Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.
A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.
Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.
Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives. Allowing simple, safe,
well understood work-arounds to known problematic software.
This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work. While writing this patch I saw a handful of such
cases. The most significant being autofs that lives in the module
autofs4.
This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.
After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module. The common pattern in the kernel is to call request_module()
without regards to the users permissions. In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted. In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.
Acked-by: Serge Hallyn <[email protected]>
Acked-by: Kees Cook <[email protected]>
Reported-by: Kees Cook <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>
.mount = pfmfs_mount,
.kill_sb = kill_anon_super,
};
+MODULE_ALIAS_FS("pfmfs");
DEFINE_PER_CPU(unsigned long, pfm_syst_info);
DEFINE_PER_CPU(struct task_struct *, pmu_owner);
.mount = spufs_mount,
.kill_sb = kill_litter_super,
};
+MODULE_ALIAS_FS("spufs");
static int __init spufs_init(void)
{
.mount = hypfs_mount,
.kill_sb = hypfs_kill_super
};
+MODULE_ALIAS_FS("s390_hypfs");
static const struct super_operations hypfs_s_ops = {
.statfs = simple_statfs,
.mount = efivarfs_mount,
.kill_sb = efivarfs_kill_sb,
};
+MODULE_ALIAS_FS("efivarfs");
/*
* Handle negative dentry.
.mount = ipathfs_mount,
.kill_sb = ipathfs_kill_super,
};
+MODULE_ALIAS_FS("ipathfs");
int __init ipath_init_ipathfs(void)
{
.mount = qibfs_mount,
.kill_sb = qibfs_kill_super,
};
+MODULE_ALIAS_FS("ipathfs");
int __init qib_init_qibfs(void)
{
.mount = ibmasmfs_mount,
.kill_sb = kill_litter_super,
};
+MODULE_ALIAS_FS("ibmasmfs");
static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent)
{
.mount = mtd_inodefs_mount,
.kill_sb = kill_anon_super,
};
+MODULE_ALIAS_FS("mtd_inodefs");
static int __init init_mtdchar(void)
{
.mount = oprofilefs_mount,
.kill_sb = kill_litter_super,
};
+MODULE_ALIAS_FS("oprofilefs");
int __init oprofilefs_register(void)
.mount = ffs_fs_mount,
.kill_sb = ffs_fs_kill_sb,
};
+MODULE_ALIAS_FS("functionfs");
/* Driver's main init/cleanup functions *************************************/
.mount = ffs_fs_mount,
.kill_sb = ffs_fs_kill_sb,
};
+MODULE_ALIAS_FS("functionfs");
/* Driver's main init/cleanup functions *************************************/
.mount = gadgetfs_mount,
.kill_sb = gadgetfs_kill_sb,
};
+MODULE_ALIAS_FS("gadgetfs");
/*----------------------------------------------------------------------*/
.mount = xenfs_mount,
.kill_sb = kill_litter_super,
};
+MODULE_ALIAS_FS("xenfs");
static int __init xenfs_init(void)
{
.owner = THIS_MODULE,
.fs_flags = FS_RENAME_DOES_D_MOVE,
};
+MODULE_ALIAS_FS("9p");
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("adfs");
static int __init init_adfs_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("affs");
static int __init init_affs_fs(void)
{
.kill_sb = afs_kill_super,
.fs_flags = 0,
};
+MODULE_ALIAS_FS("afs");
static const struct super_operations afs_super_ops = {
.statfs = afs_statfs,
.mount = autofs_mount,
.kill_sb = autofs4_kill_sb,
};
+MODULE_ALIAS_FS("autofs");
static int __init init_autofs4_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("befs");
static int __init
init_befs_fs(void)
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("bfs");
static int __init init_bfs_fs(void)
{
.mount = bm_mount,
.kill_sb = kill_litter_super,
};
+MODULE_ALIAS_FS("binfmt_misc");
static int __init init_misc_binfmt(void)
{
.kill_sb = btrfs_kill_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("btrfs");
/*
* used by btrfsctl to scan devices when no FS is mounted
.kill_sb = ceph_kill_sb,
.fs_flags = FS_RENAME_DOES_D_MOVE,
};
+MODULE_ALIAS_FS("ceph");
#define _STRINGIFY(x) #x
