Commit bcf58e72 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

userns: Make create_new_namespaces take a user_ns parameter 



Modify create_new_namespaces to explicitly take a user namespace
parameter, instead of implicitly through the task_struct.

This allows an implementation of unshare(CLONE_NEWUSER) where
the new user namespace is not stored onto the current task_struct
until after all of the namespaces are created.

Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 142e1d1d

include/linux/ipc_namespace.h

+4 −3
Original line number Diff line number Diff line
@@ -133,7 +133,8 @@ static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; } 


#if defined(CONFIG_IPC_NS)

extern struct ipc_namespace *copy_ipcs(unsigned long flags,

				       struct task_struct *tsk);

	struct user_namespace *user_ns, struct ipc_namespace *ns);



static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)

{

	if (ns)
@@ -144,12 +145,12 @@ static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns) 
extern void put_ipc_ns(struct ipc_namespace *ns);

#else

static inline struct ipc_namespace *copy_ipcs(unsigned long flags,

					      struct task_struct *tsk)

	struct user_namespace *user_ns, struct ipc_namespace *ns)

{

	if (flags & CLONE_NEWIPC)

		return ERR_PTR(-EINVAL);



	return tsk->nsproxy->ipc_ns;

	return ns;

}



static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)

include/linux/utsname.h

+3 −3
Original line number Diff line number Diff line
@@ -33,7 +33,7 @@ static inline void get_uts_ns(struct uts_namespace *ns) 
}



extern struct uts_namespace *copy_utsname(unsigned long flags,

					  struct task_struct *tsk);

	struct user_namespace *user_ns, struct uts_namespace *old_ns);

extern void free_uts_ns(struct kref *kref);



static inline void put_uts_ns(struct uts_namespace *ns)
@@ -50,12 +50,12 @@ static inline void put_uts_ns(struct uts_namespace *ns) 
}



static inline struct uts_namespace *copy_utsname(unsigned long flags,

						 struct task_struct *tsk)

	struct user_namespace *user_ns, struct uts_namespace *old_ns)

{

	if (flags & CLONE_NEWUTS)

		return ERR_PTR(-EINVAL);



	return tsk->nsproxy->uts_ns;

	return old_ns;

}

#endif

ipc/namespace.c

+4 −6
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ 


#include "util.h"



static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk,

static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,

					   struct ipc_namespace *old_ns)

{

	struct ipc_namespace *ns;
@@ -46,19 +46,17 @@ static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk, 
	ipcns_notify(IPCNS_CREATED);

	register_ipcns_notifier(ns);



	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user_ns));

	ns->user_ns = get_user_ns(user_ns);



	return ns;

}



struct ipc_namespace *copy_ipcs(unsigned long flags,

				struct task_struct *tsk)

	struct user_namespace *user_ns, struct ipc_namespace *ns)

{

	struct ipc_namespace *ns = tsk->nsproxy->ipc_ns;



	if (!(flags & CLONE_NEWIPC))

		return get_ipc_ns(ns);

	return create_ipc_ns(tsk, ns);

	return create_ipc_ns(user_ns, ns);

}



/*

kernel/nsproxy.c

+13 −9
Original line number Diff line number Diff line
@@ -57,7 +57,8 @@ static inline struct nsproxy *create_nsproxy(void) 
 * leave it to the caller to do proper locking and attach it to task.

 */

static struct nsproxy *create_new_namespaces(unsigned long flags,

			struct task_struct *tsk, struct fs_struct *new_fs)

	struct task_struct *tsk, struct user_namespace *user_ns,

	struct fs_struct *new_fs)

{

	struct nsproxy *new_nsp;

	int err;
@@ -66,31 +67,31 @@ static struct nsproxy *create_new_namespaces(unsigned long flags, 
	if (!new_nsp)

		return ERR_PTR(-ENOMEM);



	new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, task_cred_xxx(tsk, user_ns), new_fs);

	new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);

	if (IS_ERR(new_nsp->mnt_ns)) {

		err = PTR_ERR(new_nsp->mnt_ns);

		goto out_ns;

