Commit 071df104 authored by Serge E. Hallyn's avatar Serge E. Hallyn Committed by Linus Torvalds

[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: default avatarSerge 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: default avatarAdrian Bunk <bunk@stusta.de>
Signed-off-by: default avatarCedric Le Goater <clg@fr.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent bf47fdcd
......@@ -24,6 +24,7 @@
#define CLONE_UNTRACED 0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */
#define CLONE_CHILD_SETTID 0x01000000 /* set the TID in the child */
#define CLONE_STOPPED 0x02000000 /* Start in stopped state */
#define CLONE_NEWUTS 0x04000000 /* New utsname group? */
/*
* Scheduling policies
......
......@@ -47,6 +47,8 @@ static inline void get_uts_ns(struct uts_namespace *ns)
}
#ifdef CONFIG_UTS_NS
extern int unshare_utsname(unsigned long unshare_flags,
struct uts_namespace **new_uts);
extern int copy_utsname(int flags, struct task_struct *tsk);
extern void free_uts_ns(struct kref *kref);
......@@ -55,6 +57,15 @@ static inline void put_uts_ns(struct uts_namespace *ns)
kref_put(&ns->kref, free_uts_ns);
}
#else
static inline int unshare_utsname(unsigned long unshare_flags,
struct uts_namespace **new_uts)
{
if (unshare_flags & CLONE_NEWUTS)
return -EINVAL;
return 0;
}
static inline int copy_utsname(int flags, struct task_struct *tsk)
{
return 0;
......
......@@ -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)
......
......@@ -82,7 +82,7 @@ int copy_namespaces(int flags, struct task_struct *tsk)
get_nsproxy(old_ns);
if (!(flags & CLONE_NEWNS))
if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS)))
return 0;
new_ns = clone_namespaces(old_ns);
......
......@@ -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;
}
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment