)) || (!is_mb && (cvalue > 255)))
 			ereport(ERROR,
 					(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-					 errmsg("requested character too large for encoding: %d",
+					 errmsg("requested character too large for encoding: %u",
 							cvalue)));
 
 		result = (text *) palloc(VARHDRSZ + 1);
-- 
2.34.1