X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Futsname.c;h=c859164a699311a10021f37f06c369e34ac4f4d5;hb=44f549217cd26daf7063984ae4ee6e46beca9c41;hp=1824384ecfa3225f11b1a30b0e9f79dea3c46327;hpb=4865ecf1315b450ab3317a745a6678c04d311e40;p=linux-2.6

diff --git a/kernel/utsname.c b/kernel/utsname.c
index 1824384ecf..c859164a69 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -14,6 +14,41 @@
 #include <linux/utsname.h>
 #include <linux/version.h>
 
+/*
+ * Clone a new ns copying an original utsname, setting refcount to 1
+ * @old_ns: namespace to clone
+ * Return NULL on error (failure to kmalloc), new ns otherwise
+ */
+static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
+{
+	struct uts_namespace *ns;
+
+	ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
+	if (ns) {
+		memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+		kref_init(&ns->kref);
+	}
+	return ns;
+}
+
+/*
+ * unshare the current process' utsname namespace.
+ * called only in sys_unshare()
+ */
+int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts)
+{
+	if (unshare_flags & CLONE_NEWUTS) {
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		*new_uts = clone_uts_ns(current->nsproxy->uts_ns);
+		if (!*new_uts)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
 /*
  * Copy task tsk's utsname namespace, or clone it if flags
  * specifies CLONE_NEWUTS.  In latter case, changes to the
@@ -23,6 +58,7 @@
 int copy_utsname(int flags, struct task_struct *tsk)
 {
 	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
+	struct uts_namespace *new_ns;
 	int err = 0;
 
 	if (!old_ns)
@@ -30,6 +66,23 @@ int copy_utsname(int flags, struct task_struct *tsk)
 
 	get_uts_ns(old_ns);
 
+	if (!(flags & CLONE_NEWUTS))
+		return 0;
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		err = -EPERM;
+		goto out;
+	}
+
+	new_ns = clone_uts_ns(old_ns);
+	if (!new_ns) {
+		err = -ENOMEM;
+		goto out;
+	}
+	tsk->nsproxy->uts_ns = new_ns;
+
+out:
+	put_uts_ns(old_ns);
 	return err;
 }