Skip to content

K
Kernel

openeuler / Kernel
大约 1 年 前同步成功

通知 6
Star 0
Fork 0
K
Kernel

体验新版 GitCode，发现更多精彩内容 >>

切换分支/标签
  1. 14 10月, 2014 2 次提交
  3. 09 10月, 2014 1 次提交
    • I
      autofs - remove obsolete d_invalidate() from expire · b3ca406f
      由 Ian Kent 提交于 
      Biederman's umount-on-rmdir series changes d_invalidate() to sumarily remove
mounts under the passed in dentry regardless of whether they are busy
or not. So calling this in fs/autofs4/expire.c:autofs4_tree_busy() is
definitely the wrong thing to do becuase it will silently umount entries
instead of just cleaning stale dentrys.

But this call shouldn't be needed and testing shows that automounting
continues to function without it.

As Al Viro correctly surmises the original intent of the call was to
perform what shrink_dcache_parent() does.

If at some time in the future I see stale dentries accumulating
following failed mounts I'll revisit the issue and possibly add a
shrink_dcache_parent() call if needed.
Signed-off-by: NIan Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      b3ca406f
  5. 09 8月, 2014 5 次提交
  7. 04 7月, 2014 1 次提交
  9. 05 6月, 2014 1 次提交
  11. 07 5月, 2014 1 次提交
    • I
      autofs: fix lockref lookup · 6b6751f7
      由 Ian Kent 提交于 
      autofs needs to be able to see private data dentry flags for its dentrys
that are being created but not yet hashed and for its dentrys that have
been rmdir()ed but not yet freed.  It needs to do this so it can block
processes in these states until a status has been returned to indicate
the given operation is complete.

It does this by keeping two lists, active and expring, of dentrys in
this state and uses ->d_release() to keep them stable while it checks
the reference count to determine if they should be used.

But with the recent lockref changes dentrys being freed sometimes don't
transition to a reference count of 0 before being freed so autofs can
occassionally use a dentry that is invalid which can lead to a panic.
Signed-off-by: NIan Kent <raven@themaw.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6b6751f7
  13. 09 4月, 2014 1 次提交
  15. 24 1月, 2014 5 次提交
  17. 25 10月, 2013 2 次提交
  19. 17 9月, 2013 1 次提交
  21. 09 9月, 2013 1 次提交
    • I
      autofs4 - fix device ioctl mount lookup · ac838719
      由 Ian Kent 提交于 
      When reconnecting to automounts at startup an autofs ioctl is used
to find the device and inode of existing mounts so they can be used
to open a file descriptor of possibly covered mounts.

At this time the the caller might not yet "own" the mount so it can
trigger calling ->d_automount(). This causes automount to hang when
trying to reconnect to direct or offset mount types.

Consequently kern_path() can't be used but kern_path_mountpoint() can be.
Signed-off-by: NIan Kent <raven@themaw.net>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      ac838719
  23. 05 7月, 2013 1 次提交
  25. 29 6月, 2013 1 次提交
  27. 07 5月, 2013 2 次提交
  29. 04 3月, 2013 1 次提交
    • E
      fs: Limit sys_mount to only request filesystem modules. · 7f78e035
      由 Eric W. Biederman 提交于 
      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: NSerge Hallyn <serge.hallyn@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Reported-by: NKees Cook <keescook@google.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
      7f78e035
  31. 02 3月, 2013 2 次提交
  33. 26 2月, 2013 1 次提交
  35. 23 2月, 2013 1 次提交
  37. 14 12月, 2012 2 次提交
    • I
      autofs4 - use simple_empty() for empty directory check · 0259cb02
      由 Ian Kent 提交于 
      For direct (and offset) mounts, if an automounted mount is manually
umounted the trigger mount dentry can appear non-empty causing it to
not trigger mounts. This can also happen if there is a file handle
leak in a user space automounting application.

This happens because, when a ioctl control file handle is opened
on the mount, a cursor dentry is created which causes list_empty()
to see the dentry as non-empty. Since there is a case where listing
the directory of these dentrys is needed, the use of dcache_dir_*()
functions for .open() and .release() is needed.

