Merge sys_clone()/sys_unshare() nsproxy and namespace handling
sys_clone() and sys_unshare() both makes copies of nsproxy and its associated
namespaces. But they have different code paths.
This patch merges all the nsproxy and its associated namespace copy/clone
handling (as much as possible). Posted on container list earlier for
feedback.
- Create a new nsproxy and its associated namespaces and pass it back to
caller to attach it to right process.
- Changed all copy_*_ns() routines to return a new copy of namespace
instead of attaching it to task->nsproxy.
- Moved the CAP_SYS_ADMIN checks out of copy_*_ns() routines.
- Removed unnessary !ns checks from copy_*_ns() and added BUG_ON()
just incase.
- Get rid of all individual unshare_*_ns() routines and make use of
copy_*_ns() instead.
[akpm@osdl.org: cleanups, warning fix]
[clg@fr.ibm.com: remove dup_namespaces() declaration]
[serue@us.ibm.com: fix CONFIG_IPC_NS=n, clone(CLONE_NEWIPC) retval]
[akpm@linux-foundation.org: fix build with CONFIG_SYSVIPC=n]
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <containers@lists.osdl.org>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/namespace.c b/fs/namespace.c
index fd999ca..be5e56b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1441,10 +1441,9 @@
* Allocate a new namespace structure and populate it with contents
* copied from the namespace of the passed in task structure.
*/
-struct mnt_namespace *dup_mnt_ns(struct task_struct *tsk,
+static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
struct fs_struct *fs)
{
- struct mnt_namespace *mnt_ns = tsk->nsproxy->mnt_ns;
struct mnt_namespace *new_ns;
struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL;
struct vfsmount *p, *q;
@@ -1509,36 +1508,21 @@
return new_ns;
}
-int copy_mnt_ns(int flags, struct task_struct *tsk)
+struct mnt_namespace *copy_mnt_ns(int flags, struct mnt_namespace *ns,
+ struct fs_struct *new_fs)
{
- struct mnt_namespace *ns = tsk->nsproxy->mnt_ns;
struct mnt_namespace *new_ns;
- int err = 0;
- if (!ns)
- return 0;
-
+ BUG_ON(!ns);
get_mnt_ns(ns);
if (!(flags & CLONE_NEWNS))
- return 0;
+ return ns;
- if (!capable(CAP_SYS_ADMIN)) {
- err = -EPERM;
- goto out;
- }
+ new_ns = dup_mnt_ns(ns, new_fs);
- new_ns = dup_mnt_ns(tsk, tsk->fs);
- if (!new_ns) {
- err = -ENOMEM;
- goto out;
- }
-
- tsk->nsproxy->mnt_ns = new_ns;
-
-out:
put_mnt_ns(ns);
- return err;
+ return new_ns;
}
asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name,
diff --git a/include/linux/ipc.h b/include/linux/ipc.h
index 6da6772..1980867 100644
--- a/include/linux/ipc.h
+++ b/include/linux/ipc.h
@@ -92,16 +92,19 @@
#ifdef CONFIG_SYSVIPC
#define INIT_IPC_NS(ns) .ns = &init_ipc_ns,
-extern int copy_ipcs(unsigned long flags, struct task_struct *tsk);
+extern struct ipc_namespace *copy_ipcs(unsigned long flags,
+ struct ipc_namespace *ns);
#else
#define INIT_IPC_NS(ns)
-static inline int copy_ipcs(unsigned long flags, struct task_struct *tsk)
-{ return 0; }
+static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
+ struct ipc_namespace *ns)
+{
+ return ns;
+}
#endif
#ifdef CONFIG_IPC_NS
extern void free_ipc_ns(struct kref *kref);
-extern int unshare_ipcs(unsigned long flags, struct ipc_namespace **ns);
#endif
