From aa29aef4cac28d70c6678e75873554c61f31c41b Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 14 Jun 2012 02:31:10 -0700 Subject: [PATCH] userns: make each net (net_ns) belong to a user_ns The user namespace which creates a new network namespace owns that namespace and all resources created in it. This way we can target capability checks for privileged operations against network resources to the user_ns which created the network namespace in which the resource lives. Privilege to the user namespace which owns the network namespace, or any parent user namespace thereof, provides the same privilege to the network resource. This patch is reworked from a version originally by Serge E. Hallyn Change-Id: Ifa426537c47cce669099cc96e80b17e1d814457b Acked-by: Serge Hallyn Signed-off-by: Eric W. Biederman Signed-off-by: Kevin F. Haggerty --- include/net/net_namespace.h | 9 +++++++-- kernel/nsproxy.c | 2 +- net/core/net_namespace.c | 16 ++++++++++++---- 3 files changed, 20 insertions(+), 7 deletions(-) diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 2633715fac3..6e6b175e939 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -23,6 +23,7 @@ #endif #include +struct user_namespace; struct proc_dir_entry; struct net_device; struct sock; @@ -53,6 +54,8 @@ struct net { struct list_head cleanup_list; /* namespaces on death row */ struct list_head exit_list; /* Use only net_mutex */ + struct user_namespace *user_ns; /* Owning user namespace */ + unsigned int proc_inum; struct proc_dir_entry *proc_net; @@ -112,10 +115,12 @@ struct net { extern struct net init_net; #ifdef CONFIG_NET -extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns); +extern struct net *copy_net_ns(unsigned long flags, + struct user_namespace *user_ns, struct net *net_ns); #else /* CONFIG_NET */ -static inline struct net *copy_net_ns(unsigned long flags, struct net *net_ns) +static inline struct net *copy_net_ns(unsigned long flags, + struct user_namespace *user_ns, struct net *net_ns) { /* There is nothing to copy so this is a noop */ return net_ns; diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index 5b6ce19064a..b08eaeb8dab 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -90,7 +90,7 @@ static struct nsproxy *create_new_namespaces(unsigned long flags, goto out_pid; } - new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns); + new_nsp->net_ns = copy_net_ns(flags, task_cred_xxx(tsk, user_ns), tsk->nsproxy->net_ns); if (IS_ERR(new_nsp->net_ns)) { err = PTR_ERR(new_nsp->net_ns); goto out_net; diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 4a2b464dc5d..812a2c903b5 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include @@ -143,7 +144,7 @@ static void ops_free_list(const struct pernet_operations *ops, /* * setup_net runs the initializers for the network namespace object. */ -static __net_init int setup_net(struct net *net) +static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) { /* Must be called with net_mutex held */ const struct pernet_operations *ops, *saved_ops; @@ -153,6 +154,7 @@ static __net_init int setup_net(struct net *net) atomic_set(&net->count, 1); atomic_set(&net->passive, 1); net->dev_base_seq = 1; + net->user_ns = user_ns; #ifdef NETNS_REFCNT_DEBUG atomic_set(&net->use_count, 0); @@ -230,7 +232,8 @@ void net_drop_ns(void *p) net_free(ns); } -struct net *copy_net_ns(unsigned long flags, struct net *old_net) +struct net *copy_net_ns(unsigned long flags, + struct user_namespace *user_ns, struct net *old_net) { struct net *net; int rv; @@ -241,8 +244,11 @@ struct net *copy_net_ns(unsigned long flags, struct net *old_net) net = net_alloc(); if (!net) return ERR_PTR(-ENOMEM); + + get_user_ns(user_ns); + mutex_lock(&net_mutex); - rv = setup_net(net); + rv = setup_net(net, user_ns); if (rv == 0) { rtnl_lock(); list_add_tail_rcu(&net->list, &net_namespace_list); @@ -250,6 +256,7 @@ struct net *copy_net_ns(unsigned long flags, struct net *old_net) } mutex_unlock(&net_mutex); if (rv < 0) { + put_user_ns(user_ns); net_drop_ns(net); return ERR_PTR(rv); } @@ -306,6 +313,7 @@ static void cleanup_net(struct work_struct *work) /* Finally it is safe to free my network namespace structure */ list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) { list_del_init(&net->exit_list); + put_user_ns(net->user_ns); net_drop_ns(net); } } @@ -415,7 +423,7 @@ static int __init net_ns_init(void) rcu_assign_pointer(init_net.gen, ng); mutex_lock(&net_mutex); - if (setup_net(&init_net)) + if (setup_net(&init_net, &init_user_ns)) panic("Could not setup the initial network namespace"); rtnl_lock();