3.6.11.9-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Oleg Nesterov <o...@redhat.com>
[ Upstream commit 8742f229b635bf1c1c84a3dfe5e47c814c20b5c8 ]
Ensure that user_namespace->parent chain can't grow too much.
Currently we use the hardroded 32 as limit.
Reported-by: Andy Lutomirski <l...@amacapital.net>
Signed-off-by: Oleg Nesterov <o...@redhat.com>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
---
include/linux/user_namespace.h | 1 +
kernel/user_namespace.c | 4 ++++
2 files changed, 5 insertions(+)
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 4e72922..4eea4ce 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -22,6 +22,7 @@ struct user_namespace {
struct uid_gid_map gid_map;
struct kref kref;
struct user_namespace *parent;
+ int level;
kuid_t owner;
kgid_t group;
};
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index a74dc5b..5242e83 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -39,6 +39,9 @@ int create_user_ns(struct cred *new)
kuid_t owner = new->euid;
kgid_t group = new->egid;
+ 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,
@@ -62,6 +65,7 @@ int create_user_ns(struct cred *new)
kref_init(&ns->kref);
ns->parent = parent_ns;
+ ns->level = parent_ns->level + 1;
ns->owner = owner;
ns->group = group;
--
1.7.10.4
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