linux-toradex.git/include/crypto, branch v4.11-rc3

net: Work around lockdep limitation in sockets that use sockets

2017-03-10T02:23:27+00:00

Lockdep issues a circular dependency warning when AFS issues an operation
through AF_RXRPC from a context in which the VFS/VM holds the mmap_sem.

The theory lockdep comes up with is as follows:

 (1) If the pagefault handler decides it needs to read pages from AFS, it
     calls AFS with mmap_sem held and AFS begins an AF_RXRPC call, but
     creating a call requires the socket lock:

	mmap_sem must be taken before sk_lock-AF_RXRPC

 (2) afs_open_socket() opens an AF_RXRPC socket and binds it.  rxrpc_bind()
     binds the underlying UDP socket whilst holding its socket lock.
     inet_bind() takes its own socket lock:

	sk_lock-AF_RXRPC must be taken before sk_lock-AF_INET

 (3) Reading from a TCP socket into a userspace buffer might cause a fault
     and thus cause the kernel to take the mmap_sem, but the TCP socket is
     locked whilst doing this:

	sk_lock-AF_INET must be taken before mmap_sem

However, lockdep's theory is wrong in this instance because it deals only
with lock classes and not individual locks.  The AF_INET lock in (2) isn't
really equivalent to the AF_INET lock in (3) as the former deals with a
socket entirely internal to the kernel that never sees userspace.  This is
a limitation in the design of lockdep.

Fix the general case by:

 (1) Double up all the locking keys used in sockets so that one set are
     used if the socket is created by userspace and the other set is used
     if the socket is created by the kernel.

 (2) Store the kern parameter passed to sk_alloc() in a variable in the
     sock struct (sk_kern_sock).  This informs sock_lock_init(),
     sock_init_data() and sk_clone_lock() as to the lock keys to be used.

     Note that the child created by sk_clone_lock() inherits the parent's
     kern setting.

 (3) Add a 'kern' parameter to ->accept() that is analogous to the one
     passed in to ->create() that distinguishes whether kernel_accept() or
     sys_accept4() was the caller and can be passed to sk_alloc().

     Note that a lot of accept functions merely dequeue an already
     allocated socket.  I haven't touched these as the new socket already
     exists before we get the parameter.

     Note also that there are a couple of places where I've made the accepted
     socket unconditionally kernel-based:

	irda_accept()
	rds_rcp_accept_one()
	tcp_accept_from_sock()

     because they follow a sock_create_kern() and accept off of that.

Whilst creating this, I noticed that lustre and ocfs don't create sockets
through sock_create_kern() and thus they aren't marked as for-kernel,
though they appear to be internal.  I wonder if these should do that so
that they use the new set of lock keys.

Signed-off-by: David Howells 
Signed-off-by: David S. Miller

crypto: api - Add crypto_requires_off helper

2017-02-27T10:09:39+00:00

This patch adds crypto_requires_off which is an extension of
crypto_requires_sync for similar bits such as NEED_FALLBACK.

Cc: stable@vger.kernel.org #4.10
Suggested-by: Marcelo Cerri 
Signed-off-by: Herbert Xu

crypto: algapi - make crypto_xor() and crypto_inc() alignment agnostic

2017-02-11T09:52:28+00:00

Instead of unconditionally forcing 4 byte alignment for all generic
chaining modes that rely on crypto_xor() or crypto_inc() (which may
result in unnecessary copying of data when the underlying hardware
can perform unaligned accesses efficiently), make those functions
deal with unaligned input explicitly, but only if the Kconfig symbol
HAVE_EFFICIENT_UNALIGNED_ACCESS is set. This will allow us to drop
the alignmasks from the CBC, CMAC, CTR, CTS, PCBC and SEQIV drivers.

For crypto_inc(), this simply involves making the 4-byte stride
conditional on HAVE_EFFICIENT_UNALIGNED_ACCESS being set, given that
it typically operates on 16 byte buffers.

For crypto_xor(), an algorithm is implemented that simply runs through
the input using the largest strides possible if unaligned accesses are
allowed. If they are not, an optimal sequence of memory accesses is
emitted that takes the relative alignment of the input buffers into
account, e.g., if the relative misalignment of dst and src is 4 bytes,
the entire xor operation will be completed using 4 byte loads and stores
(modulo unaligned bits at the start and end). Note that all expressions
involving misalign are simply eliminated by the compiler when
HAVE_EFFICIENT_UNALIGNED_ACCESS is defined.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Herbert Xu

crypto: doc - Fix hash export state information

2017-02-03T10:16:11+00:00

The documentation states that crypto_ahash_reqsize() provides the size
of the state structure used by crypto_ahash_export().  But it's actually
crypto_ahash_statesize() which provides this size.

Signed-off-by: Rabin Vincent 
Signed-off-by: Herbert Xu

crypto: skcipher - introduce walksize attribute for SIMD algos

2016-12-30T11:52:47+00:00

In some cases, SIMD algorithms can only perform optimally when
allowed to operate on multiple input blocks in parallel. This is
especially true for bit slicing algorithms, which typically take
the same amount of time processing a single block or 8 blocks in
parallel. However, other SIMD algorithms may benefit as well from
bigger strides.

So add a walksize attribute to the skcipher algorithm definition, and
wire it up to the skcipher walk API. To avoid confusion between the
skcipher and AEAD attributes, rename the skcipher_walk chunksize
attribute to 'stride', and set it from the walksize (in the skcipher
case) or from the chunksize (in the AEAD case).

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Herbert Xu

crypto: chacha20 - convert generic and x86 versions to skcipher

2016-12-27T09:47:31+00:00

This converts the ChaCha20 code from a blkcipher to a skcipher, which
is now the preferred way to implement symmetric block and stream ciphers.

This ports the generic and x86 versions at the same time because the
latter reuses routines of the former.

Note that the skcipher_walk() API guarantees that all presented blocks
except the final one are a multiple of the chunk size, so we can simplify
the encrypt() routine somewhat.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Herbert Xu

Merge tag 'docs-4.10-2' of git://git.lwn.net/linux

2016-12-18T00:00:34+00:00

Pull more documentation updates from Jonathan Corbet:
 "This converts the crypto DocBook to Sphinx"

* tag 'docs-4.10-2' of git://git.lwn.net/linux:
  crypto: doc - optimize compilation
  crypto: doc - clarify AEAD memory structure
  crypto: doc - remove crypto_alloc_ablkcipher
  crypto: doc - add KPP documentation
  crypto: doc - fix separation of cipher / req API
  crypto: doc - fix source comments for Sphinx
  crypto: doc - remove crypto API DocBook
  crypto: doc - convert crypto API documentation to Sphinx

crypto: doc - clarify AEAD memory structure

2016-12-13T23:38:06+00:00

The previous description have been misleading and partially incorrect.

Reported-by: Harsh Jain 
Signed-off-by: Stephan Mueller 
Signed-off-by: Jonathan Corbet

crypto: doc - add KPP documentation

2016-12-13T23:38:06+00:00

Add the KPP API documentation to the kernel crypto API Sphinx
documentation. This addition includes the documentation of the
ECDH and DH helpers which are needed to create the approrpiate input
data for the crypto_kpp_set_secret function.

Signed-off-by: Stephan Mueller 
Signed-off-by: Jonathan Corbet

crypto: doc - fix source comments for Sphinx

2016-12-13T23:38:05+00:00

Update comments to avoid any complaints from Sphinx during compilation.

Signed-off-by: Stephan Mueller 
Signed-off-by: Jonathan Corbet