From 8a93576ff9ebf803fece5422edfb5a15a2f0e1fe Mon Sep 17 00:00:00 2001
From: Alejandro Colomar <alx@kernel.org>
Date: Sat, 13 Jul 2024 11:37:25 +0200
Subject: [PATCH] lib/chkname.c: An object cannot expand further than the
 universe in which it resides

If you want a larger object, you'll have to wait at least until the
universe expands so much.

If an implementation doesn't recognize its own limitations, its a bug,
not a feature.

Closes: <https://github.com/shadow-maint/shadow/issues/1052>
Cc: Tobias Stoeckmann <tobias@stoeckmann.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
---
 lib/chkname.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/chkname.c b/lib/chkname.c
index 995562fa1..bc631f2e1 100644
--- a/lib/chkname.c
+++ b/lib/chkname.c
@@ -24,6 +24,8 @@
 #include <limits.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
+#include <sys/param.h>
 #include <unistd.h>
 
 #include "defines.h"
@@ -43,7 +45,7 @@ login_name_max_size(void)
 	if (conf == -1 && errno != 0)
 		return LOGIN_NAME_MAX;
 
-	return conf;
+	return MIN(conf, PTRDIFF_MAX);
 }
 
 
-- 
2.47.3