Fix overflow in parsing of positional parameter

Replace atol with pg_strtoint32_safe in the backend parser and with
strtoint in ECPG to reject overflows when parsing the number of a
positional parameter.  With atol from glibc, parameters $2147483648 and
$4294967297 turn into $-2147483648 and $1, respectively.

Author: Erik Wienhold <ewie@ewie.name>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/5d216d1c-91f6-4cbe-95e2-b4cbd930520c@ewie.name

src/backend/parser/scan.l

@@ -992,8 +992,14 @@ other			.
 				}
 
 {param}			{
+					ErrorSaveContext escontext = {T_ErrorSaveContext};
+					int32		val;
+
 					SET_YYLLOC();
-					yylval->ival = atol(yytext + 1);
+					val = pg_strtoint32_safe(yytext + 1, (Node *) &escontext);
+					if (escontext.error_occurred)
+						yyerror("parameter number too large");
+					yylval->ival = val;
 					return PARAM;
 				}
 {param_junk}	{

src/interfaces/ecpg/preproc/pgc.l

@@ -938,7 +938,13 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
 				}
 
 {param}			{
-					base_yylval.ival = atol(yytext+1);
+					int			val;
+
+					errno = 0;
+					val = strtoint(yytext + 1, NULL, 10);
+					if (errno == ERANGE)
+						mmfatal(PARSE_ERROR, "parameter number too large");
+					base_yylval.ival = val;
 					return PARAM;
 				}
 {param_junk}	{

src/test/regress/expected/numerology.out

@@ -206,6 +206,10 @@ PREPARE p1 AS SELECT $1a;
 ERROR:  trailing junk after parameter at or near "$1a"
 LINE 1: PREPARE p1 AS SELECT $1a;
                              ^
+PREPARE p1 AS SELECT $2147483648;
+ERROR:  parameter number too large at or near "$2147483648"
+LINE 1: PREPARE p1 AS SELECT $2147483648;
+                             ^
 SELECT 0b;
 ERROR:  invalid binary integer at or near "0b"
 LINE 1: SELECT 0b;

src/test/regress/sql/numerology.sql

@@ -52,6 +52,7 @@ SELECT 0.0e1a;
 SELECT 0.0e;
 SELECT 0.0e+a;
 PREPARE p1 AS SELECT $1a;
+PREPARE p1 AS SELECT $2147483648;
 
 SELECT 0b;
 SELECT 1b;