[PATCH] update_passwd: Avoid selinux_preserve_fcontext if SELinux is disabled

[Fabian Vogt]

Inside containers, it's possible that files have labels but otherwise
SELinux is effectively disabled/hidden (no config or /sys/fs/selinux).
In that setup, fgetfilecon succeeds but setfscreatecon fails.
Just skip all of that if SELinux is disabled.

This fixes the following error when running adduser inside a container:

adduser: can't set default file creation context to system_u:object_r:container_file_t:s0:c292,c451: Permission denied

Signed-off-by: Fabian Vogt <fvogt at suse.de>
---
 libbb/update_passwd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libbb/update_passwd.c b/libbb/update_passwd.c
index a228075cc..186ebd122 100644
--- a/libbb/update_passwd.c
+++ b/libbb/update_passwd.c
@@ -133,7 +133,10 @@ int FAST_FUNC update_passwd(const char *filename,
 	}
 	old_fd = fileno(old_fp);
 
-	selinux_preserve_fcontext(old_fd);
+#if ENABLE_SELINUX
+	if (is_selinux_enabled() > 0)
+		selinux_preserve_fcontext(old_fd);
+#endif
 
 	/* Try to create "/etc/passwd+". Wait if it exists. */
 	i = 30;
-- 
2.50.1