static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
diff --git a/include/linux/mnt_namespace.h b/include/linux/mnt_namespace.h
index 4af0b1f..1fa4d98 100644
--- a/include/linux/mnt_namespace.h
+++ b/include/linux/mnt_namespace.h
@@ -14,10 +14,9 @@
int event;
};
-extern int copy_mnt_ns(int, struct task_struct *);
-extern void __put_mnt_ns(struct mnt_namespace *ns);
-extern struct mnt_namespace *dup_mnt_ns(struct task_struct *,
+extern struct mnt_namespace *copy_mnt_ns(int, struct mnt_namespace *,
struct fs_struct *);
+extern void __put_mnt_ns(struct mnt_namespace *ns);
static inline void put_mnt_ns(struct mnt_namespace *ns)
{
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 0b9f0dc..189e0dc 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -31,10 +31,11 @@
};
extern struct nsproxy init_nsproxy;
-struct nsproxy *dup_namespaces(struct nsproxy *orig);
int copy_namespaces(int flags, struct task_struct *tsk);
void get_task_namespaces(struct task_struct *tsk);
void free_nsproxy(struct nsproxy *ns);
+int unshare_nsproxy_namespaces(unsigned long, struct nsproxy **,
+ struct fs_struct *);
static inline void put_nsproxy(struct nsproxy *ns)
{
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 2833806..169c6c2 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -29,7 +29,7 @@
kref_get(&ns->kref);
}
-extern int copy_pid_ns(int flags, struct task_struct *tsk);
+extern struct pid_namespace *copy_pid_ns(int flags, struct pid_namespace *ns);
extern void free_pid_ns(struct kref *kref);
static inline void put_pid_ns(struct pid_namespace *ns)
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index e10267d..f8d3b32 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -49,9 +49,7 @@
}
#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 struct uts_namespace *copy_utsname(int flags, struct uts_namespace *ns);
extern void free_uts_ns(struct kref *kref);
static inline void put_uts_ns(struct uts_namespace *ns)
@@ -59,21 +57,12 @@
kref_put(&ns->kref, free_uts_ns);
}
#else
-static inline int unshare_utsname(unsigned long unshare_flags,
- struct uts_namespace **new_uts)
+static inline struct uts_namespace *copy_utsname(int flags,
+ struct uts_namespace *ns)
{
- if (unshare_flags & CLONE_NEWUTS)
- return -EINVAL;
-
- return 0;
+ return ns;
}
-static inline int copy_utsname(int flags, struct task_struct *tsk)
-{
- if (flags & CLONE_NEWUTS)
- return -EINVAL;
- return 0;
-}
static inline void put_uts_ns(struct uts_namespace *ns)
{
}
diff --git a/ipc/util.c b/ipc/util.c
index 0b65238..0ad5b1c 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -85,53 +85,20 @@
return ERR_PTR(err);
}
-int unshare_ipcs(unsigned long unshare_flags, struct ipc_namespace **new_ipc)
+struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
{
- struct ipc_namespace *new;
-
- if (unshare_flags & CLONE_NEWIPC) {
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- new = clone_ipc_ns(current->nsproxy->ipc_ns);
- if (IS_ERR(new))
- return PTR_ERR(new);
-
- *new_ipc = new;
- }
-
- return 0;
-}
-
-int copy_ipcs(unsigned long flags, struct task_struct *tsk)
-{
- struct ipc_namespace *old_ns = tsk->nsproxy->ipc_ns;
struct ipc_namespace *new_ns;
- int err = 0;
- if (!old_ns)
- return 0;
-
