Revert "crypto: remove CONFIG_CRYPTO_STATS"

This reverts commit 2beb81fbf0c01a62515a1bcef326168494ee2bd0.

While removing CONFIG_CRYPTO_STATS is a worthy goal, this also
removed unrelated infrastructure such as crypto_comp_alg_common.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: remove CONFIG_CRYPTO_STATS

Remove support for the "Crypto usage statistics" feature
(CONFIG_CRYPTO_STATS). This feature does not appear to have ever been
used, and it is harmful because it significantly reduces performance and
is a large maintenance burden.

Covering each of these points in detail:

1. Feature is not being used

Since these generic crypto statistics are only readable using netlink,
it's fairly straightforward to look for programs that use them. I'm
unable to find any evidence that any such programs exist. For example,
Debian Code Search returns no hits except the kernel header and kernel
code itself and translations of the kernel header:
https://codesearch.debian.net/search?q=CRYPTOCFGA_STAT&literal=1&perpkg=1

The patch series that added this feature in 2018
(https://lore.kernel.org/linux-crypto/1537351855-16618-1-git-send-email-clabbe@baylibre.com/)
said "The goal is to have an ifconfig for crypto device." This doesn't
appear to have happened.

It's not clear that there is real demand for crypto statistics. Just
because the kernel provides other types of statistics such as I/O and
networking statistics and some people find those useful does not mean
that crypto statistics are useful too.

Further evidence that programs are not using CONFIG_CRYPTO_STATS is that
it was able to be disabled in RHEL and Fedora as a bug fix
(https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/2947).

Even further evidence comes from the fact that there are and have been
bugs in how the stats work, but they were never reported. For example,
before Linux v6.7 hash stats were double-counted in most cases.

There has also never been any documentation for this feature, so it
might be hard to use even if someone wanted to.

2. CONFIG_CRYPTO_STATS significantly reduces performance

Enabling CONFIG_CRYPTO_STATS significantly reduces the performance of
the crypto API, even if no program ever retrieves the statistics. This
primarily affects systems with large number of CPUs. For example,
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2039576 reported
that Lustre client encryption performance improved from 21.7GB/s to
48.2GB/s by disabling CONFIG_CRYPTO_STATS.

It can be argued that this means that CONFIG_CRYPTO_STATS should be
optimized with per-cpu counters similar to many of the networking
counters. But no one has done this in 5+ years. This is consistent
with the fact that the feature appears to be unused, so there seems to
be little interest in improving it as opposed to just disabling it.

It can be argued that because CONFIG_CRYPTO_STATS is off by default,
performance doesn't matter. But Linux distros tend to error on the side
of enabling options. The option is enabled in Ubuntu and Arch Linux,
and until recently was enabled in RHEL and Fedora (see above). So, even
just having the option available is harmful to users.

3. CONFIG_CRYPTO_STATS is a large maintenance burden

There are over 1000 lines of code associated with CONFIG_CRYPTO_STATS,
spread among 32 files. It significantly complicates much of the
implementation of the crypto API. After the initial submission, many
fixes and refactorings have consumed effort of multiple people to keep
this feature "working". We should be spending this effort elsewhere.

Cc: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - remove excess kerneldoc members

Commit 31865c4c4db2 ("crypto: skcipher - Add lskcipher") moved some
fields from 'struct skcipher_alg' into SKCIPHER_ALG_COMMON but didn't
remove the corresponding kerneldoc members, which results in these
warnings when running 'make htmldocs':

./include/crypto/skcipher.h:182: warning: Excess struct member 'min_keysize' description in 'skcipher_alg'
./include/crypto/skcipher.h:182: warning: Excess struct member 'max_keysize' description in 'skcipher_alg'
./include/crypto/skcipher.h:182: warning: Excess struct member 'ivsize' description in 'skcipher_alg'
./include/crypto/skcipher.h:182: warning: Excess struct member 'chunksize' description in 'skcipher_alg'
./include/crypto/skcipher.h:182: warning: Excess struct member 'stat' description in 'skcipher_alg'
./include/crypto/skcipher.h:182: warning: Excess struct member 'base' description in 'skcipher_alg'

SKCIPHER_ALG_COMMON already has the documentation for all these fields.

