linux-toradex.git/fs/f2fs, branch v4.12

crypto: Work around deallocated stack frame reference gcc bug on sparc.

2017-06-08T09:36:03+00:00

On sparc, if we have an alloca() like situation, as is the case with
SHASH_DESC_ON_STACK(), we can end up referencing deallocated stack
memory.  The result can be that the value is clobbered if a trap
or interrupt arrives at just the right instruction.

It only occurs if the function ends returning a value from that
alloca() area and that value can be placed into the return value
register using a single instruction.

For example, in lib/libcrc32c.c:crc32c() we end up with a return
sequence like:

        return  %i7+8
         lduw   [%o5+16], %o0   ! MEM[(u32 *)__shash_desc.1_10 + 16B],

%o5 holds the base of the on-stack area allocated for the shash
descriptor.  But the return released the stack frame and the
register window.

So if an intererupt arrives between 'return' and 'lduw', then
the value read at %o5+16 can be corrupted.

Add a data compiler barrier to work around this problem.  This is
exactly what the gcc fix will end up doing as well, and it absolutely
should not change the code generated for other cpus (unless gcc
on them has the same bug :-)

With crucial insight from Eric Sandeen.

Cc: 
Reported-by: Anatoly Pugachev 
Signed-off-by: David S. Miller 
Signed-off-by: Herbert Xu

Merge branch 'akpm' (patches from Andrew)

2017-05-09T01:17:56+00:00

Merge more updates from Andrew Morton:

 - the rest of MM

 - various misc things

 - procfs updates

 - lib/ updates

 - checkpatch updates

 - kdump/kexec updates

 - add kvmalloc helpers, use them

 - time helper updates for Y2038 issues. We're almost ready to remove
   current_fs_time() but that awaits a btrfs merge.

 - add tracepoints to DAX

* emailed patches from Andrew Morton : (114 commits)
  drivers/staging/ccree/ssi_hash.c: fix build with gcc-4.4.4
  selftests/vm: add a test for virtual address range mapping
  dax: add tracepoint to dax_insert_mapping()
  dax: add tracepoint to dax_writeback_one()
  dax: add tracepoints to dax_writeback_mapping_range()
  dax: add tracepoints to dax_load_hole()
  dax: add tracepoints to dax_pfn_mkwrite()
  dax: add tracepoints to dax_iomap_pte_fault()
  mtd: nand: nandsim: convert to memalloc_noreclaim_*()
  treewide: convert PF_MEMALLOC manipulations to new helpers
  mm: introduce memalloc_noreclaim_{save,restore}
  mm: prevent potential recursive reclaim due to clearing PF_MEMALLOC
  mm/huge_memory.c: deposit a pgtable for DAX PMD faults when required
  mm/huge_memory.c: use zap_deposited_table() more
  time: delete CURRENT_TIME_SEC and CURRENT_TIME
  gfs2: replace CURRENT_TIME with current_time
  apparmorfs: replace CURRENT_TIME with current_time()
  lustre: replace CURRENT_TIME macro
  fs: ubifs: replace CURRENT_TIME_SEC with current_time
  fs: ufs: use ktime_get_real_ts64() for birthtime
  ...

fs: f2fs: use ktime_get_real_seconds for sit_info times

2017-05-09T00:15:15+00:00

CURRENT_TIME_SEC is not y2038 safe.

Replace use of CURRENT_TIME_SEC with ktime_get_real_seconds in segment
timestamps used by GC algorithm including the segment mtime timestamps.

Link: http://lkml.kernel.org/r/1491613030-11599-2-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Deepa Dinamani 
Reviewed-by: Arnd Bergmann 
Cc: Jaegeuk Kim 
Cc: Chao Yu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce kv[mz]alloc helpers

2017-05-09T00:15:12+00:00

Patch series "kvmalloc", v5.

There are many open coded kmalloc with vmalloc fallback instances in the
tree.  Most of them are not careful enough or simply do not care about
the underlying semantic of the kmalloc/page allocator which means that
a) some vmalloc fallbacks are basically unreachable because the kmalloc
part will keep retrying until it succeeds b) the page allocator can
invoke a really disruptive steps like the OOM killer to move forward
which doesn't sound appropriate when we consider that the vmalloc
fallback is available.

As it can be seen implementing kvmalloc requires quite an intimate
knowledge if the page allocator and the memory reclaim internals which
strongly suggests that a helper should be implemented in the memory
subsystem proper.

Most callers, I could find, have been converted to use the helper
instead.  This is patch 6.  There are some more relying on __GFP_REPEAT
in the networking stack which I have converted as well and Eric Dumazet
was not opposed [2] to convert them as well.