Consequently simple_empty() must be used instead of list_empty()
when checking for an empty directory.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0259cb02
    • I
      autofs4 - dont clear DCACHE_NEED_AUTOMOUNT on rootless mount · f55fb0c2
      由 Ian Kent 提交于 
      The DCACHE_NEED_AUTOMOUNT flag is cleared on mount and set on expire
for autofs rootless multi-mount dentrys to prevent unnecessary calls
to ->d_automount().

Since DCACHE_MANAGE_TRANSIT is always set on autofs dentrys ->d_managed()
is always called so the check can be done in ->d_manage() without the
need to change the flag. This still avoids unnecessary calls to
->d_automount(), adds negligible overhead and eliminates a seriously
ugly check in the expire code.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f55fb0c2
  39. 15 11月, 2012 1 次提交
    • E
      userns: Support autofs4 interacing with multiple user namespaces · 45634cd8
      由 Eric W. Biederman 提交于 
      Use kuid_t and kgid_t in struct autofs_info and struct autofs_wait_queue.

When creating directories and symlinks default the uid and gid of
the mount requester to the global root uid and gid.  autofs4_wait
will update these fields when a mount is requested.

When generating autofsv5 packets report the uid and gid of the mount
requestor in user namespace of the process that opened the pipe,
reporting unmapped uids and gids as overflowuid and overflowgid.

In autofs_dev_ioctl_requester return the uid and gid of the last mount
requester converted into the calling processes user namespace.  When the
uid or gid don't map return overflowuid and overflowgid as appropriate,
allowing failure to find a mount requester to be distinguished from
failure to map a mount requester.

The uid and gid mount options specifying the user and group of the
root autofs inode are converted into kuid and kgid as they are parsed
defaulting to the current uid and current gid of the process that
mounts autofs.

Mounting of autofs for the present remains confined to processes in
the initial user namespace.

Cc: Ian Kent <raven@themaw.net>
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
      45634cd8
  41. 11 10月, 2012 1 次提交
  43. 27 9月, 2012 2 次提交
  45. 17 8月, 2012 2 次提交
    • I
      autofs4 - fix expire check · d807ff83
      由 Ian Kent 提交于 
      In some cases when an autofs indirect mount is contained in a file
system that is marked as shared (such as when systemd does the
equivalent of "mount --make-rshared /" early in the boot), mounts
stop expiring.

When this happens the first expiry check on a mountpoint dentry in
autofs_expire_indirect() sees a mountpoint dentry with a higher
than minimal reference count. Consequently the dentry is condidered
busy and the actual expiry check is never done.

This particular check was originally meant as an optimisation to
detect a path walk in progress but with the addition of rcu-walk
it can be ineffective anyway.

Removing the test allows automounts to expire again since the
actual expire check doesn't rely on the dentry reference count.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d807ff83
    • I
      autofs4 - fix get_next_positive_subdir() · a45440f0
      由 Ian Kent 提交于 
      Following a report of a crash during an automount expire I found that
the locking in fs/autofs4/expire.c:get_next_positive_subdir() was wrong.
Not only is the locking wrong but the function is more complex than it
needs to be.

The function is meant to calculate (and dget) the next entry in the list
of directories contained in the root of an autofs mount point (an autofs
indirect mount to be precise). The main problem was that the d_lock of
the owner of the list was not being taken when walking the list, which
lead to list corruption under load. The only other lock that needs to
be taken is against the next dentry candidate so it can be checked for
usability.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a45440f0
  47. 23 7月, 2012 1 次提交
  49. 14 7月, 2012 1 次提交
    • A
      stop passing nameidata to ->lookup() · 00cd8dd3
      由 Al Viro 提交于 
      Just the flags; only NFS cares even about that, but there are
legitimate uses for such argument.  And getting rid of that
completely would require splitting ->lookup() into a couple
of methods (at least), so let's leave that alone for now...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      00cd8dd3