From 7989fb82e0fe26d3cbd9627825fb044f0f915a7d Mon Sep 17 00:00:00 2001
From: Mahendra Singh Thalor <mahi6run@gmail.com>
Date: Tue, 20 Jan 2026 11:52:46 +0530
Subject: [PATCH 1/2] don't allow newline or carriage return character in name 
 for  database/user/role

While creating database, if database name has any newline or carriage
return character in name, then through error becuase these special
character are not allowed in dbname when dump command is executed.

do same for "CREATE ROLE", "CREATE USER" also.

This will add check for:
"CREATE DATABASE", "CREATE ROLE", "CREATE USER",
"RENAME DATABASE/USER/ROLE"

-------------------------
As we will not allow these \n\r in names, then we will never get these
names in dump also.

If we are dumping from older branch, then we will fail with same old error.
(dump will fail in older branches so no need to add extra handling for dump.)

Also remove comment added by 142c24c23447f212e642a0ffac9af878b93f490d commit.

Remove one test of 8b845520fb0aa50fea7aae44a45cee1b6d87845d commit.
---
 src/backend/commands/dbcommands.c     |  4 ++++
 src/backend/commands/define.c         | 18 ++++++++++++++++++
 src/backend/commands/user.c           |  4 ++++
 src/bin/pg_dump/t/010_dump_connstr.pl | 14 --------------
 src/bin/scripts/t/020_createdb.pl     | 12 ++++++++++++
 src/bin/scripts/t/040_createuser.pl   |  4 ++++
 src/fe_utils/string_utils.c           |  6 ------
 src/include/commands/defrem.h         |  1 +
 8 files changed, 43 insertions(+), 20 deletions(-)
 mode change 100644 => 100755 src/bin/pg_dump/t/010_dump_connstr.pl
 mode change 100644 => 100755 src/bin/scripts/t/020_createdb.pl
 mode change 100644 => 100755 src/bin/scripts/t/040_createuser.pl

diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index 87949054f26..e8ac4c2eef0 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -742,6 +742,8 @@ createdb(ParseState *pstate, const CreatedbStmt *stmt)
 	CreateDBStrategy dbstrategy = CREATEDB_WAL_LOG;
 	createdb_failure_params fparms;
 
+	check_lfcr_in_objname(dbname, "database");
+
 	/* Extract options from the statement node tree */
 	foreach(option, stmt->options)
 	{
@@ -1910,6 +1912,8 @@ RenameDatabase(const char *oldname, const char *newname)
 	int			npreparedxacts;
 	ObjectAddress address;
 
+	check_lfcr_in_objname(newname, "database");
+
 	/*
 	 * Look up the target database's OID, and get exclusive lock on it. We
 	 * need this for the same reasons as DROP DATABASE.
diff --git a/src/backend/commands/define.c b/src/backend/commands/define.c
index 4172cc9bacb..cd166602e02 100644
--- a/src/backend/commands/define.c
+++ b/src/backend/commands/define.c
@@ -374,3 +374,21 @@ errorConflictingDefElem(DefElem *defel, ParseState *pstate)
 			errmsg("conflicting or redundant options"),
 			parser_errposition(pstate, defel->location));
 }
+
+/*
+ * check_lfcr_in_objname
+ *
+ * If name has a newline or carriage return character then error will be reported
+ * as these special characters are not allowed in names due to shell command error
+ * in dump.
+ */
+void
+check_lfcr_in_objname(const char *objname, const char *objtype)
+{
+	/* Report error if name has \n or \r character. */
+	if (strpbrk(objname, "\n\r"))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE)),
+				 errmsg("%s name contains a newline or carriage return character", objtype),
+				 errdetail("invalid %s name is  \"%s\"", objtype, objname));
+}
diff --git a/src/backend/commands/user.c b/src/backend/commands/user.c
index 8fb9ea25db0..13f1162b4d3 100644
--- a/src/backend/commands/user.c
+++ b/src/backend/commands/user.c
@@ -171,6 +171,8 @@ CreateRole(ParseState *pstate, CreateRoleStmt *stmt)
 	DefElem    *dbypassRLS = NULL;
 	GrantRoleOptions popt;
 
+	check_lfcr_in_objname(stmt->role, "role");
+
 	/* The defaults can vary depending on the original statement type */
 	switch (stmt->stmt_type)
 	{
@@ -1348,6 +1350,8 @@ RenameRole(const char *oldname, const char *newname)
 	ObjectAddress address;
 	Form_pg_authid authform;
 
