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linux/fs/xfs
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Eric W. Biederman 7f78e03513 fs: Limit sys_mount to only request filesystem modules. 
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 <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-03 19:36:31 -08:00
..
Kconfig fs/xfs: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:04 -08:00
kmem.c xfs: switch to proper __bitwise type for KM_... flags 2012-05-29 23:28:32 -04:00
kmem.h xfs: switch to proper __bitwise type for KM_... flags 2012-05-29 23:28:32 -04:00
Makefile xfs: remove xfs_flushinval_pages 2012-11-14 15:15:08 -06:00
mrlock.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
time.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
uuid.c xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
uuid.h xfs: add CRC infrastructure 2012-11-19 20:11:24 -06:00
xfs_acl.c userns: Pass a userns parameter into posix_acl_to_xattr and posix_acl_from_xattr 2012-09-18 01:01:35 -07:00
xfs_acl.h xfs: Fix build breakage in xfs_iops.c when CONFIG_FS_POSIX_ACL is not set 2011-08-01 02:35:04 -04:00
xfs_ag.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_alloc_btree.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_alloc_btree.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_alloc.c xfs: don't zero structure members after a memset(0) 2013-01-03 16:00:07 -06:00
xfs_alloc.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_aops.c xfs: Fix possible use-after-free with AIO 2013-01-26 09:43:58 -06:00
xfs_aops.h Prefix IO_XX flags with XFS_IO_XX to avoid namespace colision. 2012-07-22 11:00:55 -05:00
xfs_attr_leaf.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_attr_leaf.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_attr_sf.h
xfs_attr.c xfs: refactor space log reservation for XFS_TRANS_ATTR_SET 2013-02-01 14:56:31 -06:00
xfs_attr.h
xfs_bit.c
xfs_bit.h
xfs_bmap_btree.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_bmap_btree.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_bmap.c xfs: xfs_bmap_add_attrfork_local is too generic 2013-02-14 17:35:51 -06:00
xfs_bmap.h xfs: move allocation stack switch up to xfs_bmapi_allocate 2012-10-18 17:42:48 -05:00
xfs_btree.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_btree.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_buf_item.c xfs: recheck buffer pinned status after push trylock failure 2013-02-14 17:23:42 -06:00
xfs_buf_item.h xfs: rename bli_format to avoid confusion with bli_formats 2013-01-16 16:07:37 -06:00
xfs_buf.c xfs: remove log force from xfs_buf_trylock() 2013-02-14 17:24:53 -06:00
xfs_buf.h xfs: use b_maps[] for discontiguous buffers 2013-01-16 16:07:11 -06:00
xfs_cksum.h xfs: add CRC infrastructure 2012-11-19 20:11:24 -06:00
xfs_da_btree.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_da_btree.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_dfrag.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
xfs_dfrag.h
xfs_dinode.h xfs: fix typo in comment of xfs_dinode_t. 2012-06-14 12:28:26 -05:00
xfs_dir2_block.c xfs: recalculate leaf entry pointer after compacting a dir2 block 2013-01-16 16:08:55 -06:00
xfs_dir2_data.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_dir2_format.h xfs: cleanup struct xfs_dir2_free 2011-07-13 13:43:48 +02:00
xfs_dir2_leaf.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_dir2_node.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_dir2_priv.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_dir2_sf.c xfs: remove struct xfs_dabuf and infrastructure 2012-07-01 14:50:07 -05:00
xfs_dir2.c xfs: remove struct xfs_dabuf and infrastructure 2012-07-01 14:50:07 -05:00
xfs_dir2.h xfs: reshuffle dir2 headers 2011-07-13 13:43:48 +02:00
xfs_discard.c xfs: check for possible overflow in xfs_ioc_trim 2012-08-23 14:48:44 -05:00
xfs_discard.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_dquot_item.c xfs: clean up xfs_bit.h includes 2012-05-14 16:21:00 -05:00
xfs_dquot_item.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_dquot.c xfs: calculate XFS_TRANS_QM_DQALLOC space log reservation at mount time 2013-02-01 14:43:51 -06:00
xfs_dquot.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_error.c xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_error.h xfs: kill support/debug.[ch] 2011-03-07 10:09:35 +11:00
xfs_export.c fs: encode_fh: return FILEID_INVALID if invalid fid_type 2013-02-26 02:46:10 -05:00
xfs_export.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_extent_busy.c xfs: make xfs_extent_busy_trim not static 2012-05-14 16:21:04 -05:00
xfs_extent_busy.h xfs: make xfs_extent_busy_trim not static 2012-05-14 16:21:04 -05:00
xfs_extfree_item.c xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_extfree_item.h xfs: Pull EFI/EFD handling out from under the AIL lock 2010-12-20 11:59:49 +11:00
xfs_file.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
xfs_filestream.c xfs: rename allocation range fields in struct xfs_bmalloca 2011-10-11 21:15:06 -05:00
xfs_filestream.h
xfs_fs.h xfs: add minimum file size filtering to eofblocks scan 2012-11-08 15:32:29 -06:00
xfs_fsops.c xfs: make use of XFS_SB_LOG_RES() at xfs_fs_log_dummy() 2013-02-01 14:55:59 -06:00
xfs_fsops.h xfs: ensure log covering transactions are synchronous 2011-01-11 20:28:17 -06:00
