The flags field in 'struct shash_desc' never actually does anything.
The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP.
However, no shash algorithm ever sleeps, making this flag a no-op.
With this being the case, inevitably some users who can't sleep wrongly
pass MAY_SLEEP. These would all need to be fixed if any shash algorithm
actually started sleeping. For example, the shash_ahash_*() functions,
which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP
from the ahash API to the shash API. However, the shash functions are
called under kmap_atomic(), so actually they're assumed to never sleep.
Even if it turns out that some users do need preemption points while
hashing large buffers, we could easily provide a helper function
crypto_shash_update_large() which divides the data into smaller chunks
and calls crypto_shash_update() and cond_resched() for each chunk. It's
not necessary to have a flag in 'struct shash_desc', nor is it necessary
to make individual shash algorithms aware of this at all.
Therefore, remove shash_desc::flags, and document that the
crypto_shash_*() functions can be called from any context.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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: cac5818c25 ("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>
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>
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>
In the quest to remove all stack VLA usage from the kernel[1], this
removes the VLAs in SHASH_DESC_ON_STACK (via crypto_shash_descsize())
by using the maximum allowable size (which is now more clearly captured
in a macro), along with a few other cases. Similar limits are turned into
macros as well.
A review of existing sizes shows that SHA512_DIGEST_SIZE (64) is the
largest digest size and that sizeof(struct sha3_state) (360) is the
largest descriptor size. The corresponding maximums are reduced.
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Prevent improper use of req->result field in ahash update, init, export and
import functions in drivers code. A driver should use ahash request context
if it needs to save internal state.
Signed-off-by: Kamil Konieczny <k.konieczny@partner.samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
SPHINX build emits multiple warnings of kind:
warning: duplicate section name 'Note'
(when building kernel via make target 'htmldocs')
This is caused by repeated use of comments of form:
* Note: soau soaeusoa uoe
We can change the format without loss of clarity and clear the build
warnings.
Add '**[mandatory]**' or '**[optional]**' as kernel-doc field element
description prefix
This renders in HTML as (prefixes in bold)
final
[mandatory] Retrieve result from the driver. This function finalizes the
transformation and retrieves the resulting hash from the driver and
pushes it back to upper layers. No data processing happens at this
point unless hardware requires it to finish the transformation (then
the data buffered by the device driver is processed).
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently, almost none of the keyed hash algorithms check whether a key
has been set before proceeding. Some algorithms are okay with this and
will effectively just use a key of all 0's or some other bogus default.
However, others will severely break, as demonstrated using
"hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash
via a (potentially exploitable) stack buffer overflow.
A while ago, this problem was solved for AF_ALG by pairing each hash
transform with a 'has_key' bool. However, there are still other places
in the kernel where userspace can specify an arbitrary hash algorithm by
name, and the kernel uses it as unkeyed hash without checking whether it
is really unkeyed. Examples of this include:
- KEYCTL_DH_COMPUTE, via the KDF extension
- dm-verity
- dm-crypt, via the ESSIV support
- dm-integrity, via the "internal hash" mode with no key given
- drbd (Distributed Replicated Block Device)
This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no
privileges to call.
Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the
->crt_flags of each hash transform that indicates whether the transform
still needs to be keyed or not. Then, make the hash init, import, and
digest functions return -ENOKEY if the key is still needed.
The new flag also replaces the 'has_key' bool which algif_hash was
previously using, thereby simplifying the algif_hash implementation.
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* fix documentation of return values for crypto_ahash_init(),
crypto_ahash_finup(), crypto_ahash_final(),
crypto_ahash_digest() and crypto_ahash_update()
Also while at it:
* add notes for device driver developers in struct ahash_alg
description
* fix description of @final method in struct ahash_alg
* fix typo in crypto_ahash_finup() description
Signed-off-by: Kamil Konieczny <k.konieczny@partner.samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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 <rabinv@axis.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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>
This patch adds helpers to retrieve the alg name and driver name
of crypto_shash and crypto_ahash objects.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As the size of an ahash_request or shash_desc is variable, it's
awkward to zero them explicitly. This patch adds helpers to do
that which should be used when they are created on the stack.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds a way for ahash users to determine whether a key
is required by a crypto_ahash transform.
