fscrypt_put_encryption_info() is only called when evicting an inode, so
the 'struct fscrypt_info *ci' parameter is always NULL, and there cannot
be races with other threads.  This was cruft left over from the broken
key revocation code.  Remove the unused parameter and the cmpxchg().

Also remove the #ifdefs around the fscrypt_put_encryption_info() calls,
since fscrypt_notsupp.h defines a no-op stub for it.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Document that encryption reduces the maximum length of a symlink target
slightly.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Filesystems don't need fscrypt_fname_encrypted_size() anymore, so
unexport it and move it to fscrypt_private.h.

We also never calculate the encrypted size of a filename without having
the fscrypt_info present since it is needed to know the amount of
NUL-padding which is determined by the encryption policy, and also we
will always truncate the NUL-padding to the maximum filename length.
Therefore, also make fscrypt_fname_encrypted_size() assume that the
fscrypt_info is present, and make it truncate the returned length to the
specified max_len.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Previously fscrypt_fname_alloc_buffer() was used to allocate buffers for
both presented (decrypted or encoded) and encrypted filenames.  That was
confusing, because it had to allocate the worst-case size for either,
e.g. including NUL-padding even when it was meaningless.

But now that fscrypt_setup_filename() no longer calls it, it is only
used in the ->get_link() and ->readdir() paths, which specifically want
a buffer for presented filenames.  Therefore, switch the behavior over
to allocating the buffer for presented filenames only.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Currently, when encrypting a filename (either a real filename or a
symlink target) we calculate the amount of NUL-padding twice: once
before encryption and once during encryption in fname_encrypt().  It is
needed before encryption to allocate the needed buffer size as well as
calculate the size the symlink target will take up on-disk before
creating the symlink inode.  Calculating the size during encryption as
well is redundant.

Remove this redundancy by always calculating the exact size beforehand,
and making fname_encrypt() just add as much NUL padding as is needed to
fill the output buffer.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Now that all filesystems have been converted to use the symlink helper
functions, they no longer need the declaration of 'struct
fscrypt_symlink_data'.  Move it from fscrypt.h to fscrypt_private.h.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fscrypt_fname_usr_to_disk() sounded very generic but was actually only
used to encrypt symlinks.  Remove it now that all filesystems have been
switched over to fscrypt_encrypt_symlink().
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ubifs_symlink() forgot to free the kmalloc()'ed buffer holding the
encrypted symlink target, creating a memory leak.  Fix it.

(UBIFS could actually encrypt directly into ui->data, removing the
temporary buffer, but that is left for the patch that switches to use
the symlink helper functions.)

Fixes: ca7f85be ("ubifs: Add support for encrypted symlinks")
Cc: <stable@vger.kernel.org> # v4.10+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Filesystems also have duplicate code to support ->get_link() on
encrypted symlinks.  Factor it out into a new function
fscrypt_get_symlink().  It takes in the contents of the encrypted
symlink on-disk and provides the target (decrypted or encoded) that
should be returned from ->get_link().
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Currently, filesystems supporting fscrypt need to implement some tricky
logic when creating encrypted symlinks, including handling a peculiar
on-disk format (struct fscrypt_symlink_data) and correctly calculating
the size of the encrypted symlink.  Introduce helper functions to make
things a bit easier:

- fscrypt_prepare_symlink() computes and validates the size the symlink
  target will require on-disk.
- fscrypt_encrypt_symlink() creates the encrypted target if needed.

The new helpers actually fix some subtle bugs.  First, when checking
whether the symlink target was too long, filesystems didn't account for
the fact that the NUL padding is meant to be truncated if it would cause
the maximum length to be exceeded, as is done for filenames in
directories.  Consequently users would receive ENAMETOOLONG when
creating symlinks close to what is supposed to be the maximum length.
For example, with EXT4 with a 4K block size, the maximum symlink target
length in an encrypted directory is supposed to be 4093 bytes (in
comparison to 4095 in an unencrypted directory), but in
FS_POLICY_FLAGS_PAD_32-mode only up to 4064 bytes were accepted.

Second, symlink targets of "." and ".." were not being encrypted, even
though they should be, as these names are special in *directory entries*
but not in symlink targets.  Fortunately, we can fix this simply by
starting to encrypt them, as old kernels already accept them in
encrypted form.

