1 files changed, 51 insertions, 178 deletions

diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index 0775b9ec952a..4bca3f78c8ea 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -12,13 +12,15 @@
 #include <linux/seq_file.h>
 #include <linux/proc_ns.h>
 #include <linux/export.h>
+#include <linux/nstree.h>
 #include <linux/time.h>
 #include <linux/slab.h>
 #include <linux/cred.h>
 #include <linux/err.h>
 #include <linux/mm.h>
+#include <linux/cleanup.h>
 
-#include <vdso/datapage.h>
+#include "namespace_internal.h"
 
 ktime_t do_timens_ktime_to_host(clockid_t clockid, ktime_t tim,
 				struct timens_offsets *ns_offsets)
@@ -88,29 +90,27 @@ static struct time_namespace *clone_time_ns(struct user_namespace *user_ns,
 		goto fail;
 
 	err = -ENOMEM;
-	ns = kmalloc(sizeof(*ns), GFP_KERNEL_ACCOUNT);
+	ns = kzalloc_obj(*ns, GFP_KERNEL_ACCOUNT);
 	if (!ns)
 		goto fail_dec;
 
-	refcount_set(&ns->ns.count, 1);
-
-	ns->vvar_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
-	if (!ns->vvar_page)
+	err = timens_vdso_alloc_vvar_page(ns);
+	if (err)
 		goto fail_free;
 
-	err = ns_alloc_inum(&ns->ns);
+	err = ns_common_init(ns);
 	if (err)
 		goto fail_free_page;
 
 	ns->ucounts = ucounts;
-	ns->ns.ops = &timens_operations;
 	ns->user_ns = get_user_ns(user_ns);
 	ns->offsets = old_ns->offsets;
 	ns->frozen_offsets = false;
+	ns_tree_add(ns);
 	return ns;
 
 fail_free_page:
-	__free_page(ns->vvar_page);
+	timens_vdso_free_vvar_page(ns);
 fail_free:
 	kfree(ns);
 fail_dec:
@@ -130,7 +130,7 @@ fail:
  *
  * Return: timens_for_children namespace or ERR_PTR.
  */
-struct time_namespace *copy_time_ns(unsigned long flags,
+struct time_namespace *copy_time_ns(u64 flags,
 	struct user_namespace *user_ns, struct time_namespace *old_ns)
 {
 	if (!(flags & CLONE_NEWTIME))
@@ -139,155 +139,47 @@ struct time_namespace *copy_time_ns(unsigned long flags,
 	return clone_time_ns(user_ns, old_ns);
 }
 
-static struct timens_offset offset_from_ts(struct timespec64 off)
-{
-	struct timens_offset ret;
-
-	ret.sec = off.tv_sec;
-	ret.nsec = off.tv_nsec;
-
-	return ret;
-}
-
-/*
- * A time namespace VVAR page has the same layout as the VVAR page which
- * contains the system wide VDSO data.
- *
- * For a normal task the VVAR pages are installed in the normal ordering:
- *     VVAR
- *     PVCLOCK
- *     HVCLOCK
- *     TIMENS   <- Not really required
- *
- * Now for a timens task the pages are installed in the following order:
- *     TIMENS
- *     PVCLOCK
- *     HVCLOCK
- *     VVAR
- *
- * The check for vdso_data->clock_mode is in the unlikely path of
- * the seq begin magic. So for the non-timens case most of the time
- * 'seq' is even, so the branch is not taken.
- *
- * If 'seq' is odd, i.e. a concurrent update is in progress, the extra check
- * for vdso_data->clock_mode is a non-issue. The task is spin waiting for the
- * update to finish and for 'seq' to become even anyway.
- *
- * Timens page has vdso_data->clock_mode set to VDSO_CLOCKMODE_TIMENS which
- * enforces the time namespace handling path.
- */
-static void timens_setup_vdso_data(struct vdso_data *vdata,
-				   struct time_namespace *ns)
-{
-	struct timens_offset *offset = vdata->offset;
-	struct timens_offset monotonic = offset_from_ts(ns->offsets.monotonic);
-	struct timens_offset boottime = offset_from_ts(ns->offsets.boottime);
-
-	vdata->seq			= 1;
-	vdata->clock_mode		= VDSO_CLOCKMODE_TIMENS;
-	offset[CLOCK_MONOTONIC]		= monotonic;
-	offset[CLOCK_MONOTONIC_RAW]	= monotonic;
-	offset[CLOCK_MONOTONIC_COARSE]	= monotonic;
-	offset[CLOCK_BOOTTIME]		= boottime;
-	offset[CLOCK_BOOTTIME_ALARM]	= boottime;
-}
-
-struct page *find_timens_vvar_page(struct vm_area_struct *vma)
-{
-	if (likely(vma->vm_mm == current->mm))
-		return current->nsproxy->time_ns->vvar_page;
-
-	/*
-	 * VM_PFNMAP | VM_IO protect .fault() handler from being called
-	 * through interfaces like /proc/$pid/mem or
-	 * process_vm_{readv,writev}() as long as there's no .access()
-	 * in special_mapping_vmops().
-	 * For more details check_vma_flags() and __access_remote_vm()
-	 */
-
-	WARN(1, "vvar_page accessed remotely");
-
-	return NULL;
-}
-
-/*
- * Protects possibly multiple offsets writers racing each other
- * and tasks entering the namespace.
- */
-static DEFINE_MUTEX(offset_lock);
-
-static void timens_set_vvar_page(struct task_struct *task,
-				struct time_namespace *ns)
-{
-	struct vdso_data *vdata;
-	unsigned int i;
-
-	if (ns == &init_time_ns)
-		return;
-
-	/* Fast-path, taken by every task in namespace except the first. */
-	if (likely(ns->frozen_offsets))
-		return;
-
-	mutex_lock(&offset_lock);
-	/* Nothing to-do: vvar_page has been already initialized. */
-	if (ns->frozen_offsets)
-		goto out;
-
-	ns->frozen_offsets = true;
-	vdata = arch_get_vdso_data(page_address(ns->vvar_page));
-
-	for (i = 0; i < CS_BASES; i++)
-		timens_setup_vdso_data(&vdata[i], ns);
-
-out:
-	mutex_unlock(&offset_lock);
-}
+DEFINE_MUTEX(timens_offset_lock);
 
