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  1. 24 5月, 2016 6 次提交
  3. 11 5月, 2016 2 次提交
  5. 15 1月, 2016 1 次提交
    • V
      kmemcg: account certain kmem allocations to memcg · 5d097056
      由 Vladimir Davydov 提交于 
      Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5d097056
  7. 09 12月, 2015 1 次提交
    • A
      don't put symlink bodies in pagecache into highmem · 21fc61c7
      由 Al Viro 提交于 
      kmap() in page_follow_link_light() needed to go - allowing to hold
an arbitrary number of kmaps for long is a great way to deadlocking
the system.

new helper (inode_nohighmem(inode)) needs to be used for pagecache
symlinks inodes; done for all in-tree cases.  page_follow_link_light()
instrumented to yell about anything missed.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      21fc61c7
  9. 07 12月, 2015 1 次提交
  11. 26 6月, 2015 1 次提交
  13. 24 6月, 2015 1 次提交
  15. 11 5月, 2015 3 次提交
    • A
      don't pass nameidata to ->follow_link() · 6e77137b
      由 Al Viro 提交于 
      its only use is getting passed to nd_jump_link(), which can obtain
it from current->nameidata
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      6e77137b
    • A
      new ->follow_link() and ->put_link() calling conventions · 680baacb
      由 Al Viro 提交于 
      a) instead of storing the symlink body (via nd_set_link()) and returning
an opaque pointer later passed to ->put_link(), ->follow_link() _stores_
that opaque pointer (into void * passed by address by caller) and returns
the symlink body.  Returning ERR_PTR() on error, NULL on jump (procfs magic
symlinks) and pointer to symlink body for normal symlinks.  Stored pointer
is ignored in all cases except the last one.

Storing NULL for opaque pointer (or not storing it at all) means no call
of ->put_link().

b) the body used to be passed to ->put_link() implicitly (via nameidata).
Now only the opaque pointer is.  In the cases when we used the symlink body
to free stuff, ->follow_link() now should store it as opaque pointer in addition
to returning it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      680baacb
    • A
      befs: switch to simple_follow_link() · d0deec19
      由 Al Viro 提交于 
      Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      d0deec19
  17. 17 4月, 2015 3 次提交
  19. 16 4月, 2015 1 次提交
  21. 18 2月, 2015 1 次提交
  23. 14 12月, 2014 1 次提交
  25. 20 11月, 2014 1 次提交
  27. 14 10月, 2014 1 次提交
  29. 09 8月, 2014 1 次提交
  31. 19 6月, 2014 1 次提交
  33. 07 6月, 2014 4 次提交
  35. 04 4月, 2014 3 次提交
  37. 13 3月, 2014 1 次提交
    • T
      fs: push sync_filesystem() down to the file system's remount_fs() · 02b9984d
      由 Theodore Ts'o 提交于 
      Previously, the no-op "mount -o mount /dev/xxx" operation when the
file system is already mounted read-write causes an implied,
unconditional syncfs().  This seems pretty stupid, and it's certainly
documented or guaraunteed to do this, nor is it particularly useful,
except in the case where the file system was mounted rw and is getting
remounted read-only.

However, it's possible that there might be some file systems that are
actually depending on this behavior.  In most file systems, it's
probably fine to only call sync_filesystem() when transitioning from
read-write to read-only, and there are some file systems where this is
not needed at all (for example, for a pseudo-filesystem or something
like romfs).
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Jan Kara <jack@suse.cz>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Anders Larsen <al@alarsen.net>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: Petr Vandrovec <petr@vandrovec.name>
Cc: xfs@oss.sgi.com
Cc: linux-btrfs@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Cc: codalist@coda.cs.cmu.edu
Cc: linux-ext4@vger.kernel.org
Cc: linux-f2fs-devel@lists.sourceforge.net
Cc: fuse-devel@lists.sourceforge.net
Cc: cluster-devel@redhat.com
Cc: linux-mtd@lists.infradead.org
Cc: jfs-discussion@lists.sourceforge.net
Cc: linux-nfs@vger.kernel.org
Cc: linux-nilfs@vger.kernel.org
Cc: linux-ntfs-dev@lists.sourceforge.net
Cc: ocfs2-devel@oss.oracle.com
Cc: reiserfs-devel@vger.kernel.org
      02b9984d
  39. 25 1月, 2014 1 次提交
  41. 25 10月, 2013 1 次提交
  43. 29 6月, 2013 1 次提交
  45. 01 6月, 2013 1 次提交
  47. 18 3月, 2013 1 次提交
  49. 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