Commit Graph

337 Commits

Author SHA1 Message Date
Zhao Hongjiang ae11e0f184 userns: fix return value on mntns_install() failure
Change return value from -EINVAL to -EPERM when the permission check fails.

Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-11-19 05:59:22 -08:00
Eric W. Biederman 0c55cfc416 vfs: Allow unprivileged manipulation of the mount namespace.
- Add a filesystem flag to mark filesystems that are safe to mount as
  an unprivileged user.

- Add a filesystem flag to mark filesystems that don't need MNT_NODEV
  when mounted by an unprivileged user.

- Relax the permission checks to allow unprivileged users that have
  CAP_SYS_ADMIN permissions in the user namespace referred to by the
  current mount namespace to be allowed to mount, unmount, and move
  filesystems.

Acked-by: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-11-19 05:59:21 -08:00
Eric W. Biederman 7a472ef4be vfs: Only support slave subtrees across different user namespaces
Sharing mount subtress with mount namespaces created by unprivileged
users allows unprivileged mounts created by unprivileged users to
propagate to mount namespaces controlled by privileged users.

Prevent nasty consequences by changing shared subtrees to slave
subtress when an unprivileged users creates a new mount namespace.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-11-19 05:59:20 -08:00
Eric W. Biederman 771b137168 vfs: Add a user namespace reference from struct mnt_namespace
This will allow for support for unprivileged mounts in a new user namespace.

Acked-by: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-11-19 05:59:19 -08:00
Eric W. Biederman 8823c079ba vfs: Add setns support for the mount namespace
setns support for the mount namespace is a little tricky as an
arbitrary decision must be made about what to set fs->root and
fs->pwd to, as there is no expectation of a relationship between
the two mount namespaces.  Therefore I arbitrarily find the root
mount point, and follow every mount on top of it to find the top
of the mount stack.  Then I set fs->root and fs->pwd to that
location.  The topmost root of the mount stack seems like a
reasonable place to be.

Bind mount support for the mount namespace inodes has the
possibility of creating circular dependencies between mount
namespaces.  Circular dependencies can result in loops that
prevent mount namespaces from every being freed.  I avoid
creating those circular dependencies by adding a sequence number
to the mount namespace and require all bind mounts be of a
younger mount namespace into an older mount namespace.

Add a helper function proc_ns_inode so it is possible to
detect when we are attempting to bind mound a namespace inode.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-11-19 05:59:18 -08:00
Jeff Layton 91a27b2a75 vfs: define struct filename and have getname() return it
getname() is intended to copy pathname strings from userspace into a
kernel buffer. The result is just a string in kernel space. It would
however be quite helpful to be able to attach some ancillary info to
the string.

For instance, we could attach some audit-related info to reduce the
amount of audit-related processing needed. When auditing is enabled,
we could also call getname() on the string more than once and not
need to recopy it from userspace.

This patchset converts the getname()/putname() interfaces to return
a struct instead of a string. For now, the struct just tracks the
string in kernel space and the original userland pointer for it.

Later, we'll add other information to the struct as it becomes
convenient.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-12 20:14:55 -04:00
Al Viro 808d4e3cfd consitify do_mount() arguments
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-11 20:02:04 -04:00
Al Viro 156cacb1d0 do_add_mount()/umount -l races
normally we deal with lock_mount()/umount races by checking that
mountpoint to be is still in our namespace after lock_mount() has
been done.  However, do_add_mount() skips that check when called
with MNT_SHRINKABLE in flags (i.e. from finish_automount()).  The
reason is that ->mnt_ns may be a temporary namespace created exactly
to contain automounts a-la NFS4 referral handling.  It's not the
namespace of the caller, though, so check_mnt() would fail here.
We still need to check that ->mnt_ns is non-NULL in that case,
though.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-22 20:48:18 -04:00
Jan Kara eb04c28288 fs: Add freezing handling to mnt_want_write() / mnt_drop_write()
Most of places where we want freeze protection coincides with the places where
we also have remount-ro protection. So make mnt_want_write() and
mnt_drop_write() (and their _file alternative) prevent freezing as well.
For the few cases that are really interested only in remount-ro protection
provide new function variants.

BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-31 09:40:38 +04:00
David Howells f015f1267b VFS: Comment mount following code
Add comments describing what the directions "up" and "down" mean and ref count
handling to the VFS mount following family of functions.