 void free_time_ns(struct time_namespace *ns)
 {
+	ns_tree_remove(ns);
 	dec_time_namespaces(ns->ucounts);
 	put_user_ns(ns->user_ns);
-	ns_free_inum(&ns->ns);
-	__free_page(ns->vvar_page);
-	kfree(ns);
-}
-
-static struct time_namespace *to_time_ns(struct ns_common *ns)
-{
-	return container_of(ns, struct time_namespace, ns);
+	ns_common_free(ns);
+	timens_vdso_free_vvar_page(ns);
+	/* Concurrent nstree traversal depends on a grace period. */
+	kfree_rcu(ns, ns.ns_rcu);
 }
 
 static struct ns_common *timens_get(struct task_struct *task)
 {
-	struct time_namespace *ns = NULL;
+	struct time_namespace *ns;
 	struct nsproxy *nsproxy;
 
-	task_lock(task);
+	guard(task_lock)(task);
 	nsproxy = task->nsproxy;
-	if (nsproxy) {
-		ns = nsproxy->time_ns;
-		get_time_ns(ns);
-	}
-	task_unlock(task);
+	if (!nsproxy)
+		return NULL;
 
-	return ns ? &ns->ns : NULL;
+	ns = nsproxy->time_ns;
+	get_time_ns(ns);
+	return &ns->ns;
 }
 
 static struct ns_common *timens_for_children_get(struct task_struct *task)
 {
-	struct time_namespace *ns = NULL;
+	struct time_namespace *ns;
 	struct nsproxy *nsproxy;
 
-	task_lock(task);
+	guard(task_lock)(task);
 	nsproxy = task->nsproxy;
-	if (nsproxy) {
-		ns = nsproxy->time_ns_for_children;
-		get_time_ns(ns);
-	}
-	task_unlock(task);
+	if (!nsproxy)
+		return NULL;
 
-	return ns ? &ns->ns : NULL;
+	ns = nsproxy->time_ns_for_children;
+	get_time_ns(ns);
+	return &ns->ns;
 }
 
 static void timens_put(struct ns_common *ns)
@@ -295,12 +187,6 @@ static void timens_put(struct ns_common *ns)
 	put_time_ns(to_time_ns(ns));
 }
 
-void timens_commit(struct task_struct *tsk, struct time_namespace *ns)
-{
-	timens_set_vvar_page(tsk, ns);
-	vdso_join_timens(tsk, ns);
-}
-
 static int timens_install(struct nsset *nsset, struct ns_common *new)
 {
 	struct nsproxy *nsproxy = nsset->nsproxy;
@@ -364,36 +250,33 @@ static void show_offset(struct seq_file *m, int clockid, struct timespec64 *ts)
 
 void proc_timens_show_offsets(struct task_struct *p, struct seq_file *m)
 {
-	struct ns_common *ns;
-	struct time_namespace *time_ns;
+	struct time_namespace *time_ns __free(time_ns) = NULL;
+	struct ns_common *ns = timens_for_children_get(p);
 
