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: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Daniel Lezcano <daniel.lezcano@free.fr> Acked-by: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -54,7 +54,7 @@ static inline void get_uts_ns(struct uts_namespace *ns)
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}
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extern struct uts_namespace *copy_utsname(unsigned long flags,
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struct uts_namespace *ns);
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struct task_struct *tsk);
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extern void free_uts_ns(struct kref *kref);
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static inline void put_uts_ns(struct uts_namespace *ns)
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@ -71,12 +71,12 @@ static inline void put_uts_ns(struct uts_namespace *ns)
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}
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static inline struct uts_namespace *copy_utsname(unsigned long flags,
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struct uts_namespace *ns)
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struct task_struct *tsk)
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{
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if (flags & CLONE_NEWUTS)
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return ERR_PTR(-EINVAL);
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return ns;
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return tsk->nsproxy->uts_ns;
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}
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#endif
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@ -69,16 +69,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
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goto out_ns;
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}
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new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
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new_nsp->uts_ns = copy_utsname(flags, tsk);
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if (IS_ERR(new_nsp->uts_ns)) {
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err = PTR_ERR(new_nsp->uts_ns);
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goto out_uts;
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}
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if (new_nsp->uts_ns != tsk->nsproxy->uts_ns) {
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put_user_ns(new_nsp->uts_ns->user_ns);
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new_nsp->uts_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
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get_user_ns(new_nsp->uts_ns->user_ns);
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}
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new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
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if (IS_ERR(new_nsp->ipc_ns)) {
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@ -1181,7 +1181,7 @@ SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
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int errno;
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char tmp[__NEW_UTS_LEN];
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if (!capable(CAP_SYS_ADMIN))
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if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
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return -EPERM;
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if (len < 0 || len > __NEW_UTS_LEN)
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return -EINVAL;
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@ -31,7 +31,8 @@ static struct uts_namespace *create_uts_ns(void)
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* @old_ns: namespace to clone
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* Return NULL on error (failure to kmalloc), new ns otherwise
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*/
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static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
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static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
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struct uts_namespace *old_ns)
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{
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struct uts_namespace *ns;
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@ -41,8 +42,7 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
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down_read(&uts_sem);
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memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
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ns->user_ns = old_ns->user_ns;
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get_user_ns(ns->user_ns);
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ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
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up_read(&uts_sem);
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return ns;
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}
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@ -53,8 +53,10 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
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* utsname of this process won't be seen by parent, and vice
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* versa.
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*/
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struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns)
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struct uts_namespace *copy_utsname(unsigned long flags,
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struct task_struct *tsk)
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{
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struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
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struct uts_namespace *new_ns;
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BUG_ON(!old_ns);
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@ -63,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *ol
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if (!(flags & CLONE_NEWUTS))
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return old_ns;
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new_ns = clone_uts_ns(old_ns);
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new_ns = clone_uts_ns(tsk, old_ns);
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put_uts_ns(old_ns);
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return new_ns;
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