When two crypto algorithm lookups occur at the same time with
different names for the same algorithm, e.g., ctr(aes-generic)
and ctr(aes), they will both be instantiated.  However, only one
of them can be registered.  The second instantiation will fail
with EEXIST.

Avoid failing the second lookup by making it retry, but only once
because there are tricky names such as gcm_base(ctr(aes),ghash)
that will always fail, despite triggering instantiation and EEXIST.

Reported-by: Ingo Franzki <ifranzki@linux.ibm.com>
Fixes: 2825982d9d66 ("[CRYPTO] api: Added event notification")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

The negative-sense of CRYPTO_MANAGER_DISABLE_TESTS is a longstanding
mistake that regularly causes confusion.  Especially bad is that you can
have CRYPTO=n && CRYPTO_MANAGER_DISABLE_TESTS=n, which is ambiguous.

Replace CRYPTO_MANAGER_DISABLE_TESTS with CRYPTO_SELFTESTS which has the
expected behavior.

The tests continue to be disabled by default.

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

Do not copy the exit function in crypto_clone_tfm as it should
only be set after init_tfm or clone_tfm has succeeded.

Move the setting into crypto_clone_ahash and crypto_clone_shash
instead.

Also clone the fb if necessary.

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

Add a helper to clone crypto requests and eliminate code duplication.
Use kmemdup in the helper.

Also add an fb field to crypto_tfm.

This also happens to fix the existing implementations which were
buggy.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202504230118.1CxUaUoX-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202504230004.c7mrY0C6-lkp@intel.com/
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

If the bit CRYPTO_ALG_DUP_FIRST is set, an algorithm will be
duplicated by kmemdup before registration.  This is inteded for
hardware-based algorithms that may be unplugged at will.

Do not use this if the algorithm data structure is embedded in a
bigger data structure.  Perform the duplication in the driver
instead.

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

Move the cra_type->destroy call out of crypto_alg_put and into
crypto_unregister_alg and crypto_free_instance.  This ensures
that it's always done in process context so calls such as flush_work
can be done.

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

The 'comp' compression API has been superseded by the acomp API, which
is a bit more cumbersome to use, but ultimately more flexible when it
comes to hardware implementations.

Now that all the users and implementations have been removed, let's
remove the core plumbing of the 'comp' API as well.

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

Add a cra_type->destroy hook so that resources can be freed after
the last user of a registered algorithm is gone.

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

When the lookup is retried after instance construction, it uses
the type and mask from the larval, which may not match the values
used by the caller.  For example, if the caller is requesting for
a !NEEDS_FALLBACK algorithm, it may end up getting an algorithm
that needs fallbacks.

Fix this by making the caller supply the type/mask and using that
for the lookup.

Reported-by: Coiby Xu <coxu@redhat.com>
Fixes: 96ad59552059 ("crypto: api - Remove instance larval fulfilment")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

On Fri, Aug 30, 2024 at 10:51:54AM -0700, Eric Biggers wrote:
>
> Given below in defconfig form, use 'make olddefconfig' to apply.  The failures
> are nondeterministic and sometimes there are different ones, for example:
>
> [    0.358017] alg: skcipher: failed to allocate transform for cbc(twofish-generic): -2
> [    0.358365] alg: self-tests for cbc(twofish) using cbc(twofish-generic) failed (rc=-2)
> [    0.358535] alg: skcipher: failed to allocate transform for cbc(camellia-generic): -2
> [    0.358918] alg: self-tests for cbc(camellia) using cbc(camellia-generic) failed (rc=-2)
> [    0.371533] alg: skcipher: failed to allocate transform for xts(ecb(aes-generic)): -2
> [    0.371922] alg: self-tests for xts(aes) using xts(ecb(aes-generic)) failed (rc=-2)
>
> Modules are not enabled, maybe that matters (I haven't checked yet).

Yes I think that was the key.  This triggers a massive self-test
run which executes in parallel and reveals a few race conditions
in the system.  I think it boils down to the following scenario:

Base algorithm X-generic, X-optimised
Template Y
Optimised algorithm Y-X-optimised

Everything gets registered, and then the self-tests are started.
When Y-X-optimised gets tested, it requests the creation of the
generic Y(X-generic).  Which then itself undergoes testing.

The race is that after Y(X-generic) gets registered, but just
before it gets tested, X-optimised finally finishes self-testing
which then causes all spawns of X-generic to be destroyed.  So
by the time the self-test for Y(X-generic) comes along, it can
no longer find the algorithm.  This error then bubbles up all
the way up to the self-test of Y-X-optimised which then fails.

Note that there is some complexity that I've omitted here because
when the generic self-test fails to find Y(X-generic) it actually
triggers the construction of it again which then fails for various
other reasons (these are not important because the construction
should *not* be triggered at this point).

So in a way the error is expected, and we should probably remove
the pr_err for the case where ENOENT is returned for the algorithm
that we're currently testing.

The solution is two-fold.  First when an algorithm undergoes
self-testing it should not trigger its construction.  Secondly
if an instance larval fails to materialise due to it being destroyed
by a more optimised algorithm coming along, it should obviously
retry the construction.

Remove the check in __crypto_alg_lookup that stops a larval from
matching new requests based on differences in the mask.  It is better
to block new requests even if it is wrong and then simply retry the
lookup.  If this ends up being the wrong larval it will sort iself
out during the retry.

Reduce the CRYPTO_ALG_TYPE_MASK bits in type during larval creation
as otherwise LSKCIPHER algorithms may not match SKCIPHER larvals.

Also block the instance creation during self-testing in the function
crypto_larval_lookup by checking for CRYPTO_ALG_TESTED in the mask
field.

Finally change the return value when crypto_alg_lookup fails in
crypto_larval_wait to EAGAIN to redo the lookup.

Fixes: 37da5d0ffa7b ("crypto: api - Do not wait for tests during registration")
Reported-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>