Specify the encoding of input to fmtId()

This commit adds fmtIdEnc() and fmtQualifiedIdEnc(), which allow to specify
the encoding as an explicit argument.  Additionally setFmtEncoding() is
provided, which defines the encoding when no explicit encoding is provided, to
avoid breaking all code using fmtId().

All users of fmtId()/fmtQualifiedId() are either converted to the explicit
version or a call to setFmtEncoding() has been added.

This commit does not yet utilize the now well-defined encoding, that will
happen in a subsequent commit.

Reviewed-by: Noah Misch <noah@leadboat.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Backpatch-through: 13
Security: CVE-2025-1094

13 files changed, 115 insertions, 24 deletions

diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index 707a3fc844c..b9d7ab98c3e 100644
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -2822,6 +2822,7 @@ processEncodingEntry(ArchiveHandle *AH, TocEntry *te)
 			pg_fatal("unrecognized encoding \"%s\"",
 					 ptr1);
 		AH->public.encoding = encoding;
+		setFmtEncoding(encoding);
 	}
 	else
 		pg_fatal("invalid ENCODING item: %s",
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 520e1338c28..ca15b40939c 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -1281,6 +1281,7 @@ setup_connection(Archive *AH, const char *dumpencoding,
 	 * we know how to escape strings.
 	 */
 	AH->encoding = PQclientEncoding(conn);
+	setFmtEncoding(AH->encoding);
 
 	std_strings = PQparameterStatus(conn, "standard_conforming_strings");
 	AH->std_strings = (std_strings && strcmp(std_strings, "on") == 0);
diff --git a/src/bin/pg_dump/pg_dumpall.c b/src/bin/pg_dump/pg_dumpall.c
index 396f79781c5..64a60a26092 100644
--- a/src/bin/pg_dump/pg_dumpall.c
+++ b/src/bin/pg_dump/pg_dumpall.c
@@ -524,6 +524,7 @@ main(int argc, char *argv[])
 	 * we know how to escape strings.
 	 */
 	encoding = PQclientEncoding(conn);
+	setFmtEncoding(encoding);
 	std_strings = PQparameterStatus(conn, "standard_conforming_strings");
 	if (!std_strings)
 		std_strings = "off";
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 6c75c8da6da..26dfdde195a 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -1450,6 +1450,7 @@ exec_command_encoding(PsqlScanState scan_state, bool active_branch)
 				/* save encoding info into psql internal data */
 				pset.encoding = PQclientEncoding(pset.db);
 				pset.popt.topt.encoding = pset.encoding;
+				setFmtEncoding(pset.encoding);
 				SetVariable(pset.vars, "ENCODING",
 							pg_encoding_to_char(pset.encoding));
 			}
@@ -4135,6 +4136,8 @@ SyncVariables(void)
 	pset.popt.topt.encoding = pset.encoding;
 	pset.sversion = PQserverVersion(pset.db);
 
+	setFmtEncoding(pset.encoding);
+
 	SetVariable(pset.vars, "DBNAME", PQdb(pset.db));
 	SetVariable(pset.vars, "SERVICE", PQservice(pset.db));
 	SetVariable(pset.vars, "USER", PQuser(pset.db));
diff --git a/src/bin/scripts/common.c b/src/bin/scripts/common.c
index 343e8618a56..7b8f7d4c526 100644
--- a/src/bin/scripts/common.c
+++ b/src/bin/scripts/common.c
@@ -111,8 +111,9 @@ appendQualifiedRelation(PQExpBuffer buf, const char *spec,
 		exit(1);
 	}
 	appendPQExpBufferStr(buf,
-						 fmtQualifiedId(PQgetvalue(res, 0, 1),
-										PQgetvalue(res, 0, 0)));
+						 fmtQualifiedIdEnc(PQgetvalue(res, 0, 1),
+										   PQgetvalue(res, 0, 0),
+										   PQclientEncoding(conn)));
 	appendPQExpBufferStr(buf, columns);
 	PQclear(res);
 	termPQExpBuffer(&sql);
diff --git a/src/bin/scripts/createdb.c b/src/bin/scripts/createdb.c
index b0e47477862..7c0cf32d6a1 100644
--- a/src/bin/scripts/createdb.c
+++ b/src/bin/scripts/createdb.c
@@ -198,6 +198,8 @@ main(int argc, char *argv[])
 
 	conn = connectMaintenanceDatabase(&cparams, progname, echo);
 