Signed-off-by: Valerie Aurora <vaurora@redhat.com> (Original author)
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:38:32 +04:00
David Howells be34d1a3bc VFS: Make clone_mnt()/copy_tree()/collect_mounts() return errors
copy_tree() can theoretically fail in a case other than ENOMEM, but always
returns NULL which is interpreted by callers as -ENOMEM.  Change it to return
an explicit error.

Also change clone_mnt() for consistency and because union mounts will add new
error cases.

Thanks to Andreas Gruenbacher <agruen@suse.de> for a bug fix.
[AV: folded braino fix by Dan Carpenter]

Original-author: Valerie Aurora <vaurora@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Valerie Aurora <valerie.aurora@gmail.com>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:37:27 +04:00
Al Viro 6ce6e24e72 get rid of magic in proc_namespace.c
don't rely on proc_mounts->m being the first field; container_of()
is there for purpose.  No need to bother with ->private, while
we are at it - the same container_of will do nicely.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:32:48 +04:00
Al Viro f7a99c5b7c get rid of ->mnt_longterm
it's enough to set ->mnt_ns of internal vfsmounts to something
distinct from all struct mnt_namespace out there; then we can
just use the check for ->mnt_ns != NULL in the fast path of
mntput_no_expire()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:32:47 +04:00
Al Viro 63d37a84ab vfs: umount_tree() might be called on subtree that had never made it
__mnt_make_shortterm() in there undoes the effect of __mnt_make_longterm()
we'd done back when we set ->mnt_ns non-NULL; it should not be done to
vfsmounts that had never gone through commit_tree() and friends.  Kudos to
lczerner for catching that one...

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-30 21:04:55 -04:00
Andi Kleen 962830df36 brlocks/lglocks: API cleanups
lglocks and brlocks are currently generated with some complicated macros
in lglock.h.  But there's no reason to not just use common utility
functions and put all the data into a common data structure.

In preparation, this patch changes the API to look more like normal
function calls with pointers, not magic macros.

The patch is rather large because I move over all users in one go to keep
it bisectable.  This impacts the VFS somewhat in terms of lines changed.
But no actual behaviour change.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-29 23:28:41 -04:00
Linus Torvalds 98793265b4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (53 commits)
  Kconfig: acpi: Fix typo in comment.
  misc latin1 to utf8 conversions
  devres: Fix a typo in devm_kfree comment
  btrfs: free-space-cache.c: remove extra semicolon.
  fat: Spelling s/obsolate/obsolete/g
  SCSI, pmcraid: Fix spelling error in a pmcraid_err() call
  tools/power turbostat: update fields in manpage
  mac80211: drop spelling fix
  types.h: fix comment spelling for 'architectures'
  typo fixes: aera -> area, exntension -> extension
  devices.txt: Fix typo of 'VMware'.
  sis900: Fix enum typo 'sis900_rx_bufer_status'
  decompress_bunzip2: remove invalid vi modeline
  treewide: Fix comment and string typo 'bufer'
  hyper-v: Update MAINTAINERS
  treewide: Fix typos in various parts of the kernel, and fix some comments.
  clockevents: drop unknown Kconfig symbol GENERIC_CLOCKEVENTS_MIGR
  gpio: Kconfig: drop unknown symbol 'CS5535_GPIO'
  leds: Kconfig: Fix typo 'D2NET_V2'
  sound: Kconfig: drop unknown symbol ARCH_CLPS7500
  ...

Fix up trivial conflicts in arch/powerpc/platforms/40x/Kconfig (some new
kconfig additions, close to removed commented-out old ones)
2012-01-08 13:21:22 -08:00
Miklos Szeredi 8e8b87964b vfs: prevent remount read-only if pending removes
If there are any inodes on the super block that have been unlinked
(i_nlink == 0) but have not yet been deleted then prevent the
remounting the super block read-only.

Reported-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06 23:20:13 -05:00
Miklos Szeredi 4ed5e82fe7 vfs: protect remounting superblock read-only
Currently remouting superblock read-only is racy in a major way.

With the per mount read-only infrastructure it is now possible to
prevent most races, which this patch attempts.

Before starting the remount read-only, iterate through all mounts
belonging to the superblock and if none of them have any pending
writes, set sb->s_readonly_remount.  This indicates that remount is in
progress and no further write requests are allowed.  If the remount
succeeds set MS_RDONLY and reset s_readonly_remount.

