change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/ipc/namespace.c
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@@ -42,7 +42,7 @@
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 		goto fail;
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 	err = -ENOMEM;
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-	ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
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+	ns = kzalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
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 	if (ns == NULL)
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 		goto fail_dec;
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@@ -117,6 +117,10 @@
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 static void free_ipc_ns(struct ipc_namespace *ns)
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 {
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+	/* mq_put_mnt() waits for a grace period as kern_unmount()
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+	 * uses synchronize_rcu().
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+	 */
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+	mq_put_mnt(ns);
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 	sem_exit_ns(ns);
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 	msg_exit_ns(ns);
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 	shm_exit_ns(ns);
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@@ -126,6 +130,21 @@
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 	ns_free_inum(&ns->ns);
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 	kfree(ns);
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 }
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+
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+static LLIST_HEAD(free_ipc_list);
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+static void free_ipc(struct work_struct *unused)
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+{
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+	struct llist_node *node = llist_del_all(&free_ipc_list);
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+	struct ipc_namespace *n, *t;
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+
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+	llist_for_each_entry_safe(n, t, node, mnt_llist)
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+		free_ipc_ns(n);
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+}
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+
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+/*
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+ * The work queue is used to avoid the cost of synchronize_rcu in kern_unmount.
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+ */
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+static DECLARE_WORK(free_ipc_work, free_ipc);
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 /*
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  * put_ipc_ns - drop a reference to an ipc namespace.
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@@ -148,8 +167,9 @@
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 	if (refcount_dec_and_lock(&ns->count, &mq_lock)) {
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 		mq_clear_sbinfo(ns);
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 		spin_unlock(&mq_lock);
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-		mq_put_mnt(ns);
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-		free_ipc_ns(ns);
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+
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+		if (llist_add(&ns->mnt_llist, &free_ipc_list))
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+			schedule_work(&free_ipc_work);
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 	}
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 }
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@@ -177,15 +197,14 @@
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 	return put_ipc_ns(to_ipc_ns(ns));
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 }
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-static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new)
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+static int ipcns_install(struct nsset *nsset, struct ns_common *new)
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 {
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+	struct nsproxy *nsproxy = nsset->nsproxy;
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 	struct ipc_namespace *ns = to_ipc_ns(new);
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 	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
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-	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
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+	    !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
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 		return -EPERM;
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-	/* Ditch state from the old ipc namespace */
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-	exit_sem(current);
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 	put_ipc_ns(nsproxy->ipc_ns);
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 	nsproxy->ipc_ns = get_ipc_ns(ns);
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 	return 0;