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Subject[PATCH] add pid->user_ns
[ Here is the patch which you'd need to be able to add the boot
check against pid_ns ]

This will allow us to check whether a task has privilege over the
pid namespace.

Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
include/linux/pid_namespace.h | 9 +++++++--
kernel/nsproxy.c | 2 +-
kernel/pid.c | 1 +
kernel/pid_namespace.c | 13 ++++++++++---
4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 38d1032..c1b5a48 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -7,6 +7,9 @@
#include <linux/nsproxy.h>
#include <linux/kref.h>

+struct user_namespace;
+extern struct user_namespace init_user_ns;
+
struct pidmap {
atomic_t nr_free;
void *page;
@@ -30,6 +33,7 @@ struct pid_namespace {
#ifdef CONFIG_BSD_PROCESS_ACCT
struct bsd_acct_struct *bacct;
#endif
+ struct user_namespace *user_ns;
};

extern struct pid_namespace init_pid_ns;
@@ -42,7 +46,7 @@ static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
return ns;
}

-extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *ns);
+extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct task_struct *tsk);
extern void free_pid_ns(struct kref *kref);
extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);

@@ -61,8 +65,9 @@ static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
}

static inline struct pid_namespace *
-copy_pid_ns(unsigned long flags, struct pid_namespace *ns)
+copy_pid_ns(unsigned long flags, struct task_struct *tsk)
{
+ struct pid_namespace *ns = task_active_pid_ns(tsk);
if (flags & CLONE_NEWPID)
ns = ERR_PTR(-EINVAL);
return ns;
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 9aeab4b..97e21ea 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -84,7 +84,7 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
goto out_ipc;
}

- new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
+ new_nsp->pid_ns = copy_pid_ns(flags, tsk);
if (IS_ERR(new_nsp->pid_ns)) {
err = PTR_ERR(new_nsp->pid_ns);
goto out_pid;
diff --git a/kernel/pid.c b/kernel/pid.c
index e432057..4a1e66f 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -78,6 +78,7 @@ struct pid_namespace init_pid_ns = {
.last_pid = 0,
.level = 0,
.child_reaper = &init_task,
+ .user_ns = &init_user_ns,
};
EXPORT_SYMBOL_GPL(init_pid_ns);

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index e9c9adc..6818ea5 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -10,6 +10,7 @@

#include <linux/pid.h>
#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
#include <linux/syscalls.h>
#include <linux/err.h>
#include <linux/acct.h>
@@ -69,7 +70,8 @@ err_alloc:
return NULL;
}

-static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_pid_ns)
+static struct pid_namespace *create_pid_namespace(struct task_struct *tsk,
+ struct pid_namespace *parent_pid_ns)
{
struct pid_namespace *ns;
unsigned int level = parent_pid_ns->level + 1;
@@ -97,6 +99,8 @@ static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_p
for (i = 1; i < PIDMAP_ENTRIES; i++)
atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);

+ ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
+
err = pid_ns_prepare_proc(ns);
if (err)
goto out_put_parent_pid_ns;
@@ -122,13 +126,15 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
kmem_cache_free(pid_ns_cachep, ns);
}

-struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
+struct pid_namespace *copy_pid_ns(unsigned long flags, struct task_struct *tsk)
{
+ struct pid_namespace *old_ns = task_active_pid_ns(tsk);
+
if (!(flags & CLONE_NEWPID))
return get_pid_ns(old_ns);
if (flags & (CLONE_THREAD|CLONE_PARENT))
return ERR_PTR(-EINVAL);
- return create_pid_namespace(old_ns);
+ return create_pid_namespace(tsk, old_ns);
}

void free_pid_ns(struct kref *kref)
@@ -139,6 +145,7 @@ void free_pid_ns(struct kref *kref)

parent = ns->parent;
destroy_pid_namespace(ns);
+ put_user_ns(ns->user_ns);

if (parent != NULL)
put_pid_ns(parent);
--
1.7.5.4


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