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authorEric W. Biederman <ebiederm@xmission.com>2016-05-23 22:51:59 +0300
committerEric W. Biederman <ebiederm@xmission.com>2016-06-23 23:41:53 +0300
commitd91ee87d8d85a0808c01787e8b4a6b48f2ba487b (patch)
tree1399ccf15d61a3a1dbdd5b89e1673a01325588ae /fs/nfsd
parentb236017acffa73d52eac9427f42d8993067d20fb (diff)
downloadlinux-d91ee87d8d85a0808c01787e8b4a6b48f2ba487b.tar.xz
vfs: Pass data, ns, and ns->userns to mount_ns
Today what is normally called data (the mount options) is not passed to fill_super through mount_ns. Pass the mount options and the namespace separately to mount_ns so that filesystems such as proc that have mount options, can use mount_ns. Pass the user namespace to mount_ns so that the standard permission check that verifies the mounter has permissions over the namespace can be performed in mount_ns instead of in each filesystems .mount method. Thus removing the duplication between mqueuefs and proc in terms of permission checks. The extra permission check does not currently affect the rpc_pipefs filesystem and the nfsd filesystem as those filesystems do not currently allow unprivileged mounts. Without unpvileged mounts it is guaranteed that the caller has already passed capable(CAP_SYS_ADMIN) which guarantees extra permission check will pass. Update rpc_pipefs and the nfsd filesystem to ensure that the network namespace reference is always taken in fill_super and always put in kill_sb so that the logic is simpler and so that errors originating inside of fill_super do not cause a network namespace leak. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/nfsctl.c13
1 files changed, 4 insertions, 9 deletions
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 9690cb4dd588..5a6ae2522266 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1154,20 +1154,15 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
#endif
/* last one */ {""}
};
- struct net *net = data;
- int ret;
-
- ret = simple_fill_super(sb, 0x6e667364, nfsd_files);
- if (ret)
- return ret;
- sb->s_fs_info = get_net(net);
- return 0;
+ get_net(sb->s_fs_info);
+ return simple_fill_super(sb, 0x6e667364, nfsd_files);
}
static struct dentry *nfsd_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
- return mount_ns(fs_type, flags, current->nsproxy->net_ns, nfsd_fill_super);
+ struct net *net = current->nsproxy->net_ns;
+ return mount_ns(fs_type, flags, data, net, net->user_ns, nfsd_fill_super);
}
static void nfsd_umount(struct super_block *sb)