+	setFmtEncoding(PQclientEncoding(conn));
+
 	initPQExpBuffer(&sql);
 
 	appendPQExpBuffer(&sql, "CREATE DATABASE %s",
diff --git a/src/bin/scripts/createuser.c b/src/bin/scripts/createuser.c
index 6aaf8332770..81e6abfc46e 100644
--- a/src/bin/scripts/createuser.c
+++ b/src/bin/scripts/createuser.c
@@ -292,6 +292,8 @@ main(int argc, char *argv[])
 
 	conn = connectMaintenanceDatabase(&cparams, progname, echo);
 
+	setFmtEncoding(PQclientEncoding(conn));
+
 	initPQExpBuffer(&sql);
 
 	printfPQExpBuffer(&sql, "CREATE ROLE %s", fmtId(newuser));
diff --git a/src/bin/scripts/dropdb.c b/src/bin/scripts/dropdb.c
index ad762ffd43a..0b630818277 100644
--- a/src/bin/scripts/dropdb.c
+++ b/src/bin/scripts/dropdb.c
@@ -129,13 +129,6 @@ main(int argc, char *argv[])
 			exit(0);
 	}
 
-	initPQExpBuffer(&sql);
-
-	appendPQExpBuffer(&sql, "DROP DATABASE %s%s%s;",
-					  (if_exists ? "IF EXISTS " : ""),
-					  fmtId(dbname),
-					  force ? " WITH (FORCE)" : "");
-
 	/* Avoid trying to drop postgres db while we are connected to it. */
 	if (maintenance_db == NULL && strcmp(dbname, "postgres") == 0)
 		maintenance_db = "template1";
@@ -149,6 +142,12 @@ main(int argc, char *argv[])
 
 	conn = connectMaintenanceDatabase(&cparams, progname, echo);
 
+	initPQExpBuffer(&sql);
+	appendPQExpBuffer(&sql, "DROP DATABASE %s%s%s;",
+					  (if_exists ? "IF EXISTS " : ""),
+					  fmtIdEnc(dbname, PQclientEncoding(conn)),
+					  force ? " WITH (FORCE)" : "");
+
 	if (echo)
 		printf("%s\n", sql.data);
 	result = PQexec(conn, sql.data);
diff --git a/src/bin/scripts/dropuser.c b/src/bin/scripts/dropuser.c
index 8e5429a5cf1..39bb1686173 100644
--- a/src/bin/scripts/dropuser.c
+++ b/src/bin/scripts/dropuser.c
@@ -143,7 +143,8 @@ main(int argc, char *argv[])
 
 	initPQExpBuffer(&sql);
 	appendPQExpBuffer(&sql, "DROP ROLE %s%s;",
-					  (if_exists ? "IF EXISTS " : ""), fmtId(dropuser));
+					  (if_exists ? "IF EXISTS " : ""),
+					  fmtIdEnc(dropuser, PQclientEncoding(conn)));
 
 	if (echo)
 		printf("%s\n", sql.data);
diff --git a/src/bin/scripts/reindexdb.c b/src/bin/scripts/reindexdb.c
index 076462a62f0..665864fd22b 100644
--- a/src/bin/scripts/reindexdb.c
+++ b/src/bin/scripts/reindexdb.c
@@ -511,7 +511,8 @@ run_reindex_command(PGconn *conn, ReindexType type, const char *name,
 
 	if (tablespace)
 	{
-		appendPQExpBuffer(&sql, "%sTABLESPACE %s", sep, fmtId(tablespace));
+		appendPQExpBuffer(&sql, "%sTABLESPACE %s", sep,
+						  fmtIdEnc(tablespace, PQclientEncoding(conn)));
 		sep = comma;
 	}
 