xfs_globals.c xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_ialloc_btree.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_ialloc_btree.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_ialloc.c xfs: don't zero structure members after a memset(0) 2013-01-03 16:00:07 -06:00
xfs_ialloc.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_icache.c xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_icache.h xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_inode_item.c xfs remove the XFS_TRANS_DEBUG routines 2012-12-17 16:29:00 -06:00
xfs_inode_item.h xfs remove the XFS_TRANS_DEBUG routines 2012-12-17 16:29:00 -06:00
xfs_inode.c xfs remove the XFS_TRANS_DEBUG routines 2012-12-17 16:29:00 -06:00
xfs_inode.h xfs: memory barrier before wake_up_bit() 2013-02-07 09:39:48 -06:00
xfs_inum.h xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_ioctl32.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
xfs_ioctl32.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_ioctl.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
xfs_ioctl.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_iomap.c xfs: limit speculative prealloc size on sparse files 2013-02-14 17:21:32 -06:00
xfs_iomap.h
xfs_iops.c xfs: remove xfs_flush_pages 2012-11-14 15:12:45 -06:00
xfs_iops.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_itable.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_itable.h
xfs_linux.h xfs: add CRC infrastructure 2012-11-19 20:11:24 -06:00
xfs_log_cil.c xfs: rename log structure to xlog 2012-06-21 14:21:11 -05:00
xfs_log_priv.h xfs: fix sparse reported log CRC endian issue 2012-12-03 12:10:59 -06:00
xfs_log_recover.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
xfs_log_recover.h
xfs_log.c xfs: fix fs/xfs/xfs_log.c:1740:39: error: 'B_TRUE' undeclared 2013-01-18 15:11:57 -06:00
xfs_log.h xfs: xfs_quiesce_attr() should quiesce the log like unmount 2012-10-17 13:39:14 -05:00
xfs_message.c xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_message.h treewide: use __printf not __attribute__((format(printf,...))) 2011-10-31 17:30:54 -07:00
xfs_mount.c xfs: make use of XFS_SB_LOG_RES() at xfs_mount_log_sb() 2013-02-01 14:55:08 -06:00
xfs_mount.h xfs: refactor space log reservation for XFS_TRANS_ATTR_SET 2013-02-01 14:56:31 -06:00
xfs_mru_cache.c xfs: convert to alloc_workqueue() 2011-02-01 11:42:43 +01:00
xfs_mru_cache.h
xfs_qm_bhv.c xfs: Remove boolean_t typedef completely. 2013-01-17 17:32:57 -06:00
xfs_qm_syscalls.c xfs: calculate XFS_TRANS_QM_QUOTAOFF_END space log reservation at mount time 2013-02-01 14:45:50 -06:00
xfs_qm.c xfs: calculate xfs_qm_write_sb_changes() space log reservation at mount time 2013-02-01 14:42:32 -06:00
xfs_qm.h xfs: remove the global xfs_Gqm structure 2012-03-14 12:06:32 -05:00
xfs_quota_priv.h xfs: use per-filesystem radix trees for dquot lookup 2012-03-14 11:09:06 -05:00
xfs_quota.h Define new macro XFS_ALL_QUOTA_ACTIVE and simply some usage 2012-02-03 11:32:20 -06:00
xfs_quotaops.c userns: Convert qutoactl 2012-09-18 01:01:39 -07:00
xfs_rename.c xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_rtalloc.c xfs: uncached buffer reads need to return an error 2012-11-15 21:34:05 -06:00
xfs_rtalloc.h xfs: Remove the macro XFS_BUF_PTR 2011-07-25 15:03:13 -05:00
xfs_sb.h xfs: add CRC infrastructure 2012-11-19 20:11:24 -06:00
xfs_stats.c xfs: use common code for quota statistics 2012-03-14 11:09:06 -05:00
xfs_stats.h xfs: use common code for quota statistics 2012-03-14 11:09:06 -05:00
xfs_super.c fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
xfs_super.h xfs: xfs_sync_data is redundant. 2012-10-17 12:01:25 -05:00
xfs_sysctl.c xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_sysctl.h xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_trace.c xfs: clean up xfs_bit.h includes 2012-05-14 16:21:00 -05:00
xfs_trace.h xfs: fix shutdown hang on invalid inode during create 2013-01-26 09:34:38 -06:00
xfs_trans_ail.c xfs remove the XFS_TRANS_DEBUG routines 2012-12-17 16:29:00 -06:00
xfs_trans_buf.c xfs: fix the multi-segment log buffer format 2013-01-16 16:08:08 -06:00
xfs_trans_dquot.c xfs: Remove boolean_t typedef completely. 2013-01-17 17:32:57 -06:00
xfs_trans_extfree.c xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_trans_inode.c xfs remove the XFS_TRANS_DEBUG routines 2012-12-17 16:29:00 -06:00
xfs_trans_priv.h xfs: re-enable xfsaild idle mode and fix associated races 2012-07-29 16:27:57 -05:00
xfs_trans_space.h
xfs_trans.c xfs: refactor space log reservation for XFS_TRANS_ATTR_SET 2013-02-01 14:56:31 -06:00
xfs_trans.h xfs: refactor space log reservation for XFS_TRANS_ATTR_SET 2013-02-01 14:56:31 -06:00
xfs_types.h xfs: Remove boolean_t typedef completely. 2013-01-17 17:32:57 -06:00
xfs_utils.c xfs: remove the alloc_done argument to xfs_dialloc 2012-07-29 16:00:31 -05:00
xfs_utils.h xfs: propagate umode_t 2012-01-03 22:55:00 -05:00
xfs_vnode.h xfs: remove remaining scraps of struct xfs_iomap 2012-03-15 13:40:16 -05:00
xfs_vnodeops.c xfs: Remove boolean_t typedef completely. 2013-01-17 17:32:57 -06:00
xfs_vnodeops.h xfs: byte range granularity for XFS_IOC_ZERO_RANGE 2012-11-29 14:21:46 -06:00
xfs_xattr.c xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs.h xfs: don't expect xfs headers to be in subdirectories 2011-08-12 13:57:55 -05:00