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authorBadari Pulavarty <pbadari@us.ibm.com>2007-05-08 00:25:21 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:00 -0700
commite3222c4ecc649c4ae568e61dda9349482401b501 (patch)
treed96614ef67d947a3dd8ab0929a4755bce9fdbcc1 /kernel
parent4fc75ff4816c3483b4b772b2f6cb3d8fd88ca547 (diff)
downloadlinux-e3222c4ecc649c4ae568e61dda9349482401b501.tar.bz2
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/fork.c85
-rw-r--r--kernel/nsproxy.c139
-rw-r--r--kernel/pid.c11
-rw-r--r--kernel/utsname.c41
4 files changed, 98 insertions, 178 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index b7d169def942..fd211b9dddd4 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1516,26 +1516,6 @@ static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
}
/*
- * 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 @@ static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **n
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 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
{
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 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
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 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
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 @@ 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;
- }
-
- 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 @@ bad_unshare_cleanup_sigh:
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 f5b9ee6f6bbb..1bc4b55241a8 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -38,10 +38,8 @@ void get_task_namespaces(struct task_struct *tsk)
/*
* 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 @@ static inline struct nsproxy *clone_namespaces(struct nsproxy *orig)
}
/*
- * 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 @@ int copy_namespaces(int flags, struct task_struct *tsk)
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;
}
- 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;
+ 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;
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 @@ void free_nsproxy(struct nsproxy *ns)
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 9c80bc23d6b8..d3ad724afa83 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -360,16 +360,11 @@ struct pid *find_ge_pid(int nr)
}
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 c859164a6993..160c8c5136bd 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -32,58 +32,25 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_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
* 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)