userns: Implement unshare of the user namespace
- Add CLONE_THREAD to the unshare flags if CLONE_NEWUSER is selected
As changing user namespaces is only valid if all there is only
a single thread.
- Restore the code to add CLONE_VM if CLONE_THREAD is selected and
the code to addCLONE_SIGHAND if CLONE_VM is selected.
Making the constraints in the code clear.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 2ddd816..78e2ecb 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -186,7 +186,7 @@
* On success, returns the new nsproxy.
*/
int unshare_nsproxy_namespaces(unsigned long unshare_flags,
- struct nsproxy **new_nsp, struct fs_struct *new_fs)
+ struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
{
struct user_namespace *user_ns;
int err = 0;
@@ -195,12 +195,12 @@
CLONE_NEWNET | CLONE_NEWPID)))
return 0;
- if (!nsown_capable(CAP_SYS_ADMIN))
+ user_ns = new_cred ? new_cred->user_ns : current_user_ns();
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
return -EPERM;
- user_ns = current_user_ns();
*new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
- new_fs ? new_fs : current->fs);
+ new_fs ? new_fs : current->fs);
if (IS_ERR(*new_nsp)) {
err = PTR_ERR(*new_nsp);
goto out;