If the remounting is unsuccessful just reset s_readonly_remount.
This can result in transient EROFS errors, despite the fact the
remount failed.  Unfortunately hodling off writes is difficult as
remount itself may touch the filesystem (e.g. through load_nls())
which would deadlock.

A later patch deals with delayed writes due to nlink going to zero.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06 23:20:12 -05:00
Miklos Szeredi 39f7c4db1d vfs: keep list of mounts for each superblock
Keep track of vfsmounts belonging to a superblock.  List is protected
by vfsmount_lock.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06 23:20:12 -05:00
Al Viro 34c80b1d93 vfs: switch ->show_options() to struct dentry *
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06 23:19:54 -05:00
Al Viro d10577a8d8 vfs: trim includes a bit
[folded fix for missing magic.h from Tetsuo Handa]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:13 -05:00
Al Viro be08d6d260 switch mnt_namespace ->root to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:13 -05:00
Al Viro 0226f4923f vfs: take /proc/*/mounts and friends to fs/proc_namespace.c
rationale: that stuff is far tighter bound to fs/namespace.c than to
the guts of procfs proper.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:13 -05:00
Al Viro 3a2393d71d vfs: opencode mntget() mnt_set_mountpoint()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:12 -05:00
Al Viro 909b0a88ef vfs: spread struct mount - remaining argument of next_mnt()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:12 -05:00
Al Viro c63181e6b6 vfs: move fsnotify junk to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:12 -05:00
Al Viro 52ba1621de vfs: move mnt_devname
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:11 -05:00
Al Viro 1a4eeaf2a8 vfs: move mnt_list to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:11 -05:00
Al Viro fc7be130c7 vfs: switch pnode.h macros to struct mount *
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:11 -05:00
Al Viro 863d684f94 vfs: move the rest of int fields to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:10 -05:00
Al Viro 15169fe784 vfs: mnt_id/mnt_group_id moved
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:10 -05:00
Al Viro 143c8c91ce vfs: mnt_ns moved to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:09 -05:00
Al Viro 900148dcac vfs: spread struct mount - mntput_no_expire
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:09 -05:00
Al Viro 95bc5f25c1 vfs: spread struct mount - do_add_mount and graft_tree
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:09 -05:00
Al Viro 6776db3d32 vfs: take mnt_share/mnt_slave/mnt_slave_list and mnt_expire to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:08 -05:00
Al Viro 32301920f4 vfs: and now we can make ->mnt_master point to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:08 -05:00
Al Viro d10e8def07 vfs: take mnt_master to struct mount
make IS_MNT_SLAVE take struct mount * at the same time

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:08 -05:00
Al Viro 14cf1fa8f5 vfs: spread struct mount - remaining argument of mnt_set_mountpoint()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:07 -05:00
Al Viro a8d56d8e4f vfs: spread struct mount - propagate_mnt()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:07 -05:00
Al Viro 6fc7871fed vfs: spread struct mount - get_dominating_id / do_make_slave
next pile of horrors, similar to mnt_parent one; this time it's
mnt_master.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:06 -05:00
Al Viro 6b41d536f7 vfs: take mnt_child/mnt_mounts to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:06 -05:00
Al Viro 68e8a9feab vfs: all counters taken to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:06 -05:00
Al Viro 83adc75322 vfs: spread struct mount - work with counters
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:05 -05:00
Al Viro a73324da7a vfs: move mnt_mountpoint to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:05 -05:00
Al Viro 0714a53380 vfs: now it can be done - make mnt_parent point to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:05 -05:00
Al Viro 3376f34fff vfs: mnt_parent moved to struct mount
the second victim...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:04 -05:00
Al Viro 643822b41e vfs: spread struct mount - is_path_reachable
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:04 -05:00
Al Viro 676da58df7 vfs: spread struct mount - mnt_has_parent
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:04 -05:00
Al Viro 1ab5973862 vfs: spread struct mount - do_umount/propagate_mount_busy
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:03 -05:00
Al Viro 44d964d609 vfs: spread struct mount mnt_set_mountpoint child argument
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:03 -05:00
Al Viro 87129cc0e3 vfs: spread struct mount - clone_mnt/copy_tree argument
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:03 -05:00
Al Viro 692afc312b vfs: spread struct mount - shrink_submounts/select_submounts
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:02 -05:00
Al Viro 761d5c38eb vfs: spread struct mount - umount_tree argument
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:02 -05:00
Al Viro 1b8e5564b9 vfs: the first spoils - mnt_hash moved
taken out of struct vfsmount into struct mount

