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Commit bb96a6f5 authored by Serge E. Hallyn's avatar Serge E. Hallyn Committed by Linus Torvalds
Browse files

userns: allow sethostname in a container 



Changelog:
	Feb 23: let clone_uts_ns() handle setting uts->user_ns
		To do so we need to pass in the task_struct who'll
		get the utsname, so we can get its user_ns.
	Feb 23: As per Oleg's coment, just pass in tsk, instead of two
		of its members.

Signed-off-by: default avatarSerge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: default avatarDaniel Lezcano <daniel.lezcano@free.fr>
Acked-by: default avatarDavid Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3486740a

include/linux/utsname.h

+3 −3
Original line number Diff line number Diff line
@@ -54,7 +54,7 @@ static inline void get_uts_ns(struct uts_namespace *ns) 
}



extern struct uts_namespace *copy_utsname(unsigned long flags,

					struct uts_namespace *ns);

					  struct task_struct *tsk);

extern void free_uts_ns(struct kref *kref);



static inline void put_uts_ns(struct uts_namespace *ns)
@@ -71,12 +71,12 @@ static inline void put_uts_ns(struct uts_namespace *ns) 
}



static inline struct uts_namespace *copy_utsname(unsigned long flags,

					struct uts_namespace *ns)

						 struct task_struct *tsk)

{

	if (flags & CLONE_NEWUTS)

		return ERR_PTR(-EINVAL);



	return ns;

	return tsk->nsproxy->uts_ns;

}

#endif

kernel/nsproxy.c

+1 −6
Original line number Diff line number Diff line
@@ -69,16 +69,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags, 
		goto out_ns;

	}



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

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

	if (IS_ERR(new_nsp->uts_ns)) {

		err = PTR_ERR(new_nsp->uts_ns);

		goto out_uts;

	}

	if (new_nsp->uts_ns != tsk->nsproxy->uts_ns) {

		put_user_ns(new_nsp->uts_ns->user_ns);

		new_nsp->uts_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;

		get_user_ns(new_nsp->uts_ns->user_ns);

	}



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

	if (IS_ERR(new_nsp->ipc_ns)) {

kernel/sys.c

+1 −1
Original line number Diff line number Diff line
@@ -1181,7 +1181,7 @@ SYSCALL_DEFINE2(sethostname, char __user *, name, int, len) 
	int errno;

	char tmp[__NEW_UTS_LEN];



	if (!capable(CAP_SYS_ADMIN))

	if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))

		return -EPERM;

	if (len < 0 || len > __NEW_UTS_LEN)

		return -EINVAL;

kernel/utsname.c

+7 −5
Original line number Diff line number Diff line
@@ -31,7 +31,8 @@ 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 uts_namespace *old_ns)

static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,

					  struct uts_namespace *old_ns)

{

	struct uts_namespace *ns;
@@ -41,8 +42,7 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns) 


	down_read(&uts_sem);

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

	ns->user_ns = old_ns->user_ns;

	get_user_ns(ns->user_ns);

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

	up_read(&uts_sem);

	return ns;

}
@@ -53,8 +53,10 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns) 
 * utsname of this process won't be seen by parent, and vice

 * versa.

 */

struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns)

struct uts_namespace *copy_utsname(unsigned long flags,

				   struct task_struct *tsk)

{

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

	struct uts_namespace *new_ns;



	BUG_ON(!old_ns);
@@ -63,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *ol 
	if (!(flags & CLONE_NEWUTS))

		return old_ns;



	new_ns = clone_uts_ns(old_ns);

	new_ns = clone_uts_ns(tsk, old_ns);



	put_uts_ns(old_ns);

	return new_ns;