[1] http://lkml.kernel.org/r/20170130094940.13546-1-mhocko@kernel.org
[2] http://lkml.kernel.org/r/1485273626.16328.301.camel@edumazet-glaptop3.roam.corp.google.com

This patch (of 9):

Using kmalloc with the vmalloc fallback for larger allocations is a
common pattern in the kernel code.  Yet we do not have any common helper
for that and so users have invented their own helpers.  Some of them are
really creative when doing so.  Let's just add kv[mz]alloc and make sure
it is implemented properly.  This implementation makes sure to not make
a large memory pressure for > PAGE_SZE requests (__GFP_NORETRY) and also
to not warn about allocation failures.  This also rules out the OOM
killer as the vmalloc is a more approapriate fallback than a disruptive
user visible action.

This patch also changes some existing users and removes helpers which
are specific for them.  In some cases this is not possible (e.g.
ext4_kvmalloc, libcfs_kvzalloc) because those seems to be broken and
require GFP_NO{FS,IO} context which is not vmalloc compatible in general
(note that the page table allocation is GFP_KERNEL).  Those need to be
fixed separately.

While we are at it, document that __vmalloc{_node} about unsupported gfp
mask because there seems to be a lot of confusion out there.
kvmalloc_node will warn about GFP_KERNEL incompatible (which are not
superset) flags to catch new abusers.  Existing ones would have to die
slowly.

[sfr@canb.auug.org.au: f2fs fixup]
  Link: http://lkml.kernel.org/r/20170320163735.332e64b7@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170306103032.2540-2-mhocko@kernel.org
Signed-off-by: Michal Hocko 
Signed-off-by: Stephen Rothwell 
Reviewed-by: Andreas Dilger 	[ext4 part]
Acked-by: Vlastimil Babka 
Cc: John Hubbard 
Cc: David Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'for-f2fs-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

2017-05-08T19:24:17+00:00

Pull f2fs updates from Jaegeuk Kim:
 "In this round, we've focused on enhancing performance with regards to
  block allocation, GC, and discard/in-place-update IO controls. There
  are a bunch of clean-ups as well as minor bug fixes.

  Enhancements:
   - disable heap-based allocation by default
   - issue small-sized discard commands by default
   - change the policy of data hotness for logging
   - distinguish IOs in terms of size and wbc type
   - start SSR earlier to avoid foreground GC
   - enhance data structures managing discard commands
   - enhance in-place update flow
   - add some more fault injection routines
   - secure one more xattr entry

  Bug fixes:
   - calculate victim cost for GC correctly
   - remain correct victim segment number for GC
   - race condition in nid allocator and initializer
   - stale pointer produced by atomic_writes
   - fix missing REQ_SYNC for flush commands
   - handle missing errors in more corner cases"

* tag 'for-f2fs-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (111 commits)
  f2fs: fix a mount fail for wrong next_scan_nid
  f2fs: enhance scalability of trace macro
  f2fs: relocate inode_{,un}lock in F2FS_IOC_SETFLAGS
  f2fs: Make flush bios explicitely sync
  f2fs: show available_nids in f2fs/status
  f2fs: flush dirty nats periodically
  f2fs: introduce CP_TRIMMED_FLAG to avoid unneeded discard
  f2fs: allow cpc->reason to indicate more than one reason
  f2fs: release cp and dnode lock before IPU
  f2fs: shrink size of struct discard_cmd
  f2fs: don't hold cmd_lock during waiting discard command
  f2fs: nullify fio->encrypted_page for each writes
  f2fs: sanity check segment count
  f2fs: introduce valid_ipu_blkaddr to clean up
  f2fs: lookup extent cache first under IPU scenario
  f2fs: reconstruct code to write a data page
  f2fs: introduce __wait_discard_cmd
  f2fs: introduce __issue_discard_cmd
  f2fs: enable small discard by default
  f2fs: delay awaking discard thread
  ...

f2fs: switch to using fscrypt_match_name()

2017-05-04T15:44:39+00:00

Switch f2fs directory searches to use the fscrypt_match_name() helper
function.  There should be no functional change.

