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Message-Id: <1353083750-3621-3-git-send-email-ebiederm@xmission.com>
Date: Fri, 16 Nov 2012 08:35:42 -0800
From: "Eric W. Biederman" <ebiederm@...ssion.com>
To: Linux Containers <containers@...ts.linux-foundation.org>
Cc: <linux-kernel@...r.kernel.org>, Oleg Nesterov <oleg@...sign.ru>,
Serge Hallyn <serge@...lyn.com>,
Gao feng <gaofeng@...fujitsu.com>,
Andrew Morton <akpm@...ux-foundation.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [PATCH 03/11] pidns: Capture the user namespace and filter ns_last_pid
From: "Eric W. Biederman" <ebiederm@...ssion.com>
- Capture the the user namespace that creates the pid namespace
- Use that user namespace to test if it is ok to write to
/proc/sys/kernel/ns_last_pid.
Acked-by: Serge Hallyn <serge.hallyn@...onical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
include/linux/pid_namespace.h | 8 +++++---
kernel/nsproxy.c | 2 +-
kernel/pid.c | 1 +
kernel/pid_namespace.c | 16 +++++++++++-----
4 files changed, 18 insertions(+), 9 deletions(-)
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 65e3e87..c89c9cf 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -31,6 +31,7 @@ struct pid_namespace {
#ifdef CONFIG_BSD_PROCESS_ACCT
struct bsd_acct_struct *bacct;
#endif
+ struct user_namespace *user_ns;
kgid_t pid_gid;
int hide_pid;
int reboot; /* group exit code if this pidns was rebooted */
@@ -46,7 +47,8 @@ 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 user_namespace *user_ns, struct pid_namespace *ns);
extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
extern int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd);
extern void put_pid_ns(struct pid_namespace *ns);
@@ -59,8 +61,8 @@ static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
return ns;
}
-static inline struct pid_namespace *
-copy_pid_ns(unsigned long flags, struct pid_namespace *ns)
+static inline struct pid_namespace *copy_pid_ns(unsigned long flags,
+ struct user_namespace *user_ns, struct pid_namespace *ns)
{
if (flags & CLONE_NEWPID)
ns = ERR_PTR(-EINVAL);
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index b576f7f..5fe88e1 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, task_cred_xxx(tsk, user_ns), task_active_pid_ns(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 aebd4f5..2a624f1 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 7b07cc0..7580aa0 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>
@@ -74,7 +75,8 @@ err_alloc:
/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
#define MAX_PID_NS_LEVEL 32
-static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_pid_ns)
+static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns,
+ struct pid_namespace *parent_pid_ns)
{
struct pid_namespace *ns;
unsigned int level = parent_pid_ns->level + 1;
@@ -102,6 +104,7 @@ static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_p
kref_init(&ns->kref);
ns->level = level;
ns->parent = get_pid_ns(parent_pid_ns);
+ ns->user_ns = get_user_ns(user_ns);
set_bit(0, ns->pidmap[0].page);
atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);
@@ -117,6 +120,7 @@ static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_p
out_put_parent_pid_ns:
put_pid_ns(parent_pid_ns);
+ put_user_ns(user_ns);
out_free_map:
kfree(ns->pidmap[0].page);
out_free:
@@ -134,13 +138,14 @@ 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 user_namespace *user_ns, struct pid_namespace *old_ns)
{
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(user_ns, old_ns);
}
static void free_pid_ns(struct kref *kref)
@@ -239,9 +244,10 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
static int pid_ns_ctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
+ struct pid_namespace *pid_ns = task_active_pid_ns(current);
struct ctl_table tmp = *table;
- if (write && !capable(CAP_SYS_ADMIN))
+ if (write && !ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
/*
@@ -250,7 +256,7 @@ static int pid_ns_ctl_handler(struct ctl_table *table, int write,
* it should synchronize its usage with external means.
*/
- tmp.data = ¤t->nsproxy->pid_ns->last_pid;
+ tmp.data = &pid_ns->last_pid;
return proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
}
--
1.7.5.4
--
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