From: Tobias Stoeckmann <tobias@stoeckmann.org>
Date: Sat, 3 Feb 2024 00:07:58 +0000 (+0100)
Subject: lib/chkname.c: Take NUL byte into account
X-Git-Tag: 4.15.0-rc2~15
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=403a2e3771be6b1c0c6fc16b2be65b4d36f759ab;p=thirdparty%2Fshadow.git

lib/chkname.c: Take NUL byte into account

The _SC_LOGIN_NAME_MAX value includes space for the NUL byte. The length
of name must smaller than this value to be valid.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
---

diff --git a/lib/chkname.c b/lib/chkname.c
index cbfbff51a..1c5963496 100644
--- a/lib/chkname.c
+++ b/lib/chkname.c
@@ -80,7 +80,7 @@ bool is_valid_user_name (const char *name)
 	 * User names length are limited by the kernel
 	 */
 	maxlen = sysconf(_SC_LOGIN_NAME_MAX);
-	if (strlen(name) > maxlen)
+	if (strlen(name) >= maxlen)
 		return false;
 
 	return is_valid_name (name);
diff --git a/tests/unit/test_chkname.c b/tests/unit/test_chkname.c
index af982940d..e0f9f84b4 100644
--- a/tests/unit/test_chkname.c
+++ b/tests/unit/test_chkname.c
@@ -134,15 +134,15 @@ test_is_valid_user_name_long(void **state)
 	char    *name;
 
 	max = sysconf(_SC_LOGIN_NAME_MAX);
-	name = MALLOC(max + 2, char);
+	name = MALLOC(max + 1, char);
 	assert_true(name != NULL);
 
-	memset(name, '_', max + 1);
+	memset(name, '_', max);
 
-	name[max + 1] = '\0';
+	name[max] = '\0';
 	assert_true(false == is_valid_user_name(name));
 
-	name[max] = '\0';
+	name[max - 1] = '\0';
 	assert_true(is_valid_user_name(name));
 
 	free(name);