[PATCH] namespaces: utsname: implement CLONE_NEWUTS flag

Implement a CLONE_NEWUTS flag, and use it at clone and sys_unshare.

[clg@fr.ibm.com: IPC unshare fix]
[bunk@stusta.de: cleanup]
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 17 insertions, 3 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 33fcf0733ca6..c08cf05dd59b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1607,13 +1607,14 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
         struct files_struct *fd, *new_fd = NULL;
         struct sem_undo_list *new_ulist = NULL;
         struct nsproxy *new_nsproxy, *old_nsproxy;
+        struct uts_namespace *uts, *new_uts = NULL;
 
         check_unshare_flags(&unshare_flags);
 
         /* Return -EINVAL for all unsupported flags */
         err = -EINVAL;
         if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
-                                CLONE_VM|CLONE_FILES|CLONE_SYSVSEM))
+                                CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|CLONE_NEWUTS))
                 goto bad_unshare_out;
 
         if ((err = unshare_thread(unshare_flags)))
@@ -1630,14 +1631,17 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
                 goto bad_unshare_cleanup_vm;
         if ((err = unshare_semundo(unshare_flags, &new_ulist)))
                 goto bad_unshare_cleanup_fd;
+        if ((err = unshare_utsname(unshare_flags, &new_uts)))
+                goto bad_unshare_cleanup_semundo;
 
-        if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist) {
+        if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist ||
+                                new_uts) {
 
                 old_nsproxy = current->nsproxy;
                 new_nsproxy = dup_namespaces(old_nsproxy);
                 if (!new_nsproxy) {
                         err = -ENOMEM;
-                        goto bad_unshare_cleanup_semundo;
+                        goto bad_unshare_cleanup_uts;
                 }
 
                 task_lock(current);
@@ -1676,10 +1680,20 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
                         new_fd = fd;
                 }
 
+                if (new_uts) {
+                        uts = current->nsproxy->uts_ns;
+                        current->nsproxy->uts_ns = new_uts;
+                        new_uts = uts;
+                }
+
                 task_unlock(current);
                 put_nsproxy(old_nsproxy);
         }
 
+bad_unshare_cleanup_uts:
+        if (new_uts)
+                put_uts_ns(new_uts);
+
 bad_unshare_cleanup_semundo:
 bad_unshare_cleanup_fd:
         if (new_fd)