diff options
author | Oleg Nesterov <oleg@redhat.com> | 2013-08-08 12:55:32 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-11 21:35:25 -0400 |
commit | 5c5f9cd2b539879c4291fa24773795314e777354 (patch) | |
tree | fcda00e4125fa6c70a067e87ad08bab634c1996f /kernel/user_namespace.c | |
parent | c98ebcb618645d40cfec14b0534ff32126c114ce (diff) |
userns: limit the maximum depth of user_namespace->parent chain
commit 8742f229b635bf1c1c84a3dfe5e47c814c20b5c8 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/user_namespace.c')
-rw-r--r-- | kernel/user_namespace.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 6e50a44610ee..9064b919a406 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c | |||
@@ -62,6 +62,9 @@ int create_user_ns(struct cred *new) | |||
62 | kgid_t group = new->egid; | 62 | kgid_t group = new->egid; |
63 | int ret; | 63 | int ret; |
64 | 64 | ||
65 | if (parent_ns->level > 32) | ||
66 | return -EUSERS; | ||
67 | |||
65 | /* | 68 | /* |
66 | * Verify that we can not violate the policy of which files | 69 | * Verify that we can not violate the policy of which files |
67 | * may be accessed that is specified by the root directory, | 70 | * may be accessed that is specified by the root directory, |
@@ -92,6 +95,7 @@ int create_user_ns(struct cred *new) | |||
92 | atomic_set(&ns->count, 1); | 95 | atomic_set(&ns->count, 1); |
93 | /* Leave the new->user_ns reference with the new user namespace. */ | 96 | /* Leave the new->user_ns reference with the new user namespace. */ |
94 | ns->parent = parent_ns; | 97 | ns->parent = parent_ns; |
98 | ns->level = parent_ns->level + 1; | ||
95 | ns->owner = owner; | 99 | ns->owner = owner; |
96 | ns->group = group; | 100 | ns->group = group; |
97 | 101 | ||