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:02 -05:00
Al Viro d5e50f74dd vfs: spread struct mount to remaining users of ->mnt_hash
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:01 -05:00
Al Viro cb338d06e9 vfs: spread struct mount - clone_mnt/copy_tree result
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:01 -05:00
Al Viro 0f0afb1dcf vfs: spread struct mount - change_mnt_propagation/set_mnt_shared
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:01 -05:00
Al Viro b105e270b4 vfs: spread struct mount - alloc_vfsmnt/free_vfsmnt/mnt_alloc_id/mnt_free_id
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:00 -05:00
Al Viro cbbe362cd6 vfs: spread struct mount - tree_contains_unbindable
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:00 -05:00
Al Viro 0fb54e5056 vfs: spread struct mount - attach_recursive_mnt
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:00 -05:00
Al Viro 4b8b21f4fe vfs: spread struct mount - mount group id handling
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:59 -05:00
Al Viro 4b2619a571 vfs: spread struct mount - commit_tree
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:59 -05:00
Al Viro 419148da6e vfs: spread struct mount - attach_mnt/detach_mnt
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:59 -05:00
Al Viro 315fc83e56 vfs: spread struct mount - namespace.c internal iterators
next_mnt() return value, first argument
skip_mnt_tree() return value and argument

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:58 -05:00
Al Viro c71053659e vfs: spread struct mount - __lookup_mnt() result
switch __lookup_mnt() to returning struct mount *; callers adjusted.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:58 -05:00
Al Viro 7d6fec45a5 vfs: start hiding vfsmount guts series
Almost all fields of struct vfsmount are used only by core VFS (and
a fairly small part of it, at that).  The plan: embed struct vfsmount
into struct mount, making the latter visible only to core parts of VFS.
Then move fields from vfsmount to mount, eventually leaving only
mnt_root/mnt_sb/mnt_flags in struct vfsmount.  Filesystem code still
gets pointers to struct vfsmount and remains unchanged; all such
pointers go to struct vfsmount embedded into the instances of struct
mount allocated by fs/namespace.c.  When fs/namespace.c et.al. get
a pointer to vfsmount, they turn it into pointer to mount (using
container_of) and work with that.

This is the first part of series; struct mount is introduced,
allocation switched to using it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:57 -05:00
Al Viro 2a79f17e4a vfs: mnt_drop_write_file()
new helper (wrapper around mnt_drop_write()) to be used in pair with
mnt_want_write_file().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:40 -05:00
Al Viro 79e801a906 vfs: make do_kern_mount() static
the only user outside of fs/namespace.c has died

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:39 -05:00
Al Viro aa0a4cf0ab vfs: dentry_reset_mounted() doesn't use vfsmount argument
lose it

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:37 -05:00
Al Viro 6c449c8dfe unexport put_mnt_ns(), make create_mnt_ns() static outright
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:37 -05:00
Al Viro afac7cba7e vfs: more mnt_parent cleanups
a) mount --move is checking that ->mnt_parent is non-NULL before
looking if that parent happens to be shared; ->mnt_parent is never
NULL and it's not even an misspelled !mnt_has_parent()

b) pivot_root open-codes is_path_reachable(), poorly.

c) so does path_is_under(), while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:36 -05:00
Al Viro b2dba1af3c vfs: new internal helper: mnt_has_parent(mnt)
vfsmounts have ->mnt_parent pointing either to a different vfsmount
or to itself; it's never NULL and termination condition in loops
traversing the tree towards root is mnt == mnt->mnt_parent.  At least
one place (see the next patch) is confused about what's going on;
let's add an explicit helper checking it right way and use it in
all places where we need it.  Not that there had been too many,
but...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:36 -05:00
Al Viro aa9c0e07bb vfs: kill pointless helpers in namespace.c
mnt_{inc,dec}_count() is not cleaner than doing the corresponding
mnt_add_count() directly and mnt_set_count() is not used at all.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:36 -05:00
Al Viro 02125a8264 fix apparmor dereferencing potentially freed dentry, sanitize __d_path() API
__d_path() API is asking for trouble and in case of apparmor d_namespace_path()
getting just that.  The root cause is that when __d_path() misses the root
it had been told to look for, it stores the location of the most remote ancestor
in *root.  Without grabbing references.  Sure, at the moment of call it had
been pinned down by what we have in *path.  And if we raced with umount -l, we
could have very well stopped at vfsmount/dentry that got freed as soon as
prepend_path() dropped vfsmount_lock.