Fixes: 31865c4c4db2 ("crypto: skcipher - Add lskcipher")
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Make use of internal state

This patch adds code to the skcipher/lskcipher API to make use
of the internal state if present. In particular, the skcipher
lskcipher wrapper will allocate a buffer for the IV/state and
feed that to the underlying lskcipher algorithm.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Add internal state support

Unlike chaining modes such as CBC, stream ciphers other than CTR
usually hold an internal state that must be preserved if the
operation is to be done piecemeal. This has not been represented
in the API, resulting in the inability to split up stream cipher
operations.

This patch adds the basic representation of an internal state to
skcipher and lskcipher. In the interest of backwards compatibility,
the default has been set such that existing users are assumed to
be operating in one go as opposed to piecemeal.

With the new API, each lskcipher/skcipher algorithm has a new
attribute called statesize. For skcipher, this is the size of
the buffer that can be exported or imported similar to ahash.
For lskcipher, instead of providing a buffer of ivsize, the user
now has to provide a buffer of ivsize + statesize.

Each skcipher operation is assumed to be final as they are now,
but this may be overridden with a request flag. When the override
occurs, the user may then export the partial state and reimport
it later.

For lskcipher operations this is reversed. All operations are
not final and the state will be exported unless the FINAL bit is
set. However, the CONT bit still has to be set for the state
to be used.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Remove obsolete skcipher_alg helpers

As skcipher spawn users can no longer assume the spawn is of type
struct skcipher_alg, these helpers are no longer used. Remove them.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Add lskcipher

Add a new API type lskcipher designed for taking straight kernel
pointers instead of SG lists. Its relationship to skcipher will
be analogous to that between shash and ahash.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Count error stats differently

Move all stat code specific to skcipher into the skcipher code.

While we're at it, change the stats so that bytes and counts
are always incremented even in case of error. This allows the
reference counting to be removed as we can now increment the
counters prior to the operation.

After the operation we simply increase the error count if necessary.
This is safe as errors can only occur synchronously (or rather,
the existing code already ignored asynchronous errors which are
only visible to the callback function).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: api - Replace kernel.h with the necessary inclusions

When kernel.h is used in the headers it adds a lot into dependency hell,
especially when there are circular dependencies are involved.

Replace kernel.h inclusion with the list of what is really being used.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: api - check for ERR pointers in crypto_destroy_tfm()

Given that crypto_alloc_tfm() may return ERR pointers, and to avoid
crashes on obscure error paths where such pointers are presented to
crypto_destroy_tfm() (such as [0]), add an ERR_PTR check there
before dereferencing the second argument as a struct crypto_tfm
pointer.

[0] https://lore.kernel.org/linux-crypto/000000000000de949705bc59e0f6@google.com/

Reported-by: syzbot+12cf5fbfdeba210a89dd@syzkaller.appspotmail.com
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

mm, treewide: rename kzfree() to kfree_sensitive()

As said by Linus:

A symmetric naming is only helpful if it implies symmetries in use.
Otherwise it's actively misleading.

In "kzalloc()", the z is meaningful and an important part of what the
caller wants.

In "kzfree()", the z is actively detrimental, because maybe in the
future we really _might_ want to use that "memfill(0xdeadbeef)" or
something. The "zero" part of the interface isn't even _relevant_.

The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.

Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.

The renaming is done by using the command sequence:

git grep -w --name-only kzfree |\
xargs sed -i 's/kzfree/kfree_sensitive/'

followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.

[akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h]
[akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more]

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

crypto: skcipher - drop duplicated word in kernel-doc

Drop the doubled word "request" in a kernel-doc comment.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - add crypto_skcipher_min_keysize()

Add a helper function crypto_skcipher_min_keysize() to mirror
crypto_skcipher_max_keysize().