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds the missing helper crypto_ahash_blocksize which
returns the block size of an ahash algorithm.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds the helper AHASH_REQUEST_ON_STACK for those users
of ahash that are synchronous only.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch fix some typos found in crypto-API.xml.
It is because the file is generated from comments in sources,
so I had to fix typo in sources.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fix documentation typo for shash_alg->descsize.
Add documentation for initially uncovered member variables.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The API function calls exported by the kernel crypto API for SHASHes
to be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The API function calls exported by the kernel crypto API for AHASHes
to be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The hash data structures needed to be filled in by cipher developers are
documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Add a macro which replaces the use of a Variable Length Array In Struct (VLAIS)
with a C99 compliant equivalent. This macro instead allocates the appropriate
amount of memory using an char array.
The new code can be compiled with both gcc and clang.
struct shash_desc contains a flexible array member member ctx declared with
CRYPTO_MINALIGN_ATTR, so sizeof(struct shash_desc) aligns the beginning
of the array declared after struct shash_desc with long long.
No trailing padding is required because it is not a struct type that can
be used in an array.
The CRYPTO_MINALIGN_ATTR is required so that desc is aligned with long long
as would be the case for a struct containing a member with
CRYPTO_MINALIGN_ATTR.
If you want to get to the ctx at the end of the shash_desc as before you can do
so using shash_desc_ctx(shash)
Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Michał Mirosław <mirqus@gmail.com>
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>
When an shash algorithm is exported as ahash, ahash will access
its digest size through hash_alg_common. That's why the shash
layout needs to match hash_alg_common. This wasn't the case
because the alignment weren't identical.
This patch fixes the problem.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch exports the finup operation where available and adds
a default finup operation for ahash. The operations final, finup
and digest also will now deal with unaligned result pointers by
copying it. Finally export/import operations are will now be
exported too.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that all ahash implementations have been converted to the new
ahash type, we can remove old_ahash_alg and its associated support.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch converts crypto_ahash to the new style. The old ahash
algorithm type is retained until the existing ahash implementations
are also converted. All ahash users will automatically get the
new crypto_ahash type.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch changes descsize to a run-time attribute so that
implementations can change it in their init functions.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch changes the kfree call to kzfree for async requests.
As the request may contain sensitive data it needs to be zeroed
before it can be reallocated by others.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch replaces the full descriptor export with an export of
the partial hash state. This allows the use of a consistent export
format across all implementations of a given algorithm.
This is useful because a number of cases require the use of the
partial hash state, e.g., PadLock can use the SHA1 hash state
to get around the fact that it can only hash contiguous data
chunks.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This function is needed by algorithms that don't know their own
block size, e.g., in s390 where the code is common between multiple
versions of SHA.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We were freeing an offset into the slab object instead of the
start. This patch fixes it by calling crypto_destroy_tfm which
allows the correct address to be given.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
It is often useful to save the partial state of a hash function
so that it can be used as a base for two or more computations.
The most prominent example is HMAC where all hashes start from
a base determined by the key. Having an import/export interface
means that we only have to compute that base once rather than
for each message.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The shash interface replaces the current synchronous hash interface.
It improves over hash in two ways. Firstly shash is reentrant,
meaning that the same tfm may be used by two threads simultaneously
as all hashing state is stored in a local descriptor.
The other enhancement is that shash no longer takes scatter list
entries. This is because shash is specifically designed for
synchronous algorithms and as such scatter lists are unnecessary.
All existing hash users will be converted to shash once the
algorithms have been completely converted.
There is also a new finup function that combines update with final.
This will be extended to ahash once the algorithm conversion is
done.
This is also the first time that an algorithm type has their own
registration function. Existing algorithm types will be converted
to this way in due course.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
All new crypto interfaces should go into individual files as much
as possible in order to ensure that crypto.h does not collapse under
its own weight.
This patch moves the ahash code into crypto/hash.h and crypto/internal/hash.h
respectively.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Eric Biggers