Signed-off-by: Eric Biggers 
Acked-by: Jaegeuk Kim 
Signed-off-by: Theodore Ts'o

fscrypt: avoid collisions when presenting long encrypted filenames

2017-05-04T15:44:36+00:00

When accessing an encrypted directory without the key, userspace must
operate on filenames derived from the ciphertext names, which contain
arbitrary bytes.  Since we must support filenames as long as NAME_MAX,
we can't always just base64-encode the ciphertext, since that may make
it too long.  Currently, this is solved by presenting long names in an
abbreviated form containing any needed filesystem-specific hashes (e.g.
to identify a directory block), then the last 16 bytes of ciphertext.
This needs to be sufficient to identify the actual name on lookup.

However, there is a bug.  It seems to have been assumed that due to the
use of a CBC (ciphertext block chaining)-based encryption mode, the last
16 bytes (i.e. the AES block size) of ciphertext would depend on the
full plaintext, preventing collisions.  However, we actually use CBC
with ciphertext stealing (CTS), which handles the last two blocks
specially, causing them to appear "flipped".  Thus, it's actually the
second-to-last block which depends on the full plaintext.

This caused long filenames that differ only near the end of their
plaintexts to, when observed without the key, point to the wrong inode
and be undeletable.  For example, with ext4:

    # echo pass | e4crypt add_key -p 16 edir/
    # seq -f "edir/abcdefghijklmnopqrstuvwxyz012345%.0f" 100000 | xargs touch
    # find edir/ -type f | xargs stat -c %i | sort | uniq | wc -l
    100000
    # sync
    # echo 3 > /proc/sys/vm/drop_caches
    # keyctl new_session
    # find edir/ -type f | xargs stat -c %i | sort | uniq | wc -l
    2004
    # rm -rf edir/
    rm: cannot remove 'edir/_A7nNFi3rhkEQlJ6P,hdzluhODKOeWx5V': Structure needs cleaning
    ...

To fix this, when presenting long encrypted filenames, encode the
second-to-last block of ciphertext rather than the last 16 bytes.

Although it would be nice to solve this without depending on a specific
encryption mode, that would mean doing a cryptographic hash like SHA-256
which would be much less efficient.  This way is sufficient for now, and
it's still compatible with encryption modes like HEH which are strong
pseudorandom permutations.  Also, changing the presented names is still
allowed at any time because they are only provided to allow applications
to do things like delete encrypted directories.  They're not designed to
be used to persistently identify files --- which would be hard to do
anyway, given that they're encrypted after all.

For ease of backports, this patch only makes the minimal fix to both
ext4 and f2fs.  It leaves ubifs as-is, since ubifs doesn't compare the
ciphertext block yet.  Follow-on patches will clean things up properly
and make the filesystems use a shared helper function.

Fixes: 5de0b4d0cd15 ("ext4 crypto: simplify and speed up filename encryption")
Reported-by: Gwendal Grignou 
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers 
Signed-off-by: Theodore Ts'o

f2fs: check entire encrypted bigname when finding a dentry

2017-05-04T15:44:35+00:00

If user has no key under an encrypted dir, fscrypt gives digested dentries.
Previously, when looking up a dentry, f2fs only checks its hash value with
first 4 bytes of the digested dentry, which didn't handle hash collisions fully.
This patch enhances to check entire dentry bytes likewise ext4.

Eric reported how to reproduce this issue by:

 # seq -f "edir/abcdefghijklmnopqrstuvwxyz012345%.0f" 100000 | xargs touch
 # find edir -type f | xargs stat -c %i | sort | uniq | wc -l
100000
 # sync
 # echo 3 > /proc/sys/vm/drop_caches
 # keyctl new_session
 # find edir -type f | xargs stat -c %i | sort | uniq | wc -l
99999

Cc: 
Reported-by: Eric Biggers 
Signed-off-by: Jaegeuk Kim 
(fixed f2fs_dentry_hash() to work even when the hash is 0)
Signed-off-by: Eric Biggers 
Signed-off-by: Theodore Ts'o

f2fs: sync f2fs_lookup() with ext4_lookup()

2017-05-04T15:44:34+00:00

As for ext4, now that fscrypt_has_permitted_context() correctly handles
the case where we have the key for the parent directory but not the
child, f2fs_lookup() no longer has to work around it.  Also add the same
warning message that ext4 uses.

Signed-off-by: Eric Biggers 
Signed-off-by: Theodore Ts'o

f2fs: fix a mount fail for wrong next_scan_nid

2017-05-04T02:00:30+00:00

-write_checkpoint
   -do_checkpoint
      -next_free_nid    <--- something wrong with next free nid

-f2fs_fill_super
   -build_node_manager
      -build_free_nids
          -get_current_nat_page
             -__get_meta_page   <--- attempt to access beyond end of device

Signed-off-by: Yunlei He 
Signed-off-by: Jaegeuk Kim