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-rw-r--r--fs/namespace.c21
-rw-r--r--fs/proc/root.c4
-rw-r--r--fs/sysfs/mount.c4
-rw-r--r--include/linux/user_namespace.h4
-rw-r--r--kernel/user.c2
-rw-r--r--kernel/user_namespace.c2
6 files changed, 37 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 968d4c5eae03..d581e45c0a9f 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2763,6 +2763,27 @@ bool current_chrooted(void)
return chrooted;
}
+void update_mnt_policy(struct user_namespace *userns)
+{
+ struct mnt_namespace *ns = current->nsproxy->mnt_ns;
+ struct mount *mnt;
+
+ down_read(&namespace_sem);
+ list_for_each_entry(mnt, &ns->list, mnt_list) {
+ switch (mnt->mnt.mnt_sb->s_magic) {
+ case SYSFS_MAGIC:
+ userns->may_mount_sysfs = true;
+ break;
+ case PROC_SUPER_MAGIC:
+ userns->may_mount_proc = true;
+ break;
+ }
+ if (userns->may_mount_sysfs && userns->may_mount_proc)
+ break;
+ }
+ up_read(&namespace_sem);
+}
+
static void *mntns_get(struct task_struct *task)
{
struct mnt_namespace *ns = NULL;
diff --git a/fs/proc/root.c b/fs/proc/root.c
index c6e9fac26bac..9c7fab1d23f0 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -16,6 +16,7 @@
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/bitops.h>
+#include <linux/user_namespace.h>
#include <linux/mount.h>
#include <linux/pid_namespace.h>
#include <linux/parser.h>
@@ -108,6 +109,9 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
} else {
ns = task_active_pid_ns(current);
options = data;
+
+ if (!current_user_ns()->may_mount_proc)
+ return ERR_PTR(-EPERM);
}
sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 8d924b5ec733..afd83273e6ce 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -19,6 +19,7 @@
#include <linux/module.h>
#include <linux/magic.h>
#include <linux/slab.h>
+#include <linux/user_namespace.h>
#include "sysfs.h"
@@ -111,6 +112,9 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
struct super_block *sb;
int error;
+ if (!(flags & MS_KERNMOUNT) && !current_user_ns()->may_mount_sysfs)
+ return ERR_PTR(-EPERM);
+
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info)
return ERR_PTR(-ENOMEM);
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 4ce009324933..b6b215f13b45 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -26,6 +26,8 @@ struct user_namespace {
kuid_t owner;
kgid_t group;
unsigned int proc_inum;
+ bool may_mount_sysfs;
+ bool may_mount_proc;
};
extern struct user_namespace init_user_ns;
@@ -82,4 +84,6 @@ static inline void put_user_ns(struct user_namespace *ns)
#endif
+void update_mnt_policy(struct user_namespace *userns);
+
#endif /* _LINUX_USER_H */
diff --git a/kernel/user.c b/kernel/user.c
index e81978e8c03b..8e635a18ab52 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -51,6 +51,8 @@ struct user_namespace init_user_ns = {
.owner = GLOBAL_ROOT_UID,
.group = GLOBAL_ROOT_GID,
.proc_inum = PROC_USER_INIT_INO,
+ .may_mount_sysfs = true,
+ .may_mount_proc = true,
};
EXPORT_SYMBOL_GPL(init_user_ns);
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 0f1e42884577..a54f26f82eb2 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -96,6 +96,8 @@ int create_user_ns(struct cred *new)
set_cred_user_ns(new, ns);
+ update_mnt_policy(ns);
+
return 0;
}