+	check_lfcr_in_objname(newname, "role");
+
 	rel = table_open(AuthIdRelationId, RowExclusiveLock);
 	dsc = RelationGetDescr(rel);
 
diff --git a/src/bin/pg_dump/t/010_dump_connstr.pl b/src/bin/pg_dump/t/010_dump_connstr.pl
old mode 100644
new mode 100755
index dc7a33658db..bf2c3b6d00b
--- a/src/bin/pg_dump/t/010_dump_connstr.pl
+++ b/src/bin/pg_dump/t/010_dump_connstr.pl
@@ -153,20 +153,6 @@ $node->command_ok(
 	],
 	'pg_dumpall --dbname accepts connection string');
 
-$node->run_log(
-	[ 'createdb', '--username' => $src_bootstrap_super, "foo\n\rbar" ]);
-
-# not sufficient to use --roles-only here
-$node->command_fails(
-	[
-		'pg_dumpall', '--no-sync',
-		'--username' => $src_bootstrap_super,
-		'--file' => $discard,
-	],
-	'pg_dumpall with \n\r in database name');
-$node->run_log(
-	[ 'dropdb', '--username' => $src_bootstrap_super, "foo\n\rbar" ]);
-
 
 # make a table, so the parallel worker has something to dump
 $node->safe_psql(
diff --git a/src/bin/scripts/t/020_createdb.pl b/src/bin/scripts/t/020_createdb.pl
old mode 100644
new mode 100755
index 83b0077383a..202c4462209
--- a/src/bin/scripts/t/020_createdb.pl
+++ b/src/bin/scripts/t/020_createdb.pl
@@ -241,6 +241,18 @@ $node->command_fails(
 	],
 	'fails for invalid locale provider');
 
+$node->command_fails_like(
+    [ 'createdb', "invalid \n dbname" ],
+    qr/ERROR:  database name contains a newline or carriage return character/,
+    'fails if database name containing newline character in name'
+);
+
+$node->command_fails_like(
+    [ 'createdb', "invalid \r dbname" ],
+    qr/ERROR:  database name contains a newline or carriage return character/,
+    'fails if database name containing carriage return character in name'
+);
+
 # Check use of templates with shared dependencies copied from the template.
 my ($ret, $stdout, $stderr) = $node->psql(
 	'foobar2',
diff --git a/src/bin/scripts/t/040_createuser.pl b/src/bin/scripts/t/040_createuser.pl
old mode 100644
new mode 100755
index 0fbb91ce330..de8524f5a57
--- a/src/bin/scripts/t/040_createuser.pl
+++ b/src/bin/scripts/t/040_createuser.pl
@@ -89,5 +89,9 @@ $node->command_fails(
 		'regress_user3'
 	],
 	'fails for too many non-options');
+$node->command_fails([ 'createuser', "invalid \n username" ],
+	'fails as newline is not allowed in role name');
+$node->command_fails([ 'createuser', "invalid \r username" ],
+	'fails as carraige return is not allowed in role name');
 
 done_testing();
diff --git a/src/fe_utils/string_utils.c b/src/fe_utils/string_utils.c
index d87f1d476f3..c3f88e07cce 100644
--- a/src/fe_utils/string_utils.c
+++ b/src/fe_utils/string_utils.c
@@ -568,12 +568,6 @@ appendByteaLiteral(PQExpBuffer buf, const unsigned char *str, size_t length,
  * Append the given string to the shell command being built in the buffer,
  * with shell-style quoting as needed to create exactly one argument.
  *
- * Forbid LF or CR characters, which have scant practical use beyond designing
- * security breaches.  The Windows command shell is unusable as a conduit for
- * arguments containing LF or CR characters.  A future major release should
- * reject those characters in CREATE ROLE and CREATE DATABASE, because use
- * there eventually leads to errors here.
- *
  * appendShellString() simply prints an error and dies if LF or CR appears.
  * appendShellStringNoError() omits those characters from the result, and
  * returns false if there were any.
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index 8f4a2d9bbc1..af51ac92563 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -162,5 +162,6 @@ extern TypeName *defGetTypeName(DefElem *def);
 extern int	defGetTypeLength(DefElem *def);
 extern List *defGetStringList(DefElem *def);
 pg_noreturn extern void errorConflictingDefElem(DefElem *defel, ParseState *pstate);
+extern void check_lfcr_in_objname(const char *objname, const char *objtype);
 
 #endif							/* DEFREM_H */
-- 
2.47.3

