From 37ed4a3f3bb107bfb307610b9ab2b87db03df3a6 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Sun, 14 Apr 2013 11:44:04 -0700 Subject: userns: Changing any namespace id mappings should require privileges commit 41c21e351e79004dbb4efa4bc14a53a7e0af38c5 upstream. Changing uid/gid/projid mappings doesn't change your id within the namespace; it reconfigures the namespace. Unprivileged programs should *not* be able to write these files. (We're also checking the privileges on the wrong task.) Given the write-once nature of these files and the other security checks, this is likely impossible to usefully exploit. Signed-off-by: Andy Lutomirski Signed-off-by: Greg Kroah-Hartman --- kernel/user_namespace.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index fdf40d6cf8a4..f359dc7fb8c5 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -576,10 +576,10 @@ static ssize_t map_write(struct file *file, const char __user *buf, if (map->nr_extents != 0) goto out; - /* Require the appropriate privilege CAP_SETUID or CAP_SETGID - * over the user namespace in order to set the id mapping. + /* + * Adjusting namespace settings requires capabilities on the target. */ - if (cap_valid(cap_setid) && !ns_capable(ns, cap_setid)) + if (cap_valid(cap_setid) && !file_ns_capable(file, ns, CAP_SYS_ADMIN)) goto out; /* Get a buffer */ -- cgit v1.2.3