- get_ipc_ns(old_ns);
+ BUG_ON(!ns);
+ get_ipc_ns(ns);
if (!(flags & CLONE_NEWIPC))
- return 0;
+ return ns;
- if (!capable(CAP_SYS_ADMIN)) {
- err = -EPERM;
- goto out;
- }
+ new_ns = clone_ipc_ns(ns);
- new_ns = clone_ipc_ns(old_ns);
- if (!new_ns) {
- err = -ENOMEM;
- goto out;
- }
-
- tsk->nsproxy->ipc_ns = new_ns;
-out:
- put_ipc_ns(old_ns);
- return err;
+ put_ipc_ns(ns);
+ return new_ns;
}
void free_ipc_ns(struct kref *kref)
@@ -145,11 +112,11 @@
kfree(ns);
}
#else
-int copy_ipcs(unsigned long flags, struct task_struct *tsk)
+struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
{
if (flags & CLONE_NEWIPC)
- return -EINVAL;
- return 0;
+ return ERR_PTR(-EINVAL);
+ return ns;
}
#endif
diff --git a/kernel/fork.c b/kernel/fork.c
index b7d169d..fd211b9 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1516,26 +1516,6 @@
}
/*
- * Unshare the mnt_namespace structure if it is being shared
- */
-static int unshare_mnt_namespace(unsigned long unshare_flags,
- struct mnt_namespace **new_nsp, struct fs_struct *new_fs)
-{
- struct mnt_namespace *ns = current->nsproxy->mnt_ns;
-
- if ((unshare_flags & CLONE_NEWNS) && ns) {
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- *new_nsp = dup_mnt_ns(current, new_fs ? new_fs : current->fs);
- if (!*new_nsp)
- return -ENOMEM;
- }
-
- return 0;
-}
-
-/*
* Unsharing of sighand is not supported yet
*/
static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp)
@@ -1593,16 +1573,6 @@
return 0;
}
-#ifndef CONFIG_IPC_NS
-static inline int unshare_ipcs(unsigned long flags, struct ipc_namespace **ns)
-{
- if (flags & CLONE_NEWIPC)
- return -EINVAL;
-
- return 0;
-}
-#endif
-
/*
* unshare allows a process to 'unshare' part of the process
* context which was originally shared using clone. copy_*
@@ -1615,14 +1585,11 @@
{
int err = 0;
struct fs_struct *fs, *new_fs = NULL;
- struct mnt_namespace *ns, *new_ns = NULL;
struct sighand_struct *new_sigh = NULL;
struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL;
struct files_struct *fd, *new_fd = NULL;
struct sem_undo_list *new_ulist = NULL;
struct nsproxy *new_nsproxy = NULL, *old_nsproxy = NULL;
- struct uts_namespace *uts, *new_uts = NULL;
- struct ipc_namespace *ipc, *new_ipc = NULL;
check_unshare_flags(&unshare_flags);
@@ -1637,36 +1604,24 @@
goto bad_unshare_out;
if ((err = unshare_fs(unshare_flags, &new_fs)))
goto bad_unshare_cleanup_thread;
- if ((err = unshare_mnt_namespace(unshare_flags, &new_ns, new_fs)))
- goto bad_unshare_cleanup_fs;
if ((err = unshare_sighand(unshare_flags, &new_sigh)))
- goto bad_unshare_cleanup_ns;
+ goto bad_unshare_cleanup_fs;
if ((err = unshare_vm(unshare_flags, &new_mm)))
goto bad_unshare_cleanup_sigh;
if ((err = unshare_fd(unshare_flags, &new_fd)))
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)))
+ if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
+ new_fs)))
goto bad_unshare_cleanup_semundo;
- if ((err = unshare_ipcs(unshare_flags, &new_ipc)))
- goto bad_unshare_cleanup_uts;
- if (new_ns || new_uts || new_ipc) {
- old_nsproxy = current->nsproxy;
- new_nsproxy = dup_namespaces(old_nsproxy);
- if (!new_nsproxy) {
- err = -ENOMEM;
- goto bad_unshare_cleanup_ipc;
- }
- }
-
- if (new_fs || new_ns || new_mm || new_fd || new_ulist ||