Third, the output string length the filesystems were providing when
doing the actual encryption was incorrect, as it was forgotten to
exclude 'sizeof(struct fscrypt_symlink_data)'.  Fortunately though, this
bug didn't make a difference.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fscrypt.h included way too many other headers, given that it is included
by filesystems both with and without encryption support.  Trim down the
includes list by moving the needed includes into more appropriate
places, and removing the unneeded ones.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Only fs/crypto/fname.c cares about treating the "." and ".." filenames
specially with regards to encryption, so move fscrypt_is_dot_dotdot()
from fscrypt.h to there.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

The encryption modes are validated by fs/crypto/, not by individual
filesystems.  Therefore, move fscrypt_valid_enc_modes() from fscrypt.h
to fscrypt_private.h.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Filesystems now only define their fscrypt_operations when they are
compiled with encryption support, so move the fscrypt_operations
declaration from fscrypt.h to fscrypt_supp.h.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fscrypt_dummy_context_enabled() accesses ->s_cop, which now is only set
when the filesystem is built with encryption support.  This didn't
actually matter because no filesystems called it.  However, it will
start being used soon, so fix it by moving it from fscrypt.h to
fscrypt_supp.h and stubbing it out in fscrypt_notsupp.h.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Filesystems only ever access 'struct fscrypt_ctx' through fscrypt
functions.  But when a filesystem is built without encryption support,
these functions are all stubbed out, so the declaration of fscrypt_ctx
is unneeded.  Therefore, move it from fscrypt.h to fscrypt_supp.h.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

The fscrypt_info kmem_cache is internal to fscrypt; filesystems don't
need to access it.  So move its declaration into fscrypt_private.h.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fscrypt_control_page() is already split into two versions depending on
whether the filesystem is being built with encryption support or not.
Move them into the appropriate headers.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fscrypt_has_encryption_key() is already split into two versions
depending on whether the filesystem is being built with encryption
support or not.  Move them into the appropriate headers.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This reverts commit 04e35f44.

SELinux runs with secureexec for all non-"noatsecure" domain transitions,
which means lots of processes end up hitting the stack hard-limit change
that was introduced in order to fix a race with prlimit(). That race fix
will need to be redesigned.
Reported-by: Laura Abbott <labbott@redhat.com>
Reported-by: Tomáš Trnka <trnka@scm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull Page Table Isolation (PTI) v4.14 backporting base tree from Ingo Molnar:
 "This tree contains the v4.14 PTI backport preparatory tree, which
  consists of four merges of upstream trees and 7 cherry-picked commits,
  which the upcoming PTI work depends on"

NOTE! The resulting tree is exactly the same as the original base tree
(ie the diff between this commit and its immediate first parent is
empty).

The only reason for this merge is literally to have a common point for
the actual PTI changes so that the commits can be shared in both the
4.15 and 4.14 trees.

* 'WIP.x86-pti.base-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/kasan: Don't use vmemmap_populate() to initialize shadow
  locking/barriers: Convert users of lockless_dereference() to READ_ONCE()
  locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()
  bpf: fix build issues on um due to mising bpf_perf_event.h
  perf/x86: Enable free running PEBS for REGS_USER/INTR
  x86: Make X86_BUG_FXSAVE_LEAK detectable in CPUID on AMD
  x86/cpufeature: Add User-Mode Instruction Prevention definitions

Merge branch 'WIP.x86-pti.base.prep-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull Page Table Isolation (PTI) preparatory tree from Ingo Molnar:
 "This does a rename to free up linux/pti.h to be used by the upcoming
  page table isolation feature"

* 'WIP.x86-pti.base.prep-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  drivers/misc/intel/pti: Rename the header file to free up the namespace

Pull timer fix from Thomas Gleixner:
 "A single bugfix which prevents arbitrary sigev_notify values in
  posix-timers"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  posix-timer: Properly check sigevent->sigev_notify

Pull dmaengine fixes from Vinod Koul:
 "This time consisting of fixes in a bunch of drivers and the dmatest
  module:

   - Fix for disable clk on error path in fsl-edma driver
   - Disable clk fail fix in jz4740 driver
   - Fix long pending bug in dmatest driver for dangling pointer
   - Fix potential NULL pointer dereference in at_hdmac driver
   - Error handling path in ioat driver"

* tag 'dmaengine-fix-4.15-rc4' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: fsl-edma: disable clks on all error paths
  dmaengine: jz4740: disable/unprepare clk if probe fails
  dmaengine: dmatest: move callback wait queue to thread context
  dmaengine: at_hdmac: fix potential NULL pointer dereference in atc_prep_dma_interleaved
  dmaengine: ioat: Fix error handling path

With CONFIG_MTD=m and CONFIG_CRAMFS=y, we now get a link failure:

  fs/cramfs/inode.o: In function `cramfs_mount': inode.c:(.text+0x220): undefined reference to `mount_mtd'
  fs/cramfs/inode.o: In function `cramfs_mtd_fill_super':
  inode.c:(.text+0x6d8): undefined reference to `mtd_point'
  inode.c:(.text+0xae4): undefined reference to `mtd_unpoint'

This adds a more specific Kconfig dependency to avoid the broken
configuration.

Alternatively we could make CRAMFS itself depend on "MTD || !MTD" with a
similar result.

