diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2013-08-08 18:55:32 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-08-08 13:11:39 -0700 |
| commit | 8742f229b635bf1c1c84a3dfe5e47c814c20b5c8 (patch) | |
| tree | 3d9f64cf0c9d705b9f422d137c8067fa2d41f3c8 | |
| parent | 55f5bfd4c94b923d965d47f5c1889ef8f98fcef1 (diff) | |
userns: limit the maximum depth of user_namespace->parent chain
Ensure that user_namespace->parent chain can't grow too much.
Currently we use the hardroded 32 as limit.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/user_namespace.h | 1 | ||||
| -rw-r--r-- | kernel/user_namespace.c | 4 |
2 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index b6b215f13b4..14105c26a83 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -23,6 +23,7 @@ struct user_namespace { struct uid_gid_map projid_map; atomic_t count; struct user_namespace *parent; + int level; kuid_t owner; kgid_t group; unsigned int proc_inum; diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 6e50a44610e..9064b919a40 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -62,6 +62,9 @@ int create_user_ns(struct cred *new) kgid_t group = new->egid; int ret; + if (parent_ns->level > 32) + return -EUSERS; + /* * Verify that we can not violate the policy of which files * may be accessed that is specified by the root directory, @@ -92,6 +95,7 @@ int create_user_ns(struct cred *new) atomic_set(&ns->count, 1); /* Leave the new->user_ns reference with the new user namespace. */ ns->parent = parent_ns; + ns->level = parent_ns->level + 1; ns->owner = owner; ns->group = group; |