- new_uts || new_ipc) {
+ if (new_fs || new_mm || new_fd || new_ulist || new_nsproxy) {
task_lock(current);
if (new_nsproxy) {
+ old_nsproxy = current->nsproxy;
current->nsproxy = new_nsproxy;
new_nsproxy = old_nsproxy;
}
@@ -1677,12 +1632,6 @@
new_fs = fs;
}
- if (new_ns) {
- ns = current->nsproxy->mnt_ns;
- current->nsproxy->mnt_ns = new_ns;
- new_ns = ns;
- }
-
if (new_mm) {
mm = current->mm;
active_mm = current->active_mm;
@@ -1698,32 +1647,12 @@
new_fd = fd;
}
- if (new_uts) {
- uts = current->nsproxy->uts_ns;
- current->nsproxy->uts_ns = new_uts;
- new_uts = uts;
- }
-
- if (new_ipc) {
- ipc = current->nsproxy->ipc_ns;
- current->nsproxy->ipc_ns = new_ipc;
- new_ipc = ipc;
- }
-
task_unlock(current);
}
if (new_nsproxy)
put_nsproxy(new_nsproxy);
-bad_unshare_cleanup_ipc:
- if (new_ipc)
- put_ipc_ns(new_ipc);
-
-bad_unshare_cleanup_uts:
- if (new_uts)
- put_uts_ns(new_uts);
-
bad_unshare_cleanup_semundo:
bad_unshare_cleanup_fd:
if (new_fd)
@@ -1738,10 +1667,6 @@
if (atomic_dec_and_test(&new_sigh->count))
kmem_cache_free(sighand_cachep, new_sigh);
-bad_unshare_cleanup_ns:
- if (new_ns)
- put_mnt_ns(new_ns);
-
bad_unshare_cleanup_fs:
if (new_fs)
put_fs_struct(new_fs);
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index f5b9ee6..1bc4b55 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -38,10 +38,8 @@
/*
* creates a copy of "orig" with refcount 1.
- * This does not grab references to the contained namespaces,
- * so that needs to be done by dup_namespaces.
*/
-static inline struct nsproxy *clone_namespaces(struct nsproxy *orig)
+static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
{
struct nsproxy *ns;
@@ -52,26 +50,49 @@
}
/*
- * copies the nsproxy, setting refcount to 1, and grabbing a
- * reference to all contained namespaces. Called from
- * sys_unshare()
+ * Create new nsproxy and all of its the associated namespaces.
+ * Return the newly created nsproxy. Do not attach this to the task,
+ * leave it to the caller to do proper locking and attach it to task.
*/
-struct nsproxy *dup_namespaces(struct nsproxy *orig)
+static struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk,
+ struct fs_struct *new_fs)
{
- struct nsproxy *ns = clone_namespaces(orig);
+ struct nsproxy *new_nsp;
- if (ns) {
- if (ns->mnt_ns)
- get_mnt_ns(ns->mnt_ns);
- if (ns->uts_ns)
- get_uts_ns(ns->uts_ns);
- if (ns->ipc_ns)
- get_ipc_ns(ns->ipc_ns);
- if (ns->pid_ns)
- get_pid_ns(ns->pid_ns);
- }
+ new_nsp = clone_nsproxy(tsk->nsproxy);
+ if (!new_nsp)
+ return ERR_PTR(-ENOMEM);
- return ns;
+ new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
+ if (IS_ERR(new_nsp->mnt_ns))
+ goto out_ns;
+
+ new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
+ if (IS_ERR(new_nsp->uts_ns))
+ goto out_uts;
+
+ new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
+ if (IS_ERR(new_nsp->ipc_ns))
+ goto out_ipc;
+
+ new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
+ if (IS_ERR(new_nsp->pid_ns))
+ goto out_pid;
+
+ return new_nsp;
+
+out_pid:
+ if (new_nsp->ipc_ns)
+ put_ipc_ns(new_nsp->ipc_ns);
+out_ipc:
+ if (new_nsp->uts_ns)
+ put_uts_ns(new_nsp->uts_ns);
+out_uts:
+ if (new_nsp->mnt_ns)
+ put_mnt_ns(new_nsp->mnt_ns);
+out_ns:
+ kfree(new_nsp);
+ return ERR_PTR(-ENOMEM);
