[PATCH 09/43] mqueue: Explicitly capture the user namespace to send the notification to.

"Eric W. Beiderman
2012-04-08T05:22:50Z

From: Eric W. Biederman <ebiederm@xmission.com>

Stop relying on user->user_ns which is going away and instead capture
the user_namespace of the process we are supposed to notify.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
ipc/mqueue.c | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 28bd64d..b53cf34 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -66,6 +66,7 @@ struct mqueue_inode_info {

struct sigevent notify;
struct pid* notify_owner;
+ struct user_namespace *notify_user_ns;
struct user_struct *user; /* user who created, for accounting */
struct sock *notify_sock;
struct sk_buff *notify_cookie;
@@ -139,6 +140,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
INIT_LIST_HEAD(&info->e_wait_q[0].list);
INIT_LIST_HEAD(&info->e_wait_q[1].list);
info->notify_owner = NULL;
+ info->notify_user_ns = NULL;
info->qsize = 0;
info->user = NULL; /* set when all is ok */
memset(&info->attr, 0, sizeof(info->attr));
@@ -536,7 +538,7 @@ static void __do_notify(struct mqueue_inode_info *info)
rcu_read_lock();
sig_i.si_pid = task_tgid_nr_ns(current,
ns_of_pid(info->notify_owner));
- sig_i.si_uid = user_ns_map_uid(info->user->user_ns,
+ sig_i.si_uid = user_ns_map_uid(info->notify_user_ns,
current_cred(), current_uid());
rcu_read_unlock();

@@ -550,7 +552,9 @@ static void __do_notify(struct mqueue_inode_info *info)
}
/* after notification unregisters process */
put_pid(info->notify_owner);
+ put_user_ns(info->notify_user_ns);
info->notify_owner = NULL;
+ info->notify_user_ns = NULL;
}
wake_up(&info->wait_q);
}
@@ -575,7 +579,9 @@ static void remove_notification(struct mqueue_inode_info *info)
netlink_sendskb(info->notify_sock, info->notify_cookie);
}
put_pid(info->notify_owner);
+ put_user_ns(info->notify_user_ns);
info->notify_owner = NULL;
+ info->notify_user_ns = NULL;
}

static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
@@ -1140,6 +1146,7 @@ retry:
}

info->notify_owner = get_pid(task_tgid(current));
+ info->notify_user_ns = get_user_ns(current_user_ns());
inode->i_atime = inode->i_ctime = CURRENT_TIME;
}
spin_unlock(&info->lock);
--
1.7.2.5