It is safe to compare these pointers with pre-existing (and known to be still
alive) vfsmount and dentry, as long as all we are asking is "is it the same
address?".  Dereferencing is not safe and apparmor ended up stepping into
that.  d_namespace_path() really wants to examine the place where we stopped,
even if it's not connected to our namespace.  As the result, it looked
at ->d_sb->s_magic of a dentry that might've been already freed by that point.
All other callers had been careful enough to avoid that, but it's really
a bad interface - it invites that kind of trouble.

The fix is fairly straightforward, even though it's bigger than I'd like:
	* prepend_path() root argument becomes const.
	* __d_path() is never called with NULL/NULL root.  It was a kludge
to start with.  Instead, we have an explicit function - d_absolute_root().
Same as __d_path(), except that it doesn't get root passed and stops where
it stops.  apparmor and tomoyo are using it.
	* __d_path() returns NULL on path outside of root.  The main
caller is show_mountinfo() and that's precisely what we pass root for - to
skip those outside chroot jail.  Those who don't want that can (and do)
use d_path().
	* __d_path() root argument becomes const.  Everyone agrees, I hope.
	* apparmor does *NOT* try to use __d_path() or any of its variants
when it sees that path->mnt is an internal vfsmount.  In that case it's
definitely not mounted anywhere and dentry_path() is exactly what we want
there.  Handling of sysctl()-triggered weirdness is moved to that place.
	* if apparmor is asked to do pathname relative to chroot jail
and __d_path() tells it we it's not in that jail, the sucker just calls
d_absolute_path() instead.  That's the other remaining caller of __d_path(),
BTW.
        * seq_path_root() does _NOT_ return -ENAMETOOLONG (it's stupid anyway -
the normal seq_file logics will take care of growing the buffer and redoing
the call of ->show() just fine).  However, if it gets path not reachable
from root, it returns SEQ_SKIP.  The only caller adjusted (i.e. stopped
ignoring the return value as it used to do).

Reviewed-by: John Johansen <john.johansen@canonical.com>
ACKed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
2011-12-06 23:57:18 -05:00
Al Viro d31da0f0ba mount_subtree() pointless use-after-free
d'oh... we'd carefully pinned mnt->mnt_sb down, dropped mnt and attempt
to grab s_umount on mnt->mnt_sb.  The trouble is, *mnt might've been
overwritten by now...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-11-22 12:31:21 -05:00
Al Viro ea441d1104 new helper: mount_subtree()
takes vfsmount and relative path, does lookup within that vfsmount
(possibly triggering automounts) and returns the result as root
of subtree suitable for return by ->mount() (i.e. a reference to
dentry and an active reference to its superblock grabbed, superblock
locked exclusive).

btrfs and nfs switched to it instead of open-coding the sucker.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-11-16 22:00:34 -05:00
Al Viro c133449587 switch create_mnt_ns() to saner calling conventions, fix double mntput() in nfs
Life is much saner if create_mnt_ns(mnt) drops mnt in case of error...
Switch it to such calling conventions, switch callers, fix double mntput() in
fs/nfs/super.c one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-11-16 16:12:14 -05:00
Jiri Kosina 2290c0d06d Merge branch 'master' into for-next
Sync with Linus tree to have 157550ff ("mtd: add GPMI-NAND driver
in the config and Makefile") as I have patch depending on that one.
2011-11-13 20:55:53 +01:00
Kautuk Consul a127e2d518 namespace: mnt_want_write: Remove unused label 'out'
I was studying the code and I saw that the out label is not being used
at all so I removed it and its usage from the function.

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-10-29 21:22:14 +02:00
Bryan Schumaker a877ee03ac vfs: add "device" tag to /proc/self/mountstats
nfsiostat was failing to find mounted filesystems on kernels after
2.6.38 because of changes to show_vfsstat() by commit
c7f404b40a.  This patch adds back the
"device" tag before the nfs server entry so scripts can parse the
mountstats file correctly.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
CC: stable@kernel.org [>=2.6.39]
Signed-off-by: Christoph Hellwig <hch@lst.de>
2011-10-28 13:55:08 +02:00
Trond Myklebust 815d405cef VFS: Fix the remaining automounter semantics regressions
The concensus seems to be that system calls such as stat() etc should
not trigger an automount.  Neither should the l* versions.