}
/*
@@ -92,47 +113,21 @@
if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
return 0;
- new_ns = clone_namespaces(old_ns);
- if (!new_ns) {
- err = -ENOMEM;
+ if (!capable(CAP_SYS_ADMIN)) {
+ err = -EPERM;
+ goto out;
+ }
+
+ new_ns = create_new_namespaces(flags, tsk, tsk->fs);
+ if (IS_ERR(new_ns)) {
+ err = PTR_ERR(new_ns);
goto out;
}
tsk->nsproxy = new_ns;
-
- err = copy_mnt_ns(flags, tsk);
- if (err)
- goto out_ns;
-
- err = copy_utsname(flags, tsk);
- if (err)
- goto out_uts;
-
- err = copy_ipcs(flags, tsk);
- if (err)
- goto out_ipc;
-
- err = copy_pid_ns(flags, tsk);
- if (err)
- goto out_pid;
-
out:
put_nsproxy(old_ns);
return err;
-
-out_pid:
- if (new_ns->ipc_ns)
- put_ipc_ns(new_ns->ipc_ns);
-out_ipc:
- if (new_ns->uts_ns)
- put_uts_ns(new_ns->uts_ns);
-out_uts:
- if (new_ns->mnt_ns)
- put_mnt_ns(new_ns->mnt_ns);
-out_ns:
- tsk->nsproxy = old_ns;
- kfree(new_ns);
- goto out;
}
void free_nsproxy(struct nsproxy *ns)
@@ -147,3 +142,41 @@
put_pid_ns(ns->pid_ns);
kfree(ns);
}
+
+/*
+ * Called from unshare. Unshare all the namespaces part of nsproxy.
+ * On sucess, returns the new nsproxy and a reference to old nsproxy
+ * to make sure it stays around.
+ */
+int unshare_nsproxy_namespaces(unsigned long unshare_flags,
+ struct nsproxy **new_nsp, struct fs_struct *new_fs)
+{
+ struct nsproxy *old_ns = current->nsproxy;
+ int err = 0;
+
+ if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
+ return 0;
+
+#ifndef CONFIG_IPC_NS
+ if (unshare_flags & CLONE_NEWIPC)
+ return -EINVAL;
+#endif
+
+#ifndef CONFIG_UTS_NS
+ if (unshare_flags & CLONE_NEWUTS)
+ return -EINVAL;
+#endif
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ get_nsproxy(old_ns);
+
+ *new_nsp = create_new_namespaces(unshare_flags, current,
+ new_fs ? new_fs : current->fs);
+ if (IS_ERR(*new_nsp)) {
+ err = PTR_ERR(*new_nsp);
+ put_nsproxy(old_ns);
+ }
+ return err;
+}
diff --git a/kernel/pid.c b/kernel/pid.c
index 9c80bc2..d3ad724 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -360,16 +360,11 @@
}
EXPORT_SYMBOL_GPL(find_get_pid);
-int copy_pid_ns(int flags, struct task_struct *tsk)
+struct pid_namespace *copy_pid_ns(int flags, struct pid_namespace *old_ns)
{
- struct pid_namespace *old_ns = tsk->nsproxy->pid_ns;
- int err = 0;
-
- if (!old_ns)
- return 0;
-
+ BUG_ON(!old_ns);
get_pid_ns(old_ns);
- return err;
+ return old_ns;
}
void free_pid_ns(struct kref *kref)
diff --git a/kernel/utsname.c b/kernel/utsname.c
index c859164..160c8c5 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -32,58 +32,25 @@
}
/*
- * 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
* utsname of this process won't be seen by parent, and vice
* versa.
*/
-int copy_utsname(int flags, struct task_struct *tsk)
+struct uts_namespace *copy_utsname(int flags, struct uts_namespace *old_ns)
{
- struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
struct uts_namespace *new_ns;
- int err = 0;
- if (!old_ns)
- return 0;
-
+ BUG_ON(!old_ns);
get_uts_ns(old_ns);
if (!(flags & CLONE_NEWUTS))
- return 0;
-
- if (!capable(CAP_SYS_ADMIN)) {
- err = -EPERM;
- goto out;
- }
+ return old_ns;
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;
+ return new_ns;
}
void free_uts_ns(struct kref *kref)