-	ns = timens_for_children_get(p);
 	if (!ns)
 		return;
+
 	time_ns = to_time_ns(ns);
 
 	show_offset(m, CLOCK_MONOTONIC, &time_ns->offsets.monotonic);
 	show_offset(m, CLOCK_BOOTTIME, &time_ns->offsets.boottime);
-	put_time_ns(time_ns);
 }
 
 int proc_timens_set_offset(struct file *file, struct task_struct *p,
 			   struct proc_timens_offset *offsets, int noffsets)
 {
-	struct ns_common *ns;
-	struct time_namespace *time_ns;
+	struct time_namespace *time_ns __free(time_ns) = NULL;
+	struct ns_common *ns = timens_for_children_get(p);
 	struct timespec64 tp;
-	int i, err;
+	int i;
 
-	ns = timens_for_children_get(p);
 	if (!ns)
 		return -ESRCH;
+
 	time_ns = to_time_ns(ns);
 
-	if (!file_ns_capable(file, time_ns->user_ns, CAP_SYS_TIME)) {
-		put_time_ns(time_ns);
+	if (!file_ns_capable(file, time_ns->user_ns, CAP_SYS_TIME))
 		return -EPERM;
-	}
 
 	for (i = 0; i < noffsets; i++) {
 		struct proc_timens_offset *off = &offsets[i];
@@ -406,15 +289,12 @@ int proc_timens_set_offset(struct file *file, struct task_struct *p,
 			ktime_get_boottime_ts64(&tp);
 			break;
 		default:
-			err = -EINVAL;
-			goto out;
+			return -EINVAL;
 		}
 
-		err = -ERANGE;
-
 		if (off->val.tv_sec > KTIME_SEC_MAX ||
 		    off->val.tv_sec < -KTIME_SEC_MAX)
-			goto out;
+			return -ERANGE;
 
 		tp = timespec64_add(tp, off->val);
 		/*
@@ -422,16 +302,13 @@ int proc_timens_set_offset(struct file *file, struct task_struct *p,
 		 * still unreachable.
 		 */
 		if (tp.tv_sec < 0 || tp.tv_sec > KTIME_SEC_MAX / 2)
-			goto out;
+			return -ERANGE;
 	}
 
-	mutex_lock(&offset_lock);
-	if (time_ns->frozen_offsets) {
-		err = -EACCES;
-		goto out_unlock;
-	}
+	guard(mutex)(&timens_offset_lock);
+	if (time_ns->frozen_offsets)
+		return -EACCES;
 
-	err = 0;
 	/* Don't report errors after this line */
 	for (i = 0; i < noffsets; i++) {
 		struct proc_timens_offset *off = &offsets[i];
@@ -449,17 +326,11 @@ int proc_timens_set_offset(struct file *file, struct task_struct *p,
 		*offset = off->val;
 	}
 
-out_unlock:
-	mutex_unlock(&offset_lock);
-out:
-	put_time_ns(time_ns);
-
-	return err;
+	return 0;
 }
 
 const struct proc_ns_operations timens_operations = {
 	.name		= "time",
-	.type		= CLONE_NEWTIME,
 	.get		= timens_get,
 	.put		= timens_put,
 	.install	= timens_install,
@@ -469,7 +340,6 @@ const struct proc_ns_operations timens_operations = {
 const struct proc_ns_operations timens_for_children_operations = {
 	.name		= "time_for_children",
 	.real_ns_name	= "time",
-	.type		= CLONE_NEWTIME,
 	.get		= timens_for_children_get,
 	.put		= timens_put,
 	.install	= timens_install,
@@ -477,9 +347,12 @@ const struct proc_ns_operations timens_for_children_operations = {
 };
 
 struct time_namespace init_time_ns = {
-	.ns.count	= REFCOUNT_INIT(3),
+	.ns		= NS_COMMON_INIT(init_time_ns),
 	.user_ns	= &init_user_ns,
-	.ns.inum	= PROC_TIME_INIT_INO,
-	.ns.ops		= &timens_operations,
 	.frozen_offsets	= true,
 };
+
+void __init time_ns_init(void)
+{
+	ns_tree_add(&init_time_ns);
+}