#define STRINGIFY(x) _STRINGIFY(x)
.kill_sb = kill_anon_super,
.fs_flags = FS_BINARY_MOUNTDATA,
};
+MODULE_ALIAS_FS("coda");
.mount = configfs_do_mount,
.kill_sb = kill_litter_super,
};
+MODULE_ALIAS_FS("configfs");
struct dentry *configfs_pin_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("cramfs");
static int __init init_cramfs_fs(void)
{
.mount = debug_mount,
.kill_sb = kill_litter_super,
};
+MODULE_ALIAS_FS("debugfs");
static struct dentry *__create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
.fs_flags = FS_USERNS_MOUNT | FS_USERNS_DEV_MOUNT,
#endif
};
+MODULE_ALIAS_FS("devpts");
/*
* The normal naming convention is simply /dev/pts/<number>; this conforms
.kill_sb = ecryptfs_kill_block_super,
.fs_flags = 0
};
+MODULE_ALIAS_FS("ecryptfs");
/**
* inode_info_init_once
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("efs");
static struct pt_types sgi_pt_types[] = {
{0x00, "SGI vh"},
.mount = exofs_mount,
.kill_sb = generic_shutdown_super,
};
+MODULE_ALIAS_FS("exofs");
static int __init init_exofs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("ext2");
static int __init init_ext2_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("ext3");
static int __init init_ext3_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("ext2");
#define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
#else
#define IS_EXT2_SB(sb) (0)
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("ext3");
#define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
#else
#define IS_EXT3_SB(sb) (0)
return 0;
return 1;
}
-MODULE_ALIAS("ext2");
#else
static inline void register_as_ext2(void) { }
static inline void unregister_as_ext2(void) { }
return 0;
return 1;
}
-MODULE_ALIAS("ext3");
#else
static inline void register_as_ext3(void) { }
static inline void unregister_as_ext3(void) { }
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("ext4");
static int __init ext4_init_feat_adverts(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("f2fs");
static int __init init_inodecache(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("msdos");
static int __init init_msdos_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("vfat");
static int __init init_vfat_fs(void)
{
int len = dot ? dot - name : strlen(name);
fs = __get_fs_type(name, len);
- if (!fs && (request_module("%.*s", len, name) == 0))
+ if (!fs && (request_module("fs-%.*s", len, name) == 0))
fs = __get_fs_type(name, len);
if (dot && fs && !(fs->fs_flags & FS_HAS_SUBTYPE)) {
MODULE_DESCRIPTION("Veritas Filesystem (VxFS) driver");
MODULE_LICENSE("Dual BSD/GPL");
-MODULE_ALIAS("vxfs"); /* makes mount -t vxfs autoload the module */
static void vxfs_put_super(struct super_block *);
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("vxfs"); /* makes mount -t vxfs autoload the module */
static int __init
vxfs_init(void)
.mount = fuse_ctl_mount,
.kill_sb = fuse_ctl_kill_sb,
};
+MODULE_ALIAS_FS("fusectl");
int __init fuse_ctl_init(void)
{
.mount = fuse_mount,
.kill_sb = fuse_kill_sb_anon,
};
+MODULE_ALIAS_FS("fuse");
#ifdef CONFIG_BLOCK
static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
.kill_sb = fuse_kill_sb_blk,
.fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
};
+MODULE_ALIAS_FS("fuseblk");
static inline int register_fuseblk(void)
{
#include <linux/gfs2_ondisk.h>
#include <linux/quotaops.h>
#include <linux/lockdep.h>
+#include <linux/module.h>
#include "gfs2.h"
#include "incore.h"
.kill_sb = gfs2_kill_sb,
.owner = THIS_MODULE,
};
+MODULE_ALIAS_FS("gfs2");
struct file_system_type gfs2meta_fs_type = {
.name = "gfs2meta",
.mount = gfs2_mount_meta,
.owner = THIS_MODULE,
};
-
+MODULE_ALIAS_FS("gfs2meta");
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("hfs");
static void hfs_init_once(void *p)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("hfsplus");
static void hfsplus_init_once(void *p)
{
.kill_sb = kill_anon_super,
.fs_flags = 0,
};
+MODULE_ALIAS_FS("hppfs");
static int __init init_hppfs(void)
