diff options
Diffstat (limited to 'kernel/nsproxy.c')
-rw-r--r-- | kernel/nsproxy.c | 90 |
1 files changed, 77 insertions, 13 deletions
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index ed9882108cd2..b7954fd60475 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -19,6 +19,7 @@ #include <net/net_namespace.h> #include <linux/ipc_namespace.h> #include <linux/time_namespace.h> +#include <linux/fs_struct.h> #include <linux/proc_ns.h> #include <linux/file.h> #include <linux/syscalls.h> @@ -257,12 +258,79 @@ void exit_task_namespaces(struct task_struct *p) switch_task_namespaces(p, NULL); } +static void put_nsset(struct nsset *nsset) +{ + unsigned flags = nsset->flags; + + if (flags & CLONE_NEWUSER) + put_cred(nsset_cred(nsset)); + if (nsset->nsproxy) + free_nsproxy(nsset->nsproxy); +} + +static int prepare_nsset(int nstype, struct nsset *nsset) +{ + struct task_struct *me = current; + + nsset->nsproxy = create_new_namespaces(0, me, current_user_ns(), me->fs); + if (IS_ERR(nsset->nsproxy)) + return PTR_ERR(nsset->nsproxy); + + if (nstype == CLONE_NEWUSER) + nsset->cred = prepare_creds(); + else + nsset->cred = current_cred(); + if (!nsset->cred) + goto out; + + if (nstype == CLONE_NEWNS) + nsset->fs = me->fs; + + nsset->flags = nstype; + return 0; + +out: + put_nsset(nsset); + return -ENOMEM; +} + +/* + * This is the point of no return. There are just a few namespaces + * that do some actual work here and it's sufficiently minimal that + * a separate ns_common operation seems unnecessary for now. + * Unshare is doing the same thing. If we'll end up needing to do + * more in a given namespace or a helper here is ultimately not + * exported anymore a simple commit handler for each namespace + * should be added to ns_common. + */ +static void commit_nsset(struct nsset *nsset) +{ + unsigned flags = nsset->flags; + struct task_struct *me = current; + +#ifdef CONFIG_USER_NS + if (flags & CLONE_NEWUSER) { + /* transfer ownership */ + commit_creds(nsset_cred(nsset)); + nsset->cred = NULL; + } +#endif + +#ifdef CONFIG_IPC_NS + if (flags & CLONE_NEWIPC) + exit_sem(me); +#endif + + /* transfer ownership */ + switch_task_namespaces(me, nsset->nsproxy); + nsset->nsproxy = NULL; +} + SYSCALL_DEFINE2(setns, int, fd, int, nstype) { - struct task_struct *tsk = current; - struct nsproxy *new_nsproxy; struct file *file; struct ns_common *ns; + struct nsset nsset = {}; int err; file = proc_ns_fget(fd); @@ -274,20 +342,16 @@ SYSCALL_DEFINE2(setns, int, fd, int, nstype) if (nstype && (ns->ops->type != nstype)) goto out; - new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs); - if (IS_ERR(new_nsproxy)) { - err = PTR_ERR(new_nsproxy); + err = prepare_nsset(ns->ops->type, &nsset); + if (err) goto out; - } - err = ns->ops->install(new_nsproxy, ns); - if (err) { - free_nsproxy(new_nsproxy); - goto out; + err = ns->ops->install(&nsset, ns); + if (!err) { + commit_nsset(&nsset); + perf_event_namespaces(current); } - switch_task_namespaces(tsk, new_nsproxy); - - perf_event_namespaces(tsk); + put_nsset(&nsset); out: fput(file); return err; |