[Devel] [patch -mm 11/17] user namespace: add user_namespace ptr to vfsmount

[clg at fr.ibm.com]

From: Serge E. Hallyn <serue at us.ibm.com>

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 <serue at us.ibm.com>
---
 fs/namespace.c        |    4 ++++
 include/linux/mount.h |    2 ++
 include/linux/sched.h |   12 ++++++++++++
 3 files changed, 18 insertions(+)

Index: 2.6.19-rc6-mm2/fs/namespace.c
===================================================================
--- 2.6.19-rc6-mm2.orig/fs/namespace.c
+++ 2.6.19-rc6-mm2/fs/namespace.c
@@ -25,6 +25,7 @@
 #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 +57,8 @@ 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 = current->nsproxy->user_ns;
+		get_user_ns(mnt->mnt_user_ns);
 		atomic_set(&mnt->mnt_count, 1);
 		INIT_LIST_HEAD(&mnt->mnt_hash);
 		INIT_LIST_HEAD(&mnt->mnt_child);
@@ -88,6 +91,7 @@ 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);
 }
Index: 2.6.19-rc6-mm2/include/linux/mount.h
===================================================================
--- 2.6.19-rc6-mm2.orig/include/linux/mount.h
+++ 2.6.19-rc6-mm2/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
@@ -53,6 +54,7 @@ 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;
 };
 
Index: 2.6.19-rc6-mm2/include/linux/sched.h
===================================================================
--- 2.6.19-rc6-mm2.orig/include/linux/sched.h
+++ 2.6.19-rc6-mm2/include/linux/sched.h
@@ -83,6 +83,8 @@ struct sched_param {
 #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>
 
@@ -1589,6 +1591,16 @@ extern int cond_resched(void);
 extern int cond_resched_lock(spinlock_t * lock);
 extern int cond_resched_softirq(void);
 
+static inline int task_mnt_same_uid(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?:

-- 
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