From bcf58e725ddc45d31addbc6627d4f0edccc824c1 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 26 Jul 2012 04:02:49 -0700 Subject: [PATCH] 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: Serge Hallyn Signed-off-by: "Eric W. Biederman" --- include/linux/ipc_namespace.h | 7 ++++--- include/linux/utsname.h | 6 +++--- ipc/namespace.c | 10 ++++------ kernel/nsproxy.c | 22 +++++++++++++--------- kernel/utsname.c | 9 ++++----- 5 files changed, 28 insertions(+), 26 deletions(-) diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h index 5499c92a9153..f03af702a39d 100644 --- a/include/linux/ipc_namespace.h +++ b/include/linux/ipc_namespace.h @@ -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) diff --git a/include/linux/utsname.h b/include/linux/utsname.h index 2b345206722a..221f4a0a7502 100644 --- a/include/linux/utsname.h +++ b/include/linux/utsname.h @@ -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 diff --git a/ipc/namespace.c b/ipc/namespace.c index 6ed33c05cb66..72c868277793 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -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); } /* diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index 4357a0a7d17d..2ddd81657a2a 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -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; diff --git a/kernel/utsname.c b/kernel/utsname.c index 4a9362f9325d..fdc619eb61ef 100644 --- a/kernel/utsname.c +++ b/kernel/utsname.c @@ -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; -- 2.20.1