Fixes: 99c18ce5 ("cramfs: direct memory access support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull vfs fixes from Al Viro:
 "The alloc_super() one is a regression in this merge window, lazytime
  thing is older..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  VFS: Handle lazytime in do_mount()
  alloc_super(): do ->s_umount initialization earlier

Pull ext4 fixes from Ted Ts'o:
 "Fix a regression which caused us to fail to interpret symlinks in very
  ancient ext3 file system images.

  Also fix two xfstests failures, one of which could cause an OOPS, plus
  an additional bug fix caught by fuzz testing"

* tag 'ext4_for_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix crash when a directory's i_size is too small
  ext4: add missing error check in __ext4_new_inode()
  ext4: fix fdatasync(2) after fallocate(2) operation
  ext4: support fast symlinks from ext3 file systems

[ Note, this is a Git cherry-pick of the following commit:

    d17a1d97: ("x86/mm/kasan: don't use vmemmap_populate() to initialize shadow")

  ... for easier x86 PTI code testing and back-porting. ]

The KASAN shadow is currently mapped using vmemmap_populate() since that
provides a semi-convenient way to map pages into init_top_pgt.  However,
since that no longer zeroes the mapped pages, it is not suitable for
KASAN, which requires zeroed shadow memory.

Add kasan_populate_shadow() interface and use it instead of
vmemmap_populate().  Besides, this allows us to take advantage of
gigantic pages and use them to populate the shadow, which should save us
some memory wasted on page tables and reduce TLB pressure.

Link: http://lkml.kernel.org/r/20171103185147.2688-2-pasha.tatashin@oracle.comSigned-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Bob Picco <bob.picco@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

[ Note, this is a Git cherry-pick of the following commit:

    506458ef ("locking/barriers: Convert users of lockless_dereference() to READ_ONCE()")

  ... for easier x86 PTI code testing and back-porting. ]

READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it
can be used instead of lockless_dereference() without any change in
semantics.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

[ Note, this is a Git cherry-pick of the following commit:

    76ebbe78 ("locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()")

  ... for easier x86 PTI code testing and back-porting. ]

In preparation for the removal of lockless_dereference(), which is the
same as READ_ONCE() on all architectures other than Alpha, add an
implicit smp_read_barrier_depends() to READ_ONCE() so that it can be
used to head dependency chains on all architectures.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-3-git-send-email-will.deacon@arm.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

[ Note, this is a Git cherry-pick of the following commit:

    a23f06f0 ("bpf: fix build issues on um due to mising bpf_perf_event.h")

  ... for easier x86 PTI code testing and back-porting. ]

Since c895f6f7 ("bpf: correct broken uapi for
BPF_PROG_TYPE_PERF_EVENT program type") um (uml) won't build
on i386 or x86_64:

  [...]
    CC      init/main.o
  In file included from ../include/linux/perf_event.h:18:0,
                   from ../include/linux/trace_events.h:10,
                   from ../include/trace/syscall.h:7,
                   from ../include/linux/syscalls.h:82,
                   from ../init/main.c:20:
  ../include/uapi/linux/bpf_perf_event.h:11:32: fatal error:
  asm/bpf_perf_event.h: No such file or directory #include
  <asm/bpf_perf_event.h>
  [...]

Lets add missing bpf_perf_event.h also to um arch. This seems
to be the only one still missing.

Fixes: c895f6f7 ("bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Suggested-by: Richard Weinberger <richard@sigma-star.at>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Richard Weinberger <richard@sigma-star.at>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

[ Note, this is a Git cherry-pick of the following commit:

    a47ba4d7 ("perf/x86: Enable free running PEBS for REGS_USER/INTR")

  ... for easier x86 PTI code testing and back-porting. ]

Currently free running PEBS is disabled when user or interrupt
registers are requested. Most of the registers are actually
available in the PEBS record and can be supported.

So we just need to check for the supported registers and then
allow it: it is all except for the segment register.

For user registers this only works when the counter is limited
to ring 3 only, so this also needs to be checked.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170831214630.21892-1-andi@firstfloor.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

[ Note, this is a Git cherry-pick of the following commit:

    2b67799bdf25 ("x86: Make X86_BUG_FXSAVE_LEAK detectable in CPUID on AMD")

  ... for easier x86 PTI code testing and back-porting. ]

The latest AMD AMD64 Architecture Programmer's Manual
adds a CPUID feature XSaveErPtr (CPUID_Fn80000008_EBX[2]).

If this feature is set, the FXSAVE, XSAVE, FXSAVEOPT, XSAVEC, XSAVES
/ FXRSTOR, XRSTOR, XRSTORS always save/restore error pointers,
thus making the X86_BUG_FXSAVE_LEAK workaround obsolete on such CPUs.
Signed-Off-By: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Link: https://lkml.kernel.org/r/bdcebe90-62c5-1f05-083c-eba7f08b2540@assembler.czSigned-off-by: Ingo Molnar <mingo@kernel.org>