This will be used by the self-tests.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - remove crypto_skcipher::decrypt

Due to the removal of the blkcipher and ablkcipher algorithm types,
crypto_skcipher::decrypt is now redundant since it always equals
crypto_skcipher_alg(tfm)->decrypt.

Remove it and update crypto_skcipher_decrypt() accordingly.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - remove crypto_skcipher::encrypt

Due to the removal of the blkcipher and ablkcipher algorithm types,
crypto_skcipher::encrypt is now redundant since it always equals
crypto_skcipher_alg(tfm)->encrypt.

Remove it and update crypto_skcipher_encrypt() accordingly.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - remove crypto_skcipher::setkey

Due to the removal of the blkcipher and ablkcipher algorithm types,
crypto_skcipher::setkey now always points to skcipher_setkey().

Simplify by removing this function pointer and instead just making
skcipher_setkey() be crypto_skcipher_setkey() directly.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - remove crypto_skcipher::keysize

Due to the removal of the blkcipher and ablkcipher algorithm types,
crypto_skcipher::keysize is now redundant since it always equals
crypto_skcipher_alg(tfm)->max_keysize.

Remove it and update crypto_skcipher_default_keysize() accordingly.

Also rename crypto_skcipher_default_keysize() to
crypto_skcipher_max_keysize() to clarify that it specifically returns
the maximum key size, not some unspecified "default".

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - remove crypto_skcipher::ivsize

Due to the removal of the blkcipher and ablkcipher algorithm types,
crypto_skcipher::ivsize is now redundant since it always equals
crypto_skcipher_alg(tfm)->ivsize.

Remove it and update crypto_skcipher_ivsize() accordingly.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: ablkcipher - remove deprecated and unused ablkcipher support

Now that all users of the deprecated ablkcipher interface have been
moved to the skcipher interface, ablkcipher is no longer used and
can be removed.

Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - remove the "blkcipher" algorithm type

Now that all "blkcipher" algorithms have been converted to "skcipher",
remove the blkcipher algorithm type.

The skcipher (symmetric key cipher) algorithm type was introduced a few
years ago to replace both blkcipher and ablkcipher (synchronous and
asynchronous block cipher). The advantages of skcipher include:

- A much less confusing name, since none of these algorithm types have
ever actually been for raw block ciphers, but rather for all
length-preserving encryption modes including block cipher modes of
operation, stream ciphers, and other length-preserving modes.

- It unified blkcipher and ablkcipher into a single algorithm type
which supports both synchronous and asynchronous implementations.
Note, blkcipher already operated only on scatterlists, so the fact
that skcipher does too isn't a regression in functionality.

- Better type safety by using struct skcipher_alg, struct
crypto_skcipher, etc. instead of crypto_alg, crypto_tfm, etc.

- It sometimes simplifies the implementations of algorithms.

Also, the blkcipher API was no longer being tested.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - unify the crypto_has_skcipher*() functions

crypto_has_skcipher() and crypto_has_skcipher2() do the same thing: they
check for the availability of an algorithm of type skcipher, blkcipher,
or ablkcipher, which also meets any non-type constraints the caller
specified. And they have exactly the same prototype.

Therefore, eliminate the redundancy by removing crypto_has_skcipher()
and renaming crypto_has_skcipher2() to crypto_has_skcipher().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: algif_skcipher - Use chunksize instead of blocksize

When algif_skcipher does a partial operation it always process data
that is a multiple of blocksize. However, for algorithms such as
CTR this is wrong because even though it can process any number of
bytes overall, the partial block must come at the very end and not
in the middle.

This is exactly what chunksize is meant to describe so this patch
changes blocksize to chunksize.