{
.mount = hugetlbfs_mount,
.kill_sb = kill_litter_super,
};
+MODULE_ALIAS_FS("hugetlbfs");
static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("iso9660");
static int __init init_iso9660_fs(void)
{
module_init(init_iso9660_fs)
module_exit(exit_iso9660_fs)
MODULE_LICENSE("GPL");
-/* Actual filesystem name is iso9660, as requested in filesystems.c */
-MODULE_ALIAS("iso9660");
.mount = jffs2_mount,
.kill_sb = jffs2_kill_sb,
};
+MODULE_ALIAS_FS("jffs2");
static int __init init_jffs2_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("jfs");
static void init_once(void *foo)
{
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("logfs");
static int __init logfs_init(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("minix");
static int __init init_minix_fs(void)
{
.kill_sb = kill_anon_super,
.fs_flags = FS_BINARY_MOUNTDATA,
};
+MODULE_ALIAS_FS("ncpfs");
static int __init init_ncp_fs(void)
{
.kill_sb = nfs_kill_super,
.fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};
+MODULE_ALIAS_FS("nfs");
EXPORT_SYMBOL_GPL(nfs_fs_type);
struct file_system_type nfs_xdev_fs_type = {
.kill_sb = nfs_kill_super,
.fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};
+MODULE_ALIAS_FS("nfs4");
EXPORT_SYMBOL_GPL(nfs4_fs_type);
static int __init register_nfs4_fs(void)
MODULE_PARM_DESC(send_implementation_id,
"Send implementation ID with NFSv4.1 exchange_id");
MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
-MODULE_ALIAS("nfs4");
#endif /* CONFIG_NFS_V4 */
.mount = nfsd_mount,
.kill_sb = nfsd_umount,
};
+MODULE_ALIAS_FS("nfsd");
#ifdef CONFIG_PROC_FS
static int create_proc_exports_entry(void)
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("nilfs2");
static void nilfs_inode_init_once(void *obj)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("ntfs");
/* Stable names for the slab caches. */
static const char ntfs_index_ctx_cache_name[] = "ntfs_index_ctx_cache";
.mount = dlmfs_mount,
.kill_sb = kill_litter_super,
};
+MODULE_ALIAS_FS("ocfs2_dlmfs");
static int __init init_dlmfs_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("omfs");
static int __init init_omfs_fs(void)
{
.mount = openprom_mount,
.kill_sb = kill_anon_super,
};
+MODULE_ALIAS_FS("openpromfs");
static void op_inode_init_once(void *data)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("qnx4");
static int __init init_qnx4_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("qnx6");
static int __init init_qnx6_fs(void)
{
.kill_sb = reiserfs_kill_sb,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("reiserfs");
MODULE_DESCRIPTION("ReiserFS journaled filesystem");
.kill_sb = romfs_kill_sb,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("romfs");
/*
* inode storage initialiser
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("sysv");
static struct file_system_type v7_fs_type = {
.owner = THIS_MODULE,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("v7");
static int __init init_sysv_fs(void)
{
module_init(init_sysv_fs)
module_exit(exit_sysv_fs)
-MODULE_ALIAS("v7");
MODULE_LICENSE("GPL");
.mount = ubifs_mount,
.kill_sb = kill_ubifs_super,
};
+MODULE_ALIAS_FS("ubifs");
/*
* Inode slab cache constructor.
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("ufs");
static int __init init_ufs_fs(void)
{
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
+MODULE_ALIAS_FS("xfs");
STATIC int __init
xfs_init_zones(void)
struct lock_class_key i_mutex_dir_key;
};
+#define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
+
extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
void *data, int (*fill_super)(struct super_block *, void *, int));
extern struct dentry *mount_bdev(struct file_system_type *fs_type,
.mount = rpc_mount,
.kill_sb = rpc_kill_sb,
};
+MODULE_ALIAS_FS("rpc_pipefs");
static void
init_once(void *foo)
kmem_cache_destroy(rpc_inode_cachep);
unregister_filesystem(&rpc_pipe_fs_type);
}
-
-/* Make 'mount -t rpc_pipefs ...' autoload this module. */
-MODULE_ALIAS("rpc_pipefs");