@@ -551,7 +552,8 @@ run_reindex_command(PGconn *conn, ReindexType type, const char *name,
 	{
 		case REINDEX_DATABASE:
 		case REINDEX_SYSTEM:
-			appendPQExpBufferStr(&sql, fmtId(name));
+			appendPQExpBufferStr(&sql,
+								 fmtIdEnc(name, PQclientEncoding(conn)));
 			break;
 		case REINDEX_INDEX:
 		case REINDEX_TABLE:
@@ -774,8 +776,9 @@ get_parallel_object_list(PGconn *conn, ReindexType type,
 	for (i = 0; i < ntups; i++)
 	{
 		appendPQExpBufferStr(&buf,
-							 fmtQualifiedId(PQgetvalue(res, i, 1),
-											PQgetvalue(res, i, 0)));
+							 fmtQualifiedIdEnc(PQgetvalue(res, i, 1),
+											   PQgetvalue(res, i, 0),
+											   PQclientEncoding(conn)));
 
 		simple_string_list_append(tables, buf.data);
 		resetPQExpBuffer(&buf);
@@ -787,8 +790,9 @@ get_parallel_object_list(PGconn *conn, ReindexType type,
 			 * the order of tables list.
 			 */
 			appendPQExpBufferStr(&buf,
-								 fmtQualifiedId(PQgetvalue(res, i, 1),
-												PQgetvalue(res, i, 2)));
+								 fmtQualifiedIdEnc(PQgetvalue(res, i, 1),
+												   PQgetvalue(res, i, 2),
+												   PQclientEncoding(conn)));
 
 			simple_string_list_append(user_list, buf.data);
 			resetPQExpBuffer(&buf);
diff --git a/src/bin/scripts/vacuumdb.c b/src/bin/scripts/vacuumdb.c
index 74fbc7ef033..982bf070be6 100644
--- a/src/bin/scripts/vacuumdb.c
+++ b/src/bin/scripts/vacuumdb.c
@@ -784,8 +784,9 @@ vacuum_one_database(ConnParams *cparams,
 	for (i = 0; i < ntups; i++)
 	{
 		appendPQExpBufferStr(&buf,
-							 fmtQualifiedId(PQgetvalue(res, i, 1),
-											PQgetvalue(res, i, 0)));
+							 fmtQualifiedIdEnc(PQgetvalue(res, i, 1),
+											   PQgetvalue(res, i, 0),
+											   PQclientEncoding(conn)));
 
 		if (objects_listed && !PQgetisnull(res, i, 2))
 			appendPQExpBufferStr(&buf, PQgetvalue(res, i, 2));
diff --git a/src/fe_utils/string_utils.c b/src/fe_utils/string_utils.c
index 8d5a3b4a6e4..2945e28a277 100644
--- a/src/fe_utils/string_utils.c
+++ b/src/fe_utils/string_utils.c
@@ -19,6 +19,7 @@
 
 #include "common/keywords.h"
 #include "fe_utils/string_utils.h"
+#include "mb/pg_wchar.h"
 
 static PQExpBuffer defaultGetLocalPQExpBuffer(void);
 
@@ -26,6 +27,8 @@ static PQExpBuffer defaultGetLocalPQExpBuffer(void);
 int			quote_all_identifiers = 0;
 PQExpBuffer (*getLocalPQExpBuffer) (void) = defaultGetLocalPQExpBuffer;
 
+static int	fmtIdEncoding = -1;
+
 
 /*
  * Returns a temporary PQExpBuffer, valid until the next call to the function.
@@ -55,13 +58,47 @@ defaultGetLocalPQExpBuffer(void)
 }
 
 /*
+ * Set the encoding that fmtId() and fmtQualifiedId() use.
+ *
+ * This is not safe against multiple connections having different encodings,
+ * but there is no real other way to address the need to know the encoding for
+ * fmtId()/fmtQualifiedId() input for safe escaping. Eventually we should get
+ * rid of fmtId().
+ */
+void
+setFmtEncoding(int encoding)
+{
+	fmtIdEncoding = encoding;
+}
+
+/*
+ * Return the currently configured encoding for fmtId() and fmtQualifiedId().
+ */
+static int
+getFmtEncoding(void)
+{
+	if (fmtIdEncoding != -1)
+		return fmtIdEncoding;
+
+	/*
+	 * In assertion builds it seems best to fail hard if the encoding was not
+	 * set, to make it easier to find places with missing calls. But in
+	 * production builds that seems like a bad idea, thus we instead just
+	 * default to UTF-8.
+	 */
+	Assert(fmtIdEncoding != -1);
+
+	return PG_UTF8;
+}
+
+/*
  *	Quotes input string if it's not a legitimate SQL identifier as-is.
  *
- *	Note that the returned string must be used before calling fmtId again,
+ *	Note that the returned string must be used before calling fmtIdEnc again,
  *	since we re-use the same return buffer each time.
  */
 const char *
-fmtId(const char *rawid)
+fmtIdEnc(const char *rawid, int encoding)
 {
 	PQExpBuffer id_return = getLocalPQExpBuffer();
 
