From c37bbb0fdcc01610fd55604eb6927210a1d20044 Mon Sep 17 00:00:00 2001 From: "Serge E. Hallyn" Date: Wed, 3 Dec 2008 13:17:06 -0600 Subject: [PATCH] user namespaces: let user_ns be cloned with fairsched (These two patches are in the next-unacked branch of git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/userns-2.6. If they get some ACKs, then I hope to feed this into security-next. After these two, I think we're ready to tackle userns+capabilities) Fairsched creates a per-uid directory under /sys/kernel/uids/. So when you clone(CLONE_NEWUSER), it tries to create /sys/kernel/uids/0, which already exists, and you get back -ENOMEM. This was supposed to be fixed by sysfs tagging, but that was postponed (ok, rejected until sysfs locking is fixed). So, just as with network namespaces, we just don't create those directories for user namespaces other than the init. Signed-off-by: Serge E. Hallyn Signed-off-by: James Morris --- kernel/user.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/user.c b/kernel/user.c index 97202cb29adc..6c924bc48c08 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -246,6 +246,8 @@ static int uids_user_create(struct user_struct *up) int error; memset(kobj, 0, sizeof(struct kobject)); + if (up->user_ns != &init_user_ns) + return 0; kobj->kset = uids_kset; error = kobject_init_and_add(kobj, &uids_ktype, NULL, "%d", up->uid); if (error) { @@ -281,6 +283,8 @@ static void remove_user_sysfs_dir(struct work_struct *w) unsigned long flags; int remove_user = 0; + if (up->user_ns != &init_user_ns) + return; /* Make uid_hash_remove() + sysfs_remove_file() + kobject_del() * atomic. */