This patch therefore adds a LOOKUP_AUTOMOUNT flag to tag those lookups
that _should_ trigger an automount on the last path element.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[ Edited to leave out the cases that are already covered by LOOKUP_OPEN,
  LOOKUP_DIRECTORY and LOOKUP_CREATE - all of which also fundamentally
  force automounting for their own reasons   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-09-26 19:16:46 -07:00
Tim Chen 423e0ab086 VFS : mount lock scalability for internal mounts
For a number of file systems that don't have a mount point (e.g. sockfs
and pipefs), they are not marked as long term. Therefore in
mntput_no_expire, all locks in vfs_mount lock are taken instead of just
local cpu's lock to aggregate reference counts when we release
reference to file objects.  In fact, only local lock need to have been
taken to update ref counts as these file systems are in no danger of
going away until we are ready to unregister them.

The attached patch marks file systems using kern_mount without
mount point as long term.  The contentions of vfs_mount lock
is now eliminated.  Before un-registering such file system,
kern_unmount should be called to remove the long term flag and
make the mount point ready to be freed.

Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-24 10:08:32 -04:00
Kay Sievers f15146380d fs: seq_file - add event counter to simplify poll() support
Moving the event counter into the dynamically allocated 'struc seq_file'
allows poll() support without the need to allocate its own tracking
structure.

All current users are switched over to use the new counter.

Requested-by: Andrew Morton akpm@linux-foundation.org
Acked-by: NeilBrown <neilb@suse.de>
Tested-by: Lucas De Marchi lucas.demarchi@profusion.mobi
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20 20:47:50 -04:00
Roman Borisov 7c6e984dfc fs/namespace.c: bound mount propagation fix
This issue was discovered by users of busybox.  And the bug is actual for
busybox users, I don't know how it affects others.  Apparently, mount is
called with and without MS_SILENT, and this affects mount() behaviour.
But MS_SILENT is only supposed to affect kernel logging verbosity.

The following script was run in an empty test directory:

mkdir -p mount.dir mount.shared1 mount.shared2
touch mount.dir/a mount.dir/b
mount -vv --bind         mount.shared1 mount.shared1
mount -vv --make-rshared mount.shared1
mount -vv --bind         mount.shared2 mount.shared2
mount -vv --make-rshared mount.shared2
mount -vv --bind mount.shared2 mount.shared1
mount -vv --bind mount.dir     mount.shared2
ls -R mount.dir mount.shared1 mount.shared2
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
rm -f mount.dir/a mount.dir/b mount.dir/c
rmdir mount.dir mount.shared1 mount.shared2

mount -vv was used to show the mount() call arguments and result.
Output shows that flag argument has 0x00008000 = MS_SILENT bit:

mount: mount('mount.shared1','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared1','',0x0010c000,''):0
mount: mount('mount.shared2','mount.shared2','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared2','',0x0010c000,''):0
mount: mount('mount.shared2','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('mount.dir','mount.shared2','(null)',0x00009000,'(null)'):0
mount.dir:
a
b

mount.shared1:

mount.shared2:
a
b

After adding --loud option to remove MS_SILENT bit from just one mount cmd:

mkdir -p mount.dir mount.shared1 mount.shared2
touch mount.dir/a mount.dir/b
mount -vv --bind         mount.shared1 mount.shared1 2>&1
mount -vv --make-rshared mount.shared1               2>&1
mount -vv --bind         mount.shared2 mount.shared2 2>&1
mount -vv --loud --make-rshared mount.shared2               2>&1  # <-HERE
mount -vv --bind mount.shared2 mount.shared1         2>&1
mount -vv --bind mount.dir     mount.shared2         2>&1
ls -R mount.dir mount.shared1 mount.shared2      2>&1
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
rm -f mount.dir/a mount.dir/b mount.dir/c
rmdir mount.dir mount.shared1 mount.shared2

The result is different now - look closely at mount.shared1 directory listing.
Now it does show files 'a' and 'b':

mount: mount('mount.shared1','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared1','',0x0010c000,''):0
mount: mount('mount.shared2','mount.shared2','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared2','',0x00104000,''):0
mount: mount('mount.shared2','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('mount.dir','mount.shared2','(null)',0x00009000,'(null)'):0

mount.dir:
a
b

mount.shared1:
a
b

mount.shared2:
a
b

The analysis shows that MS_SILENT flag which is ON by default in any
busybox-> mount operations cames to flags_to_propagation_type function and
causes the error return while is_power_of_2 checking because the function
expects only one bit set.  This doesn't allow to do busybox->mount with
any --make-[r]shared, --make-[r]private etc options.

Moreover, the recently added flags_to_propagation_type() function doesn't
allow us to do such operations as --make-[r]private --make-[r]shared etc.
when MS_SILENT is on.  The idea or clearing the MS_SILENT flag came from
to Denys Vlasenko.

Signed-off-by: Roman Borisov <ext-roman.borisov@nokia.com>
Reported-by: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Chuck Ebbert <cebbert@redhat.com>
Cc: Alexander Shishkin <virtuoso@slind.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-26 07:26:44 -04:00
Linus Torvalds be85bccaa5 Revert "vfs: Export file system uuid via /proc/<pid>/mountinfo"
This reverts commit 93f1c20bc8.

It turns out that libmount misparses it because it adds a '-' character
in the uuid string, which libmount then incorrectly confuses with the
separator string (" - ") at the end of all the optional arguments.

Upstream libmount (in the util-linux tree) has been fixed, but until
that fix actually percolates up to users, we'd better not expose this
change in the kernel.

Let's revisit this later (possibly by exposing the UUID without any '-'
characters in it, avoiding the user-space bug).

Reported-by: Dave Jones <davej@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Karel Zak <kzak@redhat.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-12 13:35:56 -07:00
Mandeep Singh Baines 80cdc6dae7 fs: use appropriate printk priority levels
printk()s without a priority level default to KERN_WARNING.  To reduce
noise at KERN_WARNING, this patch set the priority level appriopriately
for unleveled printks()s.  This should be useful to folks that look at
dmesg warnings closely.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:10 -07:00
Al Viro b12cea9198 change the locking order for namespace_sem
Have it nested inside ->i_mutex.  Instead of using follow_down()
under namespace_sem, followed by grabbing i_mutex and checking that
mountpoint to be is not dead, do the following:
	grab i_mutex
	check that it's not dead
	grab namespace_sem
	see if anything is mounted there
	if not, we've won
	otherwise
		drop locks
		put_path on what we had
		replace with what's mounted
		retry everything with new mountpoint to be

New helper (lock_mount()) does that.  do_add_mount(), do_move_mount(),
do_loopback() and pivot_root() switched to it; in case of the last
two that eliminates a race we used to have - original code didn't
do follow_down().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-18 08:55:38 -04:00
Al Viro 27cb1572e3 fix deadlock in pivot_root()
Don't hold vfsmount_lock over the loop traversing ->mnt_parent;
do check_mnt(new.mnt) under namespace_sem instead; combined with
namespace_sem held over all that code it'll guarantee the stability
of ->mnt_parent chain all the way to the root.

Doing check_mnt() outside of namespace_sem in case of pivot_root()
is wrong anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-18 08:54:59 -04:00
Al Viro 9d412a43c3 vfs: split off vfsmount-related parts of vfs_kern_mount()
new function: mount_fs().  Does all work done by vfs_kern_mount()
except the allocation and filling of vfsmount; returns root dentry
or ERR_PTR().

vfs_kern_mount() switched to using it and taken to fs/namespace.c,
along with its wrappers.

alloc_vfsmnt()/free_vfsmnt() made static.

functions in namespace.c slightly reordered.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-17 22:10:41 -04:00
Al Viro 474a00ee13 kill simple_set_mnt()
not needed anymore, since all users (->get_sb() instances) are gone.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-17 21:31:32 -04:00
Linus Torvalds 054cfaacf8 Merge branch 'mnt_devname' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'mnt_devname' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  vfs: bury ->get_sb()
  nfs: switch NFS from ->get_sb() to ->mount()
  nfs: stop mangling ->mnt_devname on NFS
  vfs: new superblock methods to override /proc/*/mount{s,info}
  nfs: nfs_do_{ref,sub}mount() superblock argument is redundant
  nfs: make nfs_path() work without vfsmount
  nfs: store devname at disconnected NFS roots
  nfs: propagate devname to nfs{,4}_get_root()
2011-03-16 19:09:57 -07:00
Al Viro c7f404b40a vfs: new superblock methods to override /proc/*/mount{s,info}
a) ->show_devname(m, mnt) - what to put into devname columns in mounts,
mountinfo and mountstats
b) ->show_path(m, mnt) - what to put into relative path column in mountinfo

