From: Tobias Stoeckmann <tobias@stoeckmann.org>
Date: Wed, 11 Mar 2026 21:34:05 +0000 (+0100)
Subject: useradd: Check sysconf return value
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=3dadabbe684a75e2ca12ce1c233985c0edb04f9c;p=thirdparty%2Fshadow.git

useradd: Check sysconf return value

Verify that sysconf does not return -1. It is not important if it's due
to an error or due to a missing upper boundary. In both cases, fall back
to a constant value.

Reviewed-by: Alejandro Colomar <alx@kernel.org>
Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
---

diff --git a/src/useradd.c b/src/useradd.c
index 6570cee83..5534e1d86 100644
--- a/src/useradd.c
+++ b/src/useradd.c
@@ -221,6 +221,10 @@ static bool home_added = false;
 #define DBTRFS_SUBVOLUME_HOME	"BTRFS_SUBVOLUME_HOME"
 #define DLOG_INIT		"LOG_INIT"
 
+#ifndef NGROUPS_MAX
+#define NGROUPS_MAX		65536
+#endif
+
 /* local function prototypes */
 NORETURN static void fail_exit (int, bool);
 static void get_defaults(const struct option_flags *);
@@ -2529,6 +2533,8 @@ int main (int argc, char **argv)
 #endif
 
 	sys_ngroups = sysconf (_SC_NGROUPS_MAX);
+	if (sys_ngroups == -1)
+		sys_ngroups = NGROUPS_MAX;
 	user_groups = xmalloc_T(1 + sys_ngroups, char *);
 	/*
 	 * Initialize the list to be empty