@@ -134,7 +171,24 @@ fmtId(const char *rawid)
 }
 
 /*
- * fmtQualifiedId - construct a schema-qualified name, with quoting as needed.
+ *	Quotes input string if it's not a legitimate SQL identifier as-is.
+ *
+ *	Note that the returned string must be used before calling fmtId again,
+ *	since we re-use the same return buffer each time.
+ *
+ *  NB: This assumes setFmtEncoding() previously has been called to configure
+ *  the encoding of rawid. It is preferable to use fmtIdEnc() with an
+ *  explicit encoding.
+ */
+const char *
+fmtId(const char *rawid)
+{
+	return fmtIdEnc(rawid, getFmtEncoding());
+}
+
+/*
+ * fmtQualifiedIdEnc - construct a schema-qualified name, with quoting as
+ * needed.
  *
  * Like fmtId, use the result before calling again.
  *
@@ -142,7 +196,7 @@ fmtId(const char *rawid)
  * use that buffer until we're finished with calling fmtId().
  */
 const char *
-fmtQualifiedId(const char *schema, const char *id)
+fmtQualifiedIdEnc(const char *schema, const char *id, int encoding)
 {
 	PQExpBuffer id_return;
 	PQExpBuffer lcl_pqexp = createPQExpBuffer();
@@ -150,9 +204,9 @@ fmtQualifiedId(const char *schema, const char *id)
 	/* Some callers might fail to provide a schema name */
 	if (schema && *schema)
 	{
-		appendPQExpBuffer(lcl_pqexp, "%s.", fmtId(schema));
+		appendPQExpBuffer(lcl_pqexp, "%s.", fmtIdEnc(schema, encoding));
 	}
-	appendPQExpBufferStr(lcl_pqexp, fmtId(id));
+	appendPQExpBufferStr(lcl_pqexp, fmtIdEnc(id, encoding));
 
 	id_return = getLocalPQExpBuffer();
 
@@ -162,6 +216,24 @@ fmtQualifiedId(const char *schema, const char *id)
 	return id_return->data;
 }
 
+/*
+ * fmtQualifiedId - construct a schema-qualified name, with quoting as needed.
+ *
+ * Like fmtId, use the result before calling again.
+ *
+ * Since we call fmtId and it also uses getLocalPQExpBuffer() we cannot
+ * use that buffer until we're finished with calling fmtId().
+ *
+ * NB: This assumes setFmtEncoding() previously has been called to configure
+ * the encoding of schema/id. It is preferable to use fmtQualifiedIdEnc()
+ * with an explicit encoding.
+ */
+const char *
+fmtQualifiedId(const char *schema, const char *id)
+{
+	return fmtQualifiedIdEnc(schema, id, getFmtEncoding());
+}
+
 
 /*
  * Format a Postgres version number (in the PG_VERSION_NUM integer format
diff --git a/src/include/fe_utils/string_utils.h b/src/include/fe_utils/string_utils.h
index 690195fa9f9..dc991a93219 100644
--- a/src/include/fe_utils/string_utils.h
+++ b/src/include/fe_utils/string_utils.h
@@ -25,7 +25,10 @@ extern PQExpBuffer (*getLocalPQExpBuffer) (void);
 
 /* Functions */
 extern const char *fmtId(const char *rawid);
+extern const char *fmtIdEnc(const char *rawid, int encoding);
 extern const char *fmtQualifiedId(const char *schema, const char *id);
+extern const char *fmtQualifiedIdEnc(const char *schema, const char *id, int encoding);
+extern void setFmtEncoding(int encoding);
 
 extern char *formatPGVersionNumber(int version_number, bool include_minor,
 								   char *buf, size_t buflen);