diff options
| -rw-r--r-- | MAINTAINERS | 2 | ||||
| -rw-r--r-- | fs/proc/namespaces.c | 4 | ||||
| -rw-r--r-- | include/linux/nsproxy.h | 2 | ||||
| -rw-r--r-- | include/linux/proc_ns.h | 3 | ||||
| -rw-r--r-- | include/linux/time_namespace.h | 71 | ||||
| -rw-r--r-- | include/linux/user_namespace.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/sched.h | 6 | ||||
| -rw-r--r-- | init/Kconfig | 7 | ||||
| -rw-r--r-- | kernel/fork.c | 16 | ||||
| -rw-r--r-- | kernel/nsproxy.c | 41 | ||||
| -rw-r--r-- | kernel/time/Makefile | 1 | ||||
| -rw-r--r-- | kernel/time/namespace.c | 217 |
12 files changed, 361 insertions, 10 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 8982c6e013b3..f6d00023e56f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13214,6 +13214,8 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/core S: Maintained F: fs/timerfd.c F: include/linux/timer* +F: include/linux/time_namespace.h +F: kernel/time_namespace.c F: kernel/time/*timer* POWER MANAGEMENT CORE diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c index dd2b35f78b09..8b5c720fe5d7 100644 --- a/fs/proc/namespaces.c +++ b/fs/proc/namespaces.c @@ -33,6 +33,10 @@ static const struct proc_ns_operations *ns_entries[] = { #ifdef CONFIG_CGROUPS &cgroupns_operations, #endif +#ifdef CONFIG_TIME_NS + &timens_operations, + &timens_for_children_operations, +#endif }; static const char *proc_ns_get_link(struct dentry *dentry, diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h index 2ae1b1a4d84d..074f395b9ad2 100644 --- a/include/linux/nsproxy.h +++ b/include/linux/nsproxy.h @@ -35,6 +35,8 @@ struct nsproxy { struct mnt_namespace *mnt_ns; struct pid_namespace *pid_ns_for_children; struct net *net_ns; + struct time_namespace *time_ns; + struct time_namespace *time_ns_for_children; struct cgroup_namespace *cgroup_ns; }; extern struct nsproxy init_nsproxy; diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h index d31cb6215905..d312e6281e69 100644 --- a/include/linux/proc_ns.h +++ b/include/linux/proc_ns.h @@ -32,6 +32,8 @@ extern const struct proc_ns_operations pidns_for_children_operations; extern const struct proc_ns_operations userns_operations; extern const struct proc_ns_operations mntns_operations; extern const struct proc_ns_operations cgroupns_operations; +extern const struct proc_ns_operations timens_operations; +extern const struct proc_ns_operations timens_for_children_operations; /* * We always define these enumerators @@ -43,6 +45,7 @@ enum { PROC_USER_INIT_INO = 0xEFFFFFFDU, PROC_PID_INIT_INO = 0xEFFFFFFCU, PROC_CGROUP_INIT_INO = 0xEFFFFFFBU, + PROC_TIME_INIT_INO = 0xEFFFFFFAU, }; #ifdef CONFIG_PROC_FS diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h new file mode 100644 index 000000000000..8c74cc12ad24 --- /dev/null +++ b/include/linux/time_namespace.h @@ -0,0 +1,71 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_TIMENS_H +#define _LINUX_TIMENS_H + + +#include <linux/sched.h> +#include <linux/kref.h> +#include <linux/nsproxy.h> +#include <linux/ns_common.h> +#include <linux/err.h> + +struct user_namespace; +extern struct user_namespace init_user_ns; + +struct time_namespace { + struct kref kref; + struct user_namespace *user_ns; + struct ucounts *ucounts; + struct ns_common ns; +} __randomize_layout; + +extern struct time_namespace init_time_ns; + +#ifdef CONFIG_TIME_NS +static inline struct time_namespace *get_time_ns(struct time_namespace *ns) +{ + kref_get(&ns->kref); + return ns; +} + +struct time_namespace *copy_time_ns(unsigned long flags, + struct user_namespace *user_ns, + struct time_namespace *old_ns); +void free_time_ns(struct kref *kref); +int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk); + +static inline void put_time_ns(struct time_namespace *ns) +{ + kref_put(&ns->kref, free_time_ns); +} + +#else +static inline struct time_namespace *get_time_ns(struct time_namespace *ns) +{ + return NULL; +} + +static inline void put_time_ns(struct time_namespace *ns) +{ +} + +static inline +struct time_namespace *copy_time_ns(unsigned long flags, + struct user_namespace *user_ns, + struct time_namespace *old_ns) +{ + if (flags & CLONE_NEWTIME) + return ERR_PTR(-EINVAL); + + return old_ns; +} + +static inline int timens_on_fork(struct nsproxy *nsproxy, + struct task_struct *tsk) +{ + return 0; +} + +#endif + +#endif /* _LINUX_TIMENS_H */ diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index fb9f4f799554..6ef1c7109fc4 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -45,6 +45,7 @@ enum ucount_type { UCOUNT_NET_NAMESPACES, UCOUNT_MNT_NAMESPACES, UCOUNT_CGROUP_NAMESPACES, + UCOUNT_TIME_NAMESPACES, #ifdef CONFIG_INOTIFY_USER UCOUNT_INOTIFY_INSTANCES, UCOUNT_INOTIFY_WATCHES, diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h index 4a0217832464..2e3bc22c6f20 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -36,6 +36,12 @@ /* Flags for the clone3() syscall. */ #define CLONE_CLEAR_SIGHAND 0x100000000ULL /* Clear any signal handler and reset to SIG_DFL. */ +/* + * cloning flags intersect with CSIGNAL so can be used with unshare and clone3 + * syscalls only: + */ +#define CLONE_NEWTIME 0x00000080 /* New time namespace */ + #ifndef __ASSEMBLY__ /** * struct clone_args - arguments for the clone3 syscall diff --git a/init/Kconfig b/init/Kconfig index a34064a031a5..b34314fc75f7 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1080,6 +1080,13 @@ config UTS_NS In this namespace tasks see different info provided with the uname() system call +config TIME_NS + bool "TIME namespace" + default y + help + In this namespace boottime and monotonic clocks can be set. + The time will keep going with the same pace. + config IPC_NS bool "IPC namespace" depends on (SYSVIPC || POSIX_MQUEUE) diff --git a/kernel/fork.c b/kernel/fork.c index 2508a4f238a3..363595815144 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1832,6 +1832,7 @@ static __latent_entropy struct task_struct *copy_process( struct multiprocess_signals delayed; struct file *pidfile = NULL; u64 clone_flags = args->flags; + struct nsproxy *nsp = current->nsproxy; /* * Don't allow sharing the root directory with processes in a different @@ -1874,8 +1875,16 @@ static __latent_entropy struct task_struct *copy_process( */ if (clone_flags & CLONE_THREAD) { if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) || - (task_active_pid_ns(current) != - current->nsproxy->pid_ns_for_children)) + (task_active_pid_ns(current) != nsp->pid_ns_for_children)) + return ERR_PTR(-EINVAL); + } + + /* + * If the new process will be in a different time namespace + * do not allow it to share VM or a thread group with the forking task. + */ + if (clone_flags & (CLONE_THREAD | CLONE_VM)) { + if (nsp->time_ns != nsp->time_ns_for_children) return ERR_PTR(-EINVAL); } @@ -2811,7 +2820,8 @@ static int check_unshare_flags(unsigned long unshare_flags) if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET| - CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP)) + CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP| + CLONE_NEWTIME)) return -EINVAL; /* * Not implemented, but pretend it works if there is nothing diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index c815f58e6bc0..ed9882108cd2 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -18,6 +18,7 @@ #include <linux/pid_namespace.h> #include <net/net_namespace.h> #include <linux/ipc_namespace.h> +#include <linux/time_namespace.h> #include <linux/proc_ns.h> #include <linux/file.h> #include <linux/syscalls.h> @@ -40,6 +41,10 @@ struct nsproxy init_nsproxy = { #ifdef CONFIG_CGROUPS .cgroup_ns = &init_cgroup_ns, #endif +#ifdef CONFIG_TIME_NS + .time_ns = &init_time_ns, + .time_ns_for_children = &init_time_ns, +#endif }; static inline struct nsproxy *create_nsproxy(void) @@ -106,8 +111,18 @@ static struct nsproxy *create_new_namespaces(unsigned long flags, goto out_net; } + new_nsp->time_ns_for_children = copy_time_ns(flags, user_ns, + tsk->nsproxy->time_ns_for_children); + if (IS_ERR(new_nsp->time_ns_for_children)) { + err = PTR_ERR(new_nsp->time_ns_for_children); + goto out_time; + } + new_nsp->time_ns = get_time_ns(tsk->nsproxy->time_ns); + return new_nsp; +out_time: + put_net(new_nsp->net_ns); out_net: put_cgroup_ns(new_nsp->cgroup_ns); out_cgroup: @@ -136,15 +151,16 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) struct nsproxy *old_ns = tsk->nsproxy; struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns); struct nsproxy *new_ns; + int ret; if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWPID | CLONE_NEWNET | - CLONE_NEWCGROUP)))) { - get_nsproxy(old_ns); - return 0; - } - - if (!ns_capable(user_ns, CAP_SYS_ADMIN)) + CLONE_NEWCGROUP | CLONE_NEWTIME)))) { + if (likely(old_ns->time_ns_for_children == old_ns->time_ns)) { + get_nsproxy(old_ns); + return 0; + } + } else if (!ns_capable(user_ns, CAP_SYS_ADMIN)) return -EPERM; /* @@ -162,6 +178,12 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) if (IS_ERR(new_ns)) return PTR_ERR(new_ns); + ret = timens_on_fork(new_ns, tsk); + if (ret) { + free_nsproxy(new_ns); + return ret; + } + tsk->nsproxy = new_ns; return 0; } @@ -176,6 +198,10 @@ void free_nsproxy(struct nsproxy *ns) put_ipc_ns(ns->ipc_ns); if (ns->pid_ns_for_children) put_pid_ns(ns->pid_ns_for_children); + if (ns->time_ns) + put_time_ns(ns->time_ns); + if (ns->time_ns_for_children) + put_time_ns(ns->time_ns_for_children); put_cgroup_ns(ns->cgroup_ns); put_net(ns->net_ns); kmem_cache_free(nsproxy_cachep, ns); @@ -192,7 +218,8 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags, int err = 0; if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | - CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP))) + CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP | + CLONE_NEWTIME))) return 0; user_ns = new_cred ? new_cred->user_ns : current_user_ns(); diff --git a/kernel/time/Makefile b/kernel/time/Makefile index 1867044800bb..c8f00168afe8 100644 --- a/kernel/time/Makefile +++ b/kernel/time/Makefile @@ -19,3 +19,4 @@ obj-$(CONFIG_TICK_ONESHOT) += tick-oneshot.o tick-sched.o obj-$(CONFIG_HAVE_GENERIC_VDSO) += vsyscall.o obj-$(CONFIG_DEBUG_FS) += timekeeping_debug.o obj-$(CONFIG_TEST_UDELAY) += test_udelay.o +obj-$(CONFIG_TIME_NS) += namespace.o diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c new file mode 100644 index 000000000000..2662a69e0382 --- /dev/null +++ b/kernel/time/namespace.c @@ -0,0 +1,217 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Author: Andrei Vagin <avagin@openvz.org> + * Author: Dmitry Safonov <dima@arista.com> + */ + +#include <linux/time_namespace.h> +#include <linux/user_namespace.h> +#include <linux/sched/signal.h> +#include <linux/sched/task.h> +#include <linux/proc_ns.h> +#include <linux/export.h> +#include <linux/time.h> +#include <linux/slab.h> +#include <linux/cred.h> +#include <linux/err.h> + +static struct ucounts *inc_time_namespaces(struct user_namespace *ns) +{ + return inc_ucount(ns, current_euid(), UCOUNT_TIME_NAMESPACES); +} + +static void dec_time_namespaces(struct ucounts *ucounts) +{ + dec_ucount(ucounts, UCOUNT_TIME_NAMESPACES); +} + +/** + * clone_time_ns - Clone a time namespace + * @user_ns: User namespace which owns a new namespace. + * @old_ns: Namespace to clone + * + * Clone @old_ns and set the clone refcount to 1 + * + * Return: The new namespace or ERR_PTR. + */ +static struct time_namespace *clone_time_ns(struct user_namespace *user_ns, + struct time_namespace *old_ns) +{ + struct time_namespace *ns; + struct ucounts *ucounts; + int err; + + err = -ENOSPC; + ucounts = inc_time_namespaces(user_ns); + if (!ucounts) + goto fail; + + err = -ENOMEM; + ns = kmalloc(sizeof(*ns), GFP_KERNEL); + if (!ns) + goto fail_dec; + + kref_init(&ns->kref); + + err = ns_alloc_inum(&ns->ns); + if (err) + goto fail_free; + + ns->ucounts = ucounts; + ns->ns.ops = &timens_operations; + ns->user_ns = get_user_ns(user_ns); + return ns; + +fail_free: + kfree(ns); +fail_dec: + dec_time_namespaces(ucounts); +fail: + return ERR_PTR(err); +} + +/** + * copy_time_ns - Create timens_for_children from @old_ns + * @flags: Cloning flags + * @user_ns: User namespace which owns a new namespace. + * @old_ns: Namespace to clone + * + * If CLONE_NEWTIME specified in @flags, creates a new timens_for_children; + * adds a refcounter to @old_ns otherwise. + * + * Return: timens_for_children namespace or ERR_PTR. + */ +struct time_namespace *copy_time_ns(unsigned long flags, + struct user_namespace *user_ns, struct time_namespace *old_ns) +{ + if (!(flags & CLONE_NEWTIME)) + return get_time_ns(old_ns); + + return clone_time_ns(user_ns, old_ns); +} + +void free_time_ns(struct kref *kref) +{ + struct time_namespace *ns; + + ns = container_of(kref, struct time_namespace, kref); + dec_time_namespaces(ns->ucounts); + put_user_ns(ns->user_ns); + ns_free_inum(&ns->ns); + kfree(ns); +} + +static struct time_namespace *to_time_ns(struct ns_common *ns) +{ + return container_of(ns, struct time_namespace, ns); +} + +static struct ns_common *timens_get(struct task_struct *task) +{ + struct time_namespace *ns = NULL; + struct nsproxy *nsproxy; + + task_lock(task); + nsproxy = task->nsproxy; + if (nsproxy) { + ns = nsproxy->time_ns; + get_time_ns(ns); + } + task_unlock(task); + + return ns ? &ns->ns : NULL; +} + +static struct ns_common *timens_for_children_get(struct task_struct *task) +{ + struct time_namespace *ns = NULL; + struct nsproxy *nsproxy; + + task_lock(task); + nsproxy = task->nsproxy; + if (nsproxy) { + ns = nsproxy->time_ns_for_children; + get_time_ns(ns); + } + task_unlock(task); + + return ns ? &ns->ns : NULL; +} + +static void timens_put(struct ns_common *ns) +{ + put_time_ns(to_time_ns(ns)); +} + +static int timens_install(struct nsproxy *nsproxy, struct ns_common *new) +{ + struct time_namespace *ns = to_time_ns(new); + + if (!current_is_single_threaded()) + return -EUSERS; + + if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || + !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) + return -EPERM; + + get_time_ns(ns); + put_time_ns(nsproxy->time_ns); + nsproxy->time_ns = ns; + + get_time_ns(ns); + put_time_ns(nsproxy->time_ns_for_children); + nsproxy->time_ns_for_children = ns; + return 0; +} + +int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk) +{ + struct ns_common *nsc = &nsproxy->time_ns_for_children->ns; + struct time_namespace *ns = to_time_ns(nsc); + + /* create_new_namespaces() already incremented the ref counter */ + if (nsproxy->time_ns == nsproxy->time_ns_for_children) + return 0; + + get_time_ns(ns); + put_time_ns(nsproxy->time_ns); + nsproxy->time_ns = ns; + + return 0; +} + +static struct user_namespace *timens_owner(struct ns_common *ns) +{ + return to_time_ns(ns)->user_ns; +} + +const struct proc_ns_operations timens_operations = { + .name = "time", + .type = CLONE_NEWTIME, + .get = timens_get, + .put = timens_put, + .install = timens_install, + .owner = timens_owner, +}; + +const struct proc_ns_operations timens_for_children_operations = { + .name = "time_for_children", + .type = CLONE_NEWTIME, + .get = timens_for_children_get, + .put = timens_put, + .install = timens_install, + .owner = timens_owner, +}; + +struct time_namespace init_time_ns = { + .kref = KREF_INIT(3), + .user_ns = &init_user_ns, + .ns.inum = PROC_TIME_INIT_INO, + .ns.ops = &timens_operations, +}; + +static int __init time_ns_init(void) +{ + return 0; +} +subsys_initcall(time_ns_init); |