Leaving those NULL gives old behaviour.  NFS switched to using those.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-16 16:48:06 -04:00
Linus Torvalds 0f6e0e8448 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (33 commits)
  AppArmor: kill unused macros in lsm.c
  AppArmor: cleanup generated files correctly
  KEYS: Add an iovec version of KEYCTL_INSTANTIATE
  KEYS: Add a new keyctl op to reject a key with a specified error code
  KEYS: Add a key type op to permit the key description to be vetted
  KEYS: Add an RCU payload dereference macro
  AppArmor: Cleanup make file to remove cruft and make it easier to read
  SELinux: implement the new sb_remount LSM hook
  LSM: Pass -o remount options to the LSM
  SELinux: Compute SID for the newly created socket
  SELinux: Socket retains creator role and MLS attribute
  SELinux: Auto-generate security_is_socket_class
  TOMOYO: Fix memory leak upon file open.
  Revert "selinux: simplify ioctl checking"
  selinux: drop unused packet flow permissions
  selinux: Fix packet forwarding checks on postrouting
  selinux: Fix wrong checks for selinux_policycap_netpeer
  selinux: Fix check for xfrm selinux context algorithm
  ima: remove unnecessary call to ima_must_measure
  IMA: remove IMA imbalance checking
  ...
2011-03-16 09:15:43 -07:00
Aneesh Kumar K.V 93f1c20bc8 vfs: Export file system uuid via /proc/<pid>/mountinfo
We add a per superblock uuid field. File systems should
update the uuid in the fill_super callback

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-15 02:21:45 -04:00
James Morris fe3fa43039 Merge branch 'master' of git://git.infradead.org/users/eparis/selinux into next 2011-03-08 11:38:10 +11:00
Eric Paris ff36fe2c84 LSM: Pass -o remount options to the LSM
The VFS mount code passes the mount options to the LSM.  The LSM will remove
options it understands from the data and the VFS will then pass the remaining
options onto the underlying filesystem.  This is how options like the
SELinux context= work.  The problem comes in that -o remount never calls
into LSM code.  So if you include an LSM specific option it will get passed
to the filesystem and will cause the remount to fail.  An example of where
this is a problem is the 'seclabel' option.  The SELinux LSM hook will
print this word in /proc/mounts if the filesystem is being labeled using
xattrs.  If you pass this word on mount it will be silently stripped and
ignored.  But if you pass this word on remount the LSM never gets called
and it will be passed to the FS.  The FS doesn't know what seclabel means
and thus should fail the mount.  For example an ext3 fs mounted over loop

# mount -o loop /tmp/fs /mnt/tmp
# cat /proc/mounts | grep /mnt/tmp
/dev/loop0 /mnt/tmp ext3 rw,seclabel,relatime,errors=continue,barrier=0,data=ordered 0 0
# mount -o remount /mnt/tmp
mount: /mnt/tmp not mounted already, or bad option
# dmesg
EXT3-fs (loop0): error: unrecognized mount option "seclabel" or missing value

This patch passes the remount mount options to an new LSM hook.

Signed-off-by: Eric Paris <eparis@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
2011-03-03 16:12:27 -05:00
J. R. Okajima bf9faa2aa3 Unlock vfsmount_lock in do_umount
By the commit
	b3e19d9 2011-01-07 fs: scale mntget/mntput
vfsmount_lock was introduced around testing mnt_count.
Fix the mis-typed 'unlock'

Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-02-24 02:10:57 -05:00
Al Viro b1e75df45a tidy up around finish_automount()
do_add_mount() and mnt_clear_expiry() are not needed outside of
namespace.c anymore, now that namei has finish_automount() to
use.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-17 01:47:59 -05:00
Al Viro 15f9a3f3e1 don't drop newmnt on error in do_add_mount()
That gets rid of the kludge in finish_automount() - we need
to keep refcount on the vfsmount as-is until we evict it from
expiry list.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-17 01:41:58 -05:00
Al Viro 19a167af7c Take the completion of automount into new helper
... and shift it from namei.c to namespace.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-17 01:35:23 -05:00