ext/pgsql: route pg_copy_from table_name through build_tablename

The COPY query for pg_copy_from embedded the table_name argument with a
raw "%s", so a caller-supplied name like `t FROM STDIN --` redirected
the data into a different table than the API documents. Use the same
build_tablename helper that pg_insert/update/select/delete have used
since bug #62978. pg_copy_to is unchanged because COPY ... TO accepts
a parenthesised query as a source spec, which the existing test
06_bug73498 relies on.

Author: iliaal

ext/pgsql/pgsql.c

@@ -273,6 +273,8 @@ static void pgsql_lob_free_obj(zend_object *obj)
 
 /* Compatibility definitions */
 
+static inline zend_result build_tablename(smart_str *querystr, PGconn *pg_link, const zend_string *table);
+
 static zend_string *_php_pgsql_trim_message(const char *message)
 {
 	size_t i = strlen(message);
@@ -3464,7 +3466,6 @@ PHP_FUNCTION(pg_copy_from)
 	zend_string *pg_delimiter = NULL;
 	char *pg_null_as = "\\\\N";
 	size_t pg_null_as_len;
-	char *query;
 	PGconn *pgsql;
 	PGresult *pgsql_result;
 	ExecStatusType status;
@@ -3489,13 +3490,21 @@ PHP_FUNCTION(pg_copy_from)
 		RETURN_THROWS();
 	}
 
-	spprintf(&query, 0, "COPY %s FROM STDIN DELIMITER E'%c' NULL AS E'%s'", ZSTR_VAL(table_name), *ZSTR_VAL(pg_delimiter), pg_null_as);
+	smart_str querystr = {0};
+	smart_str_appends(&querystr, "COPY ");
+	if (build_tablename(&querystr, pgsql, table_name) == FAILURE) {
+		smart_str_free(&querystr);
+		RETURN_FALSE;
+	}
+	smart_str_append_printf(&querystr, " FROM STDIN DELIMITER E'%c' NULL AS E'%s'", *ZSTR_VAL(pg_delimiter), pg_null_as);
+	smart_str_0(&querystr);
+
 	while ((pgsql_result = PQgetResult(pgsql))) {
 		PQclear(pgsql_result);
 	}
-	pgsql_result = PQexec(pgsql, query);
+	pgsql_result = PQexec(pgsql, ZSTR_VAL(querystr.s));
 
-	efree(query);
+	smart_str_free(&querystr);
 
 	if (pgsql_result) {
 		status = PQresultStatus(pgsql_result);

ext/pgsql/tests/pg_copy_from_table_name_escape.phpt

@@ -0,0 +1,36 @@
+--TEST--
+pg_copy_from() escapes the table name argument
+--EXTENSIONS--
+pgsql
+--SKIPIF--
+<?php include("inc/skipif.inc"); ?>
+--FILE--
+<?php
+
+include('inc/config.inc');
+
+$db = pg_connect($conn_str);
+pg_query($db, 'DROP TABLE IF EXISTS pg_copy_from_target');
+pg_query($db, 'CREATE TABLE pg_copy_from_target (v text)');
+pg_query($db, 'DROP TABLE IF EXISTS pg_copy_from_other');
+pg_query($db, 'CREATE TABLE pg_copy_from_other (v text)');
+
+$evil = "pg_copy_from_other FROM STDIN --";
+var_dump(pg_copy_from($db, $evil, ["redirected\n"]));
+
+$rows = pg_fetch_all(pg_query($db, 'SELECT v FROM pg_copy_from_other')) ?: [];
+var_dump($rows);
+
+?>
+--CLEAN--
+<?php
+include('inc/config.inc');
+$db = pg_connect($conn_str);
+pg_query($db, 'DROP TABLE IF EXISTS pg_copy_from_target');
+pg_query($db, 'DROP TABLE IF EXISTS pg_copy_from_other');
+?>
+--EXPECTF--
+Warning: pg_copy_from(): %s in %s on line %d
+bool(false)
+array(0) {
+}