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authorAndrey Vagin <avagin@openvz.org>2016-09-06 00:47:13 -0700
committerEric W. Biederman <ebiederm@xmission.com>2016-09-22 19:59:39 -0500
commitbcac25a58bfc6bd79191ac5d7afb49bea96da8c9 (patch)
tree28a8ae71b2939267deba0807bcbbed28e77470c0
parentLinux 4.8-rc1 (diff)
downloadlinux-dev-bcac25a58bfc6bd79191ac5d7afb49bea96da8c9.tar.xz
linux-dev-bcac25a58bfc6bd79191ac5d7afb49bea96da8c9.zip
kernel: add a helper to get an owning user namespace for a namespace
Return -EPERM if an owning user namespace is outside of a process current user namespace. v2: In a first version ns_get_owner returned ENOENT for init_user_ns. This special cases was removed from this version. There is nothing outside of init_user_ns, so we can return EPERM. v3: rename ns->get_owner() to ns->owner(). get_* usually means that it grabs a reference. Acked-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Andrei Vagin <avagin@openvz.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to '')
-rw-r--r--fs/namespace.c6
-rw-r--r--include/linux/proc_ns.h1
-rw-r--r--include/linux/user_namespace.h7
-rw-r--r--ipc/namespace.c6
-rw-r--r--kernel/cgroup.c6
-rw-r--r--kernel/pid_namespace.c6
-rw-r--r--kernel/user_namespace.c24
-rw-r--r--kernel/utsname.c6
-rw-r--r--net/core/net_namespace.c6
9 files changed, 68 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 7bb2cda3bfef..fea56f310547 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3348,10 +3348,16 @@ static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns)
return 0;
}
+static struct user_namespace *mntns_owner(struct ns_common *ns)
+{
+ return to_mnt_ns(ns)->user_ns;
+}
+
const struct proc_ns_operations mntns_operations = {
.name = "mnt",
.type = CLONE_NEWNS,
.get = mntns_get,
.put = mntns_put,
.install = mntns_install,
+ .owner = mntns_owner,
};
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index de0e7719d4c5..ca85a4348ffc 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -18,6 +18,7 @@ struct proc_ns_operations {
struct ns_common *(*get)(struct task_struct *task);
void (*put)(struct ns_common *ns);
int (*install)(struct nsproxy *nsproxy, struct ns_common *ns);
+ struct user_namespace *(*owner)(struct ns_common *ns);
};
extern const struct proc_ns_operations netns_operations;
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 9217169c64cb..190cf0760815 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -73,6 +73,8 @@ extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t,
extern int proc_setgroups_show(struct seq_file *m, void *v);
extern bool userns_may_setgroups(const struct user_namespace *ns);
extern bool current_in_userns(const struct user_namespace *target_ns);
+
+struct ns_common *ns_get_owner(struct ns_common *ns);
#else
static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
@@ -106,6 +108,11 @@ static inline bool current_in_userns(const struct user_namespace *target_ns)
{
return true;
}
+
+static inline struct ns_common *ns_get_owner(struct ns_common *ns)
+{
+ return ERR_PTR(-EPERM);
+}
#endif
#endif /* _LINUX_USER_H */
diff --git a/ipc/namespace.c b/ipc/namespace.c
index d87e6baa1323..578d93be619d 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -165,10 +165,16 @@ static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new)
return 0;
}
+static struct user_namespace *ipcns_owner(struct ns_common *ns)
+{
+ return to_ipc_ns(ns)->user_ns;
+}
+
const struct proc_ns_operations ipcns_operations = {
.name = "ipc",
.type = CLONE_NEWIPC,
.get = ipcns_get,
.put = ipcns_put,
.install = ipcns_install,
+ .owner = ipcns_owner,
};
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index d1c51b7f5221..86b0e8b16426 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -6403,12 +6403,18 @@ static void cgroupns_put(struct ns_common *ns)
put_cgroup_ns(to_cg_ns(ns));
}
+static struct user_namespace *cgroupns_owner(struct ns_common *ns)
+{
+ return to_cg_ns(ns)->user_ns;
+}
+
const struct proc_ns_operations cgroupns_operations = {
.name = "cgroup",
.type = CLONE_NEWCGROUP,
.get = cgroupns_get,
.put = cgroupns_put,
.install = cgroupns_install,
+ .owner = cgroupns_owner,
};
static __init int cgroup_namespaces_init(void)
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index a65ba137fd15..c02d744225e1 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -388,12 +388,18 @@ static int pidns_install(struct nsproxy *nsproxy, struct ns_common *ns)
return 0;
}
+static struct user_namespace *pidns_owner(struct ns_common *ns)
+{
+ return to_pid_ns(ns)->user_ns;
+}
+
const struct proc_ns_operations pidns_operations = {
.name = "pid",
.type = CLONE_NEWPID,
.get = pidns_get,
.put = pidns_put,
.install = pidns_install,
+ .owner = pidns_owner,
};
static __init int pid_namespaces_init(void)
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 68f594212759..0ef683a03c20 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -1004,12 +1004,36 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
return commit_creds(cred);
}
+struct ns_common *ns_get_owner(struct ns_common *ns)
+{
+ struct user_namespace *my_user_ns = current_user_ns();
+ struct user_namespace *owner, *p;
+
+ /* See if the owner is in the current user namespace */
+ owner = p = ns->ops->owner(ns);
+ for (;;) {
+ if (!p)
+ return ERR_PTR(-EPERM);
+ if (p == my_user_ns)
+ break;
+ p = p->parent;
+ }
+
+ return &get_user_ns(owner)->ns;
+}
+
+static struct user_namespace *userns_owner(struct ns_common *ns)
+{
+ return to_user_ns(ns)->parent;
+}
+
const struct proc_ns_operations userns_operations = {
.name = "user",
.type = CLONE_NEWUSER,
.get = userns_get,
.put = userns_put,
.install = userns_install,
+ .owner = userns_owner,
};
static __init int user_namespaces_init(void)
diff --git a/kernel/utsname.c b/kernel/utsname.c
index 831ea7108232..e1211a8a5c18 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -130,10 +130,16 @@ static int utsns_install(struct nsproxy *nsproxy, struct ns_common *new)
return 0;
}
+static struct user_namespace *utsns_owner(struct ns_common *ns)
+{
+ return to_uts_ns(ns)->user_ns;
+}
+
const struct proc_ns_operations utsns_operations = {
.name = "uts",
.type = CLONE_NEWUTS,
.get = utsns_get,
.put = utsns_put,
.install = utsns_install,
+ .owner = utsns_owner,
};
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 2c2eb1b629b1..861efa34f08c 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -996,11 +996,17 @@ static int netns_install(struct nsproxy *nsproxy, struct ns_common *ns)
return 0;
}
+static struct user_namespace *netns_owner(struct ns_common *ns)
+{
+ return to_net_ns(ns)->user_ns;
+}
+
const struct proc_ns_operations netns_operations = {
.name = "net",
.type = CLONE_NEWNET,
.get = netns_get,
.put = netns_put,
.install = netns_install,
+ .owner = netns_owner,
};
#endif