Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 180 insertions, 0 deletions

diff --git a/kernel/utsname.c b/kernel/utsname.c
new file mode 100644
index 000000000..e488d0e2a
--- /dev/null
+++ b/kernel/utsname.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Copyright (C) 2004 IBM Corporation
+ *
+ *  Author: Serge Hallyn <serue@us.ibm.com>
+ */
+
+#include <linux/export.h>
+#include <linux/uts.h>
+#include <linux/utsname.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/cred.h>
+#include <linux/user_namespace.h>
+#include <linux/proc_ns.h>
+#include <linux/sched/task.h>
+
+static struct kmem_cache *uts_ns_cache __ro_after_init;
+
+static struct ucounts *inc_uts_namespaces(struct user_namespace *ns)
+{
+	return inc_ucount(ns, current_euid(), UCOUNT_UTS_NAMESPACES);
+}
+
+static void dec_uts_namespaces(struct ucounts *ucounts)
+{
+	dec_ucount(ucounts, UCOUNT_UTS_NAMESPACES);
+}
+
+static struct uts_namespace *create_uts_ns(void)
+{
+	struct uts_namespace *uts_ns;
+
+	uts_ns = kmem_cache_alloc(uts_ns_cache, GFP_KERNEL);
+	if (uts_ns)
+		kref_init(&uts_ns->kref);
+	return uts_ns;
+}
+
+/*
+ * Clone a new ns copying an original utsname, setting refcount to 1
+ * @old_ns: namespace to clone
+ * Return ERR_PTR(-ENOMEM) on error (failure to allocate), new ns otherwise
+ */
+static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
+					  struct uts_namespace *old_ns)
+{
+	struct uts_namespace *ns;
+	struct ucounts *ucounts;
+	int err;
+
+	err = -ENOSPC;
+	ucounts = inc_uts_namespaces(user_ns);
+	if (!ucounts)
+		goto fail;
+
+	err = -ENOMEM;
+	ns = create_uts_ns();
+	if (!ns)
+		goto fail_dec;
+
+	err = ns_alloc_inum(&ns->ns);
+	if (err)
+		goto fail_free;
+
+	ns->ucounts = ucounts;
+	ns->ns.ops = &utsns_operations;
+
+	down_read(&uts_sem);
+	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+	ns->user_ns = get_user_ns(user_ns);
+	up_read(&uts_sem);
+	return ns;
+
+fail_free:
+	kmem_cache_free(uts_ns_cache, ns);
+fail_dec:
+	dec_uts_namespaces(ucounts);
+fail:
+	return ERR_PTR(err);
+}
+
+/*
+ * Copy task tsk's utsname namespace, or clone it if flags
+ * specifies CLONE_NEWUTS.  In latter case, changes to the
+ * utsname of this process won't be seen by parent, and vice
+ * versa.
+ */
+struct uts_namespace *copy_utsname(unsigned long flags,
+	struct user_namespace *user_ns, struct uts_namespace *old_ns)
+{
+	struct uts_namespace *new_ns;
+
+	BUG_ON(!old_ns);
+	get_uts_ns(old_ns);
+
+	if (!(flags & CLONE_NEWUTS))
+		return old_ns;
+
+	new_ns = clone_uts_ns(user_ns, old_ns);
+
+	put_uts_ns(old_ns);
+	return new_ns;
+}
+
+void free_uts_ns(struct kref *kref)
+{
+	struct uts_namespace *ns;
+
+	ns = container_of(kref, struct uts_namespace, kref);
+	dec_uts_namespaces(ns->ucounts);
+	put_user_ns(ns->user_ns);
+	ns_free_inum(&ns->ns);
+	kmem_cache_free(uts_ns_cache, ns);
+}
+
+static inline struct uts_namespace *to_uts_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct uts_namespace, ns);
+}
+
+static struct ns_common *utsns_get(struct task_struct *task)
+{
+	struct uts_namespace *ns = NULL;
+	struct nsproxy *nsproxy;
+
+	task_lock(task);
+	nsproxy = task->nsproxy;
+	if (nsproxy) {
+		ns = nsproxy->uts_ns;
+		get_uts_ns(ns);
+	}
+	task_unlock(task);
+
+	return ns ? &ns->ns : NULL;
+}
+
+static void utsns_put(struct ns_common *ns)
+{
+	put_uts_ns(to_uts_ns(ns));
+}
+
+static int utsns_install(struct nsset *nsset, struct ns_common *new)
+{
+	struct nsproxy *nsproxy = nsset->nsproxy;
+	struct uts_namespace *ns = to_uts_ns(new);
+
+	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
+	    !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	get_uts_ns(ns);
+	put_uts_ns(nsproxy->uts_ns);
+	nsproxy->uts_ns = ns;
+	return 0;
+}
+
+static struct user_namespace *utsns_owner(struct ns_common *ns)
+{
+	return to_uts_ns(ns)->user_ns;
+}
+
+const struct proc_ns_operations utsns_operations = {
+	.name		= "uts",
+	.type		= CLONE_NEWUTS,
+	.get		= utsns_get,
+	.put		= utsns_put,
+	.install	= utsns_install,
+	.owner		= utsns_owner,
+};
+
+void __init uts_ns_init(void)
+{
+	uts_ns_cache = kmem_cache_create_usercopy(
+			"uts_namespace", sizeof(struct uts_namespace), 0,
+			SLAB_PANIC|SLAB_ACCOUNT,
+			offsetof(struct uts_namespace, name),
+			sizeof_field(struct uts_namespace, name),
+			NULL);
+}