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 8c20c263c4b..f1ffed038b0 100644
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -2818,6 +2818,7 @@ 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 d2b0667a2a9..85adb5dee76 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -1211,6 +1211,7 @@ 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 e3ad8fb2956..c0b8467a2fc 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 be048669a3f..f3f8fd0765a 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -1336,6 +1336,7 @@ 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));
 			}
@@ -3956,6 +3957,8 @@ 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, "USER", PQuser(pset.db));
 	SetVariable(pset.vars, "HOST", PQhost(pset.db));
diff --git a/src/bin/scripts/common.c b/src/bin/scripts/common.c
index d16381eda90..4b0e26c0bb1 100644
--- a/src/bin/scripts/common.c
+++ b/src/bin/scripts/common.c
@@ -112,8 +112,9 @@ 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 30426860efa..2fa8477e0ed 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 f5f03c1145f..9c1f5d23392 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 57656ba8988..435837b65ff 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 233ccd288b7..c6357ce10bb 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 af0738d9334..e736b2baccc 100644
--- a/src/bin/scripts/reindexdb.c
+++ b/src/bin/scripts/reindexdb.c
@@ -512,7 +512,8 @@ 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;
 	}
 
@@ -552,7 +553,8 @@ 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:
@@ -775,8 +777,9 @@ 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);
@@ -788,8 +791,9 @@ 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 430582cef53..5aff0dd25d5 100644
--- a/src/bin/scripts/vacuumdb.c
+++ b/src/bin/scripts/vacuumdb.c
@@ -785,8 +785,9 @@ 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 09fd33907dd..3000da913da 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 f150a7f7ef7..500f585a4a5 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);