From: Serge E. Hallyn <[email protected]>
Subject: [PATCH 3/8] user ns: add user_namespace ptr to vfsmount
Add user_namespace ptr to vfsmount, and define a helper to compare it
to the task's user_ns.
Signed-off-by: Serge E. Hallyn <[email protected]>
---
fs/namespace.c | 3 +++
include/linux/mount.h | 2 ++
include/linux/sched.h | 20 ++++++++++++++++++++
3 files changed, 25 insertions(+), 0 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 5ef336c..9f98a67 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -25,6 +25,7 @@ #include <linux/namei.h>
#include <linux/security.h>
#include <linux/mount.h>
#include <linux/ramfs.h>
+#include <linux/user_namespace.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "pnode.h"
@@ -56,6 +57,7 @@ struct vfsmount *alloc_vfsmnt(const char
struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL);
if (mnt) {
memset(mnt, 0, sizeof(struct vfsmount));
+ mnt->mnt_user_ns = get_user_ns(current->nsproxy->user_ns);
atomic_set(&mnt->mnt_count, 1);
INIT_LIST_HEAD(&mnt->mnt_hash);
INIT_LIST_HEAD(&mnt->mnt_child);
@@ -88,6 +90,7 @@ EXPORT_SYMBOL(simple_set_mnt);
void free_vfsmnt(struct vfsmount *mnt)
{
+ put_user_ns(mnt->mnt_user_ns);
kfree(mnt->mnt_devname);
kmem_cache_free(mnt_cache, mnt);
}
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 1b7e178..acdeca7 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -21,6 +21,7 @@ struct super_block;
struct vfsmount;
struct dentry;
struct mnt_namespace;
+struct user_namespace;
#define MNT_NOSUID 0x01
#define MNT_NODEV 0x02
@@ -54,6 +55,7 @@ struct vfsmount {
struct list_head mnt_slave; /* slave list entry */
struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */
struct mnt_namespace *mnt_ns; /* containing namespace */
+ struct user_namespace *mnt_user_ns; /* namespace for uid interpretation */
int mnt_pinned;
};
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5a3f630..450fc39 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -83,6 +83,8 @@ #include <linux/resource.h>
#include <linux/timer.h>
#include <linux/hrtimer.h>
#include <linux/task_io_accounting.h>
+#include <linux/nsproxy.h>
+#include <linux/mount.h>
#include <asm/processor.h>
@@ -1586,6 +1588,24 @@ extern int cond_resched_lock(spinlock_t
extern int cond_resched_softirq(void);
/*
+ * Check whether a task and a vfsmnt belong to the same uidns.
+ * Since the initial namespace is exempt from these checks,
+ * return 1 if so. Also return 1 if the vfsmnt is exempt from
+ * such checking. Otherwise, if the uid namespaces are different,
+ * return 0.
+ */
+static inline int task_mnt_same_uidns(struct task_struct *tsk,
+ struct vfsmount *mnt)
+{
+ if (tsk->nsproxy == init_task.nsproxy)
+ return 1;
+ if (mnt->mnt_user_ns == tsk->nsproxy->user_ns)
+ return 1;
+ return 0;
+}
+
+
+/*
* Does a critical section need to be broken due to another
* task waiting?:
*/
--
1.4.1
-
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