Merge sys_clone()/sys_unshare() nsproxy and namespace handling
sys_clone() and sys_unshare() both makes copies of nsproxy and its associated
namespaces. But they have different code paths.
This patch merges all the nsproxy and its associated namespace copy/clone
handling (as much as possible). Posted on container list earlier for
feedback.
- Create a new nsproxy and its associated namespaces and pass it back to
caller to attach it to right process.
- Changed all copy_*_ns() routines to return a new copy of namespace
instead of attaching it to task->nsproxy.
- Moved the CAP_SYS_ADMIN checks out of copy_*_ns() routines.
- Removed unnessary !ns checks from copy_*_ns() and added BUG_ON()
just incase.
- Get rid of all individual unshare_*_ns() routines and make use of
copy_*_ns() instead.
[akpm@osdl.org: cleanups, warning fix]
[clg@fr.ibm.com: remove dup_namespaces() declaration]
[serue@us.ibm.com: fix CONFIG_IPC_NS=n, clone(CLONE_NEWIPC) retval]
[akpm@linux-foundation.org: fix build with CONFIG_SYSVIPC=n]
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <containers@lists.osdl.org>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index f5b9ee6..1bc4b55 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -38,10 +38,8 @@
/*
* creates a copy of "orig" with refcount 1.
- * This does not grab references to the contained namespaces,
- * so that needs to be done by dup_namespaces.
*/
-static inline struct nsproxy *clone_namespaces(struct nsproxy *orig)
+static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
{
struct nsproxy *ns;
@@ -52,26 +50,49 @@
}
/*
- * copies the nsproxy, setting refcount to 1, and grabbing a
- * reference to all contained namespaces. Called from
- * sys_unshare()
+ * Create new nsproxy and all of its the associated namespaces.
+ * Return the newly created nsproxy. Do not attach this to the task,
+ * leave it to the caller to do proper locking and attach it to task.
*/
-struct nsproxy *dup_namespaces(struct nsproxy *orig)
+static struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk,
+ struct fs_struct *new_fs)
{
- struct nsproxy *ns = clone_namespaces(orig);
+ struct nsproxy *new_nsp;
- if (ns) {
- if (ns->mnt_ns)
- get_mnt_ns(ns->mnt_ns);
- if (ns->uts_ns)
- get_uts_ns(ns->uts_ns);
- if (ns->ipc_ns)
- get_ipc_ns(ns->ipc_ns);
- if (ns->pid_ns)
- get_pid_ns(ns->pid_ns);
- }
+ new_nsp = clone_nsproxy(tsk->nsproxy);
+ if (!new_nsp)
+ return ERR_PTR(-ENOMEM);
- return ns;
+ new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
+ if (IS_ERR(new_nsp->mnt_ns))
+ goto out_ns;
+
+ new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
+ if (IS_ERR(new_nsp->uts_ns))
+ goto out_uts;
+
+ new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
+ if (IS_ERR(new_nsp->ipc_ns))
+ goto out_ipc;
+
+ new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
+ if (IS_ERR(new_nsp->pid_ns))
+ goto out_pid;
+
+ return new_nsp;
+
+out_pid:
+ if (new_nsp->ipc_ns)
+ put_ipc_ns(new_nsp->ipc_ns);
+out_ipc:
+ if (new_nsp->uts_ns)
+ put_uts_ns(new_nsp->uts_ns);
+out_uts:
+ if (new_nsp->mnt_ns)
+ put_mnt_ns(new_nsp->mnt_ns);
+out_ns:
+ kfree(new_nsp);
+ return ERR_PTR(-ENOMEM);
}
/*
@@ -92,47 +113,21 @@
if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
return 0;
- new_ns = clone_namespaces(old_ns);
- if (!new_ns) {
- err = -ENOMEM;
+ if (!capable(CAP_SYS_ADMIN)) {
+ err = -EPERM;
+ goto out;
+ }
+
+ new_ns = create_new_namespaces(flags, tsk, tsk->fs);
+ if (IS_ERR(new_ns)) {
+ err = PTR_ERR(new_ns);
goto out;
}
tsk->nsproxy = new_ns;
-
- err = copy_mnt_ns(flags, tsk);
- if (err)
- goto out_ns;
-
- err = copy_utsname(flags, tsk);
- if (err)
- goto out_uts;
-
- err = copy_ipcs(flags, tsk);
- if (err)
- goto out_ipc;
-
- err = copy_pid_ns(flags, tsk);
- if (err)
- goto out_pid;
-
out:
put_nsproxy(old_ns);
return err;
-
-out_pid:
- if (new_ns->ipc_ns)
- put_ipc_ns(new_ns->ipc_ns);
-out_ipc:
- if (new_ns->uts_ns)
- put_uts_ns(new_ns->uts_ns);
-out_uts:
- if (new_ns->mnt_ns)
- put_mnt_ns(new_ns->mnt_ns);
-out_ns:
- tsk->nsproxy = old_ns;
- kfree(new_ns);
- goto out;
}
void free_nsproxy(struct nsproxy *ns)
@@ -147,3 +142,41 @@
put_pid_ns(ns->pid_ns);
kfree(ns);
}
+
+/*
+ * Called from unshare. Unshare all the namespaces part of nsproxy.
+ * On sucess, returns the new nsproxy and a reference to old nsproxy
+ * to make sure it stays around.
+ */
+int unshare_nsproxy_namespaces(unsigned long unshare_flags,
+ struct nsproxy **new_nsp, struct fs_struct *new_fs)
+{
+ struct nsproxy *old_ns = current->nsproxy;
+ int err = 0;
+
+ if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
+ return 0;
+
+#ifndef CONFIG_IPC_NS
+ if (unshare_flags & CLONE_NEWIPC)
+ return -EINVAL;
+#endif
+
+#ifndef CONFIG_UTS_NS
+ if (unshare_flags & CLONE_NEWUTS)
+ return -EINVAL;
+#endif
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ get_nsproxy(old_ns);
+
+ *new_nsp = create_new_namespaces(unshare_flags, current,
+ new_fs ? new_fs : current->fs);
+ if (IS_ERR(*new_nsp)) {
+ err = PTR_ERR(*new_nsp);
+ put_nsproxy(old_ns);
+ }
+ return err;
+}
