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  1. 04 11月, 2015 1 次提交
  3. 03 11月, 2015 4 次提交
  5. 01 11月, 2015 1 次提交
  7. 17 10月, 2015 1 次提交
    • M
      mm, fs: obey gfp_mapping for add_to_page_cache() · 063d99b4
      由 Michal Hocko 提交于 
      Commit 6afdb859 ("mm: do not ignore mapping_gfp_mask in page cache
allocation paths") has caught some users of hardcoded GFP_KERNEL used in
the page cache allocation paths.  This, however, wasn't complete and
there were others which went unnoticed.

Dave Chinner has reported the following deadlock for xfs on loop device:
: With the recent merge of the loop device changes, I'm now seeing
: XFS deadlock on my single CPU, 1GB RAM VM running xfs/073.
:
: The deadlocked is as follows:
:
: kloopd1: loop_queue_read_work
:       xfs_file_iter_read
:       lock XFS inode XFS_IOLOCK_SHARED (on image file)
:       page cache read (GFP_KERNEL)
:       radix tree alloc
:       memory reclaim
:       reclaim XFS inodes
:       log force to unpin inodes
:       <wait for log IO completion>
:
: xfs-cil/loop1: <does log force IO work>
:       xlog_cil_push
:       xlog_write
:       <loop issuing log writes>
:               xlog_state_get_iclog_space()
:               <blocks due to all log buffers under write io>
:               <waits for IO completion>
:
: kloopd1: loop_queue_write_work
:       xfs_file_write_iter
:       lock XFS inode XFS_IOLOCK_EXCL (on image file)
:       <wait for inode to be unlocked>
:
: i.e. the kloopd, with it's split read and write work queues, has
: introduced a dependency through memory reclaim. i.e. that writes
: need to be able to progress for reads make progress.
:
: The problem, fundamentally, is that mpage_readpages() does a
: GFP_KERNEL allocation, rather than paying attention to the inode's
: mapping gfp mask, which is set to GFP_NOFS.
:
: The didn't used to happen, because the loop device used to issue
: reads through the splice path and that does:
:
:       error = add_to_page_cache_lru(page, mapping, index,
:                       GFP_KERNEL & mapping_gfp_mask(mapping));

This has changed by commit aa4d8616 ("block: loop: switch to VFS
ITER_BVEC").

This patch changes mpage_readpage{s} to follow gfp mask set for the
mapping.  There are, however, other places which are doing basically the
same.

lustre:ll_dir_filler is doing GFP_KERNEL from the function which
apparently uses GFP_NOFS for other allocations so let's make this
consistent.

cifs:readpages_get_pages is called from cifs_readpages and
__cifs_readpages_from_fscache called from the same path obeys mapping
gfp.

ramfs_nommu_expand_for_mapping is hardcoding GFP_KERNEL as well
regardless it uses mapping_gfp_mask for the page allocation.

ext4_mpage_readpages is the called from the page cache allocation path
same as read_pages and read_cache_pages

As I've noticed in my previous post I cannot say I would be happy about
sprinkling mapping_gfp_mask all over the place and it sounds like we
should drop gfp_mask argument altogether and use it internally in
__add_to_page_cache_locked that would require all the filesystems to use
mapping gfp consistently which I am not sure is the case here.  From a
quick glance it seems that some file system use it all the time while
others are selective.
Signed-off-by: NMichal Hocko <mhocko@suse.com>
Reported-by: NDave Chinner <david@fromorbit.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      063d99b4
  9. 04 10月, 2015 1 次提交
  11. 02 10月, 2015 1 次提交
    • S
      [SMB3] Do not fall back to SMBWriteX in set_file_size error cases · 646200a0
      由 Steve French 提交于 
      The error paths in set_file_size for cifs and smb3 are incorrect.

In the unlikely event that a server did not support set file info
of the file size, the code incorrectly falls back to trying SMBWriteX
(note that only the original core SMB Write, used for example by DOS,
can set the file size this way - this actually  does not work for the more
recent SMBWriteX).  The idea was since the old DOS SMB Write could set
the file size if you write zero bytes at that offset then use that if
server rejects the normal set file info call.

Fortunately the SMBWriteX will never be sent on the wire (except when
file size is zero) since the length and offset fields were reversed
in the two places in this function that call SMBWriteX causing
the fall back path to return an error. It is also important to never call
an SMB request from an SMB2/sMB3 session (which theoretically would
be possible, and can cause a brief session drop, although the client
recovers) so this should be fixed.  In practice this path does not happen
with modern servers but the error fall back to SMBWriteX is clearly wrong.

Removing the calls to SMBWriteX in the error paths in cifs_set_file_size

Pointed out by PaX/grsecurity team
Signed-off-by: NSteve French <steve.french@primarydata.com>
Reported-by: NPaX Team <pageexec@freemail.hu>
CC: Emese Revfy <re.emese@gmail.com>
CC: Brad Spengler <spender@grsecurity.net>
CC: Stable <stable@vger.kernel.org>
      646200a0
  13. 26 9月, 2015 1 次提交
  15. 24 9月, 2015 2 次提交
  17. 23 9月, 2015 2 次提交
  19. 12 9月, 2015 1 次提交
  21. 11 9月, 2015 2 次提交
  23. 05 9月, 2015 1 次提交
    • K
      fs: create and use seq_show_option for escaping · a068acf2
      由 Kees Cook 提交于 
      Many file systems that implement the show_options hook fail to correctly
escape their output which could lead to unescaped characters (e.g.  new
lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files.  This
could lead to confusion, spoofed entries (resulting in things like
systemd issuing false d-bus "mount" notifications), and who knows what
else.  This looks like it would only be the root user stepping on
themselves, but it's possible weird things could happen in containers or
in other situations with delegated mount privileges.

Here's an example using overlay with setuid fusermount trusting the
contents of /proc/mounts (via the /etc/mtab symlink).  Imagine the use
of "sudo" is something more sneaky:

  $ BASE="ovl"
  $ MNT="$BASE/mnt"
  $ LOW="$BASE/lower"
  $ UP="$BASE/upper"
  $ WORK="$BASE/work/ 0 0
  none /proc fuse.pwn user_id=1000"
  $ mkdir -p "$LOW" "$UP" "$WORK"
  $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt
  $ cat /proc/mounts
  none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0
  none /proc fuse.pwn user_id=1000 0 0
  $ fusermount -u /proc
  $ cat /proc/mounts
  cat: /proc/mounts: No such file or directory

This fixes the problem by adding new seq_show_option and
seq_show_option_n helpers, and updating the vulnerable show_option
handlers to use them as needed.  Some, like SELinux, need to be open
coded due to unusual existing escape mechanisms.

[akpm@linux-foundation.org: add lost chunk, per Kees]
[keescook@chromium.org: seq_show_option should be using const parameters]
Signed-off-by: NKees Cook <keescook@chromium.org>
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Acked-by: NJan Kara <jack@suse.com>
Acked-by: NPaul Moore <paul@paul-moore.com>
Cc: J. R. Okajima <hooanon05g@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a068acf2
  25. 20 8月, 2015 3 次提交
  27. 30 6月, 2015 1 次提交
  29. 29 6月, 2015 4 次提交
  31. 28 6月, 2015 6 次提交
  33. 21 5月, 2015 5 次提交
  35. 20 5月, 2015 1 次提交
  37. 11 5月, 2015 2 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