Fixes: 8ff590903d5f ("crypto: algif_skcipher - User-space...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - make chunksize and walksize accessors internal

The 'chunksize' and 'walksize' properties of skcipher algorithms are
implementation details that users of the skcipher API should not be
looking at. So move their accessor functions from <crypto/skcipher.h>
to <crypto/internal/skcipher.h>.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - un-inline encrypt and decrypt functions

crypto_skcipher_encrypt() and crypto_skcipher_decrypt() have grown to be
more than a single indirect function call. They now also check whether
a key has been set, and with CONFIG_CRYPTO_STATS=y they also update the
crypto statistics. That can add up to a lot of bloat at every call
site. Moreover, these always involve a function call anyway, which
greatly limits the benefits of inlining.

So change them to be non-inline.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

crypto: skcipher - remove remnants of internal IV generators

Remove dead code related to internal IV generators, which are no longer
used since they've been replaced with the "seqiv" and "echainiv"
templates. The removed code includes:

- The "givcipher" (GIVCIPHER) algorithm type. No algorithms are
registered with this type anymore, so it's unneeded.

- The "const char *geniv" member of aead_alg, ablkcipher_alg, and
blkcipher_alg. A few algorithms still set this, but it isn't used
anymore except to show via /proc/crypto and CRYPTO_MSG_GETALG.
Just hardcode "<default>" or "<none>" in those cases.

- The 'skcipher_givcrypt_request' structure, which is never used.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: user - fix use_after_free of struct xxx_request

All crypto_stats functions use the struct xxx_request for feeding stats,
but in some case this structure could already be freed.

For fixing this, the needed parameters (len and alg) will be stored
before the request being executed.
Fixes: cac5818c25d0 ("crypto: user - Implement a generic crypto statistics")
Reported-by: syzbot <syzbot+6939a606a5305e9e9799@syzkaller.appspotmail.com>

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: user - convert all stats from u32 to u64

All the 32-bit fields need to be 64-bit. In some cases, UINT32_MAX crypto
operations can be done in seconds.

Reported-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: user - Implement a generic crypto statistics

This patch implement a generic way to get statistics about all crypto
usages.

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Remove SKCIPHER_REQUEST_ON_STACK()

Now that all the users of the VLA-generating SKCIPHER_REQUEST_ON_STACK()
macro have been moved to SYNC_SKCIPHER_REQUEST_ON_STACK(), we can remove
the former.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Introduce crypto_sync_skcipher

In preparation for removal of VLAs due to skcipher requests on the stack
via SKCIPHER_REQUEST_ON_STACK() usage, this introduces the infrastructure
for the "sync skcipher" tfm, which is for handling the on-stack cases of
skcipher, which are always non-ASYNC and have a known limited request
size.

The crypto API additions:

struct crypto_sync_skcipher (wrapper for struct crypto_skcipher)
crypto_alloc_sync_skcipher()
crypto_free_sync_skcipher()
crypto_sync_skcipher_setkey()
crypto_sync_skcipher_get_flags()
crypto_sync_skcipher_set_flags()
crypto_sync_skcipher_clear_flags()
crypto_sync_skcipher_blocksize()
crypto_sync_skcipher_ivsize()
crypto_sync_skcipher_reqtfm()
skcipher_request_set_sync_tfm()
SYNC_SKCIPHER_REQUEST_ON_STACK() (with tfm type check)

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - prevent using skciphers without setting key

Similar to what was done for the hash API, update the skcipher API to
track whether each transform has been keyed, and reject
encryption/decryption if a key is needed but one hasn't been set.

This isn't as important as the equivalent fix for the hash API because
symmetric ciphers almost always require a key (the "null cipher" is the
only exception), so are unlikely to be used without one. Still,
tracking the key will prevent accidental unkeyed use. algif_skcipher
also had to track the key anyway, so the new flag replaces that and
simplifies the algif_skcipher implementation.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - introduce walksize attribute for SIMD algos

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 <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: doc - fix source comments for Sphinx

Update comments to avoid any complaints from Sphinx during compilation.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

crypto: skcipher - Add comment for skcipher_alg->base

This patch adds a missing comment for the base parameter in struct
skcipher_alg.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Remove top-level givcipher interface

This patch removes the old crypto_grab_skcipher helper and replaces
it with crypto_grab_skcipher2.