	}



	new_nsp->uts_ns = copy_utsname(flags, tsk);

	new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);

	if (IS_ERR(new_nsp->uts_ns)) {

		err = PTR_ERR(new_nsp->uts_ns);

		goto out_uts;

	}



	new_nsp->ipc_ns = copy_ipcs(flags, tsk);

	new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);

	if (IS_ERR(new_nsp->ipc_ns)) {

		err = PTR_ERR(new_nsp->ipc_ns);

		goto out_ipc;

	}



	new_nsp->pid_ns = copy_pid_ns(flags, task_cred_xxx(tsk, user_ns), tsk->nsproxy->pid_ns);

	new_nsp->pid_ns = copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns);

	if (IS_ERR(new_nsp->pid_ns)) {

		err = PTR_ERR(new_nsp->pid_ns);

		goto out_pid;

	}



	new_nsp->net_ns = copy_net_ns(flags, task_cred_xxx(tsk, user_ns), tsk->nsproxy->net_ns);

	new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);

	if (IS_ERR(new_nsp->net_ns)) {

		err = PTR_ERR(new_nsp->net_ns);

		goto out_net;
@@ -152,7 +153,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) 
		goto out;

	}



	new_ns = create_new_namespaces(flags, tsk, tsk->fs);

	new_ns = create_new_namespaces(flags, tsk,

				       task_cred_xxx(tsk, user_ns), tsk->fs);

	if (IS_ERR(new_ns)) {

		err = PTR_ERR(new_ns);

		goto out;
@@ -186,6 +188,7 @@ void free_nsproxy(struct nsproxy *ns) 
int unshare_nsproxy_namespaces(unsigned long unshare_flags,

		struct nsproxy **new_nsp, struct fs_struct *new_fs)

{

	struct user_namespace *user_ns;

	int err = 0;



	if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
@@ -195,7 +198,8 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags, 
	if (!nsown_capable(CAP_SYS_ADMIN))

		return -EPERM;



	*new_nsp = create_new_namespaces(unshare_flags, current,

	user_ns = current_user_ns();

	*new_nsp = create_new_namespaces(unshare_flags, current, user_ns,

				new_fs ? new_fs : current->fs);

	if (IS_ERR(*new_nsp)) {

		err = PTR_ERR(*new_nsp);
@@ -252,7 +256,7 @@ SYSCALL_DEFINE2(setns, int, fd, int, nstype) 
	if (nstype && (ops->type != nstype))

		goto out;



	new_nsproxy = create_new_namespaces(0, tsk, tsk->fs);

	new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);

	if (IS_ERR(new_nsproxy)) {

		err = PTR_ERR(new_nsproxy);

		goto out;

kernel/utsname.c

+4 −5
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ static struct uts_namespace *create_uts_ns(void) 
 * @old_ns: namespace to clone

 * Return NULL on error (failure to kmalloc), new ns otherwise

 */

static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,

static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,

					  struct uts_namespace *old_ns)

{

	struct uts_namespace *ns;
@@ -43,7 +43,7 @@ static struct uts_namespace *clone_uts_ns(struct task_struct *tsk, 


	down_read(&uts_sem);

	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));

	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user_ns));

	ns->user_ns = get_user_ns(user_ns);

	up_read(&uts_sem);

	return ns;

}
@@ -55,9 +55,8 @@ static struct uts_namespace *clone_uts_ns(struct task_struct *tsk, 
 * versa.

 */

struct uts_namespace *copy_utsname(unsigned long flags,

				   struct task_struct *tsk)

	struct user_namespace *user_ns, struct uts_namespace *old_ns)

{

	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;

	struct uts_namespace *new_ns;



	BUG_ON(!old_ns);
@@ -66,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags, 
	if (!(flags & CLONE_NEWUTS))

		return old_ns;



	new_ns = clone_uts_ns(tsk, old_ns);

	new_ns = clone_uts_ns(user_ns, old_ns);



	put_uts_ns(old_ns);

	return new_ns;

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