As this is the final entry point into givcipher this patch also
removes all traces of the top-level givcipher interface, including
all implicit IV generators such as chainiv.

The bottom-level givcipher interface remains until the drivers
using it are converted.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Add low-level skcipher interface

This patch allows skcipher algorithms and instances to be created
and registered with the crypto API. They are accessible through
the top-level skcipher interface, along with ablkcipher/blkcipher
algorithms and instances.

This patch also introduces a new parameter called chunk size
which is meant for ciphers such as CTR and CTS which ostensibly
can handle arbitrary lengths, but still behave like block ciphers
in that you can only process a partial block at the very end.

For these ciphers the block size will continue to be set to 1
as it is now while the chunk size will be set to the underlying
block size.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: doc - document correct return value for request allocation

Signed-off-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Fix driver name helper

The helper crypto_skcipher_driver_name was returning the alg
name and not the driver name.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Add helper to retrieve driver name

This patch adds the helper crypto_skcipher_driver_name which returns
the driver name of the alg object for a given tfm. This is needed by
ecryptfs.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Add helper to zero stack request

As the size of an skcipher_request is variable, it's awkward to
zero it explicitly. This patch adds a helper to do that which
should be used when it is created on the stack.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Add default key size helper

While converting ecryptfs over to skcipher I found that it needs
to pick a default key size if one isn't given. Rather than having
it poke into the guts of the algorithm to get max_keysize, let's
provide a helper that is meant to give a sane default (just in
case we ever get an algorithm that has no maximum key size).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Add crypto_skcipher_has_setkey

This patch adds a way for skcipher users to determine whether a key
is required by a transform.

Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: skcipher - Add top-level skcipher interface

This patch introduces the crypto skcipher interface which aims
to replace both blkcipher and ablkcipher.

It's very similar to the existing ablkcipher interface. The
main difference is the removal of the givcrypt interface. In
order to make the transition easier for blkcipher users, there
is a helper SKCIPHER_REQUEST_ON_STACK which can be used to place
a request on the stack for synchronous transforms.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: Resolve shadow warnings

Change formal parameters to not clash with global names to
eliminate many W=2 warnings.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

[CRYPTO] skcipher: Add top-level givencrypt/givdecrypt calls

This patch finally makes the givencrypt/givdecrypt operations available
to users by adding crypto_skcipher_givencrypt and crypto_skcipher_givdecrypt.
A suite of helpers to allocate and fill in the request is also available.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

[CRYPTO] skcipher: Add givcrypt operations and givcipher type

Different block cipher modes have different requirements for intialisation
vectors. For example, CBC can use a simple randomly generated IV while
modes such as CTR must use an IV generation mechanisms that give a stronger
guarantee on the lack of collisions. Furthermore, disk encryption modes
have their own IV generation algorithms.

Up until now IV generation has been left to the users of the symmetric
key cipher API. This is inconvenient as the number of block cipher modes
increase because the user needs to be aware of which mode is supposed to
be paired with which IV generation algorithm.

Therefore it makes sense to integrate the IV generation into the crypto
API. This patch takes the first step in that direction by creating two
new ablkcipher operations, givencrypt and givdecrypt that generates an
IV before performing the actual encryption or decryption.

The operations are currently not exposed to the user. That will be done
once the underlying functionality has actually been implemented.

It also creates the underlying givcipher type. Algorithms that directly
generate IVs would use it instead of ablkcipher. All other algorithms
(including all existing ones) would generate a givcipher algorithm upon
registration. This givcipher algorithm will be constructed from the geniv
string that's stored in every algorithm. That string will locate a template
which is instantiated by the blkcipher/ablkcipher algorithm in question to
give a givcipher algorithm.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>